COOLING APPARATUS FOR INTERNAL COMBUSTION ENGINE

摘要

A change in a valve opening degree from an opening degree (a) to an opening degree (d) is caused by a decrease in a radiator outlet water temperature, and at such time a flow rate through a radiator enters a boiling region. Therefore, when such entry is predicted, a target engine outlet water temperature is forcedly changed from 105° C. to 100° C. Thereupon, the valve opening degree is changed from the opening degree (a) to an opening degree (f). The flow rate through the radiator when the valve opening degree is the opening degree (f) is greater than the flow rate through the radiator when the valve opening degree is the opening degree (d), and furthermore, the flow rate through the radiator does not enter the boiling region while the valve opening degree is changing from the opening degree (a) to the opening degree (f).

主权项

1. A cooling apparatus for an internal combustion engine that circulates cooling water between the internal combustion engine and a radiator, comprising a control unit that is configured to control a circulation flow rate that is a flow rate of circulating cooling water that circulates between the internal combustion engine and the radiator so that an engine outlet water temperature that is a temperature of cooling water that flows from an outlet of a cooling water channel of the internal combustion engine is brought close to a target temperature, by using a feedforward model that is constructed so as to reduce the circulation flow rate with increasing the target temperature of the engine outlet water temperature and with decreasing a radiator outlet water temperature that is a temperature of cooling water that flows from an outlet of a cooling water channel of the radiator;
wherein the control unit is further configured to: set the target temperature to a first temperature that is higher than a temperature at which it is determined that warming up of the internal combustion engine is completed and is a lower temperature than a boiling point of cooling water that is circulated between the internal combustion engine and the radiator; calculate as a determination temperature the radiator outlet water temperature at the circulating cooling water starts boiling and also in a case where'the target temperature is at the first temperature, in accordance with a relationship between the circulation flow rate and the engine outlet water temperature that is established in a case where the circulating cooling water starts boiling; and change the he target temperature from the first temperature to a second temperature that is lower than the first temperature, in a case where the radiator outlet water temperature is less than the determination temperature.