The effect of hydrogen additives on the performance of an engine running on liquefied petroleum gas

Abstract

The effect of small additions of free hydrogen on the fuel efficiency and environmental characteristics of an automobile engine running on liquefied hydrocarbon gas has been experimentally studied. The VAZ-11194 engine, in-stalled on the test bench, was equipped with gas-balloon equipment with distributed injection of liquefied gas into the intake manifold branch. Hydrogen was supplied to the engine intake tract in front of the air filter. The influence of hydrogen additions on the course of the combustion process is analyzed on the basis of indexing data performed using Kistler candle sensors. The content of carbon monoxide and unburned hydrocarbons in the exhaust gases was measured with an ASCON-02 gas analyzer. Experiments have shown that, just as in engines running on gasoline or natural gas, small additions of hydrogen have little effect on fuel consumption and lead mainly to a reduction in emissions of toxic components with combustion products. Hydrogen additives most significantly affect the content of carbon monoxide in the exhaust gases of an engine. The presence of free hydrogen in the air-fuel mixture, which has a high chemical activity, is reflected in the kinetics of chemical reactions occurring during fuel combustion, including the kinetics of dissociation reactions. The decrease in the concentration of unburned hydrocarbons in the combustion products with the addition of free hydrogen is associated, to a large extent, with a decrease in the volume of flame extinguishing zones in the combustion chamber of the engine.