Wideband Oxygen sensor

Wideband Oxygen Sensor (which may also be called Wide Range Air Fuel (WRAF) sensors) and Air/Fuel (A/F) Sensors, are replacing conventional oxygen sensors in many late model vehicles.

A wideband O2 sensor or A/F sensor is essentially a smarter oxygen sensor with some additional internal circuitry that allows it to precisely determine the exact air/fuel ratio of the engine. Like an ordinary oxygen sensor, it reacts to changing oxygen levels in the exhaust. But unlike an ordinary oxygen sensor, the output signal from a wideband O2 sensor or A/F sensor does not change abruptly when the air/fuel mixture goes rich or lean. This makes it better suited to today’s low emission engines, and also for tuning performance engines.

 

Oxygen Sensor Outputs

An ordinary oxygen sensor is really more of a rich/lean indicator because its output voltage jumps up to 0.8 to 0.9 volts when the air/fuel mixture is rich, and drops to 0.3 volts or less when the air/fuel mixture is lean. By comparison, a wideband O2 sensor or A/F sensor provides a gradually changing current signal that corresponds to the exact air/fuel ratio.

Another difference is that the sensor’s output voltage is converted by its internal circuitry into a variable current signal that can travel in one of two directions (positive or negative). The current signal gradually increases in the positive direction when the air/fuel mixture becomes leaner. At the “stoichiometric” point when the air/fuel mixture is perfectly balanced (14.7 to 1), which is also referred to as “Lambda”, the current flow from the sensor stops and there is no current flow in either direction. And when the air/fuel ratio becomes progressively richer, the current reverses course and flows in the negative direction.

The PCM

The PCM sends a control reference voltage (typically 3.3 volts on Toyota A/F sensor applications, 2.6 volts on Bosch and GM wideband sensors) to the sensor through one pair of wires, and monitors the sensor’s output current through a second set of wires. The sensor’s output signal is then processed by the PCM, and can be read on a scan tool as the air/fuel ratio, a fuel trim value and/or a voltage value depending on the application and the display capabilities of the scan tool.

For applications that display a voltage value, anything less than the reference voltage indicate a rich air/fuel ratio while voltages above the reference voltage indicates a lean air/fuel ratio. On some of the early Toyota OBD II applications, the PCM converts the A/F sensor voltage to look like that of an ordinary oxygen sensor (this was done to comply with the display requirements of early OBD II regulations).

How a Wideband O2 Sensor Works

Internally, wideband O2 sensors and A/F sensors appear to be similar to conventional zirconia planar oxygen sensors. There is a flat ceramic strip inside the protective metal nose cone on the end of the sensor. The ceramic strip is actually a dual sensing element that combines a “Nerst effect” oxygen pump and “diffusion gap” with the oxygen sensing element. All three are laminated on the same strip of ceramic.

 

Exhaust gas

Exhaust gas enters the sensor through vents or holes in the metal shroud over the tip of the sensor and reacts with the dual sensor element. Oxygen diffuses through the ceramic substrate on the sensor element. The reaction causes the Nerst cell to generate a voltage just like an ordinary oxygen sensor. The oxygen pump compares the change in voltage to the control voltage from the PCM, and balances one against the other to maintain an internal oxygen balance. This alters the current flow through the sensor creating a positive or negative current signal that indicates the exact air/fuel ratio of the engine.

The current flow is not much, usually only about 0.020 amps or less. The PCM then converts the sensor’s analog current output into a voltage signal that can then be read on your scan tool.

What’s the difference between a wideband O2 sensor and an A/F sensor? Wideband 2 sensors typically have 5 wires while most A/F sensors have 4 wires.

O2 SENSOR HEATER CIRCUIT

Like ordinary oxygen sensors, wideband O2 sensors and A/F sensors also have an internal heater circuit to help them reach operating temperature quickly. To work properly, wideband and A/F sensors require a higher operating temperature: 1292 to 1472 degrees F versus about 600 degrees F for ordinary oxygen sensors. Consequently, if the heater circuit fails, the sensor may not put out a reliable signal.

The heater circuit is energized through a relay, which turns on when the engine is cranked and the fuel injection relay is energized. The heater circuit can pull up to 8 amps on some engines, and is usually pulse width modulated (PWM) to vary the amount of heat depending on engine temperature (this also prevents the heater from getting too hot and burning out). When the engine is cold, the duty ratio (on time) of the heater circuit will be higher than when the engine is hot. A failure in the heater circuit will usually turn on the Malfunction Indicator Lamp (MIL) and set a P0125 diagnostic trouble code (DTC).

 

Oxygen Sensor Problems

Like ordinary oxygen sensors, wideband O2 sensors and A/F sensors are vulnerable to contamination and aging. They can become sluggish and slow to respond to changes in the air/fuel mixture as contaminants build up on the sensor element. Contaminants include phosphorus from motor oil (from worn valve guides and rings), silicates from antifreeze (leaky head gasket or intake gaskets, or cracks in the combustion chamber that leak coolant), and even sulfur and other additives in gasoline. The sensors are designed to last upwards of 200,000 km but may not go the distance if the engine burns oil, develops an internal coolant leak or gets some bad gas.

Wideband 2 sensors and A/F sensors can also be fooled by air leaks in the exhaust system (leaky exhaust manifold gaskets) or compression problems (such as leaky or burned exhaust valves) that allow unburned air to pass through the engine and enter the exhaust.

Wideband A/F Sensor Diagnostics

As a rule, the OBD II system will detect any problems that affect the operation of the oxygen or A/F sensors and set a DTC that corresponds to the type of fault. Generic OBD II codes that indicate a fault in the O2 or A/F sensor heater circuit include: P0036, P0037, P0038, P0042, P0043, P0044, P0050, P0051, P0052, P0056, P0057, P0058, P0062, P0063, P0064.

Codes that indicate a possible fault in the oxygen sensor itself include any code from P0130 to P0167. There may be additional OEM “enhanced “P1” codes that will vary depending on the year, make and model of the vehicle.

The symptoms of a bad wideband O2 sensor or A/F sensor are essentially the same as those of a conventional oxygen sensor: Engine running rich, poor fuel economy and/or an emission failure due to higher than normal levels of carbon monoxide (CO) in the exhaust.

Possible causes in addition to the sensor itself having failed

Possible causes in addition to the sensor itself having failed include bad wiring connections or a faulty heater circuit relay (if there are heater codes), or a wiring fault, leaky exhaust manifold gasket or leaky exhaust valves if there are sensor codes indicating a lean fuel condition.

What to Check: How the sensor responds to changes in the air/fuel ratio. Plug a scan tool into the vehicle diagnostic connector, start the engine and create a momentary change in the air/fuel radio by snapping the throttle or feeding propane into the throttle body. Look for a response from the wideband O2 sensor or A/F sensor. No change in the indicated air/fuel ratio, Lambda value, sensor voltage value or short term fuel trim number would indicate a bad sensor that needs to be replaced.

