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A Digital EFIE operation and How it works to adjust the fuel map to run hydrogen on engines

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Digital EFIE operation

Digital EFIE operation – Previous EFIE Designs First, lets have a look at how oxygen sensors work. Have a look at Figure A below. Here we have a graph that is a representation of the voltage output of a typical oxygen sensor while the engine is running. Note, that this is only an approximation of a real voltage graph. A real graph would be much more jagged and would not be so regular as this one. But I’m using this graph to make it easier to visualize the concept of what the sensor is doing.

Narrow band oxygen sensors don’t tell the ECU what the air/fuel ratio is. They only tell if the mixture is rich or lean. The line that is marked “.45” volts denotes the make/break point for the sensor’s voltage output. Any voltages that are higher than .45 volts is considered to be rich, and any voltages that are less than .45 volts is considered to be lean. When the sensor produces .45 volts, that is considered to be the correct air/fuel mixture which happens to be 14.7 to 1, air to fuel (by weight). The trouble with narrow band sensors is that they can’t tell the ECU how rich or how lean the mix is. They only tell the ECU “rich” or “lean”. Therefore, in normal operation, they are constantly changing voltages similarly to the graph in Figure A.

Now look at Figure B. The blue line in this graph represents how an EFIE changes the voltage graph of the sensor. As the sensor produces its voltages (as represented by the red graph), the EFIE adds additional voltage. We are showing an EFIE set to 350 millivolts (.35 volts). Therefore the output of the EFIE that goes to the computer will be the voltages in the blue line on the graph. Because higher voltages mean a richer mix to the ECU, the ECU will then lean the mix when it “sees” these “richer” mixture signals coming from the oxygen sensor.

Almost all EFIE designs that are in use today work like the above graph, by adding a voltage to the output of the oxygen sensor. While this approach does work, and has been the only solution available for many years, it has 2 problems that make it not the ideal design.

1. There is a definite limit to the amount of voltage you can add. Notice that if we added .5 volts in the above graph, that the blue line would never dip below the .45 volt line. This is an illegal condition and the ECU will quickly stop using the oxygen sensor if it never sees the voltage transitioning from rich to lean. In actual fact many ECUs need to see voltages lower than .45 volts before it will consider that the mix is lean, and so often you can’t set an EFIE higher than 250 millivolts or so without throwing engine error codes.

2. It takes a relatively large change in the voltage to make a small change in the air/fuel ratio. This wouldn’t be a problem in itself, but coupled with the fact that we can only add a limited amount of voltage, this causes an end result of a small change in air/fuel ratio.

There is one other approach in EFIE design in use today, and that is to use an amplifier. Instead of adding voltage to the sensor’s output, EFIEs of this type will amplify the signal. This, in effect, multiplies the signal. This is a better approach in that the lower voltages are not increased as much as the higher voltages, and you should be able to shift the air/fuel ratio further than with a voltage “adder”. However, it is still limited to the amount it can shift the voltage before all voltages are higher than .45 volts. Also, the amplified voltages at the top of the graph can get quite high, possibly high enough that it will set off alarms in the ECU.

Enter the Digital Narrow Band EFIE

There are other EFIE designs being marketed as “digital”. In each case, as of this writing, the only thing digital about them is the pot used to control the EFIE. It’s a digital pot and will have one of 64 or 128 resistance values, or possibly more depending on the resistor chip design. While this is cool, it makes no difference in the operation of the EFIE. It will still be operating like one of those described in the section above.

Our new Digital Narrow Band EFIE operates completely differently from any other EFIE made. Our new EFIE is called digital, because it’s output is either on or off. Or in other words is either high or low. Or to put in terms the ECU will understand, the output will be either rich or lean. Or to put it in terms of voltage, the output is either going to be .100 volts or .900 volts. This is perfectly acceptable to the ECU and tells it exactly what we want it to see. But because it’s output is only one of 2 states, we rightfully call this device a “digital” device.

So how do we know when to switch from the high state to the low state? We have a comparator in the EFIE that “decides” when to switch states. If the EFIE were to be set so that there was no change in air/fuel ratio, the comparator would be set to .45 volts. This would mean that if the voltage coming in from the sensor were below .45 volts, the output would be low, and likewise if the voltage coming in from the sensor were above .45 volts, the output would be set to high. This would cause a flat response in the ECU where it would provide the same air/fuel ratio as if the EFIE were not involved.

