Sensor output value estimation device

Patent metadata

Field	Value
Publication number	US-2016160777-A1
Application number	US-201414908297-A
Country	US
Kind code	A1
Filing date	Jul 31, 2014
Priority date	Jul 31, 2013
Publication date	Jun 9, 2016
Grant date	—

Abstract

A sensor output value estimation device that effectively estimates sensor output values reflecting a response delay of a temperature sensor. The device includes an estimated gas temperature calculation unit for calculating an estimated gas temperature of an engine on a basis of at least a running condition of the engine and a state quantity of the gas in the engine. The device also includes an estimated sensor output value calculation unit for calculating an estimated sensor output value reflecting the response delay of the temperature sensor on a basis of the calculated estimated gas temperature and a pre-stored first model formula specifying a relation among the temperature change time constant of the temperature sensor, the gas flow rate, and the gas temperature.

First claim

What is claimed is:

1 . A sensor output value estimation device comprising: an estimated gas temperature calculating unit that calculates an estimated gas temperature of an engine based on at least a running condition of the engine and a quantity of state of a gas in the engine; and an estimated sensor output value calculating unit that calculates an estimated sensor output value, which reflects a response delay of a temperature sensor, based on the calculated estimated gas temperature and a pre-stored first model formula that defines a relation among a time constant of a temperature change of the temperature sensor, a gas flow rate, and a gas temperature.

2 . The sensor output value estimation device according to claim 1 , wherein the first model formula further includes a relation among a time constant of a temperature change of a pipe in which the temperature sensor is disposed, the gas flow rate, and the gas temperature.

3 . The sensor output value estimation device according to claim 1 , further comprising a diagnosis unit that makes a diagnosis on the temperature sensor based on the estimated sensor output value calculated by the estimated sensor output value calculating unit and an actual sensor output value detected by the temperature sensor.

4 . The sensor output value estimation device according to claim 1 , wherein the estimated gas temperature calculating unit calculates an amount of change in an indicated thermal efficiency of the engine based on a second model formula that defines a relation among an intake air oxygen concentration of the engine, a fuel injection timing set in accordance with the running condition, and the amount of change in the indicated thermal efficiency, and calculates an estimated exhaust gas temperature of the engine based on a third model formula that defines a relation between the calculated amount of change in the indicated thermal efficiency and an exhaust gas temperature.

5 . The sensor output value estimation device according to claim 2 , further comprising a diagnosis unit that makes a diagnosis on the temperature sensor based on the estimated sensor output value calculated by the estimated sensor output value calculating unit and an actual sensor output value detected by the temperature sensor.

6 . The sensor output value estimation device according to claim 2 , wherein the estimated gas temperature calculating unit calculates an amount of change in an indicated thermal efficiency of the engine based on a second model formula that defines a relation among an intake air oxygen concentration of the engine, a fuel injection timing set in accordance with the running condition, and the amount of change in the indicated thermal efficiency, and calculates an estimated exhaust gas temperature of the engine based on a third model formula that defines a relation between the calculated amount of change in the indicated thermal efficiency and an exhaust gas temperature.

7 . The sensor output value estimation device according to claim 3 , wherein the estimated gas temperature calculating unit calculates an amount of change in an indicated thermal efficiency of the engine based on a second model formula that defines a relation among an intake air oxygen concentration of the engine, a fuel injection timing set in accordance with the running condition, and the amount of change in the indicated thermal efficiency, and calculates an estimated exhaust gas temperature of the engine based on a third model formula that defines a relation between the calculated amount of change in the indicated thermal efficiency and an exhaust gas temperature.

8 . The sensor output value estimation device according to claim 1 , wherein the temperature sensor is a sensor for detecting a temperature of the exhaust gas from the engine.

9 . The sensor output value estimation device according to claim 1 , wherein the temperature sensor is a sensor for detecting an outlet temperature of an exhaust gas recirculation cooler.

10 . The sensor output value estimation device according to claim 1 , wherein the running condition of the engine includes an engine revolution speed and an accelerator position.

11 . The sensor output value estimation device according to claim 1 , wherein the engine is a diesel engine.

Assignees

• Isuzu Motors Ltd
• Transtron Inc

Inventors

• Hanawa Satoshi
• Ikai Yoshiaki

Classifications

• F02D2041/1431

  the system including an input-output delay · CPC title

• F02D41/222

  relating to the failure of sensors or parameter detection devices · CPC title

• G01K2205/04

  for measuring exhaust gas temperature · CPC title

• G01K7/42

  Circuits effecting compensation of thermal inertia; Circuits for predicting the stationary value of a temperature · CPC title

• F02M26/23

  Layout, e.g. schematics · CPC title