Considering the trend of engine downsizing, energy saving and emission reduction and the requirement of high thermal efficiency for gasoline engine, the influences of compression ratio and exhaust gas recirculation (EGR) technology on engine combustion performance and emission were studied on a 3cylinder directinjection supercharged gasoline engine. The results show that the increase of compression ratio is helpful to improve the fuel economy at medium and low load conditions, but the improvement is not obvious at high load conditions. It is especially true for external characteristic conditions because the increase of compression ratio will lead to significant deterioration of fuel consumption due to the limitation of knock. With the introduction of EGR, the combustion process improves and the knock suppresses. After introducing 20% EGR, the specific fuel consumption reduces by 6.9% under the medium speed and medium load conditions, but reduces little under the condition of 0.2 MPa BMEP at 2 000 r/min. Combining high compression ratio strategy with EGR can expand the operating range of EGR and further improve the fuel economy.
LI Yunhong
,
DU Jiakun
,
QIN Bo
,
CHEN Hong
,
JIANG Xiaoxiao
,
LI Genkun
. Influences of Compression Ratio and EGR on DI Miller Gasoline Engine Performance[J]. Vehicle Engine, 2020
, 0(6)
: 19
-23
.
DOI: 10.3969/j.issn.1001-2222.2020.06.004