To lower the air/fuel ratio we need to make the mix appear richer. In order to do this, we make the EFIE transition to a high output even though the input is below .45 volts. In other words, instead of using .45 volts as the switching threshold, we use .20 volts (see Figure C).

 

By adjusting the pot

By adjusting the pot on our new EFIE, we are adjusting at which voltage the comparator will use to determine if the output should be set to high or low. In the graph below, we show 2 comparator voltages for comparison. At .45 volts, we can see that the output will be high about 1/2 of the time. This is the same as it would be without the EFIE. Now notice the line at .2 volts. By setting the EFIE’s comparator at .2 volts, the EFIE output will be low for about 30% of the time and high about 70% of the time. This will make the air/fuel mix look richer than it is, and the ECU will respond by leaning out the mix.

Note that .2 volts is probably too low for your vehicle. You will probably not need to set it this low. We only set it here to make it easy to see the principal involved with our new Digital EFIE. An actual setting would probably be closer to .300 – .325 volts.

Note: When downstream sensors need to be treated, do not use this device. Use an older style, voltage adding type of EFIE. The reason for this is that we’re not certain how the downstream sensor information is used by the ECU. In some cases, we have read the voltages from downstream sensors and they don’t jump up and down as shown in the graphs above. We’ve seen them just float around in the .2 to .3 volt range, not changing much. This is not the behavior that the Digital EFIE was designed for. It may work fine. But we prefer that the ECU just see the same behavior, but shifted up a bit, the way a voltage adding type of EFIE will do. Any of our Narrow Band EFIEs that aren’t labeled “Digital” will work for this application.

Using this device, some people have been able to lean the mix to the point that the engine will die. However, in some cases, it is still necessary to do other treatments to get the leaning results needed. For instance many ECUs use the downstream sensors as part of the air/fuel calcs, and many more will use the downstream sensors to verify the upstream sensors and throw odd engine errors. In these cases, downstream EFIEs are needed to get the needed results. That’s why we created the Digital EFIE & MAP/MAF Combo It has 2 digital EFIEs for the upstream sensors and 2 analog EFIEs for the downstream sensors. This will give you the optimum treatment for each sensor, and is the most powerful solution we’ve seen yet for optimizing your engine for use with HHO or other fuel combustion enhancement technologies.

MAP Sensor, MAF sensor , and Controlling Fuel usage – Important

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MAP sensor MAF sensor and hydrogen fuel systems is the essential information we are attempting to explain in this passage.  

MAF sensor and fuel usage   How to control Fuel input into modern vehicles with CPM.   MAF sensor , MAP Sensor and Controlling Fuel usage – Hydrogen Fuel Systems

Slug preview:hydrogenfuelsystems.com.au/maf-sensor-map-sensor-controlling-fuel-usage/

Meta description preview:MAF sensor and fuel usage MAP and MAF sensor adjustment and maximizing fuel efficiency and power for diesel fueled , gasoline / petrol fueled and LPG fueled

 

MAP/MAF sensor and hydrogen fuel systems is the essential information we are attempting to explain in this passage.  The Tuning of any petrol fuelled engine relies on the tuning of the following sensors so as to attain a Stoichiometric ratio of 14.7:1.  This is the ratio of the mass of  air injected to  the mass of the fuel injected at STP.  Modern computer fuel injected engines aim to maintain this AFR ratio and monitor several sensors which signal the Engine ECU/PCM to maintain this  ratio.  These sensors are the

  1. mass air flow sensor (MAF),
  2. Air intake sensor
  3. Precat oxygen sensor ( also known as the AFR sensor)
  4. Precat oxygen sensor
  5. Coolant temperature sensor
  6. Manifold Air pressure sensor- (MAP) ( also known as the Boost pressure sensor).

When all sensors are in agreement with loading conditions, the ECU/PCM will fuel injection pulse length to supply sufficient fuel for the loading conditions on the engine.

