Engine cooling system

Patent metadata

Field	Value
Publication number	US-10851701-B2
Application number	US-201815888427-A
Country	US
Kind code	B2
Filing date	Feb 5, 2018
Priority date	Mar 16, 2017
Publication date	Dec 1, 2020
Grant date	Dec 1, 2020

Abstract

An engine cooling system includes a coolant circulation path, which circulates coolant between the water jacket and the radiator of an internal combustion engine, a pump, a control valve, which is provided in the coolant circulation path, and a controller. The controller executes a warming-up promotion control and a pressure relaxation control. In the pressure relaxation control, the controller controls the aperture ratio of the radiator port such that the lower the temperature of the radiator, the lower becomes the engine rotational speed at which the aperture ratio of the radiator port is increased.

First claim

The invention claimed is:

1. An engine cooling system comprising: a coolant circulation path, which circulates coolant between a water jacket and a radiator of an internal combustion engine; a pump, which is provided in the coolant circulation path and operates in conjunction with rotation of an output shaft of the internal combustion engine; a control valve, which is provided in the coolant circulation path and has a housing having a radiator port connected to the radiator and a valve body accommodated in the housing, the control valve being configured such that an aperture ratio of the radiator port changes in a range from 0% to 100% by movement of the valve body inside the housing; and a controller configured to control the control valve, wherein the controller is configured to execute a warming-up promotion control for setting the aperture ratio of the radiator port to 0% when warming-up of the internal combustion engine is not completed, and a pressure relaxation control executed during the warming-up promotion control, the pressure relaxing control reducing pressure in the coolant circulation path by increasing the aperture ratio of the radiator port when the engine rotational speed is equal to or higher than a predetermined engine rotational speed even if warming-up of the internal combustion engine is not completed, as compared with a case where the engine rotational speed is less than the predetermined engine rotational speed, and the controller is configured to control the aperture ratio of the radiator port in the pressure relaxation control such that as the temperature of the radiator decreases, engine rotational speed at which the aperture ratio of the radiator port is increased also decreases.

2. The engine cooling system according to claim 1 , wherein the controller is configured to execute the pressure relaxation control by estimating the temperature of the radiator using an outdoor air temperature.

3. The engine cooling system according to claim 1 , wherein the controller is configured to control the control valve in accordance with the engine rotational speed such that the higher the engine rotational speed, the higher the aperture ratio of the radiator port becomes, when the aperture ratio of the radiator port is increased in the pressure relaxation control.

4. The engine cooling system according to claim 1 , wherein the controller is configured to execute the pressure relaxation control on a condition that the aperture ratio of the radiator port is equal to or less than a reference aperture ratio lower than 100%.

5. The engine cooling system according to claim 1 , wherein the controller is configured to execute the pressure relaxation control on a condition that the engine rotational speed is equal to or higher than a reference rotational speed.

6. The engine cooling system according to claim 1 , wherein the pressure relaxation control is only executed during the warming-up promotion control.

7. An engine cooling system comprising:
a coolant circulation path, which circulates coolant between a water jacket and a radiator of an internal combustion engine;
a pump, which is provided in the coolant circulation path and operates in conjunction with rotation of an output shaft of the internal combustion engine;
a control valve, which is provided in the coolant circulation path and has a housing having a radiator port connected to the radiator and a valve body accommodated in the housing, the control valve being configured such that an aperture ratio of the radiator port changes in a range from 0% to 100% by movement of the valve body inside the housing; and
a controller configured to control the control valve, wherein
the controller is configured to execute
a warming-up promotion control for setting the aperture ratio of the radiator port to 0% when warming-up of the internal combustion engine is not completed, and
a pressure relaxation control executed during the warming-up promotion control, the pressure relaxing control reducing pressure in the coolant circulation path by increasing the aperture ratio of the radiator port when the engine rotational speed is equal to or higher than a predetermined engine rotational speed even if warming-up of the internal combustion engine is not completed, as compared with a case where the engine rotational speed is less than the predetermined engine rotational speed, and

the controller is configured to control the aperture ratio of the radiator port in the pressure relaxation control such that when the temperature of the radiator is lower than a threshold value as compared with a case in which the temperature of the radiator is equal to or higher than the threshold value, the engine rotational speed at which the aperture ratio of the radiator port is increased becomes lower.

8. The engine cooling system according to claim 7 , wherein the pressure relaxation control is only executed during the warming-up promotion control.

Assignees

• Toyota Motor Co Ltd

Inventors

• Kawamoto Naoya
• Kaneko Rihito
• Ando Hirokazu
• Niwa Yusuke

Classifications

• F01P7/167 Primary

  by adjusting the pre-set temperature according to engine parameters, e.g. engine load, engine speed · CPC title

• F01P7/16 Primary

  by thermostatic control · CPC title

• F01P2007/146

  using valves · CPC title

• F01P3/20

  Cooling circuits not specific to a single part of engine or machine (F01P3/22 takes precedence) · CPC title

• F01P2025/64

  Number of revolutions · CPC title