敲缸是制约高热效率增压汽油机技术发展的瓶颈。敲缸分为普通敲缸和超级敲缸。一般认为普通敲缸由末端气体自着火引发，而超级敲缸则对应有爆轰波发展过程。另外，混合物局部自着火和复杂的化学反应-压力波相互作用对HCCI内燃机的着火和燃烧控制带来巨大挑战。为了深入认识敲缸的产生机制，发展成熟可靠的HCCI内燃机技术，需要系统地研究大分子碳氢燃料的自着火模态与爆轰波发展过程。本项目以汽油机和HCCI内燃机高效燃烧技术为应用背景，采用数值模拟和理论分析相结合的研究手段，研究温度或组分浓度非均匀分布引发的大分子燃料自着火与非常规燃烧过程，将获得不同的自着火模态及其产生规律，揭示低温化学反应以及各种关键物理化学因素对自着火与爆轰波发展过程的影响，并在此基础上建立预测大分子燃料出现爆轰燃烧的综合判据。研究结果将为先进汽油机和HCCI内燃机燃烧技术提供科学依据，同时也有助于发展自着火与非常规燃烧模态方面的基础燃烧理论。

Knock is a severe constraint for turbocharging spark ignition engines with high thermal efficiency. It is generally accepted that conventional knock is caused by end-gas autoignition while super knock corresponds to detonation development. On the other hand, local autoignition and complex chemical reaction-pressure wave interaction bring great challenges to ignition/combustion controlling in HCCI engines. In order to fully understand the knock mechanism and to develop mature and reliable HCCI engine technologies, comprehensive studies on autoignition modes and detonation development of large hydrocarbon fuels are needed. With the application background of efficient combustion technologies of spark ignition engines and HCCI engines, the present project combines numerical simulation and theoretical analysis to study autoignition and unconventional combustion processes of large hydrocarbon fuels induced by temperature or composition inhomogeneity. It aims to identify different autoignition modes and reveal the corresponding mechanisms. The effects of low-temperature chemistry and various critical physical and chemical factors on autoignition and detonation development will be revealed. Based on that, a comprehensive criterion for detonation development for large hydrocarbon fuels will be established. The results of the present project will provide scientific basis for advanced combustion technologies of spark ignition engines and HCCI engines, and help to develop fundamental combustion theory on autoigntion and unconventional combustion modes.