Technical Paper
A Comparative Study on the Thermodynamic Analysis and Performance Characteristics of a Dedicated EGR Gasoline Engine Under Various D-lambda
2018-04-03
2018-01-1373
The concept of D-EGR (Dedicated EGR) used high EGR rate and fuel reformation to improve thermal efficiency, entire exhaust gas which supplied from a single cylinder is recirculated to the intake system and then entered into all cylinders to improve combustion. In this study, the D-EGR system is performed on a 1.5 L port fuel injection 4-cylinder gasoline engine, in comparison to the basic engine, the reduction of fuel consumption is about 20~30 g/kWh in most of the D-EGR engine operating range, a maximum 104.1 g/kWh BSFC reduction is found at 14.0bar@1800rpm, the lowest fuel consumption is decreased from 253.7 to 224.3 g/kWh by D-EGR, and the corresponding maximum brake thermal efficiency is improved from 32.6 to 36.9%. D-lambda (the lambda of dedicated cylinder) is considered as the most significant factor to influence the fuel economy and combustion stability, the suitable range of D-lambda is around 0.69~0.82 to gain better engine performance under the whole operating points.
