Effects of liquid phase LPG on emission and engine performance in vehicles with a direct injection gasoline (GDI) engine

The fact that LPG is a cheap, high combustion efficiency and environmentally friendly fuel has increased the amount of use today. In fact, many vehicle manufacturers have started to offer LPG systems from the factory. Along with this interest in gas fuels, the use of gas fuels such as LNG, LPG, CNG, hydrogen, acetylene is also increasing. But among these fuels, LPG is the most used and traded. The fact that LPG is so preferred attracts the attention of companies that produce LPG kits. They are developing their systems every day. In the first Classic LPG vehicles, LPG was sent into the cylinder with some apparatus placed in front of the carburettor. After that, the systems were developed and turned into the way gas was delivered to the intake manifold. Currently, systems that allow the delivery of LPG in the liquid phase by spraying from the engine's injectors have started to be used. Thanks to these systems, LPG has also been used in vehicles with engine technology where gasoline is sprayed from the turbocharger and injector. In these vehicles, which are generally called direct gasoline injection (GDI) engine technology, LPG is sent into the cylinder in the liquid phase using the engine's injector system. This master's thesis study examines the effects of liquid LPG use in turbo gasoline direct injector (TGDI) engine with liquid LPG system. For this purpose, it is integrated with Prins brand liquid LPG system in a vehicle with turbo GDI engine technology. The vehicle can be operated separately with gasoline and liquid LPG with a switch. No changes have been made to the engine or exhaust system. All experiments using this vehicle were carried out on the chassis dynamometer. During all engine experiments, engine torque, engine power and exhaust gas emissions (CO, CO2, HC and O2) were measured and recorded. Vehicle for experiments, four-stroke, four-cylinder, direct-injection system, which has a 1.6 TGDI turbo-petrol engine, the 2017 model brand of vehicle using a dynamometer, 2000 rpm, 2500 rpm, 3000 rpm, 3500 rpm, 4000 rpm, 4500 rpm at engine speeds of up to 5. it is operated in the gear lever position. During Operation, exhaust gas emission values were measured and recorded with the device. The results showed an increase in engine power at each engine speed along with liquid LPG. The highest increase rate was achieved at an engine speed of 4500 rpm. Maximum engine power is measured at 169 HP with the use of LPG, while this figure drops to 166 HP with gasoline. It is possible to explain this situation by the mass thermal value of LPG and the octane number. It is also believed that all LPG sprayed directly into the cylinder can effectively participate in combustion. Along with the use of liquid LPG, the engine torque value increased at 2000 rpm, 2500 rpm, 3000 rpm and 3500 rpm, while the engine speed tended to decrease at 4000 rpm and 4500 rpm. The highest increase rate was determined at 2000 rpm and the highest decrease was measured at 4500 rpm. A reduction in CO emissions was observed at all engine speeds. The highest reduction rate was achieved with 66% of the engine speed of 2000 rpm. Along with the use of liquid LPG in terms of CO2 emissions, 2000 rpm, 2500 rpm, 3000 rpm and 3500 rpm at engine speeds of 4000 rpm and 4500 rpm engine speeds increase a tendency to decrease is observed. Along with the use of liquid LPG at all engine speeds, there is a tendency to reduce HC emissions. The highest amount of reduction was achieved with an engine speed of 3500 rpm with 26%. The amount of oxygen (O2) decreased at engine speeds of 2000 rpm, 2500 rpm, 3000 rpm and 3500 rpm with the use of liquid LPG, while the engine speeds of 4000 rpm and 4500 rpm tended to increase.