Exhaust gas recirculation (EGR) ratio measuring device

Abstract

In order to improve a measurement accuracy of an EGR ratio and to downsize the device and to save labor, the EGR ratio measuring device comprises a pair of nondispersive infrared gas analyzers, that have a function of correcting a water influence and that can measure a concentration of CO2 in a gas containing water, an intake air introduction line that is connected to an intake air pipe of an internal combustion engine and that introduces a part of the intake air into one nondispersive infrared gas analyzer without removing the water, an exhaust gas introduction line that is connected to an exhaust gas pipe of the internal combustion engine and that introduces a part of the exhaust gas into the other nondispersive infrared gas analyzer without removing the water, and a temperature adjusting mechanism; that keeps a temperature of whole of the introduction lines, and a temperature of the nondispersive infrared gas analyzers, so as not to condense dew, and a configuration of the intake air introduction line including a flow channel length is set to be substantially the same as a configuration of the exhaust introduction line including a flow channel length.

Description

technical field [0001] The invention relates to an EGR rate measuring device for measuring the EGR rate of an internal combustion engine with an exhaust gas recirculation system (EGR system), i.e. measuring the amount of gas recirculated from the exhaust pipe and also the amount of recirculation The ratio of intake air volume. Background technique [0002] Such as Figure 4 As shown, the EGR device is provided with a circulation path R connecting the exhaust pipe EXT of the internal combustion engine EG and the intake pipe INT, and the combustion temperature is reduced by recirculating the exhaust gas into intake air, thereby reducing NO x . In addition, as described in Patent Document 1, there is known a parameter called an EGR rate for controlling the return amount through the EGR valve V to optimize the combustion of the internal combustion engine EG. [0003] The EGR rate is the ratio of the gas recirculation amount from the exhaust pipe EXT to the intake air amount al...

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Problems solved by technology

[0014] However, in the above configuration, a cooler for dehumidification and piping for the cooler must be installed, so not only the size of the device will be increased, but also the length of the piping from the sampling point to the analyzer will be increased. lead to deterioration of the responsiveness of the measurement

Therefore, the CO on the intake side 2 Measured value vs. CO on the exhaust side 2 Transient errors are prone to occur between measured values, which will have a negative impact on measurement accuracy

In addition, due to the CO in the gas 2 It will dissolve into the water discharged during dehumidification, so it will cause measurement errors

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