In-cylinder pressure detecting apparatus for internal combustion engine

Patent metadata

Field	Value
Publication number	US-9702787-B2
Application number	US-201514672627-A
Country	US
Kind code	B2
Filing date	Mar 30, 2015
Priority date	Apr 2, 2014
Publication date	Jul 11, 2017
Grant date	Jul 11, 2017

Abstract

An in-cylinder pressure detecting apparatus for an internal combustion engine, for detecting an in-cylinder pressure which is a pressure in a combustion chamber of the engine. The in-cylinder pressure is detected by an in-cylinder pressure detecting block, and a motoring pressure corresponding to an in-cylinder pressure when no combustion is performed in the combustion chamber, is estimated. A peak value of the detected in-cylinder pressure is obtained as a detected pressure peak value in a predetermined operating condition of the engine. An estimated motoring pressure peak value which is a peak value of the estimated motoring pressure and corresponds to the detected pressure peak value, is calculated. The detected pressure peak value is compared with the estimated motoring pressure peak value, and sensitivity correction of the in-cylinder pressure detecting block is performed based on a result of the comparison. The predetermined operating condition is an operating condition in which an exhaust gas temperature raising control is performed for raising a temperature of exhaust gases from the engine by increasing an intake air amount of the engine and retarding an ignition timing of the engine.

First claim

What is claimed is:

1. An in-cylinder pressure detecting apparatus for an internal combustion engine, for detecting an in-cylinder pressure which is a pressure in a combustion chamber of said engine, said in-cylinder pressure detecting apparatus comprising:
in-cylinder pressure detecting means for detecting the in-cylinder pressure and output the detected in-cylinder pressure;
motoring pressure estimating means for estimating a motoring pressure corresponding to an in-cylinder pressure when no combustion is performed in said combustion chamber;
detected pressure peak value obtaining means for obtaining a peak value of the detected in-cylinder pressure as a detected pressure peak value in a predetermined operating condition of said engine;
estimated motoring pressure peak value calculating means for calculating an estimated motoring pressure peak value which is a peak value of the motoring pressure estimated by said motoring pressure estimating means, the estimated motoring pressure peak value corresponding to the detected pressure peak value; and
sensitivity correcting means for comparing the detected pressure peak value with the estimated motoring pressure peak value, and performing sensitivity correction of said in-cylinder pressure detecting means based on a result of the comparison,
wherein the predetermined operating condition is an operating condition in which an exhaust gas temperature raising control is performed for raising a temperature of exhaust gases from said engine by increasing an intake air amount of said engine and retarding an ignition timing of said engine.

2. The in-cylinder pressure detecting apparatus according to claim 1 , further comprising:
intake pressure obtaining means for detecting or estimating an intake pressure of said engine;
first modifying means for modifying the detected in-cylinder pressure according to the intake pressure obtained during the intake stroke of an object cylinder of which the in-cylinder pressure is detected; and
second modifying means for modifying the estimated motoring pressure used in the sensitivity correction, according to the intake pressure obtained in the vicinity of a start timing of the compression stroke of said object cylinder,
wherein said detected pressure peak value obtaining means obtains a peak value of the modified detected in-cylinder pressure as the detected pressure peak value, and
said estimated motoring pressure peak value calculating means calculates a peak value of the modified estimated motoring pressure as the estimated motoring pressure peak value.

3. The in-cylinder pressure detecting apparatus according to claim 2 , wherein said motoring pressure estimating means calculates the estimated motoring pressure using a model equation obtained by modeling a relationship between a rotational phase of said engine and the motoring pressure, and
said second modifying means modifies the model equation according to the intake pressure obtained in the vicinity of the start timing of the compression stroke, and calculates the modified estimated motoring pressure using the modified model equation.

4. The in-cylinder pressure detecting apparatus according to claim 3 , wherein said engine has at least one fuel injection valve and at least one ignition plug, and said first modifying means performs the modification using the intake pressure obtained at a timing when there is no influence from noises due to fuel injection by said at least one fuel injection valve or noises due to ignition by said at least one ignition plug.

