A method for flexibly controlling engine combustion mode

Abstract

The invention discloses a method for flexibly controlling an engine combustion mode. Engine speed signals and throttle position signals are read by an electronic control unit to judge the engine operation load according to the read signals; if under the low load condition, an diesel injector is controlled for early injection to form PCCI combustion mode in a cylinder; if under the moderate load condition, the diesel injector is controlled for injection in advance twice, and high-pressure EGR is performed to form HP-EHPCC combustion mode; if under the medium-to-high load condition, the diesel injector is controlled for injection in advance twice, and low-pressure EGR is performed to form LP-EHPCC combustion mode; if under the high load condition, the diesel injector is controlled for delayed injection once, and the low-pressure EGR is performed to form LP-LHPCC combustion mode. High-efficiency clean combustion within a wide load range is implemented through combination of different combustion modes under different working conditions.

Description

Technical field [0001] The invention relates to an internal combustion engine, in particular to a method for flexibly controlling the combustion mode of an engine with gasoline intake port injection and diesel direct injection. Background technique [0002] The massive consumption of energy has caused a series of serious problems such as environmental pollution and global climate change. Especially in urban areas, a variety of air pollutants emitted by engines (such as PM and NOx) have many negative effects on human health and the environment. . In mid-2012, China's car ownership has increased to 114 million. Regardless of whether it is considered from the air pollution or the energy crisis, China is facing more severe tests than other countries with regard to environmental, climate and energy issues. With the continuous strengthening of world emission regulations, reducing pollutant emissions has also become an important issue. Therefore, internal combustion engines are facin...

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Problems solved by technology

[0005] Recently, Inagaki et al. used the premixed compression ignition combustion (PCI) mode of gasoline port injection and early diesel direct injection to flexibly control the in-cylinder fuel activity stratification and concentration stratification by delaying fuel injection, so as to achieve efficient and clean combustion , but exhaust gas recirculation (EGR) was not considered in the study

In addition, the self-ignitability of gasoline is poor. During cold start and low-load operation, the combustion efficiency of the dual-fuel high premixed compression ignition combustion strategy is low, and even the engine may have problems such as combustion instability, and the exhaust gas temperature is too low. After HC / CO It is also very difficult to handle

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