The MAF sensor adjusts the fuel input measured in Grams of fuel per second.  This measurement is dependent upon the temperature of the of the input air temperature (at constant Pressure P) as with increasing temperature the volume of gas increases according the universal gas law

P.V = n.R.T

Volume of gas

Increasing the temperature (T) of the gas results in the reduction of number of moles (n) of oxygen gas, per litre of air, present for the combustion reaction.  As a result the engine ECU/PCM reduces the mass of fuel / second, injected into the engine so as to maintain its desired stoichiometric ratio of 14.7:1.    This is also be explained by the fact that Colder air is denser that warm air.

The initial Primary fuel control mechanism is dependent upon the MAF sensor and Air intake sensor , which is then adjusted and trimmed  by the MAP sensor , AFR sensor, oxygen sensor and coolant temperature sensor to attain the desired stoichiometric ratio of 14.7:1.

There are a range of MAF sensors that  are designed to measure the air intake volume.

Typically older engines use Hot wire MAF sensors that are analog  sensors and show a change in voltage across the hot wire as more air flows past the sensor. Increasing airflow reduces the temperature of the hot wire and increases its electrical resistance and thus increasing the voltage of the signal sent of the ECU/PVM.  This is a slow response system and has been replaced in modern engines by Digital systems the adjust/ increase the frequency of the signal sent to the ECU/PCM as more air flows past the MAF sensor.

In GM engines there is both a MAP sensor and a MAF sensor which control the engine ECU/PCM.  In the case of GM , Holdens , the MAF sensor is the primary sensor controlling the air/ fuel ratio of the engine and the MAP is a backup sensor on the case of failure of the MAF sensor.

In other older vehicles there is no MAF sensor and the MAP sensor is the primary control sensor  for the stoichiometric air fuel ratio control.

At Idle the air pressure sensor in  the manifold reads a low pressure ( high vacuum ) just as it is on engine deceleration .  This equates to a low loading condition where little fuel is required  and sends a low voltage signal from the MAP to the ECU/CPM.   Conversely under a large load a low pressure and high voltage signal is sent to the ECU/CPM indicating more fuel is required for engine operation.

As can be seen , by adjusting the voltage signal from the MAP sensor to a  lower value , will inform the engine ECU/PCM that less fuel is required because the engine is under less loading.

Now lets consider the electronic fuel enhancer unit as used on vehicles  with hydrogen on demand systems.  Even though a Stoichiometric ratio of 14.7:1 is what the engine is tuned to run with, by reducing the amount of fuel used , then the Stoichiometric ratio will raise much higher than 14.7:1 and the computer will try and adjust by adding extra fuel.  To strop that happening , the MAF sensor must adjust to read a lower mass of fuel  by

  1. Reducing  the frequency of the digital MAF sensor
  2. Reducing the output voltage of the analog MAF sensor

Secondly the Ait intake sensor reinforces this by indicating a higher air temperature with lower percentage  oxygen per litre of air to reduce the fuel input

Next the Oxygen / AFR sensor is adjusted to read a lower percentage oxygen in the exhaust — that equates to a rich exhaust and therefore  reduce the amount of fuel so as to get the  Stoichiometric ratio to what the ECU /CPM thinks is  14.7:1

Sensors such as the Coolant temperature sensor and postCat oxygen sensor are fine tuning sensors to get the best possible airfuel ratio

To summarize : The sensors are adjusted to deliver  a very lean mixture that the ECU/CPM is tricked into accepting as the Stoichiometric ratio of  14.7:1.

Is there a danger of using a lean mixture on an engine? The answer is Yes , for  normally fuelled engines without Hydrogen.  However because of the much, much, much, much….higher flame speed of the hydrogen fuel mixture,   and because the reduction in particular matter , and  because of the much cleaner burn with no deposits, and because of the improved conditions of the exhaust gases emitted, then a much higher Stoichiometric ratio can be achieved delivering greater power output and again requiring less fuel energy used per second to maintain the Vehicle speed  / loading .

In the case of older engines without a MAF sensor then its role is taken on by the MAP Sensor.

 

 

 

Electronic fuel enhancer needs time to activate

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The electronic fuel enhancer needs time to activate

Many people fail to get the maximum  benefits out of  their hydrogen fuel system. They may be too eager to have everything operational as soon as they get in their vehicle. Drivers need to understand that the electronic fuel enhancer can’t work properly until the Engine Computer Unit (ECU) has gone through its setup tests.

Each time you start the engine the ECU must read the sensors and set the appropriate fuel map for the engine conditions. This process takes  time.

