Diagnosis device

Patent metadata

Field	Value
Publication number	US-2016169100-A1
Application number	US-201414908294-A
Country	US
Kind code	A1
Filing date	Jul 31, 2014
Priority date	Jul 31, 2013
Publication date	Jun 16, 2016
Grant date	—

Abstract

A diagnosis device diagnoses a cooler adapted to cool a fluid flowing through intake and exhaust systems of an engine, and includes: a downstream temperature sensor for detecting a fluid temperature downstream of the cooler; a fluid temperature calculation unit for calculating a fluid temperature upstream of the cooler based on a fluid state quantity; a sensor output value calculation unit for assuming an upstream temperature sensor configured to detect a fluid temperature upstream of the cooler, reflecting a sensor response delay in the calculated fluid temperature, and calculating an estimated sensor output value of the upstream temperature sensor; and a cooler diagnosis unit for diagnosing the cooling efficiency of the cooler based on an actual sensor input value entered from the downstream temperature sensor and the calculated estimated sensor output value.

First claim

What is claimed is:

1 . A diagnosis device for a cooler, the cooler being configured to cool a fluid flowing in an intake and exhaust system of an engine, the diagnosis device comprising:
a downstream temperature sensor that detects a temperature of the fluid on a downstream side of the cooler; a fluid temperature calculation unit that calculates a temperature of the fluid on an upstream side of the cooler based on at least a state quantity of the fluid; a sensor output value calculation unit that assumes an upstream temperature sensor configured to detect the temperature of the fluid on the upstream side of the cooler, and reflects a sensor response delay into the temperature of the fluid calculated by the fluid temperature calculation unit to calculate an estimated sensor output value of the upstream temperature sensor; and a cooler diagnosis unit that diagnoses a cooling efficiency of the cooler based on an actual sensor input value entered from the downstream temperature sensor and the estimated sensor output value calculated by the sensor output value calculation unit.

2 . The diagnosis device according to claim 1 , wherein the sensor output value calculation unit calculates the estimated sensor output value based on the temperature of the fluid calculated by the fluid temperature calculation meansunit, and a pre-stored model formula describing a relation among a temperature change time constant of a temperature sensor, a fluid flow rate, and a fluid temperature.

3 . The diagnosis device according to claim 2 , wherein the model formula further includes a relation among a temperature change time constant of a flow pipe in which the fluid flows, the fluid flow rate, and the fluid temperature.

4 . The diagnosis device according to claim 1 , wherein the fluid is an intake air flowing in an intake pipe connected to the engine; and
the cooler is an intercooler arranged on the intake pipe.

5 . The diagnosis device according to claim 1 , wherein the fluid is a recirculated exhaust gas which is discharged from the engine and recirculated into the intake system; and
the cooler is a recirculated exhaust gas cooler configured to cool the recirculated exhaust gas.

6 . The diagnosis device according to claim 2 , wherein the fluid is an intake air flowing in an intake pipe connected to the engine, and the cooler is an intercooler arranged on the intake pipe.

7 . The diagnosis device according to claim 3 , wherein the fluid is an intake air flowing in an intake pipe connected to the engine, and the cooler is an intercooler arranged on the intake pipe.

8 . The diagnosis device according to claim 2 , wherein the fluid is a recirculated exhaust gas which is discharged from the engine and recirculated into the intake system, and the cooler is a recirculated exhaust gas cooler configured to cool the recirculated exhaust gas.

9 . The diagnosis device according to claim 3 , wherein the fluid is a recirculated exhaust gas which is discharged from the engine and recirculated into the intake system, and the cooler is a recirculated exhaust gas cooler configured to cool the recirculated exhaust gas.

10 . The diagnosis device according to claim 1 , wherein the sensor output value calculation unit calculates the estimated sensor output value in real time.

11 . The diagnosis device according to claim 1 , wherein the engine is a diesel engine.

Assignees

• Isuzu Motors Ltd

Inventors

• Hanawa Satoshi
• Uchiyama Tadashi
• Fujie Hidekazu
• Murasawa Naoto

Classifications

• F02B77/083 Primary

  relating to maintenance, e.g. diagnostic device (relating to lubrication F01M11/10) · CPC title

• F02B29/04

  Cooling of air intake supply · CPC title

• F02D2041/0067

  Determining the EGR temperature · CPC title

• F02M26/47

  the characteristics being temperatures, pressures or flow rates · CPC title

• F02M26/22

  with coolers in the recirculation passage · CPC title