Based on a 3-cylinder 1.5L dedicated hybrid engine, the influence of three different ignition modes, using single spark plug, passive pre-chamber and triple spark plugs, on the engine combustion and emission characteristics was studied under lean-burn conditions. The test results at the speed of 2000r/min and the brake mean effective pressure of 0.8MPa show that under high-tumble intensity, the lean limit with passive pre-chamber ignition corresponded to an excess air ratio ϕa of approximately 1.70, which is slightly lower than that of single spark plug. In contrast, triple spark plug ignition can maintain stable combustion with a ϕa greater than 1.95, thereby improving the fuel consumption and raw NOx emissions. As the air dilution increases, the advantage of passive pre-chamber ignition in improving combustion phasing gradually weakens, while the corresponding ignition delay and combustion duration increase more obviously. Triple spark plug ignition can effectively accelerate the combustion rate, and this advantage becomes more significant especially when ϕa exceeds 1.70, the combustion duration could be shortened by nearly 4°CA compared to those of single spark plug and pre-chamber. When using triple spark plug ignition and a lean mixture with ϕa of 1.80, the engine achieved a highest brake thermal efficiency(BTE) of 45.06% with the fuel of 92 research octane number(RON). With RON100 fuel and further utilization of electronic supercharger, the highest BTE can be increased to 45.63% and 47.04% respectively.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |