Experimental investigation of water injection on the performance and exhaust emissions of an internal combustion engine

Internal combustion engines facilitate the human life in the last century. Besides the important benefits it provides; number of road vehicles that have an internal combustion engine more than 1 billion in the world and more than 20 million in Turkey and these has become one of the most important causes of environmental pollution. Internal combustion engines cause negative effect on the environment and human life due to harmful exhaust gases released to atmosphere because exhaust gases cause the greenhouse effect and have various carcinogenic effects. Moreover, the emission norms set by the environmental authorities are becoming increasingly shrinking and day by day more difficult to keep the targeted values. Under these circumstances, automotive manufacturers have intensified their efforts to produce more environmentally friendly engines without compromising their performance values. In this project, aimed the reduce NOx emissions caused by use of gasoline in an internal combustion engine that is transformed from single cylinder direct injection Diesel engine to spark ignition. The NOx reduction provided with internal cooling effect of water that injected to combustion chamber via gasoline injector. Water addition to combustion chamber is a technic that is have lost cost than aftertreatment system. This method is divided into two main types as emulsion and injection. In this project, water addition into the combustion chamber is made from the gasoline injector at 90 bar high pressure value. Water injection system is designed within financial support of Research Fund of Yildiz Technical University with project number 2016-06-01-YLO1. The performance and emission values of non-water conditions are accepted as reference situation. These are compared with the operating values of varying water ratios and water injection timing and ignition timing. The effects of the amount of direct water injection to combustion chamber on the engine performance and in particular on NOx emissions has been revealed in this project.