Improving the Performance of Internal Combustion Engines and Reducing Emissions by Injecting Water with the Air Entering the Engines

The current work experimentally and theoretically studied the effect of water injection on improving the performance of three different types of single-cylinder internal combustion engines. The first engine is a four-stroke diesel, the second is a four-stroke gasoline, and the third is a two-stroke gasoline engine. Different amounts of water were injected relative to fuel consumption for the three engines to find how it affected the performance, exhaust gas temperatures, and emissions. Comparing the experimental and theoretical results was done to determine the effect of spraying water on lowering the temperatures of the exhaust gases, increasing the thermal efficiency, and lowering specific fuel consumption. The experimental results for the various tested engines show that, in general, the exhaust gas temperature and gas emission decreases by increasing the mass of water injection; these differences vary based on the engine and the operating conditions. Water injected at the inlet of the gasoline engine reduces the overall emissions greater than with the diesel engine and the two-stroke engine. The current laboratory experiments have shown and confirmed by theoretical analyses that spraying water at the inlet of engines reduces braking fuel consumption by a maximum of 10% with an increase in thermal efficiency by up to a maximum of 4.5% and reducing emissions of nitrogen oxides (NOx) and exhaust gas temperature by up to 35%.