| 董文龙,万明定,王正江,等.-43 ℃下多次喷射对柴油机冷起动特性的影响[J].内燃机工程,2023,44(5):8-15. |
| -43 ℃下多次喷射对柴油机冷起动特性的影响 |
| Effects of Multiple Injection on Cold Start Characteristics of A Diesel Engine at -43 ℃ |
| DOI：10.13949/j.cnki.nrjgc.2023.05.002 |
| 关键词:柴油机 冷起动 多次喷射 燃烧 怠速稳定性 |
| Key Words:diesel engine cold start multiple injection combustion idlingspeed stability |
| 基金项目:国家自然科学基金项目（52066008） |
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| 摘要:为了改善极寒条件下柴油机的起动性能和怠速稳定性，基于起动/发电一体式电机拖动柴油机进行-43 ℃下的冷起动试验，研究了单次、两次（预喷1+主喷）和三次喷射（预喷2+预喷1+主喷）3种喷射方式对柴油机冷起动过程及燃烧特性的影响，分析了不同喷射组合对极寒条件下柴油机冷起动过程的影响规律。研究表明：在-43 ℃环境温度下，柴油机采用三次喷射时，冷起动性能明显优于单次和两次喷射。随着喷射次数的增加，起动燃烧首循环的缸内压力峰值升高，峰值相位提前，压力升高率和瞬时放热率峰值显著降低，滞燃期缩短；在冷起动过程中，相比单次喷射，两次和三次喷射时倒拖阶段和升速阶段所需时间分别减少9个循环和22个循环，最高燃烧压力升高，循环变动率分别降低37.7%和46.8%，使得起动时间分别缩短0.88 s和2.58 s，起动累积油量分别减少511 mg和1 290 mg；在起动后的怠速过程，怠速转速波动率分别降低54.2%和82.2%，随着喷射次数的增加，怠速稳定性显著提高。研究结果可为柴油机极寒条件下冷起动过程的控制和参数标定提供理论依据。 |
| Abstract:In order to improve the starting performance and idling stability of diesel engines under extremely cold conditions， a cold starting test was conducted at -43 ℃ based on a diesel engine towed by an integrated starter/generator motor. The effects of 3 injection modes， i.e. single injection， double injections （pilot injection 1+main injection） and triple injections （pilot injection 2+pilot injection 1+main injection） on the cold starting process and combustion characteristics of diesel engine were studied， and the effects of different injection combinations on the cold starting process of diesel engines under extreme cold conditions were analyzed. Results showed that at the ambient temperature of -43 ℃， the cold start performance of the diesel engine with triple injections was significantly better than that of single and double injections. With the increase in the number of injections， the peak values of in-cylinder pressure in the first cycle of starting combustion rose， the peak phase was advanced， the peak values of pressure rise rate and instantaneous heat release rate decreased significantly， and the ignition delay period was shortened. In the cold start process compared to single injection， the number of cycles required in the reversed towing stage and the acceleration stage was reduced by 9 and 22 for double and triple injections， respectively， and the maximum combustion pressure was increased and the cycle variation rate was reduced by 37.7% and 46.8%， resulting in shortening of the start-up time by 0.88 s and 2.58 s， and reduction in cumulative oil volume by 511 mg and 1 290 mg. In the idling process after starting， the idle speed fluctuation rate was reduced by 54.2% and 82.2%， and the idle speed stability was significantly improved with the increase of injection number. The research results can provide a theoretical basis for the control and parameter calibration of diesel engine cold starting process under extremely cold conditions. |
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