Scan tool

Other scan tool PIDS to look at include the OBD II oxygen heater monitor status, OBD II oxygen sensor monitor status, loop status and coolant temperature. The status of the monitors will tell you if the OBD II system has run its self-checks on the sensor. The loop status will tell you if the PCM is using the wideband O2 or A/F sensor’s input to control the air/fuel ratio. If the system remains in open loop once the engine is warm, check for a possible faulty coolant sensor.

Another way to check the output of a wideband O2 sensor or A/F sensor is to connect a digital voltmeter or graphing multimeter in series with the sensor’s voltage reference line (refer to a wiring diagram for the proper connection). Connect the black negative lead to the sensor end of the reference wire, and the red positive lead to the PCM end of the wire. The meter should then show an increase in voltage (above the reference voltage) if the air/fuel mixture is lean, or a drop in voltage (below the reference voltage) if the mixture is rich.

Wideband O2 sensor output

The output of a wideband O2 sensor or A/F sensor can also be observed on a digital storage oscilloscope by connecting one lead to the reference circuit and the other to the sensor control circuit. This will generate a waveform that changes with the air/fuel ratio. The scope can also be connected to the sensor’s heater wires to check the duty cycle of the heater circuit. You should see a square wave pattern and a decrease in the duty cycle as the engine warms up.

Wideband Oxygen Sensor Tech Tips

* On Honda 5-wire “Lean Air Fuel” (LAF) sensors, the 8-pin connector pin for the sensor contains a special “calibration” resistor. The value of the resistor can be determined by measuring between terminals 3 and 4 with an ohmmeter, and will be 2.4K ohms, 10K ohms or 15k ohms depending on the application. If the connector is damaged and must be replaced, the replacement must have the same value as the original. The reference voltage from the PCM to the sensor on these engines is 2.7 volts.

* Saturn also uses a special trim resistor in their wideband O2 sensor connector (pins 1 & 6). The resistor is typically 30 to 300 ohms. The PCM supplied reference voltage is 2.4 to 2.6 volts.

* If a O2 sensor, wideband O2 sensor or A/F sensor has failed because of coolant contamination, do not replace the sensor until the leaky head gasket or cylinder head has been replaced. The new sensor will soon fail unless the coolant leak is fixed.

* Some early Toyota applications with A/F sensors provide a “simulated” O2 sensor voltage to be displayed on a scan tool. The actual value was divided by 5 to comply with early OBD II regulations. Those regulations have since been revised, but be aware if you get a “funky” display on your scan tool

Mass Airflow  Sensors

MAF

 

Copyright AA1Car

Mass airflow sensors  MAF, which are used on a variety of multiport fuel injection systems, come in two basic varieties: hot wire and hot film. Though slightly different in design, both types of sensors measure the volume and density of the air entering the engine so the computer can calculate how much fuel is needed to maintain the correct fuel mixture.

Mass airflow sensors have no moving parts. Unlike a vane airflow meter that uses a spring-loaded flap, mass airflow sensors use electrical current to measure airflow. The sensing element, which is either a platinum wire (hot wire) or nickel foil grid (hot film), is heated electrically to keep it a certain number of degrees hotter than the incoming air. In the case of hot film MAFs, the grid is heated to 75 degrees C. above incoming ambient air temperature. With the hot wire sensors, the wire is heated to 100 degrees C. above ambient temperature. As air flows past the sensing element, it cools the element and increases the current needed to keep the element hot. Because the cooling effect varies directly with the temperature, density and humidity of the incoming air, the amount of current needed to keep the element hot is directly proportional to the air “mass” entering the engine.

 

MASS AIRFLOW SENSOR OUTPUT

Mass airflow sensors MAF sensor output to the computer depends on the type of sensor used. The hot wire version, which Bosch introduced back in ’79 on its LH-Jetronic fuel injection systems and is used on a number of multiport systems including GM’s 5.0L and 5.7L Tuned Port Injection (TPI) engines, generates an analog voltage signal that varies from 0 to 5 volts. Output at idle is usually 0.4 to 0.8 volts increasing up to 4.5 to 5.0 volts at wide open throttle.

The hot film MAFs, which AC Delco introduced in ’84 on the Buick turbo V6 and have since used on the 2.8, 3.0 and 3.8L V6 engines, produce a square wave variable frequency output. The frequency range varies from 30 to 150 Hz, with 30 Hz being average for idle and 150 Hz for wide open throttle.

fig 1- Digital MAF waveform

Another difference between the hot wire and hot film sensors is that the Bosch hot wire units have a self-cleaning cycle where the platinum wire is heated to 1000 degrees C. for one second after the engine is shut down. The momentary surge in current is controlled by the onboard computer through a relay to burn off contaminants that might otherwise foul the wire and interfere with the sensor’s ability to read incoming air mass accurately.

Fig 2.- engine performance monitor

MASS AIRFLOW SENSOR DIAGNOSTIC FAULT CODES

An engine with a bad MAF sensor may start and stall or be hard to start, it may hesitate under load, idle rough or run excessively rich or lean. The engine may also hiccup when the throttle suddenly changes position.

Often, a dirty or faulty MAF sensor will cause the engine to set a LEAN code and turn on the Check Engine Light. If the MAF sensor wire becomes dirty or is contaminated with oil (from an aftermarket reusable air filter), it will be slow to react to changes in airflow. This may cause the MAF sensor to under-report airflow, causing the engine to run lean.

On OBD II vehicles, the input from the MAF sensor is combined with those form the throttle position sensor, MAP sensor and engine speed to calculate engine load. If your scan tool can display calculated engine load, look at the value to see if the load is low at idle, and higher when the engine is running under load. No change in the reading or a reading that makes no sense could indicate a problem with any of these sensors.

If you suspect a MAF sensor problem, scan for any fault codes. Trouble codes that may indicate a problem with the mass airflow sensor include:

P0100….Mass or Volume Air Flow Circuit

P0101….Mass or Volume Air Flow Circuit Range/Performance Problem

P0102….Mass or Volume Air Flow Circuit Low Input

P0103….Mass or Volume Air Flow Circuit High Input

P0104….Mass or Volume Air Flow Circuit Intermittent

P0171….System too Lean (Bank 1)

P0172….System too Rich (Bank 1)

P0173….Fuel Trim Malfunction (Bank 2)

P0174….System too Lean (Bank 2)

P0175….System too Rich (Bank 2)

On older Pre-OBD II vehicles, you can use a scan tool or manual flash code procedure to read the codes:

GM Pre-OBD II: Code 33 (too high frequency) and Code 34 (too low frequency) on engines with multiport fuel injection only, and Code 36 on 5.0L and 5.7L engines that use the Bosch hot wire MAF if the burn-off cycle after shut-down fails to occur.

Ford Pre-OBD II: Code 26 (MAF out of range), Code 56 (MAF output too high), Code 66 (MAF output too low), and Code 76 (no MAF change during “goose” test).

Of course, don’t overlook the basics, too such as engine compression, vacuum, fuel pressure, ignition, etc., since problems in any of these areas can produce similar driveability symptoms.

 

MASS AIRFLOW SENSOR DIAGNOSIS

Unlike vane airflow meters with their movable flaps, MAFs have no moving parts so the only way to know if the unit is functioning properly is to look at the sensor’s output, or its effect on injector timing.

