关键词: 车用柴油机, 瞬态排放, 喷油正时策略, dSPACE测控平台

Abstract:

To address the deterioration of emissions during transient conditions in automotive diesel engines， the CA6DM3 National Ⅵ high-pressure common rail diesel engine was investigated. A transient measurement and control platform was constructed based on “dSPACE”， and a transient emission optimization strategy utilizing segmented fuel injection timing delay was proposed. A typical transient operating condition was selected with a speed of 1 100 r/min， a load range of 10% to 90%， and a loading time of 3 seconds. Reference air-fuel ratios slightly lower than the stable loading period， specifically 27 and 28， were chosen. A segmented fuel injection timing control strategies implemented through two methods—difference delay and proportional delay， were proposed to achieve segmented delay in fuel injection timing. The test results indicate that， while balancing the dynamic performance and fuel economy during the transient loading process of the diesel engine， adopting the difference delay segmented strategy with a reference air-fuel ratio of 28，the 6 °CA delay scheme yielded the optimal emission improvement effect. The maximum reductions in NO _x and particulate matter emissions during the transient loading process were 6.5% and 27.77%， respectively， the cumulative emission reductions were 6.8% and 31.9%.

Key words: automotive diesel engine, transient emissions, injection timing strategy, dSPACE measure and control platform