So far, researches on internal combustion engine are still ongoing, and plenty of technologies are still progressing, therefore, before electric cars become popular, internal combustion engines still could not be replaced. However, with the regulation of vehicles’ fuel consumption gradually becomes more severe, auto makers must strive to improve their engines’ fuel economy. Atkinson cycle is commonly adopted to improve engine’s fuel economy, which uses longer expansion stroke to generate more work; Miller cycle enhances thermal efficiency through the early closure of intake valves to decrease pumping losses.
Using Ricardo Wave engine simulation software to carry out Atkinson cycle’s design by importing Variable Valve Timing (VVT), and analyzing results by increasing compression ratio, air fuel ratio, so does importing Exhaust Gas Recirculation (EGR) system. Finally adopting the simulation results to design the Atkinson Cycle engine. In order to improve the fuel economy, the cylinder head from stock engine was modified to get higher Compression ratio, EGR valve and pipes were built on the exhaust pipe, and its control strategy becomes variable.
The article focuses on analyzing each parameters which would have impact on engines such as air fuel ratio, compression ratio, EGR, turbine wastegate by using Ricardo WAVE to create Atkinson cycle engine’s simulation, so does tuning a 2.2-liter turbocharged engine with those parameters. According to the experimental results, the target engine’s Brake Specific Fuel Consumption (BSFC) was improved by 14.5~18.3% under the engine speed of 2800rpm, and Brake Mean Effective Pressure (BMEP) between 6 to 8 bar, and the BSFC even achieved 214 g/kW-h at the BMEP of 7bar.
SAE/JSAE Small Engine Technology Conference