With the Bosch hot wire sensors, sensor voltage output can be read directly with a digital voltmeter by probing the appropriate terminals. If the voltage readings are out of range, or if the sensor’s voltage output fails to increase when the throttle is opened with the engine running, the sensor is defective and needs to be replaced. A dirty wire (which may be the result of a defective self-cleaning circuit or external contamination of the wire) can make the sensor slow to respond to changes in airflow. A broken or burned out wire would obviously prevent the sensor from working at all. Power to the MAF sensor is provided through a pair of relays (one for power, one for the burn-off cleaning cycle), so check the relays first if the MAF sensor appears to be dead or sluggish.

Vibration-related sensor problems

On GM MAF sensors, there are a couple of quick checks you can do for vibration-related sensor problems. Attach an analog voltmeter to the appropriate MAF sensor output terminal. With the engine idling, the sensor should be putting out a steady 2.5 volts. Tap lightly on the sensor and note the meter reading. A good sensor should show no change. If the analog needle jumps and/or the engine momentarily misfires, the sensor is bad and needs to be replaced. You can also check for heat-related problems by heating the sensor with a hair dryer and repeating the test.

This same test can also be done using a meter that reads frequency. The older AC Delco MAF sensors (like a 2.8L V6) should show a steady reading of 30 to 50 Hz at idle and 70 to 75 Hz at 3,500 rpm. The later model units (like those on a 3800 V6) should read about 2.9 kHz at idle and 5.0 kHz at 3,500 rpm. If tapping on the MAF sensor produces a sudden change in the frequency signal, it’s time for a new sensor.

On the GM hot film MAFs, you can also tap into the onboard computer data stream with a scan tool to read the MAF sensor output in “grams per second” (GPS). The reading might go from 3 to 5 GPS at idle up to 100 to 240 GPS at wide open throttle and 5000 RPM.

The scantool GPS reading at idle will vary by engine displacement. The larger the engine, the higher the GPS reading at idle. The GPS idle reading will roughly correspond to engine displacement in liters. A 3.0L V6 engine, for example, will generate a GPS reading of about 3.0 grams per second at idle. A larger 5.0L V8 would read around 5 grams per second, and a smaller 2.0L four cylinder would read around 2 grams per second at idle.

published MAF sensor GPS reading specification

Some vehicle manufacturers publish MAF sensor GPS reading specifications for specific engine speeds. The engine is held steady at the specified RPM to compare the scantool GPS reading to the spec. If the reading is off by more than 10 percent, the MAF sensor is not reading airflow correctly. The cause could be a dirty sensor that needs to be cleaned.

Fig 3 – Bosch Hot wire MAF waveform

Like throttle position sensors, there should be smooth linear transition in sensor output throughout the rpm range. If the readings jump all over the place, the computer won’t be able to deliver the right air/fuel mixture and driveability and emissions will suffer. So you should also check the sensor’s output at various speeds to see that it’s output changes appropriately. This can be done by graphing its frequency output every 500 rpm, or by observing the sensor’s waveform on a scope. The waveform should be square and show a gradual increase in frequency as engine speed and load increase. Any skips or sudden jumps or excessive noise in the pattern would tell you the sensor needs to be replaced.

MAF sensor output

Another way to check MAF sensor output is to see what effect it is has on injector timing. Using an oscilloscope or multimeter that reads milliseconds, connect the test probe to any injector ground terminal (one injector terminal is the supply voltage and the other is the ground circuit to the computer that controls timing). Then look at the duration of the injector pulses at idle (or while cranking the engine if the engine won’t start). Injector timing varies depending on the application, but if the mass airflow sensor is not producing a signal, injector timing will be about four times longer than normal (possibly making the fuel mixture too rich to start). You can also use millisecond readings to confirm fuel enrichment when the throttle is opened during acceleration, fuel leaning during light load cruising and injector shut-down during deceleration. Under light load cruise, for example, you should see about 2.5 to 2.8 Ms duration.

Fig 4 —  Ford Mass airflow sensor

CLEANING FORD MAF SENSORS

For some reason, Ford vehicles have had a history of MAF sensor problems caused by contamination. In some cases, dirt gets past a leaky air filter and fouls the sensor wire. In other cases, carbon varnish builds up on the sensor from fuel vapors backing up through the intake manifold. Either way, contamination makes the MAF sens3B”>

The engine coolant temperature (ECT) Sensor

The engine coolant temperature (ECT) sensor is a relatively simple sensor that monitors the internal temperature of the engine. Coolant inside the engine block and cylinder head(s) absorbs heat from the cylinders when the engine is running. The coolant sensor detects the change in temperature and signals the Powertrain Control Module (PCM) so it can tell if the engine is cold, warming up, at normal operating temperature or overheating.

The coolant sensor is extremely important because the sensor’s input to the PCM affects the operating strategy of the entire engine management system. That’s why the coolant sensor is often called the “master” sensor.

Many of the fuel, ignition, emissions and drivetrain functions handled by the PCM are affected by the engine’s operating temperature. A different operating strategy is used when the engine is cold than when it is warm. This is done to improve cold driveability, idle quality and emissions. Consequently, if the coolant sensor fails or is giving the PCM a false reading, it can upset a lot of things.

 

HOW THE COOLANT SENSOR AFFECTS ENGINE OPERATION

Input from the coolant sensor may be used by the PCM for any or all of the following control functions:

1. Start up fuel enrichment on fuel injected engines. When the PCM receives a cold signal from the coolant sensor, it increases injector pulse width (on time) to create a richer fuel mixture. This improves idle quality and prevents hesitation while the cold engine is warming up. As the engine approaches normal operating temperature, the PCM leans out the fuel mixture to reduce emissions and fuel consumption. A faulty coolant sensor that always reads cold may cause the fuel control system to run rich, pollute and waste fuel. A coolant sensor that always reads hot may cause cold driveability problems such as stalling, hesitation and rough idle.
2. Spark advance and retard. Spark advance is often limited for emission purposes until the engine reaches normal operating temperature. This also affects engine performance and fuel economy.
3. Exhaust gas recirculation (EGR) during warm-up. The PCM will not allow the EGR valve to open until the engine has warmed up to improve driveability. If EGR is allowed while the engine is still cold, it may cause a rough idle, stalling and/or hesitation.
4. Evaporative emissions control canister purge. Fuel vapors stored in the charcoal canister are not purged until the engine is warm to prevent driveability problems.
5. Open/closed loop feedback control of the air/fuel mixture. The PCM may ignore the oxygen sensor rich/lean feedback signal until the coolant reaches a certain temperature. While the engine is cold, the PCM will remain in “open loop” and keep the fuel mixture rich to improve idle quality and cold driveability. If the PCM fails to go into “closed loop” once the engine is warm, the fuel mixture will be too rich causing the engine to pollute and waste gas. This condition may also lead to spark plug fouling.
6. Idle speed during warm-up. The PCM will usually increase idle speed when a cold engine is first started to prevent stalling and improve idle quality.
7. Transmission torque converter clutch lockup during warm-up. The PCM may not lockup up the torque converter until the engine has warmed up to improve cold driveability.
8. Operation of the electric cooling fan. The PCM will cycle the cooling fan on and off to regulate engine cooling using input from the coolant sensor. This job is extremely important to prevent engine overheating. Note: On some vehicles, a separate coolant sensor or fan switch may be used for the cooling fan circuit only.

