Effect on Diesel Engine Performance Parameters Using on Demand Hydrogen and Oxygen

 

Hydrogen is seen as a future energy carrier since its chemical compounds make up a large part of the Earth’s surface. This study sought to analyze the impact related to the inclusion of hydrogen and oxygen gases produced on demand by an alkaline electrolyzer to the engine added directly through the fuel intake line. For this purpose, performance parameters were monitored, such as liquid fuel consumption and greenhouse gas emissions, and correlated to any effect observed on the engine’s power output and combustion behavior. A 58 kVA nominal power motor-generator was used, coupled with a resistive load bank (20 kW), where two fuel configurations were tested (diesel injection only and a mixture of diesel, hydrogen and oxygen) and compared. A total of 42 tests were performed considering both the admission gases into the fuel intake line and also diesel supply only for baseline. A substantial decrease in fuel consumption was observed (7.59%) when the blend configuration was used

 

Considering the results obtained in the tests, we can observe that the addition of 2 and O2 on the combustion mechanism resulted on an increase in the CO oxidation rate culminating in an increase in the efficiency of diesel combustion. Furthermore, the higher temperature obtained with the injection of the gases for the combustion of diesel (specially between 15 and 25 min) can explain the promotion of NO 2 destruction in the direction of NO formation, as can be seen in Figure 11 and in Equations (12)–(14), without, however, implying on relevant increase in NO 2 emission, since the conditions are not so favorable in this direction.

4. Conclusions

The objective of this work was to analyze the impact related to the inclusion of hydrogen and oxygen gases produced on demand on the engine, when added directly through fuel intake line. Fuel consumption and the amount of greenhouse gas emissions were chosen as monitoring variables to analyze the engine performance parameters. For a better understanding regarding any positive or negative effects related to the combustion profile, parameters such as IMEP and combustion duration for two configurations were analyzed (diesel only and blend). It was possible to develop criteria and standardization for each one of the performed tests, as well as to find differences and correlations between the two used fuel intake configurations. The introduction of hydrogen and oxygen gases produced by the alkaline electrolyzer brought statistically significant changes to the engine’s combustion profile, also in performance parameters such as fuel consumption and exhaust gas emission. The choice to produce the gases on demand brought about a very interesting alternative compared to studies that normally use only stored hydrogen gas, in which the energy quantification related to the expense to produce such fuel is not accounted for. It is possible to notice that in both the 30-min and the 60-min tests, there was a substantial decrease in fuel consumption (7.59% and 6.06%, respectively) despite a decrease in the average IMEP performed by the engine (1.07%) with the blend introduction. There is a high performance related to the alkaline electrolyzer production and the used configuration when considering the low electrical consumption provided between the batch of tests (134.5 ± 35.4 W) in contrast to the load generated by the engine (20 kW).

Regarding the exhaust gases emission levels, it was observed that the addition of H2 and O2 gases ensured a temperature combustion increase that caused a more complete burning of diesel and modified the quantity and behavior of greenhouse gas emissions, even with the addition in small proportions. With the change in combustion temperature, it was possible to observe a decrease in CO emission levels and an increase in NOx levels

 

For a more detailed / scientific report on this work click on the following link

https://hydrogenfuelsystems.com.au/wp-content/uploads/2025/04/Effect_on_Diesel_Engine_Performance_Para.pdf

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Sunday, April 13, 2025