Method for detecting malfunction of a cooling system based on detected coolant temperature

• US 7,743,651 B2
• Filed: 04/15/2008
• Issued: 06/29/2010
• Est. Priority Date: 12/17/1996
• Status: Expired due to Fees

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Wakahara, Keiji, Ichikawa, Akira
• Primary Examiner(s): MCCALL, ERIC SCOTT
• Application Number:
  US12/081,364
• Publication Number:
  US 20080202452A1
• Time in Patent Office: 805 Days
• Field of Search: 731/146.8, 731/147.7
• US Class Current: 73/114.68
• CPC Class Codes: F01P 11/14 Indicating devices; Other safety devices
• CPC Class Codes: F01P 11/16 concerning coolant temperature F01P11/20 takes precedence
• CPC Class Codes: F01P 2023/00 Signal processing; Details thereof
• CPC Class Codes: F01P 2023/08 Microprocessor; Microcomputer
• CPC Class Codes: F01P 2025/08 Temperature
• CPC Class Codes: F01P 2025/13 Ambient temperature
• CPC Class Codes: F01P 2025/62 Load
• CPC Class Codes: F01P 2025/64 Number of revolutions
• CPC Class Codes: F01P 2025/66 Vehicle speed
• CPC Class Codes: F01P 2031/00 Fail safe
• CPC Class Codes: F01P 2031/20 Warning devices
• CPC Class Codes: F01P 2060/14 Condenser
• CPC Class Codes: F01P 5/02 Pumping cooling-air; Arrangements of cooling-air pumps, e.g. fans or blowers
• CPC Class Codes: F02D 2200/0406 Intake manifold pressure
• CPC Class Codes: F02D 2200/0414 Air temperature
• CPC Class Codes: F02D 41/18 by measuring intake air flow
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: G01K 15/00 Testing or calibrating of thermometers
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A method for detecting a malfunction of a cooling system of an internal combustion engine, comprising: detecting a coolant temperature on a side of the engine; determining a malfunction of the cooling system with the coolant temperature and the value only after a cold start of the engine.

Claims

1. A method for detecting a malfunction of a cooling system of an internal combustion engine, comprising:

detecting a coolant temperature on the engine side of the thermostat;

detecting an engine operation condition;

detecting an ambient temperature outside a vehicle; and

detecting a malfunction of the thermostat after a cold start of the engine based on the coolant temperature, the engine operation condition, and the ambient temperature.

2. The method as in claim 1, wherein the malfunction of the cooling system includes an open-malfunction of the thermostat.