TYPES OF COOLANT SENSORS

Most coolant sensors are “thermistors” that change resistance as the temperature of the coolant changes. Most are the “NTC” (Negative Temperature Coefficient) type where resistance drops as the temperature goes up. With this type of sensor, resistance is high when the engine is cold. As the engine warms up, the internal resistance of the sensor drops until it reaches a minimum value when the engine is at normal operating temperature.

A typical GM coolant sensor, for example, may have around 10,000 ohms resistance at 32 degrees F and drop to under 200 ohms when the engine is hot (200 degrees). A Ford coolant sensor, by comparison, may read 95,000 ohms at 32 degrees and drop to 2,300 ohms at 200 degrees.

Resistance specifications will vary depending on the application, so any sensor that does not read within its specified range should be replaced.

Coolant sensors have two wires (input and return). A 5-volt reference voltage signal is sent from the PCM to the sensor. The amount of resistance in the sensor reduces the voltage signal that then returns to the PCM. The PCM then calculates coolant temperature based on the voltage value of the return signal. This number can be displayed on a scan tool, and may also be used by the instrument panel cluster or driver information center to display the temperature reading of the coolant.

On some applications, a “dual range” coolant temperature sensor may be used. When the coolant reaches a certain temperature, the PCM changes the reference voltage to the sensor so it can read the coolant temperature with higher accuracy (higher resolution).

Older vehicles

On some older vehicles, a different type of coolant sensor may be used. Some of these are essentially an on/off switch that opens or closes at a predetermined temperature. The sensor may be wired directly to a relay to turn the electric cooling fan on and off, or it may send a signal to a warning light on the instrument panel. These older coolant sensors are typically single wire sensors. On other older applications, a single wire variable resistor temperature sensor that grounds through the threads may be used to send a temperature signal to a gauge on the instrument panel. These are typically called temperature “senders” rather than sensors.

 

COOLANT SENSOR LOCATION

The coolant sensor is typically located near the thermostat housing in the intake manifold. On a few vehicles, the coolant sensor may be located in the cylinder head, or there may be two coolant sensors (one for each cylinder bank in a V6 or V8 engine) or one for the PCM and a second for the cooling fan.

The sensor is positioned so the tip will be in direct contact with the coolant. This is essential to produce a reliable signal. If the coolant level is low, it may prevent the coolant sensor from reading accurately.

COOLANT SENSOR SYMPTOMS

Because of the coolant sensor’s central role in triggering so many engine functions, a faulty sensor (or sensor circuit) will often cause cold driveability and emission problems. A bad coolant sensor can also cause a noticeable increase in fuel consumption, and it may cause a vehicle to fail an emissions test if it prevents the engine management system from going into closed loop.

Keep in mind that many coolant sensor problems are more often due to wiring faults and loose or corroded connectors than failure of the sensor itself.

Cold driveability

The coolant sensor’s impact on the engine management system, cold driveability, emissions and fuel economy can also be influenced by the thermostat. If the thermostat is stuck open, the engine will be slow to warm up and the coolant sensor will read low. Or, if someone installed the wrong thermostat for the application or removed the thermostat altogether, it will prevent the engine from reaching normal operating temperature and cause the coolant sensor to read low.

A faulty coolant sensor may also cause the engine to overheat if it fails to energize the cooling fan relay when the engine gets hot.

A faulty coolant sensor may also cause inaccurate coolant temperature gauge readings on the instrument panel.

COOLANT SENSOR DIAGNOSTIC FAULT CODES

On 1996 and newer vehicles with OBD II onboard diagnostic systems, a faulty coolant sensor may prevent some of the system monitors from running. This will prevent the vehicle from passing an OBD II emissions test because the test can’t be done unless all the required system monitors have run and passed.

The OBD II system should catch the fault, turn on the Check Engine Light or Malfunction Indicator Lamp (MIL), and set one of the following diagnostic trouble codes:

P0115….Engine Coolant Temperature Circuit
P0116….Engine Coolant Temperature Circuit Range/Performance
P0117….Engine Coolant Temperature Circuit Low Input
P0118….Engine Coolant Temperature Circuit High Input
P0119….Engine Coolant Temperature Circuit Intermittent

On older pre-OBD II vehicles, the Check Engine light may come on if the coolant sensor is shorted, open or is reading out of range. GM coolant sensor codes include codes 14 & 15, Ford codes are 21, 51 & 81, and Chrysler codes are 17 & 22.

COOLANT SENSOR DIAGNOSIS

A visual inspection of the coolant sensor will sometimes reveal a problem such as severe corrosion around the terminal, a crack in the sensor, or coolant leaks around the sensor. But in most cases, the only way to know if the coolant sensor is good or bad is to measure its resistance and voltage readings.

On vehicle systems that provide direct access to sensor data with a scan tool, the coolant sensor’s output can usually be displayed in degrees Centigrade (C) or Fahrenheit (F). The coolant sensor should read low (or ambient temperature) when the engine is cold, and high (around 200 degrees) when the engine is hot. No change in the reading or a reading that obviously does not match engine temperature would indicate a faulty sensor or a wiring problem.

Internal resistance

The internal resistance of a coolant sensor can also be checked with an ohmmeter or DVOM (digital volt ohm meter) and compared to specifications. If the sensor is open, shorted or reads out of range, it must be replaced.

If the resistance of a coolant sensor is within specifications and changes as engine temperature changes, but the engine is not going into closed loop, the fault is in the wiring or PCM. Further diagnosis will be needed to isolate the problem before any parts are replaced.

One trick here is to use a sensor simulator tool to feed a simulated temperature reading through the sensor’s wiring harness to the PCM. If the wiring continuity is good but the PCM fails to go into closed loop when you send it a “hot coolant” signal, the problem is in the PCM.

 

COOLANT SENSOR VOLTAGE CHECKS

You can also use a voltmeter or digital storage oscilloscope (DSO) to check the sensor’s output. Specs vary, but generally a cold coolant sensor will read somewhere around 3 volts. As the engine warms up and reaches operating temperature, the voltage drop should gradually decrease down to about 1.2 to 0.5 volts. If you’re using a scope to display the voltage signal, you should get a trace that gradually slopes from 3 volts down to 1.2 to 0.5 volts in three to five minutes (or however long it normally takes the engine to reach normal operating temperature).

If the voltage drop across the coolant sensor reads at or near 5 volts, it means the sensor is open or it has lost its ground connection. If the voltage is close to zero, the sensor is shorted or it has lost its reference voltage.

When working on 1985 and up Chrysler products, watch out for a sudden voltage increase as the engine warms up. This is normal and is produced by a 1000 ohm resistor that switches into the coolant sensor circuit when the sensor’s voltage drops to about 1.25 volts. This causes the voltage to jump back up to about 3.7 volts, where it again continues to drop until it reaches a fully warmed up value of about 2.0 volts.

