Method and device for achieving low emission of heavy-duty diesel engine through controlling exhaust temperature

Abstract

The invention relates to emission control for a heavy-duty diesel engine. In order to provide a method and a device for achieving the low emission of the heavy-duty diesel engine through controlling exhaust temperature, the invention adopts an exhaust temperature control unit of the engine. The method comprises the following steps of: (1) respectively reading a rotate speed signal from an engine crankshaft sensor and a load signal from an accelerator pedal sensor by the exhaust temperature electric control unit of the engine; (2) controlling exhaust gas temperature according to the judged result of the step (1); (3) adopting an auxiliary heat preservation measure on an exhaust pipe except adopting variable valve actuation (VVA), an electronic throttle, cold air filling and the like to regulate the exhaust temperature; and (4) optimizing the burning process to increase the jet pressure of fuel, and adopting a flexibly variable jet control strategy. The invention is mainly applied to the emission control for the heavy-duty diesel engine.

Description

technical field [0001] The invention relates to a heavy-duty diesel engine, in particular to a method for realizing low emission of the heavy-duty diesel engine by controlling the exhaust temperature. Background technique [0002] In the face of environmental pollution and energy shortage, diesel engine emission regulations are becoming increasingly stringent, which poses a severe challenge to the realization of efficient and clean combustion emission control technology for diesel engines. The application of diesel engines in the field of heavy-duty vehicles occupies a dominant position. How to deal with the almost stringent emission requirements is the main problem faced by heavy-duty diesel engines in the development process. [0003] As we all know, there is a trade-off relationship between NOx and soot emissions of diesel engines, and measures to improve one type of emission often lead to an increase in another type of emission. Therefore, for a long time, people have c...

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Problems solved by technology

Although these post-processing technologies have high conversion efficiency, there are problems such as complex system, high cost, and the conversion efficiency is greatly affected by boundary conditions. For example, SCR needs to be filled with NH at regular intervals. 3 to maintain normal operation, and the presence of NH 3 Leakage and other issues, DOC has the problem of thermal aging of the catalyst and catalyst poisoning, while the regeneration and reliability of the DPF will seriously affect its use

At the same time, the use of an afterprocessor will reduce the fuel economy advantage of the diesel engine

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