5. The in-cylinder pressure detecting apparatus according to claim 1 , wherein said in-cylinder pressure detecting means comprises a pressure detecting element, a charge amplifier for integrating and amplifying an output signal of said pressure detecting element, and a conversion block for converting an output voltage of said charge amplifier to a pressure value,
wherein said conversion block has a plurality of conversion tables for converting the output voltage of said charge amplifier to the detected in-cylinder pressure, and said sensitivity correcting means selects one of the plurality of conversion tables according to the result of comparing the detected pressure peak value with the estimated motoring pressure peak value.

6. The in-cylinder pressure detecting apparatus according to claim 5 , further comprising abnormality processing means for determining that the sensitivity of said in-cylinder pressure detecting means is abnormal if the result of comparing the detected pressure peak value with the estimated motoring pressure peak value indicates that the correction using the plurality of conversion tables is impossible, and selecting a conversion table having an average conversion characteristic of the plurality of conversion tables.

7. An in-cylinder pressure detecting apparatus for an internal combustion engine, for detecting an in-cylinder pressure which is a pressure in a combustion chamber of said engine, said in-cylinder pressure detecting apparatus comprising:
in-cylinder pressure detecting means for detecting the in-cylinder pressure and output the detected in-cylinder pressure;
motoring pressure estimating means for estimating a motoring pressure corresponding to an in-cylinder pressure when no combustion is performed in said combustion chamber;
detected pressure peak value obtaining means for obtaining a peak value of the detected in-cylinder pressure as a detected pressure peak value in a predetermined operating condition of said engine;
estimated motoring pressure peak value calculating means for calculating an estimated motoring pressure peak value which is a peak value of the motoring pressure estimated by said motoring pressure estimating means, the estimated motoring pressure peak value corresponding to the detected pressure peak value; and
sensitivity correcting means for comparing the detected pressure peak value with the estimated motoring pressure peak value, and performing sensitivity correction of said in-cylinder pressure detecting means based on a result of the comparison,
wherein the predetermined operating condition is an operating condition in which said engine is rotated at a predetermined high rotational speed without supplying fuel to said engine, and an intake air flow rate of said engine is made maximum upon inspection performed when a vehicle provided with said engine is shipped out from a manufacturing plant of said vehicle.

8. The in-cylinder pressure detecting apparatus according to claim 7 , further comprising:
intake pressure obtaining means for detecting or estimating an intake pressure of said engine;
first modifying means for modifying the detected in-cylinder pressure according to the intake pressure obtained during the intake stroke of an object cylinder of which the in-cylinder pressure is detected; and
second modifying means for modifying the estimated motoring pressure used in the sensitivity correction, according to the intake pressure obtained in the vicinity of a start timing of the compression stroke of said object cylinder,
wherein said detected pressure peak value obtaining means obtains a peak value of the modified detected in-cylinder pressure as the detected pressure peak value, and
said estimated motoring pressure peak value calculating means calculates a peak value of the modified estimated motoring pressure as the estimated motoring pressure peak value.

9. The in-cylinder pressure detecting apparatus according to claim 8 , wherein said motoring pressure estimating means calculates the estimated motoring pressure using a model equation obtained by modeling a relationship between a rotational phase of said engine and the motoring pressure, and
said second modifying means mod

Assignees

• Honda Motor Co Ltd
• Keihin Corp

Inventors

• Akazaki Shusuke
• Saito Shunichi

Classifications

• F02D37/02

  one of the functions being ignition · CPC title

• F02D41/2474

  Characteristics of sensors · CPC title

• F02D35/024

  using an estimation · CPC title

• G01L27/005

  Apparatus for calibrating pressure sensors · CPC title

• F02D41/0245

  by increasing temperature of the exhaust gas leaving the engine · CPC title