Sudden voltage changes

Sometimes a coolant sensor will suddenly go open or short when it reaches a certain temperature. If your voltmeter has a “minimum/maximum” function, you can catch sudden voltage fluctuations while the sensor is warming up. If you are viewing the voltage pattern on a scope, a short will appear as a sudden drop or dip in the trace to zero volts. An open would make the trace jump up to the VRef voltage line (5 volts).

If the coolant sensor reads normally when cold (high resistance and 3 or more volts), but never seems to reach normal temperature it could be telling the truth! An open thermostat or the wrong thermostat may be preventing the coolant from reaching its normal operating temperature.

COOLANT SENSOR REPLACEMENT

Most coolant sensors are not replaced unless they have failed. A coolant sensor that is shorted, open or reading out of range obviously can’t provide a reliable temperature signal and must be replaced for the engine management system to function properly. But many experts also recommend installing a new coolant sensor if you are replacing or rebuilding an engine. Why? Because coolant sensors can deteriorate with age and may not read as accurately as they did when they were new. Installing a new sensor can eliminate a lot of potential problems down the road.

It is also a good idea to replace the coolant sensor and thermostat if the engine has experienced a case of severe overheating. Abnormally high engine temperatures can damage these components and may cause them to misbehave or fail prematurely.

Replacing a coolant sensor requires draining some of the coolant from the cooling system. You do not have to drain the entire radiator. Just open the drain valve and let out enough coolant so the coolant level in the engine is below the sensor.

Coolant condition check

This would be a good to check the condition of the coolant, and to replace it if the coolant is more than three years old (conventional coolant) or five years old (long life coolant). A coolant change and a flush would also be a good idea if the coolant shows any signs of contamination.

The threads on the coolant sensor may be pre-coated with sealer to prevent coolant leaks. Tighten the sensor carefully to prevent damage.

Once the new sensor has been installed, you can refill the cooling system. Make sure all the air is out of the cooling system. Air trapped under the thermostat may cause the engine to overheat or the coolant sensor to not read correctly.

www.hydrogenfuelsystems.com.au

Gavan Knox

BSc (physics), BSc (chemisty), BEng (Civil), BEd (Physics/Maths),

glknox11@live.com

0403177183

Wideband Oxygen sensors (which may also be called Wide Range Air Fuel (WRAF) sensors) and Air/Fuel (A/F) Sensors, are replacing conventional oxygen sensors in many late model vehicles.

A wideband O2 sensor or A/F sensor is essentially a smarter oxygen sensor with some additional internal circuitry that allows it to precisely determine the exact air/fuel ratio of the engine. Like an ordinary oxygen sensor, it reacts to changing oxygen levels in the exhaust. But unlike an ordinary oxygen sensor, the output signal from a wideband O2 sensor or A/F sensor does not change abruptly when the air/fuel mixture goes rich or lean. This makes it better suited to today’s low emission engines, and also for tuning performance engines.

Oxygen Sensor Outputs

An ordinary oxygen sensor is really more of a rich/lean indicator because its output voltage jumps up to 0.8 to 0.9 volts when the air/fuel mixture is rich, and drops to 0.3 volts or less when the air/fuel mixture is lean. By comparison, a wideband O2 sensor or A/F sensor provides a gradually changing current signal that corresponds to the exact air/fuel ratio.

Another difference is that the sensor’s output voltage is converted by its internal circuitry into a variable current signal that can travel in one of two directions (positive or negative). The current signal gradually increases in the positive direction when the air/fuel mixture becomes leaner. At the “stoichiometric” point when the air/fuel mixture is perfectly balanced (14.7 to 1), which is also referred to as “Lambda”, the current flow from the sensor stops and there is no current flow in either direction. And when the air/fuel ratio becomes progressively richer, the current reverses course and flows in the negative direction.

The PCM sends a control reference voltage (typically 3.3 volts on Toyota A/F sensor applications, 2.6 volts on Bosch and GM wideband sensors) to the sensor through one pair of wires, and monitors the sensor’s output current through a second set of wires. The sensor’s output signal is then processed by the PCM, and can be read on a scan tool as the air/fuel ratio, a fuel trim value and/or a voltage value depending on the application and the display capabilities of the scan tool.

For applications that display a voltage value, anything less than the reference voltage indicate a rich air/fuel ratio while voltages above the reference voltage indicates a lean air/fuel ratio. On some of the early Toyota OBD II applications, the PCM converts the A/F sensor voltage to look like that of an ordinary oxygen sensor (this was done to comply with the display requirements of early OBD II regulations).

How a wideband O2 Sensor Works

Internally, wideband O2 sensors and A/F sensors appear to be similar to conventional zirconia planar oxygen sensors. There is a flat ceramic strip inside the protective metal nose cone on the end of the sensor. The ceramic strip is actually a dual sensing element that combines a “Nerst effect” oxygen pump and “diffusion gap” with the oxygen sensing element. All three are laminated on the same strip of ceramic.

Exhaust gas enters the sensor through vents or holes in the metal shroud over the tip of the sensor and reacts with the dual sensor element. Oxygen diffuses through the ceramic substrate on the sensor element. The reaction causes the Nerst cell to generate a voltage just like an ordinary oxygen sensor. The oxygen pump compares the change in voltage to the control voltage from the PCM, and balances one against the other to maintain an internal oxygen balance. This alters the current flow through the sensor creating a positive or negative current signal that indicates the exact air/fuel ratio of the engine.

The current flow is not much, usually only about 0.020 amps or less. The PCM then converts the sensor’s analog current output into a voltage signal that can then be read on your scan tool.

What’s the difference between a wideband O2 sensor and an A/F sensor? Wideband 2 sensors typically have 5 wires while most A/F sensors have 4 wires.

O2 SENSOR HEATER CIRCUIT

Like ordinary oxygen sensors, wideband O2 sensors and A/F sensors also have an internal heater circuit to help them reach operating temperature quickly. To work properly, wideband and A/F sensors require a higher operating temperature: 1292 to 1472 degrees F versus about 600 degrees F for ordinary oxygen sensors. Consequently, if the heater circuit fails, the sensor may not put out a reliable signal.

The heater circuit is energized through a relay, which turns on when the engine is cranked and the fuel injection relay is energized. The heater circuit can pull up to 8 amps on some engines, and is usually pulse width modulated (PWM) to vary the amount of heat depending on engine temperature (this also prevents the heater from getting too hot and burning out). When the engine is cold, the duty ratio (on time) of the heater circuit will be higher than when the engine is hot. A failure in the heater circuit will usually turn on the Malfunction Indicator Lamp (MIL) and set a P0125 diagnostic trouble code (DTC).

 

Oxygen Sensor Problems

Like ordinary oxygen sensors, wideband O2 sensors and A/F sensors are vulnerable to contamination and aging. They can become sluggish and slow to respond to changes in the air/fuel mixture as contaminants build up on the sensor element. Contaminants include phosphorus from motor oil (from worn valve guides and rings), silicates from antifreeze (leaky head gasket or intake gaskets, or cracks in the combustion chamber that leak coolant), and even sulfur and other additives in gasoline. The sensors are designed to last upwards of 200,000 km but may not go the distance if the engine burns oil, develops an internal coolant leak or gets some bad gas.

