Cooling device for internal combustion engine

Patent metadata

Field	Value
Publication number	US-10422269-B2
Application number	US-201815958501-A
Country	US
Kind code	B2
Filing date	Apr 20, 2018
Priority date	Apr 28, 2017
Publication date	Sep 24, 2019
Grant date	Sep 24, 2019

Abstract

A cooling device for an internal combustion engine includes a pump portion, a circulation water passage, a thermostat configured to switch between a state where the coolant is circulated to a heat exchange water passage on which a radiator is disposed and a state where the coolant is not circulated to the heat exchange water passage, and a control unit configured to control the pump portion. The control unit is configured to control a three-way valve such that a first pump and a second pump are connected in parallel when the thermostat switches to the state where the coolant is circulated to the heat exchange water passage and controls the three-way valve such that the first pump and the second pump are connected in series when the thermostat switches to the state where the coolant is not circulated to the heat exchange water passage.

First claim

What is claimed is:

1. A cooling device for an internal combustion engine, the cooling device comprising:
a pump portion configured to pump a coolant of the internal combustion engine;
a circulation water passage including an engine water passage of the internal combustion engine, the circulation water passage being configured to connect the pump portion and the engine water passage to each other such that the coolant returns back to the pump portion through the engine water passage after the coolant is pumped from the pump portion;
a heat exchanger configured to perform heat exchange with the coolant;
a heat exchange water passage on which the heat exchanger is disposed, the heat exchange water passage being disposed in parallel to at least a part of the circulation water passage;
a water passage switching device configured to switch between a state where the coolant is circulated to the heat exchange water passage and a state where the coolant is not circulated to the heat exchange water passage; and
a control device configured to control the pump portion, wherein:
the pump portion includes a first pump, a second pump, and a pump switching device configured to switch between a state where the first pump and the second pump are connected in parallel and a state where the first pump and the second pump are connected in series;
the control device is configured to control the pump switching device such that the first pump and the second pump are connected in parallel when the water passage switching device switches to the state where the coolant is circulated to the heat exchange water passage and the coolant is circulated to the circulation water passage and the heat exchange water passage; and
the control device is configured to control the pump switching device such that the first pump and the second pump are connected in series when the water passage switching device switches to the state where the coolant is not circulated to the heat exchange water passage and the coolant is circulated merely to the circulation water passage.

2. The cooling device according to claim 1 , wherein:
the water passage switching device is a thermostat disposed on the heat exchange water passage and configured to switch between a valve open state and a valve closed state in accordance with a coolant temperature of the coolant;
the thermostat is configured such that the coolant is circulated to the heat exchange water passage when the thermostat is in the valve open state; and
the thermostat is configured such that the circulation of the coolant to the heat exchange water passage is stopped when the thermostat is in the valve closed state.

3. The cooling device according to claim 1 , wherein:
a maximum flow rate that is output by the pump portion by the pump switching device connecting the first pump and the second pump in parallel to each other exceeds a maximum flow rate that is output by the pump portion by the pump switching device connecting the first pump and the second pump in series to each other when the water passage switching device switches to the state where the coolant is circulated to the heat exchange water passage; and
the maximum flow rate that is output by the pump portion by the pump switching device connecting the first pump and the second pump in parallel to each other is smaller than the maximum flow rate that is output by the pump portion by the pump switching device connecting the first pump and the second pump in series to each other when the water passage switching device switches to the state where the coolant is not circulated to the heat exchange water passage.

4. The cooling device according to claim 1 , wherein:
the circulation water passage and the heat exchange water passage are configured such that a flow path resistance of a path of the coolant is equal to or less than a reference flow path resistance when the water passage switching device switches to the state where the coolant is circulated to the heat exchange water passage and the flow path resistance of the path of the coolant exceeds the reference flow path resistance when the water passage switching device switches to the state where the coolant is not circulated to the heat exchange water passage;
when a curve representing a relationship between a flow rate and a water pressure at a time when the flow path resistance of the path of the coolant is any value is a resistance curve, the reference flow path resistance is a flow path resistance at a time when the resistance curve passes through an intersection point between a parallel characteristic curve and a series characteristic curve;
the parallel characteristic curve is a curve representing a relationship between a maximum flow rate and a maximum water pressure that is output by the pump portion in the state where the first pump and the second pump are connected in parallel; and
the series characteristic curve is a curve representing the relationship between the maximum flow rate and the maximum water pressure that is output by the pump portion in the state where the first pump and the second pump are connected in series.

5. The cooling device according to claim 1 , wherein the control device is configured to control the pump switching device such that the first pump and the second pump are connected in parallel irrespective of a state of the water passage switching device and drive merely one of the first pump and the second pump when a requested flow rate to the pump portion is smaller than a flow rate determined in advance.

6. The cooling device according to claim 1 , wherein:
the heat exchanger includes a first heat exchanger and a second heat exchanger;
the heat exchange water passage includes a first heat exchange water passage on which the first heat exchanger is disposed, the first heat exchange water passage being disposed in parallel to at least a part of the circulation water passage, and a second heat exchange water passage on which the second heat exchanger is disposed, the second heat exchange water passage being disposed in parallel to at least a part of the circulation water passage;
the water passage switching device includes a first water passage switching device switching between a state where the coolant is circulated to the first heat exchange water passage and a state where the coolant is not circulated to the first heat exchange water passage and a second water passage switching device switching between a state where the coolant is circulated to the second heat exchange water passage and a state where the coolant is not circulated to the second heat exchange water passage;
the water passage switching device switches to the state where the coolant is circulated to the heat exchange water passage when the first water passage switching device switches to the state where the coolant is circulated to the first heat exchange water passage and the second water passage switching device switches to the state where the coolant is circulated to the second heat exchange water passage; and
the water passage switching device switches to the state where the coolant is not circulated to the heat exchange water passage when the first water passage switching device switches to the state where the coolant is not circulated to the first heat exchange water passage and the second water passage switching device switches to the state where the coolant is not circulated to the second heat exchange water passage.

7. The cooling device according to claim 6 , wherein:
the control device is configured to store, as a first region, a region of a flow rate and a water pressure that is output simply by the first pump and the second pump being connected in parallel when the first water passage switching device and the second water passage switchi

Assignees

• Toyota Motor Co Ltd

Inventors

• Aoyama Yukitoshi
• Yamashita Akira
• Hashimoto Hiromichi
• Uno Koki

Classifications

• F01P5/10 Primary

  Pumping liquid coolant; Arrangements of coolant pumps · CPC title

• F01P7/165 Primary

  characterised by systems with two or more loops · CPC title

• F01P2007/168

  By varying the cooling capacity of a liquid-to-air heat-exchanger · CPC title

• F01P7/161

  by bypassing pumps · CPC title

• F01P3/20

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