Study Of Bio-diesel Engine Performance

With oil resources exhaustion, the growing demand for energy to satisfy the economic development and environmental problems, searching for new clean fuel to substitute for diesel oil has become an important research topic. Biodiesel due to its reproducibility, environmental conservation etc, has become the most popular alternatives of petrochemical diesel.This paper has investigated the combustion characteristics of a four-cylider turbocharged DI diesel engine fuelled with biodiesel(sunflower oil) and its effect to engine's performance and its pollutant emissions.It introduced the physical and chemical properties and the preparation method of biodiesel,and put forword the feasibility of using sunflower oil as the diesel fuel directly. Based on two wiebe curves superposition principle,established the combustion heat release rate model of sunflower oil, and the simulation calculation was conducted.By comparative experiment on YZ4102ZLQ turbocharged DI diesel engine,the comparison of engine's performance and pollutant emissions of using diesel and sunflower oil under 5 different loads at 2900r/min and 1800r/min have been gained.Then using computer program to computed the fuel's heat release and combustion characteristics parameters.On the basis, combustion characteristics of sunflower oil and their reasons and effects to engine's performance and its pollutant emissions have been researched. The experimental results showed that:1. sunflower oil has a longer ignition delay period and a later ignition compared to diesel;2. in pre-mixing combustion stage,the peak value of heat release rate was lower than diesel while the peak value was higher than diesel in diffusional combustion stage;3. sunflower oil has a decreasing combustion duration,and the end of combustion is earlier than diesel;4. the fuel consumption increases,the almost same exhaust temperature;5. the emission of smoke intensity,CO,HC are better than diesel expect for a little increasing of NOx in conditions of high load and high speed,the results is reverse in conditions of idle speed ,low load and low speed.This research lays the theoretic foundation for directly using the sunflower oil in automotive engine.