| 摘要:针对严寒环境下特种车辆柴油机冷起动困难及辅助预热策略缺乏定量依据的问题，提出一种按环境温度分区的冷起动策略。通过低温整机倒拖试验建立起动电机动力矩与发动机阻力矩匹配模型，建立不同环境温度下起动系统平衡转速分析模型；结合倒拖缸压数据与定容燃烧弹试验结果，构建压缩终了缸内热力状态与柴油喷雾自燃临界条件模型，构建随环境温度变化的临界着火转速模型。将临界着火转速与起动系统平衡转速对比，评估无辅助、仅进气加热以及进气加热与机体预热协同3种工况下的冷起动能力。结果表明：＞0 ℃可无辅助起动，-20～0 ℃需采用进气加热，-43～-20 ℃需采用进气加热与机体预热协同策略。该研究降低了对大量重复冷起动试验的依赖度，为低温地区柴油机起动与预热方案设计提供了定量依据。 |
| 关键词: 柴油机 冷起动 进气加热 机体预热 临界着火条件 |
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| Low-Temperature Cold-Start Control Strategy for Highly Boosted Low-Compression-Ratio Diesel Engines |
| Yang Ziming,Zhuo Min,Li Yikai,Shi Zhongjie,Wang Dongfang |
| 1School of Mechanical Engineering， Beijing Institute of Technology， Beijing 100081， China;2Beijing Institute of Technology（Zhuhai） ， Zhuhai 519088， China;3National Key Laboratory of Multi-perch Vehicle Driving Systems， Beijing 100081， China;4Faculty of Transportation Engineering， Kunming University of Science and Technology， Kunming 650500， China |
| Abstract:In order to address the cold-start difficulties of special-purpose vehicle diesel engines in severe low-temperature environments and the lack of quantitative guidance for auxiliary preheating strategies，a cold-start strategy partitioned by ambient temperatures is proposed.Low-temperature motoring tests were carried out to establish a matching model between starter motor torque and engine resisting torque，on the basis of which an analytical model for the starter system equilibrium speed under different ambient temperatures was developed.Motored cylinder-pressure data and constant-volume combustion bomb experiments were then used to construct a model of the in-cylinder thermodynamic state at the end of compression and the critical autoignition conditions of diesel spray，from which a critical ignition speed model varying with ambient temperature was obtained.By comparing the critical ignition speed with the starter system equilibrium speed，the cold-start capability under three operating modes（no assistance，intake-air heating only，and combined intake-air heating plus engine block preheating）was evaluated.The results show that the engine can be started reliably without auxiliary preheating when the ambient temperature is above 0 ℃；intake-air heating is required in the range of 20 ℃ to 0 ℃；and a combined intake-air heating and block preheating strategy is necessary between 43 ℃ and 20 ℃.The study reduces the dependence on extensive repetitive cold-start tests and provides a quantitative basis for the design of starting schemes and preheating systems for diesel engines operating in low-temperature regions. |
| Key words: diesel engine cold start intake air heating engine block preheating critical ignition condition |
