Engine cooling system and operation method of the engine cooling system

Patent metadata

Field	Value
Publication number	US-10082069-B2
Application number	US-201514875848-A
Country	US
Kind code	B2
Filing date	Oct 6, 2015
Priority date	Dec 12, 2014
Publication date	Sep 25, 2018
Grant date	Sep 25, 2018

Abstract

Provided is an engine cooling system including: a first coolant circulation channel passing through an engine; a second coolant circulation channel bypassing the engine; an electric water pump (EWP); a connection channel connecting the first coolant circulation channel and the second coolant circulation channel; an electromagnetic valve arranged in the connection channel to change a flow rate of a coolant passing through the engine and flowing from the first coolant circulation channel to the second coolant circulation channel; an EGR cooler, a heater core, and an exhaust heat collection device arranged in the second coolant circulation channel; and a control unit, wherein closing of the electromagnetic valve is prohibited if there is an actuation request of the EGR cooler, the heater core, and the exhaust heat collection device when there is a valve closing request of the electromagnetic valve.

First claim

The invention claimed is:

1. An engine cooling system comprising:
a first coolant circulation channel passing through an engine;
a second coolant circulation channel bypassing the engine;
a coolant pump that circulates a coolant in the first and second coolant circulation channels;
a connection channel connecting an engine outlet pipe of the first coolant circulation channel and the second coolant circulation channel;
an electromagnetic valve arranged in the connection channel to change a flow rate of the coolant passing through the engine and flowing from the first coolant circulation channel to the second coolant circulation channel;
a heat exchanger arranged in the second coolant circulation channel; and
a control unit that starts and stops the coolant pump and that opens and closes the electromagnetic valve, wherein the control unit prohibits closing of the electromagnetic valve if there is an actuation request of the heat exchanger when there is a valve closing request of the electromagnetic valve after the electromagnetic valve is opened.

2. The engine cooling system according to claim 1 , wherein the control unit prohibits closing of the electromagnetic valve if a temperature or a temperature change of a fluid for heat exchange with the coolant by the heat exchanger when the coolant pump is stopped is expected to be equal to or greater than a predetermined first threshold, or if a coolant temperature in the heat exchanger is expected to be equal to or higher than a predetermined second threshold, when there is a valve closing request of the electromagnetic valve.

3. The engine cooling system according to claim 2 , wherein the control unit closes the electromagnetic valve after stopping the coolant pump if the temperature or the temperature change of the fluid for heat exchange with the coolant by the heat exchanger when the coolant pump is stopped is expected to be smaller than the predetermined first threshold or if the coolant temperature in the heat exchanger is expected to be lower than the predetermined second threshold, when there is a valve closing request of the electromagnetic valve.

4. The engine cooling system according to claim 1 , wherein the control unit closes the electromagnetic valve after stopping the coolant pump if there is no actuation request of the heat exchanger when there is a valve closing request of the electromagnetic valve.

5. The engine cooling system according to claim 1 , wherein the electromagnetic valve is a valve that holds a valve closed state when a voltage is applied while the coolant pump is stopped and that opens when the voltage is cut off during drive of the coolant pump.

6. The engine cooling system according to claim 5 , wherein the electromagnetic valve comprises:
a casing provided with a valve seat on which a valve body is seated;
an electromagnetic coil attached in the casing closer to a coolant inlet of the valve seat; and
a spring for pressing the valve body toward the valve seat, wherein
pressing force of the spring is smaller than force that is generated by the drive of the coolant pump and that is applied to the valve body in a direction from the coolant inlet to a coolant outlet,
the valve body is sucked toward the coolant inlet and seated on the valve seat to maintain the valve closed state if a voltage is applied to the electromagnetic coil when the coolant pump is stopped, and
the valve body is separated from the valve seat to open the valve due to coolant pressure from the coolant inlet if the voltage of the electromagnetic coil is cut off during the drive of the coolant pump.

7. The engine cooling system according to claim 1 , wherein the heat exchanger is arranged in the second coolant circulation channel, downstream of a connection point of the second coolant circulation channel and the connection channel.

8. An operation method of an engine cooling system, the engine cooling system comprising:
a first coolant circulation channel passing through an engine;
a second coolant circulation channel bypassing the engine;
a coolant pump that circulates a coolant in the first and second coolant circulation channels;
a connection channel connecting an engine outlet of the first coolant circulation channel and the second coolant circulation channel;
an electromagnetic valve arranged in the connection channel to change a flow rate of the coolant passing through the engine and flowing from the first coolant circulation channel to the second coolant circulation channel; and
a heat exchanger arranged in the second coolant circulation channel, wherein
closing of the electromagnetic valve is prohibited if there is an actuation request of the heat exchanger when there is a valve closing request of the electromagnetic valve after the electromagnetic valve is opened.

9. The operation method according to claim 8 , wherein closing of the electromagnetic valve is prohibited if a temperature or a temperature change of a fluid for heat exchange with the coolant by the heat exchanger when the coolant pump is stopped is expected to be equal to or greater than a predetermined first threshold, or if a coolant temperature in the heat exchanger is expected to be equal to or higher than a predetermined second threshold, when there is a valve closing request of the electromagnetic valve.

10. The operation method according to claim 9 , wherein the electromagnetic valve is closed after stopping the coolant pump if the temperature or the temperature change of the fluid for heat exchange with the coolant by the heat exchanger when the coolant pump is stopped is expected to be smaller than the predetermined first threshold, or if the coolant temperature in the heat exchanger is expected to be lower than the predetermined second threshold, when there is a valve closing request of the electromagnetic valve.

11. The operation method according to claim 8 , wherein the electromagnetic valve is closed after stopping the coolant pump if there is no actuation request of the heat exchanger when there is a valve closing request of the electromagnetic valve.

Assignees

• Toyota Motor Co Ltd

Inventors

• Hosokawa Yohei

Classifications

• F02B29/0443

  Layout of the coolant or refrigerant circuit · CPC title

• F01P7/16 Primary

  by thermostatic control · CPC title

• Y02T10/146

  Cross-Sectional Technologies · mapped topic

• F01P7/162

  by cutting in and out of pumps · CPC title

• F01P7/08

  by cutting in or out of pumps · CPC title