Wideband 2 sensors and A/F sensors can also be fooled by air leaks in the exhaust system (leaky exhaust manifold gaskets) or compression problems (such as leaky or burned exhaust valves) that allow unburned air to pass through the engine and enter the exhaust.

Wideband A/F Sensor Diagnostics

As a rule, the OBD II system will detect any problems that affect the operation of the oxygen or A/F sensors and set a DTC that corresponds to the type of fault. Generic OBD II codes that indicate a fault in the O2 or A/F sensor heater circuit include: P0036, P0037, P0038, P0042, P0043, P0044, P0050, P0051, P0052, P0056, P0057, P0058, P0062, P0063, P0064.

Codes that indicate a possible fault in the oxygen sensor itself include any code from P0130 to P0167. There may be additional OEM “enhanced “P1” codes that will vary depending on the year, make and model of the vehicle.

The symptoms of a bad wideband O2 sensor or A/F sensor are essentially the same as those of a conventional oxygen sensor: Engine running rich, poor fuel economy and/or an emission failure due to higher than normal levels of carbon monoxide (CO) in the exhaust.

Possible causes in addition to the sensor itself having failed include bad wiring connections or a faulty heater circuit relay (if there are heater codes), or a wiring fault, leaky exhaust manifold gasket or leaky exhaust valves if there are sensor codes indicating a lean fuel condition.

What to Check: How the sensor responds to changes in the air/fuel ratio. Plug a scan tool into the vehicle diagnostic connector, start the engine and create a momentary change in the air/fuel radio by snapping the throttle or feeding propane into the throttle body. Look for a response from the wideband O2 sensor or A/F sensor. No change in the indicated air/fuel ratio, Lambda value, sensor voltage value or short term fuel trim number would indicate a bad sensor that needs to be replaced.

Other scan tool PIDS to look at include the OBD II oxygen heater monitor status, OBD II oxygen sensor monitor status, loop status and coolant temperature. The status of the monitors will tell you if the OBD II system has run its self-checks on the sensor. The loop status will tell you if the PCM is using the wideband O2 or A/F sensor’s input to control the air/fuel ratio. If the system remains in open loop once the engine is warm, check for a possible faulty coolant sensor.

Another way to check the output of a wideband O2 sensor or A/F sensor is to connect a digital voltmeter or graphing multimeter in series with the sensor’s voltage reference line (refer to a wiring diagram for the proper connection). Connect the black negative lead to the sensor end of the reference wire, and the red positive lead to the PCM end of the wire. The meter should then show an increase i9e8188db74cc41da7fa9c8a38232b9a2 voltage) if the air/fuel mixture is lean, or a drop in voltage (below the reference voltage) if the mixture is rich.

The output of a wideband O2 sensor or A/F sensor can also be observed on a digital storage oscilloscope by connecting one lead to the reference circuit and the other to the sensor control circuit. This will generate a waveform that changes with the air/fuel ratio. The scope can also be connected to the sensor’s heater wires to check the duty cycle of the heater circuit. You should see a square wave pattern and a decrease in the duty cycle as the engine warms up.

Wideband Oxygen Sensor Tech Tips

* On Honda 5-wire “Lean Air Fuel” (LAF) sensors, the 8-pin connector pin for the sensor contains a special “calibration” resistor. The value of the resistor can be determined by measuring between terminals 3 and 4 with an ohmmeter, and will be 2.4K ohms, 10K ohms or 15k ohms depending on the application. If the connector is damaged and must be replaced, the replacement must have the same value as the original. The reference voltage from the PCM to the sensor on these engines is 2.7 volts.

* Saturn also uses a special trim resistor in their wideband O2 sensor connector (pins 1 & 6). The resistor is typically 30 to 300 ohms. The PCM supplied reference voltage is 2.4 to 2.6 volts.

* If a O2 sensor, wideband O2 sensor or A/F sensor has failed because of coolant contamination, do not replace the sensor until the leaky head gasket or cylinder head has been replaced. The new sensor will soon fail unless the coolant leak is fixed.

* Some early Toyota applications with A/F sensors provide a “simulated” O2 sensor voltage to be displayed on a scan tool. The actual value was divided by 5 to comply with early OBD II regulations. Those regulations have since been revised, but be aware if you get a “funky” display on your scan tool

Product of           https://www.hydrogenfuelsystems.com.au

 

Improved Mosfet switching circuit for powering Hydrogen fuel system

MOSFET switch for hydrogen generator systems

A Simple Switch

MOSFETs are really easy to “saturate”, which just means that they are fully open, and they are dead reliable for very fast switching between their saturation and cut-off regions (fully on and fully off regions). This makes them wonderful switches, especially for high power applications like motors, lamps, etc. In most cases, you can use the same power supply that you are using for your high power device to operate the MOSFET as well, using a mechanical switch to apply the gate voltage. The image below shows exactly that type of application

Build:
For this project wewill use N channel MOSFET only

Place the N-ch MOSFET on the board. Connect the 1kΩ resistor between the gate and GND. Connect the switch between the gate and +9V. Place the 220Ω resistor and LED in series between +9V and the drain. Tie the source pin directly to GND. See image below.

Push the button and the LED should light up. The 1kΩ resistor acts as a pull-down resistor, keeping the voltage at the gate at the same potential as the negative battery terminal until the button is pushed. This puts a positive voltage at the gate, opening the channel between the drain and source pins and allowing current to flow through the LED. Note that the gate voltage is +9V and there are no negative side effects.

 

Step 3: Motor Drivers  – not applicable or necessary configuration for Hydrogen electrolysis circuits

Improved Mosfet switching circuit

Building off of Step 1, we can use the ZVN as a DC motor driver. To avoid over-current damage to the ZVN, I’m using a small 6V DC hobby motor, much like the kind you find inside of small hobby servos. With a higher current N-ch MOSFET, you can drive larger motors with larger current needs.

Looking at the schematic below you’ll see two diodes placed backward (reverse biased) across the motor contacts and across the MOSFET drain/source pins. Any electrical component that has a coil in it (inductors, relays, solenoids, motors, etc.) can generate a very large voltage spike in the reverse direction when it is turned off. (This is a common problem in airsoft, and it can lead to premature wear on the trigger contacts that turn on the motor. An easy fix for this is to add an “airsoft MOSFET”, and this is a similar example. It should be noted that the parts used here are nowhere near capable of handling the voltage/current needs of an airsoft motor, so don’t use this specific example.) The diodes give that spike a place to go so that the components are not damaged.

Improved Mosfet switching circuit

Build: Place the ZVN on the board. Connect the 1kΩ resistor between the gate and GND. Connect the switch between +6V and the gate. Connect the source to GND. Connect the drain to the negative motor lead. Tie the positive motor lead to +6V. Place one diode between the drain and source pins, with the stripe on the diode facing the drain pin. Put the other diode across the motor leads, with the stripe toward +6V. See image below.

Once everything is connected, double check it. And again. It’s really easy to get things switched and even though it probably won’t matter with this circuit, it’s a good habit to already have when it does matter. Then push the button and your motor should run in one direction.