You should NOT switch on the electronic fuel enhancer modules for the first 3 to 4  minutes of operation. This will give the ECU time to conduct its internal tests and setups.

When driving my V6  Holden Captiva I find it takes under 3 minutes to complete the ECU self tests.  With my 3.6Litre  V6 commodore I wait 4 minutes before switching on the electronic fuel enhancer. This gives the ECU time to read the sensor signals and select the engine fuel map that provides maximum power and best economy.

Without allowing enough time for the ECU  to set up the sensors and initial fuel map,  the fuel savings and power increases are harder to attain.

As long as the engine is running, the ECU will continue to monitor the sensors. Depending upon the sensor reading it continually adjusts the fuel map to provide optimum economy and power.engine cross-section working

 

 

Without allowing enough time for the ECU  to set up the sensors and initial fuel map,  the fuel savings and power increases are harder to attain.

As long as the engine is running, the ECU will continue to monitor the one more word sensors. Depending upon the sensor reading it continually adjusts the fuel map to provide optimum economy and power five more words are needed..

MOSFET current controlled circuits for power supplies

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MOSFET current controlled circuits

MOSFET current controlled circuits are a great way of controlling a current source. This video is an excellent Youtube site for the design and  operation of  a MOSFET.  You can use MOSFET circuit as a current controlling circuit.

This is a great video.  The video explains the functionality of MOSFETs but also explains how to actually use them in a real-world application.

Electrical knowledge

If you have  limited Electrical knowledge, this video is most informative and easily understood  information. The information is  backed up with fact/cheat sheets on the  website . THis  is really a nice touch.

https://www.youtube.com/watch?v=GrvvkYTW_0k

MOSFET current controlled circuits are a great way of controlling a current source. This video is an excellent Youtube site for the design and  operation of  a MOSFET.  You can use MOSFET circuit as a current controlling circuit.

This is a great video.  The video explains the functionality of MOSFETs but also explains how to actually use them in a real-world application.

If you have  limited Electrical knowledge, this video is most informative and easily understood  information. The information is  backed up with fact/cheat sheets on the  website . THis  is really a nice touch.

MOSFET current controlled circuits are a great way of controlling a current source. This video is an excellent Youtube site for the design and  operation of  a MOSFET.  You can use MOSFET circuit as a current controlling circuit.

This is a great video.  The video explains the functionality of MOSFETs but also explains how to actually use them in a real-world application.

If you have  limited Electrical knowledge, this video is most informative and easily understood  information. The information is  backed up with fact/cheat sheets on the  website . THis  is really a nice touch.

MOSFET current controlled circuits are a great way of controlling a current source. This video is an excellent Youtube site for the design and  operation of  a MOSFET.  You can use MOSFET circuit as a current controlling circuit.

This is a great video.  The video explains the functionality of MOSFETs but also explains how to actually use them in a real-world application.

If you have  limited Electrical knowledge, this video is most informative and easily understood  information. The information is  backed up with fact/cheat sheets on the  website . THis  is really a nice touch.

MOSFET current control circuit for a Hydrogen generator system 1.0

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MOSFET current control circuit   MOSFET power supply to replace PWM DC power supply

increase power / electricity use to produce hydrogen

Annual Cost Savings Fuel cost reduction when hydrogen is used to supplement diesel for a single ship

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hydrogen fuel systems for cars, hydrogen fuel systems for trucks, hydrogen fuel systems power supply, new agents wanted for hydrogen fuel systems, Uncategorized

 

saving fuel cost  Hydrogen on demand  and shipping  –   Increasing diesel fuel economy

Information –  Phillips company

Annual Cost Savings Fuel cost reduction when hydrogen is used to supplement diesel for a single ship

hho and shipping

Using Hydrogen fuel systems on Trawlers and work vessels – page 11 AMSA

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Page 11 of this document  frmm the Australian Maritime Safety Authority  documents the savings to be achieved in shipping using Hydrogen and diesel / petrol

AMSA299-Working-Boats6

Design of a MOSFET as a Switch to control the current flow in a Hydrogen generator circuit

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MOSFET power Supply

Mosfet circuits such as the one listed  below should be used to control a electrolysis circuit  as

  1.  it is fully capable of locking in the current flow at a gven value
  2. does not suffer from thermal runnaway
  3. does not waste electrical energy in powering the electronic circuit
  4. does not reduce the usable output voltage of the power supply

The oxidation / reduction potential or voltage of a electro-winning circuit is fixed and the amount of wasted voltage in modern PWM circuits means that it reduces the number of cells that can be run from a vehicle battery  and reduces the maximum amount of gas that is produced.   Consequently a Simple MOSFET power switching circuit that does not waste voltage is an ideal alternative to a PWM design.

