An engine assembly with low pressure egr system and condensate control strategy

Abstract

The invention belongs to the technical field of vehicle engineering, and discloses an engine assembly with a low-pressure EGR system and a control strategy for condensed water. Low pressure is reached when the ambient temperature is higher than the first temperature threshold, the temperature of the coolant is higher than the second temperature threshold, the ambient humidity is not higher than the preset humidity threshold, and the cylinder pressure of the engine is not lower than the preset pressure threshold When the EGR system is turned on, the low-pressure EGR system is turned on. Although there is condensed water at this time, because the first connecting pipe body of the throttle valve is installed above the intake manifold at an inclination relative to the horizontal plane, the condensed water produced by the cooling of the gas is in the Under the action of gravity, it flows downstream. Compared with setting the throttle valve under the intake manifold, condensed water will not accumulate in the throttle valve, and the inclined setting of the throttle valve can reduce the height of the whole engine, and the structure is more compact. .

Description

technical field [0001] The invention relates to the technical field of vehicle engineering, in particular to an engine assembly with a low-pressure EGR system and a condensed water control strategy. Background technique [0002] The exhaust gas recirculation system (referred to as EGR system) is to return part of the exhaust gas in the exhaust pipe to the intake manifold of the engine, and reintroduce it into the combustion chamber of the engine together with the fresh mixed gas to reduce the combustion temperature in the cylinder and improve the compression ratio. To reduce fuel consumption. [0003] In order to further reduce fuel consumption and improve thermal efficiency, engineers developed a low-pressure EGR system, which has high requirements for engine reliability design. The condensate problem caused by low pressure EGR technology is a major factor affecting the application of this technology and the reliability of the engine. The temperature of the exhaust gas di...

AI Technical Summary

Problems solved by technology

The temperature of the exhaust gas discharged from the engine is relatively high, and the exhaust gas merges with the filtered fresh air, and then enters the intake manifold through the intercooler and the throttle valve, and the gas cooled by the intercooler is very easy to produce condensed water in a low temperature environment , the condensed water will then accumulate at the low point, and when the vehicle accelerates, it will cause the condensed water to pour into the engine intake port, and then enter the combustion chamber through the intake port, causing the engine to misfire, that is, the ignition in the engine cylinder is not successful, resulting in fuel failure. combustion

At the same time, in a low temperature environment, the accumulation of condensed water will cause icing, causing the internal structure to burst, affecting the reliability and service life of the engine

[0004] In the existing engine assembly based on the low-pressure EGR system, the throttle valve is usually installed vertically above or below the intake manifold. When it is installed above the intake manifold, although it can ensure that the condensed water does not accumulate in the intercooler and the throttle valve, it will increase the height of the whole machine, resulting in insufficient space for the whole vehicle, and also limiting the application of low-pressure EGR technology

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