Improved Mosfet switching circuit

Conclusion

As you can see MOSFETs are extremely useful. They are arguably the most important electronic component in use today when you look at how much we rely on them for our everyday electronic devices. There isn’t a day that goes by that you don’t use several million transistors just to do something simple, like look at what time it is. Or make your coffee, check your email, watch a movie, listen to music, or read this I’ble.

You may have noticed that there is no mention of MOSFETs as amplifiers here. I did that on purpose, but that isn’t to say that they can’t be used as such. My experience has been that analog signal amplification duties are best handled by BJTs, and fast, high current switching is best done by MOSFETs. I realize that is a generalization, as there are plenty of examples for both transistor types working both ways very well. I encourage you to do the research yourself if you wish to learn more on those applications.

 

Improved power supplies

Have been doing a many hours R and D on development of a new improved power supply for hydrogen fuels systems.  The Issue I have experienced is the excessive wastage of electrical energy in operating a power supply originally designed to power DC motors , that have  an excessive amount of electrical circuitry whose only function is to prevent back voltage that reduces the efficiency and Power output of an inductive DC motor circuit.

Improved power supplies

There are many potential sites available online , both on you tube and on research URL sites that describe effective DC control / switching circuits that use MOSFET components .   Many of these are still biased to DC motor circuits but we have managed to modify several simple circuits that use Banks of MOSFET’s connected in parallel with biasing 10k pots , to control / switch the current on in these Electrolysis circuits , without wasting excessive voltage on the internal circuitry.

After many many many hours of operation and testing of these switching Power supply circuits we will now get them made professionally and install them in the latest models of hydrogen fuel systems.

There are several advantages of the new circuitry

1. All available battery voltage / electrical energy is available for the  electrolysis cells
2. No overvoltage is wqsted through the PWM heat sink , thus preventing problem s of electronic thermal runaway problem
3. The MOSFET is a VOLTAGE CONTROLLED DEVICE rather than a current controlled device as in transistors ad IC’s thus  leaving little chance of thermal runaway damage and making it easier to set, control and use
4. Less parts , simpler construction and less maintenance problems
5. Truly able to use as a set and forget technology
6. Cheaper to manufacture and cheaper to repair if so needed

Improved power supplies

Recommended Mosfets for these systems are the 10 amp 12 volt MOSFETS, – 5 OF THEM CONNECTED IN PARALLEL.  Providing control for up to 50 amp of current .

Once the systems are manufactured professionally by our fabricator, they will be mounted into a protective ventilated cage  onto a designed circuitboard

Photos will follow soon  and schematics will be available on this site

Hydrogen fuel systems

Hydrogen systems for Diesel Engines University Research

Hydrogen fuel systems. Today October 3 2017, On Holidays at Ramada resort, Dunsborough WA,  I was conducting research online for the following research topic

“hydrogen systems for diesel engines university research”

I was able to find many authentic research articles including ones from a group from with URL address

www.sciencedirect.com/science/article/pii/S1876610213000040

Science direct is a University research URL requiring membership.,  However there are many reference links showing authors and published papers which can be easily located online through a google search

One such paper I found to start with was headed “Combustion characteristics of diesel-hydrogen dual fuel engine at low load” and was located at the URL1-s2.0-S1876610213000040-main hydrogen dual fuel

Which I downloaded and have copied onto this post

The research report was well written and a clear concise document providing proof of the use of Hydrogen as a duel fuel for use with diesel

Hydrogen fuel systems

“In the present study, hydrogen utilization as diesel engine fuel at low load operation was investigated. Hydrogen cannot be used directly in a diesel engine due to its auto ignition temperature higher than that of diesel fuel. One alternative method is to use hydrogen in enrichment or induction. To investigate the combustion characteristics of this dual fuel engine, a single cylinder diesel research engine was converted to utilize hydrogen as fuel. Hydrogen was introduced to the intake manifold using a mixer before entering the combustion chamber. The engine was run at a constant speed of 2000 rpm and 10 Nm load. Hydrogen was introduced at the flow rate of 21.4, 36.2, and 49.6 liter/minute. Specific energy consumption, indicated efficiency, and cylinder pressure were investigated. At this low load, the hydrogen enrichment reduced the cylinder peak pressure and the engine efficiency.”

Hydrogen fuel systems

“The advantages of using hydrogen as fuel for internal combustion engine is among other a long-term renewable and less polluting fuel, non-toxic, odorless, and has wide range flammability. Other hydrogen properties that would be a challenge to solve when using it for internal combustion engine fuel, i.e.: low ignition energy, small quenching distance, and low density”

Hydrogen fuel systems

“5. Conclusion Experiments and simulation works were conducted on DI diesel engine with hydrogen in the dual fuel mode. Under constant load and speed engine operation, hydrogen induction into the intake manifold 10 W.B. Santoso et al. / Energy Procedia 32 ( 2013 ) 3 – 10 reduces the diesel fuel consumption. Diesel reduction of 50, 90, and 97% was achieved during the investigation. These relatively high percentages of hydrogen fuel are detrimental to the engine performance in terms of energy consumption and efficiency. An increasing hydrogen flow rate at the low load operation results in a higher SEC. It means that more fuel is necessary to produce the same power output. At this low load operation, the efficiency decreases with hydrogen enrichment. This condition affects the values of SEC. Measurement of in-cylinder pressure was carried out to investigate the combustion process inside the combustion chamber. Hydrogen enrichment reduced the peak pressure and retarded the start of combustion. CFD simulation reveals that hydrogen enrichment in such a high percentage resulted in slower reaction progress due to lower combustion rate of reaction. Temperature distributions along the cut plane at the spray axis showed the progress of the combustion processes. Acknowledgment The authors wish to thank Universiti Malaysia Pahang for supporting this research under GRS 100303. Fully support from LIPI by providing the experiment and simulation facilities are grateful acknowledged.

References [1] Fulton J, Lynch F, Marmora R. Hydrogen for reducing emissions from alternative fuel vehicle. SAE Technical Paper 1993;No. 931813.

[2] Saravanan N, Nagarajan G. An experimental investigation of hydrogen-enriched air induction in a diesel engine system. Int J Hydrogen Energy. 2008; 33:1769-1775

. [3] Pundir BP, Kumar R. Combustion and smoke emission studies on a hydrogen fuel supplemented DI diesel engine. SAE Technical Paper. 2007;No. 2007-01-0055.

[4] Saravanan N, Nagarajan G, Kalaiselvan KM, Dhanasekaran C. An experimental investigation on hydrogen as a dual fuel for diesel engine system with exhaust gas recirculation technique. Renewable Energy. 2008;33:422-427.

[5] McWilliam L, Megaritis T, Zhao H. Experimental investigation of the effects of combined hydrogen and diesel combustion on the emissions of a HSDI diesel engine. SAE Technical Paper. 2008;No. 2008-01-1787.

[6] Saravanan N, Nagarajan G, Dhanasekaran C, Kalaiselvan KM. Experimental investigation of hydrogen port fuel injection in DI diesel engine. Int J Hydrogen Energy. 2007;32:4071-4080.

[7] Lilik GK, Zhang H, Herreros JM, Haworth DC, Boehman AL. Hydrogen assisted diesel combustion. Int J Hydrogen Energy. 2010;35:4382-4398.

