A kind of EGR system and the control method and control device of the intake air temperature after cooling

Abstract

The invention provides an EGR system and a cooled EGR inlet temperature control method and control device, wherein the cooled EGR inlet temperature control method and control device are used for controlling the cooled EGR inlet temperature. The control device comprises a first bypass pipeline, a second bypass pipeline and a temperature controller connected with the first bypass pipeline and the second bypass pipeline. The temperature controller is controlled by the cooled EGR inlet temperature, the first bypass pipeline is in parallel connection with an EGR cooler, and the second bypass pipeline is in parallel connection with a first main pipeline. When the cooled EGR inlet temperature is too low only, the temperature controller controls the first bypass pipeline to be opened, and when the cooled EGR inlet temperature is too high only, the temperature controller controls the second bypass pipeline to be closed. By means of the control method, the amount of cooling water is increased or decreased when the gas inlet temperature is detected too low or too high. By means of the cooled EGR inlet temperature control method and control device, the problems of glue solidification and sulfate generation of the EGR cooler are solved, reliability of the cooler is improved, the service life of the cooler is prolonged, and the fault rate of a diesel engine is reduced.

Description

technical field [0001] The invention relates to the technical field of diesel engines, in particular to a method and a control device for controlling the temperature of intake air after EGR cooling. Background technique [0002] With the improvement of environmental protection requirements, the emission requirements of diesel engines are also getting higher and higher. Many diesel engines reduce the combustion temperature through the EGR (ExhaustGas Recirculation, exhaust gas recirculation) cooler to reduce NOx emissions. However, the diesel engine has certain requirements on the intake air temperature after being cooled by the EGR cooler. Too high or too low will affect the emission; when the exhaust gas temperature is too low, it will also affect the service life of the EGR cooler. [0003] Please refer to figure 1 , figure 1 It is a structural schematic diagram of an arrangement mode of an EGR system in the prior art. [0004] Now the EGR cooler uses the cooling water...

AI Technical Summary

Problems solved by technology

However, the resistance of the waterway will change during the flow of cooling water, which will cause changes in water flow distribution, water pump flow, cooling water temperature and diesel engine load, etc. The intake temperature of the gas at 5' is too high or too low, which exceeds the limit of the intake temperature required by the diesel engine to utilize the circulating exhaust gas at 5', which affects the emission performance of the diesel engine and the service life of the EGR cooler

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