MOSFET as a Switch

Hydrogen in internal combustion engines- NASA investigation

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Results from 1977 investigation into the use of hydrogen on demand for use in internal combustion engines.

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.gov/19770016170.pdf

This investigation concluded there was a significant reduction in emissions and a decrease in the total energy consumption of a multicylinder piston engine running on gasoline (petrol) and a hydrogen-gasoline mixture.

Hydrogen

The results was show to extend the efficient lean operating range of gasoline by adding hydrogen.  Both botted hydrogen and hydrogen produced by a methanol steam reformer were used and compared to results from all gasoline.

The results were used to explain the advantages of adding hydrogen to gasoline as to a method of extending the lean operating range.   The minimum –energy –consumption equivalence ratio  was extended to leaner conditions by adding hydrogen while the minimum energy consumption did not change  – showing that more usable energy was provided.   All emission levels decreased at the leaner conditions and there was a significantly  increased flame speed and reduced engine lag over all equivalence ratios   (60 cm/sec increase to 120 cm/sec at low RPM         to              110 cm/sec increase to 150 cm/sec at high RPM)

  • It was shown that pure hydrogen injection produced the same results as for hydrogen produced from the methanol reformer process
  • The minimum-energy-consumption equivalence ratio decreased from 0.79 to 0.67….. an 18 % reduction
  • Oxides of nitrogen production are appreciably lower for hydrogen / gasoline mixture . Gasoline with reformed hydrogen from methanol have higher NOx  emissions as the reformer must produce gas at a high enough temperature to prevent water and methanol condensation and the higher inlet temperature can cause higher peak combustion temperatures and therefore higher NOx emissions
  • Whilst there are limitations of using the methanol reformation process , with proper design and catalyst selection to produce the hydrogen it is a possible way to use the energy lost in exhaust gases to produce hydrogen as an interesting supplementary or alternative fuel source..

Operational temperature hydrogen fuel system – commonly known as HHO systems

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Operational temperature hydrogen fuel system – commonly known as HHO systems

  1. Hydrogen and oxygen gas mixture produced at Lower temperatures has a higher concentration  than the same gas at higher temperature as is shown by the following formula .

PV =nRT.  At one atmosphere pressure the volume of gas is directly proportional to the temperature (in degrees Kelvin)

  1. A common misconception is that water vapour in the air/ fuel intake will reduce  fuel efficiency …. This belief is wrong as small amounts of water vapour increases the octane rating of fuel and increases power and economy ( See Enola Gay case 1945, Harrier jump jets)
  2. It is proven that cooler temperatures in the electrolysis cell increase the lifespan of electrodes by reducing Corrosion.
  3. Increasing the temperature of an electrolysis cell reduces the internal resistance allowing more current to flow and overloading the vehicle/ engine electrical supply. Increasing the temperature of the electrical / electronic Power supply can lead  to “Thermal Runaway” and ultimate failure of the electronic power control circuitry
  4. To prevent the situation of heat from the electrolysis system, Excessive overvoltage is avoided. Applied voltage is 13.8 volts from your battery and 13.2 volts is used by the oxidation / reduction process within the cells ( 2.2 volts per cell – 6 ells) .  Overvoltage does increase the current flow , without increasing hydrogen gas production.  Extra voltage ( ENERGY / AMP OF CURRENT FLOW) is converted directly into heat  , making the water boil and electrodes corrode.
  5. Using a MOSFET current control circuit as shown in web.mit .www.  search SP07-L25 ,current control circuits are designed that do not use up available voltage and energy , and yet have full control of the current source…. Ie thermal runaway is never an issue.
  6. electronics-tutorials.ws search MOSFET’s   – an excellent site on MOSFET theory in DC switching circuits.
  7. See also Darlington transistrors ( 2 npn transiators)  as a means of power current control circuit