[8] Saravanan N, Nagarajan G, Dhanasekaran C, Kalaiselvan KM. Experimental investigation of hydrogen fuel injection in DI dual fuel diesel engine. SAE Technical Paper. 2007;No. 2007-01-1465.

[9] Saravanan N, Nagarajan G. An experimental investigation on a diesel engine with hydrogen fuel injection in intake manifold. SAE Technical Paper. 2008;No. 2008-01-1784.

[10] Saravanan N, Nagarajan G. Performance and emission studies on port injection of hydrogen with varied flow rates with Diesel as an ignition source. Applied Energy. 2010;87:2218-2229.

[11] Bose PK, Maji D. An experimental investigation on engine performance and emissions of a single cylinder diesel engine using hydrogen as inducted fuel and diesel as injected fuel with exhaust gas recirculation. Int J Hydrogen Energy. 2009;34:4847- 4854.

[12] Szwaja S, Grab-Rogalinski K. Hydrogen combustion in a compression ignition diesel engine. Int J Hydrogen Energy. 2009;34:4413-4421

Following are the instructions for Servicing HHO System  as used by trucks and cars using the HydrogenFuelSystem pty ltd system for hydrogen Generation

1. One litre of water should last 15 hour s of continuous operation.
2. Add Distilled water to recycling container to bring it to the full mark –8cm from top of tank.
3. After 3 months of operation, the liquid should be flushed out and drained. New/Fresh solution should be used.
4. For trucks and other engines using a 24 volt and 30 amp, supplying one litre of water should last between 5 to 6 hours of continuous operation.
5. Concentration of 11 grams per litre equates a pH of 13.6. This is the ideal concentration of the solution in the system
6. In order to make up the solution the ideal way is to make a concentrated solution of potassium hydroxide by dissolving 50 grams in 150 mls of water.
7. With the system running , slowly add small amounts of the concentrated solution to the recycling tank until the current flow in the system measures 20 amp. This is a time consuming process and time shhold be allowed to mix the potassium hyrdroxide solution thoroughly before adding more electrolyte .  The complete operation should take 5 min to set up. Unused Potassium Hydroxide should be stored and disposed of safely through  your local city AUTHORITY.  Do not pour  it into nito the  garden  or down the drain as is is very poisonous chemical and pollution should be avoided.  iF YOU only make up small of electrolyte is can safely be kept for the next cycle when you flush out the system and make a fresh electrolyte .
8. Once operational only water needs to be added to fill the reservoir up to the level of 8 cm from the top of the recycling container

Product of           https://www.hydrogenfuelsystems.com.au

How to avoid Poor terminal connections fault.      Last week  (June 2017) I checked the operation of My Hydrogen generator system and noticed that one of the terminals in the engine bay , that was delivering current through a relay unit  to the Hydrogen system , had been affected by heat such that the plastic insulation was deformed  as shown in the photo 1 below

I checked the temperature of every terminal  in the systems as it was operating and noticed that the suspect terminal was operating  at 60 celcius , while all other terminals were operating at 32 celcius.

Apart from the deformed plastic the suspect terminal looked fine and was conducting current through the relay.

I replaced the terminal and sPrayed it with lanolin lubricant to stop any future oxidation of the copper leads.

I have operated the system for the past 7 days and have consistently shown an increase in fuel economy of 1.7 km/litre, so that I am now achieving 19.5 km/litre.

I tested the terminal with a multimeter and noticed only a small increase in terminal resistance in low current flow conditions , but also noted that the internal resistance increases by over a 200 mili ohm when operating at 12 volt and 20 amp

This equates to a waste of electrical Power of P=I x I x R  =  20 x 20 x 0.2  = 80 watts  (80 joules per second)

The input Power = V x I = 12 x 20 = 240 watt (240 joules per second)

Wasting 80 watt  for a  total of 240 watt input is  a massive 33%

I recommend testing the terminals with Infra red laser thermometers , to check the condtion of the electrical terminals and  identify faulty terminals which could adversely affect the operation of your Hydrogen generator system.

Moral to the story is it is crucial to check and ensure that all terminals are in good condition  – and preferable treated with a liquid such as with  lanolin corrosion inhibitor.. Alternately with oxidation any electrolysis unit will generate heat rather that hydrogen

https@www.hydrogenfuelsystems.com.au

glknox11@live.com

gavan

0403177183

BSc, BSc, BEng, BEd

Question:

Hydrogen buildup in “on-demand” generators. -If I have my car on but not running will the gas build up in my car?

Answer:

Hydrogen buildup in “on-demand” generators. – If wired correctly, NO, there will be no gas build up.

Ideally you connect to a spot that is only on when the engine is running. Often this spot exists in the fuse box, or your fuel pump is wired this way. Tap into that wire to activate the relay that sends electrical power to your hydrogen generator.  When the vehicle engine stops the relay is switched off and power supply to the hydrogen generator is switched off.

How hydrogen improves combustion

The modern diesel internal combustion engines burns approximately 70% of diesel fuel in the combustion process. The other 30% turns into unburned hydrocarbons that clog up the DPF and EGRs while the remainder contaminates the oil, and blows out the stack producing pollution and smog. Hydrogen burns 14-times faster than diesel and expands by 20,000-times its volume. When introduced via a delivery line on the vacuum side of the turbo, the hydrogen excites the diesel molecules, increasing the speed of the burn and therefore burning more of the diesel fuel.

How does this extend DPF regen cycles and EGR replacements?

Simply put, by burning more of the fuel, there is less soot left over. By reducing the quantity of soot there is less for the DPF to filter and less to clog up the EGR valve

You’re right to ask, “Why does this work?” when you know other such “solutions” haven’t worked in the past.

While it’s fairly easy to create a hydrogen injection system that works some of the time, the trick has always been to make a RELIABLE hydrogen injection system that works all of the time. “Hydrogen fuel systems” has used science and engineering, along with manufacturing best practices to achieve the balance required. However, although “Hydrogen fuel systems” knew they had the long sought after solution, they knew it would take quantification, verification and certification in order to prove it to the world.

Do you think, “It’s too good to be true; if it worked this well, everyone would have one.”?

It’s taken decades for the public and institutions to swing behind the long-proven idea that smoking is bad for you. Just because something is good, doesn’t mean that everyone adopts it quickly. There are a lot of bogus claims and underperforming products out there. It’s going to take time for the vast majority of companies to get behind this. In the mean time, those who do adopt this technology will have a definite, measurable advantage over their competition.

Are you concerned about OEM endorsement?

“Hydrogen fuel systems” is working with an OEM, however we do not yet have an OEM endorsement. The automotive industry is a conservative one. Think back to how long it was before Halogen lights were allowed on Australian cars. The same goes for radial tires. An OEM endorsement is coming, but not yet.

We understand downtime is your worst enemy and would not put you in a position where you have to pay out of pocket for an issue our product caused.

How much is this going to cost you?

With our leasing plan your will see savings significantly higher than your lease payments very soon. In reality this will cost you nothing. At 10% savings of fuel used you will make a profit after the first few months.