US 9,038,445 B2Granted

Method and apparatus for diagnosing engine fault

AssigneeHonda Motor Co., Ltd.

InventorsHiroshi Ito, Takayuki Abe, Tetsuya Ohno, Mahito Shikama

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Abstract

According to a method and an apparatus of the present invention for diagnosing a fault of an engine, a cranking rotation state is created by rotating a crank shaft while explosions in each cylinder are stopped; a variation of angular velocity of the crank shaft is detected for each cylinder in the cranking rotation state; a cylinder the compression pressure of which is insufficient is detected based on the variation; and if a cylinder indicated as a misfiring cylinder by a fault code is the same as the cylinder detected as being insufficient in compression pressure in the cranking rotation state, the cylinder is specified.

Claims20

Dependent claims

A method of diagnosing an engine for a fault, which is monitored by a misfire monitor for judging a misfiring cylinder that suffers from a misfire while an engine having a plurality of cylinders is in operation, and storing a diagnostic trouble code representative of the misfiring cylinder, comprising:

detecting variations in angular velocity of a crankshaft in a power stroke of the engine for each of the cylinders while the engine is in normal operation, and determining one of the cylinders, which exhibits small variations in angular velocity, as the misfiring cylinder;
detecting variations in angular velocity of the crankshaft in a power stroke of the engine for each of the cylinders while the engine is being cranked to rotate the crankshaft while canceling fuel explosion in all of the cylinders simultaneously, and determining one of the cylinders, which exhibits small variations in angular velocity, as the compression pressure shortage cylinder;
and
identifying one of the cylinders, as a cylinder to be repaired, which coincides with the misfiring cylinder represented by the diagnostic trouble code and the compression pressure shortage cylinder that is determined while the engine is being cranked.

1 more element

An apparatus for diagnosing an engine for a fault, which is monitored by a misfire monitor for judging a misfiring cylinder that suffers from a misfire while an engine having a plurality of cylinders is in operation, and storing a diagnostic trouble code representative of the misfiring cylinder, wherein:

the apparatus detects variations in angular velocity of the crankshaft in a power stroke of the engine for each of the cylinders while the engine is in normal operation, and determines one of the cylinders, which exhibits small variations in angular velocity, as the misfiring cylinder;
the apparatus detects variations in angular velocity of the crankshaft for each of the cylinders while the engine is being cranked to rotate a crankshaft while canceling fuel explosion in all of the cylinders simultaneously, and determines one of the cylinders, which exhibits small variations in angular velocity, as the compression pressure shortage cylinder;
and
the apparatus identifies one of the cylinders as a cylinder to be repaired, which coincides with the misfiring cylinder represented by the diagnostic trouble code and the compression pressure shortage cylinder that is determined while the engine is being cranked.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 14/006,446Filed 24 Feb 2012
Priority: JP 2011-06510424 Mar 2011
Published: US 2014/0007664 A19 Jan 2014
Granted: 26 May 2015
Term ends: Not estimatedThe source records don’t support an estimate.

Classification11 codes

G01M 15/11
Testing internal-combustion engines: by detecting misfire
F02D 41/123
For deceleration: the fuel injection being cut-off
F02D 41/1498
With detection of the mechanical response of the engine: measuring engine roughness
F02D 41/22
Electrical control of supply of combustible mixture or its constituents: safety or indicating devices for abnormal conditions

Family

US 2014/0007664 A1Pre-grant publication · published 9 Jan 2014
US 9,038,445 B2This patent

From the US filing history. Foreign family members aren’t listed.

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