Misfire detecting device of an internal combustion engine

• US 5,127,262 A
• Filed: 05/07/1991
• Issued: 07/07/1992
• Est. Priority Date: 06/13/1990
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Nakagawa, Akihiro, Demizu, Akira, Kuroda, Toshiki
• Primary Examiner(s): MYRACLE, JERRY
• Application Number:
  US07/696,799
• Time in Patent Office: 427 Days
• Field of Search: 73/117.3, 73/115, 123/425, 123/435
• US Class Current: 73/114.06
• CPC Class Codes: G01M 15/08 by monitoring pressure in cylinders

Abstract

A misfire detecting device of an internal combustion engine comprises a pressure detector(s) for detecting an inner cylinder pressure of the engine, a crank angle detector for detecting a crank angle, and a misfire detector for detecting a misfire based on signals from the pressure detector and the crank angle detector. The misfire detector judges that the engine is under a misfire, when a comparison is made between a first integrated value of an indicated inner cylinder pressure before a predetermined crank angle of a combustion cycle of the engine and a second integrated value of the indicated inner cylinder pressure after the predetermined crank angle, and when there is a difference between the first value and the second value by less than a predetermined value.

Claims

1. A misfire detecting device for an internal combustion engine, comprising:

a) pressure detecting means for detecting an inner cylinder pressure of the engine;

b) crank angle detecting means for detecting a crank angle; and

c) misfire detecting means for detecting a misfire based on signals from the pressure detecting means and the crank angle detecting means;

d) said misfire detecting means comprising;

1) means for generating a first integrated value of the detected inner cylinder pressure extending over a predetermined angular range before a predetermined crank angle during a compression cycle of the engine,

2) means for generating a second integrated value of the detected inner cylinder pressure extending over said predetermined angular range after said predetermined crank angle during a combustion cycle of the engine, and

3) means for comparing the first and the second integrated values and for judging that the engine is misfiring when there is a difference between the first and the second integrated values of less than a predetermined amount.

2. The misfire detecting device for an internal combustion engine according to claim 1,

wherein the predetermined crank angle is a top dead center between compression and combustion cycles.