Design Of Turbo-cooling System For Spark Ignition Engine

In recent years, engine emissions and energy sources become more short-handed, and the development tendency of engine gradually to the high compression ratio, high pressure ratio and so on. The main factor limiting the increase of compression ratio and pressure ratio of gasoline engine is knocking. The temperature of intake gas of boost gasoline engine is still high through the intercooler, and knocking tendency is still great. Limited by the heat transfer medium, the volume and efficiency factors, it is not significant to further reduces intake air temperature by improving the effect of the intercooler. Turbo-expansion is a concept which is aimed at reducing the intake temperature of pressure-charged gasoline engines by making the cold air through the air turbine in order to extended the knock limit(relative to a conventional charge-cooled system). An extension to the knock limit allows several possible shifts in the compromise adopted in pressure charged gasoline engines, including increased specific output, an increase in trapped compression ratio.Engine performance modeling is used in this section, to study the application of turbo-cooling to gasoline engines. The modeling of engines is carried out using Gamma Technologies’ GT-Suite commercial code for simulating the operation of a 1.5L SI engine as the baseline turbocharged engine. The simulation results indicate that the SI engine power, fuel consumption, inlet flow density and the pressure ratio obtained from the simulation and real tests vary identically on the whole, the model’s calculation error can be confined in a range of 3%. So making use of this model to further build the model of air turbine re-cooling turbo-charging system for SI is feasible and credible.Building the turbo-cooling system on the baseline turbocharged engine modeling and then change the circulation area of air turbine to obtain a different inlet temperature drop. Changing the intake pressure via PID control, and analysis the different intake air temperature and the intake pressure on the effect of the gasoline engine power and economy. Finally, choose the intake air temperature dropped to 20 ° C are simulated.The potential benefits of sub-ambient charge air cooling for internal combustion engines include improved performance, fuel economy and exhaust emissions. A high efficiency expander is critical to achieving good overall system performance.This paper presents the design of a turbo-expander using automotive turbocharger technology.According to the simulation results of the preliminary design of the turbocharger air compressor, a turbine impeller and volute casing and pressure, combined with the air intake temperature turbocharger features low, carried out the structural design of the turbocharger air, and draw CAD design drawings.