Failure diagnosis system for automobile engine

• US 5,932,801 A
• Filed: 05/19/1998
• Issued: 08/03/1999
• Est. Priority Date: 05/23/1997
• Status: Expired due to Term

• Current Assignee: Daifuku Company Limited
• Original Assignee: Daifuku Company Limited
• Inventors: Kato, Toshihiko, Li, Ziye, Akishita, Sadao
• Primary Examiner(s): DOMBROSKE, GEORGE M
• Application Number:
  US09/081,247
• Time in Patent Office: 441 Days
• Field of Search: 73/660, 73/116, 73/117.2, 73/117.3, 73/118.1, 701/111, 701/35
• US Class Current: 73/114.02
• CPC Class Codes: G01M 15/12 by monitoring vibrations

Abstract

A failure diagnosis system for automobile engines comprises an inverter motor (6) connected to a rotary shaft of an engine to be measured (2) and intended to rotate the engine (2), a microphone (8) for detecting an engine sound of the engine to be measured (2), a digital tape recorder for recording therein the engine sound detected by the microphone and an engine failure detector for extracting characteristics of the engine sound from the engine sound recorded in the recorder by a wavelet transform so as to detect a failure of the engine by the characteristics of the engine sound.

Claims

1. A failure diagnosis system for automobile engines comprising:

a drive unit connected to a rotary shaft of an engine to be measured and rotating the engine;

sound detecting means for detecting the sound of the engine to be measured;

first rotation angle detecting means for detecting the rotation angle of a crank shaft of the engine to be measured;

second rotation angle detecting means for detecting the rotation angle of a cam shaft of the engine to be measured;

recording means for recording an engine sound detection signal of the sound detecting means and the rotation angles of the crank shaft detected by the first rotation angle detecting means and the cam shaft detected by the second rotation angle detecting means; and

an engine failure detector for extracting a tappet sound of the engine from the engine sound detection signal recorded in the recording means by a wavelet transform such that any plural number of samples of the expansion factors of the wavelet transform are averaged, thereby detecting a cylinder valve at which an abnormality has occurred by the rotation angles of the crank shaft and the cam shaft obtained when the tappet sound of the engine has been extracted.

3. A failure diagnosis system for automobile engines as set forth in claim 1 or 2, wherein the system is installed during the fabrication process of the engine.

2. A failure diagnosis system for automobile engines comprising:

a drive unit connected to a rotary shaft of an engine to be measured and rotating the engine;

vibration detecting means for detecting the vibration of the engine to be measured;

first rotation angle detecting means for detecting the rotation angle of a crank shaft of the engine to be measured;

second rotation angle detecting means for detecting the rotation angle of a cam shaft of the engine to be measured;

recording means for recording an engine vibration detection signal of the vibration detecting means and the rotation angles of the crank shaft detected by the first rotation angle detecting means and the cam shaft detected by the second rotation angle detecting means; and

an engine failure detector for extracting a tappet sound of the engine from the vibration detection signal recorded in the recording means by a wavelet transform such that any plural number of samples of the expansion factors of the wavelet transform are averaged, thereby detecting a cylinder valve at which an abnormality has occurred by the rotation angles of the crank shaft and the cam shaft obtained when the tappet sound of the engine has been extracted.