Internal Combustion Engine Exhaust Dew Point Detection System

Abstract

The invention provides an internal combustion engine exhaust dew point detecting system. The system comprises an initializing module, a cold start processing module, a heat integral dew point detecting module, a heat integral calculating and comparing module, a dew point monitoring module and a dew point detecting and replacing module; the initializing module is used for calculating and outputtingother module initialization condition state quantities according to an operation state of an internal combustion engine; the heat integral dew point detecting module is used for performing heat integral calculation, heat threshold calculation and gas pulse detection on heat transferred by tail gas of the internal combustion engine; the heat integral calculating and comparing module judges possibility of forming condensed water in an exhaust pipe according to a heat integral result and a heat threshold; the cold start processing module is used for calculating repeated cold start times of the internal combustion engine and correcting the heat threshold; and the dew point detecting and replacing module is used for finishing a dew point detecting function when system signals are wrong or broken down. The system enables part of gas sensors related to exhaust of the internal combustion engine to safely operate.

Description

technical field [0001] The invention relates to the technical field of internal combustion engine electronic control, in particular to a dew point detection system in an internal combustion engine energy saving and emission reduction control strategy. Background technique [0002] Chinese patent CN 101688496A provides a control strategy for exhaust gas sensor heater. The technical means and the achieved effect of this patent are: when the internal combustion engine starts at low temperature, it does not immediately supply power to the sensor heater, but waits until the internal combustion engine water temperature reaches the set value before starting to energize and heat; the set value of the cooling water temperature is controlled by the air-fuel ratio feedback. It is set according to the water temperature; when the temperature of the sensor element reaches the temperature set in consideration of the dew point, full power supply heating is started. The patent protects the ...

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Problems solved by technology

[0006] 1. Only temperature is used as an indicator of whether the dew point is reached, but when the cooling water temperature of the internal combustion engine or the temperature of the exhaust pipe reaches the set temperature, the internal combustion engine may still produce condensed water due to some reasons and working conditions, or in the exhaust system. Condensed water is generated in complex components, and the dew point cannot be guaranteed, and it has a great influence on the installation position of the temperature sensor, and it takes a long time to check the accuracy

[0007] 2. The equation and algorithm for determining the dew point are complex, involving many parameters and variables, and difficult to obtain. Some performance parameters of the internal combustion engine itself are not well utilized for dew point detection, which increases the difficulty of dew point detection and additional detection equipment

[0008] 3. Does not take into account repeated cold starts, gas pulses, alternative dew point detection methods when some sensors of the internal combustion engine are abnormal, and the judgment of the dew point achieved by the heat transfer of exhaust gas

[0009] 4. Dew point detection takes a long time, which affects the emission control of internal combustion engines

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