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为了弄清燃烧室沉积物对发动机排气碳氢的影响，使用一台实验用单缸火花点火发动机来形成燃烧室沉积物。在燃烧室沉积物存在的条件下，开展了不同工况下碳氢排放的实验研究，分析了燃烧室沉积物对发动机动力性和燃油经济性的影响。实验结果表明：当发动机运行一段时间后，其燃烧室表面沉积物将达到一稳定平衡厚度，此时排气碳氢浓度随转速的升高、冷却水温的增加以及点火推迟而降低。在本实验各类工况下，沉积物的存在将使发动机排气碳氢浓度增加２０％～３０％。同时沉积物的存在将使发动机的功率和燃油经济性有所提高（功率增加１．１％～１．６％，燃油经济性提高２．７％～３．０％），此现象被认为主要是因沉积物的隔热作用，而不是压缩比的增加所致。
To understand the effect of combustion chamber deposits on engine exhaust hydrocarbon, an experimental single-cylinder spark-ignition engine was used to create combustion chamber deposits. In the presence of combustion chamber sediment under the conditions of carried out under different conditions of experimental study of hydrocarbon emissions, combustion chamber deposition on the engine power and fuel economy. The experimental results show that when the engine runs for a period of time, the surface sediment of the combustion chamber will reach a stable equilibrium thickness. At this time, the concentration of exhaust hydrocarbon decreases with the increase of rotational speed, the increase of cooling water temperature and the delay of ignition. Under the various working conditions in this experiment, the presence of sediment will increase the hydrocarbon concentration of engine exhaust gas by 20% ~ 30%. At the same time, the presence of sediment will improve the engine power and fuel economy (power 1.1% ~ 1.6%, fuel economy increased by 2.7% ~ 3.0%), this phenomenon is considered to be the main It is due to the insulation of the sediments, not the increase of the compression ratio.