Low-temperature combustion method of internal-combustion engine with fuel reformation inside cylinders and system

Abstract

The invention relates to the internal-combustion engine technical field, in particular to a low-temperature combustion method of an internal-combustion engine with fuel reformation inside cylinders and system. High-cetane-number fuel is sprayed inside a rich burn air cylinder of a multi-cylinder engine to ignite rich burn combination gas of natural gas and air with a fuel-air equivalence ratio of 1.5-4.0, reformation combination gas which is rich in H2 and CO is generated after the natural gas is rich burned, and then after the reformation combination gas and the air are mixed to enter a lean burn air cylinder for combustion again, a lean burn mode of which the high-cetane-number fuel ignites the reformation combination gas is in the lean burn air cylinder, and a fuel-air equivalence ratio is less than 1. The low-temperature combustion method of the internal-combustion engine with the fuel reformation inside the cylinders and system has the advantages that compared with an existing ignition type natural gas engine, heat efficiency is increased by 30%, and the level of a diesel engine is achieved; emission can achieve an Euro 5 emission standard; use and production cost of the engine is greatly lower than the diesel engine in the same emission standard; and knocking is restrained and NOx is reduced in the process of heavy load, HC and CO emission is reduced in the process of small load, and meanwhile quantity of the required ignition high-cetane-number fuel is small.

Description

technical field [0001] The invention relates to the technical field of internal combustion, in particular to a method and system for low-temperature combustion of an internal combustion engine for in-cylinder fuel modification. Background technique [0002] Natural gas is a clean energy with large reserves in the world. It is used in automobile engines, and the spark ignition mode has been widely used. In order to further improve efficiency, the compression ignition mode has become an international research and development hotspot in recent years. The domestic research on the combustion of natural gas in the compression ignition mode is mainly after 2000. Tsinghua University (2000), Jilin University (2000), Tianjin University (2002) ), Xi'an Jiaotong University (2002), Shandong University (2011) and others have successively carried out studies on engine power, economy and combustion emission characteristics of diesel blended with natural gas, using natural gas inlet premixin...

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Problems solved by technology

[0003] In order to solve the problem of heavy load knocking, Westport, Canada has developed the HPDI system of direct injection of natural gas in the diesel cylinder in recent years, so that the engine can achieve the same torque and power as the same diesel engine, and the rate of natural gas replacing diesel can reach more than 90%. However, there are still the above-mentioned problems of high NOx emission, complex system and high cost

[0004] Generally speaking, natural gas dual-fuel engines in the world all adopt high-temperature ignition combustion mode, and there are still three technical bottlenecks mentioned above that have not been resolved.

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