Patent ID: 7168399
Filing Date: 2007-01-30
Classification: F01P

Abstract:
1. An abnormality diagnosis apparatus for diagnosing abnormality of a recirculating liquid cooling system for an internal combustion engine, wherein the cooling system includes a radiator, a circulation line system, which circulates liquid coolant through the internal combustion engine and the radiator and includes a bypass fluid line that bypasses the radiator, a flow rate control means for controlling a bypass flow rate of liquid coolant flowing through the bypass fluid line, and a coolant temperature sensor, which measures coolant temperature in the circulation line system, the abnormality diagnosis apparatus comprising: a coolant temperature control means for controlling the coolant temperature in the circulation line system by controlling the flow rate control means; and an abnormality diagnosis means for diagnosing the flow rate control means to determine whether an abnormality exists based on behavior of the measured coolant temperature, which is measured through the coolant temperature sensor during a warm-up period of the internal combustion engine.