摘要
在缸盖与进气管之间设置了紧凑的油束热碰壁系统,热壁面可在4 min左右（供电功率为600 W,无空气流动）被加热至250 ℃,并顺利起动发动机.该方法将得到准均质预混合气,若其中散布的油滴未能在着火前充分蒸发,将发生油滴扩散燃烧现象,生成NOx和颗粒物排放.但试验发现,NOx排放基本都低于10×10^-6,限制均质压燃（HCCI）燃烧运行范围的主要因素是PM排放.若不采取其它措施,热壁面温度为370 ℃时,在发动机转速为700～1000 r/min,过量空气系数为4～5时,排气不透光度低于5%.引入冷却废气再循环可将系统HCCI燃烧的大负荷边界拓宽至过量空气系数为2.6（900 r/min）.采用进气加热能使HCCI燃烧的小负荷边界达到过量空气系数为6.1（700 r/min）.
A compact spray hot-impingement system was fixed between the intake manifold and cylinder head. The hot surface could be heated up to 250 ℃ within 4 minutes （ power supply is 600 W, without air flow）, and smooth start-up of engine could be realized. It was found that the fuel-air mixture made by spray-hot-impingement was quasi-homogeneous. If the fuel droplets could not fully vaporize before ignition, a droplet-diffusive-combustion would occur, resulting in NO, and PM emissions. Test results revealed that NOx emissions were usually lower than 10 × 10^-6, and the limit of HCCI （Homogeneous Charge Compression Ignition）combustion was PM emission. Without other measures, when the hot surface temperature was about 370 ℃, the exhaust opacity was lower than 5% in the range of φa = 4 to 5 at the engine speed of 700 r/min to 1 000 r/min. Cooled EGR could extend the high load limit to φa = 2.6 at the engine speed of 900 r/min. Intake heating could extend the low load limit to φa = 6.1 at the engine speed of 700 r/min.
出处
《内燃机学报》
EI
CAS
CSCD
北大核心
2007年第4期296-303,共8页
Transactions of Csice
基金
国家重点基础研究发展计划资助项目(2001CB209201)
中国高技术研究发展计划项目(2006AA11A1A2)
