EGR COOLING APPARATUS

• US 20180298853A1
• Filed: 03/28/2018
• Published: 10/18/2018
• Est. Priority Date: 04/14/2017
• Status: Abandoned Application

• Current Assignee: Aisan Kogyo Kabushiki Kaisha
• Original Assignee: Aisan Kogyo Kabushiki Kaisha
• Inventors: YOSHIOKA, Mamoru
• Application Number:
  US15/937,957
• Publication Number:
  US 20180298853A1
• Time in Patent Office: Days
• CPC Class Codes: F01P 2007/146 using valves
• CPC Class Codes: F01P 2025/44 Outlet manifold temperature
• CPC Class Codes: F01P 3/12 Arrangements for cooling other engine or machine parts
• CPC Class Codes: F01P 3/20 Cooling circuits not specific to a single part of engine or machine F01P3/22 takes precedence
• CPC Class Codes: F01P 7/14 the coolant being liquid
• CPC Class Codes: F01P 7/165 characterised by systems with two or more loops
• CPC Class Codes: F01P 7/167 by adjusting the pre-set temperature according to engine parameters, e.g. engine load, engine speed
• CPC Class Codes: F02M 26/28 with liquid-cooled heat exchangers

Abstract

An EGR cooling apparatus includes a first EGR cooling-water passage (passage parts) to cause cooling water flowing out of an engine to an engine cooling water passage to return to the engine cooling water passage via an EGR cooler; a second EGR cooling-water passage (passage parts) to cause cooling water flowing out of a radiator to the engine cooling water passage to return to the second EGR cooling-water passage via the EGR cooler; a three-way valve for switching a flow of cooling water for the EGR cooler between a first EGR cooling-water passage and a second EGR cooling-water passage; and an electronic control unit (ECU) to control the three-way valve to switch a flow of cooling water to the EGR cooler between the first EGR cooling-water passage during warm-up of the engine and a second EGR cooling-water passage after warm-up.

Claims

1. An EGR cooling apparatus provided with an EGR cooler and configured to cause a cooling water that circulates through an engine cooling device for cooling an engine to flow to the EGR cooler to cool EGR gas flowing through the EGR cooler,

wherein the engine cooling device includes a radiator, an engine-side water pump, and an engine cooling water passage,

the engine cooling device is configured to operate the engine-side water pump to cause the cooling water to circulate through the engine cooling water passage via the engine, the radiator, and the engine-side water pump,

the engine, the radiator, and the EGR cooler each include a water inlet for inflow of the cooling water and a water outlet for outflow of the cooling water, and

the EGR cooling apparatus includes:

a first EGR cooling-water passage configured to allow the cooling water flowing out from the water outlet of the engine to the engine cooling water passage to return to the engine cooling water passage via the EGR cooler;

a second EGR cooling-water passage configured to allow the cooling water flowing out from the water outlet of the radiator to the engine cooling water passage to return to the engine cooling water passage via the EGR cooler;

a flow switching unit configured to switch a flow of the cooling water for the EGR cooler between the first EGR cooling-water passage and the second EGR cooling-water passage; and

a control unit configured to control the flow switching unit to switch the flow of the cooling water for the EGR cooler to the first EGR cooling-water passage when the engine is in a state during warm-up and switch the flow of the cooling water to the second EGR cooling-water passage when the engine is in a state after warm-up.

2. The EGR cooling apparatus according to claim 1, wherein

the flow switching unit includes a single three-way valve,

the control unit is configured to turn the three-way valve to an OFF state to cause the cooling water flowing out from the water outlet of the engine to the engine cooling water passage to flow through the first EGR cooling-water passage via the EGR cooler and the three-way valve and return to the engine cooling water passage near the engine-side water pump, and

the control unit is configured to turn the three-way valve to an ON state to cause the cooling water flowing out from the water outlet of the radiator to the engine cooling water passage to flow through the second EGR cooling-water passage via the three-way valve and the EGR cooler and return to the engine cooling water passage near the water outlet of the engine.

3. The EGR cooling apparatus according to claim 1, wherein

the flow switching unit includes a first three-way valve and a second three-way valve,

the control unit is configured to turn the first three-way valve and the second three-way valve to an OFF state to cause the cooling water flowing out from the water outlet of the engine to the engine cooling water passage to flow through the first EGR cooling-water passage via the second three-way valve, the EGR cooler, and the first three-way valve and return to the engine cooling water passage near the engine-side water pump, and

the control unit is configured to turn the first three-way valve and the second three-way valve to an ON state to cause the cooling water flowing out from the water outlet of the radiator to the engine cooling water passage to flow through the second EGR cooling-water passage via the first three-way valve, the EGR cooler, and the second three-way valve and return to the engine cooling water passage near the water inlet of the radiator.

4. The EGR cooling apparatus according to claim 1, further including a radiator-side water pump placed in the second EGR cooling-water passage, the radiator-side water pump being configured to pressure-feed the cooling water flowing out from the water outlet of the radiator to the EGR cooler,

wherein the control unit turns the radiator-side water pump to an ON state when a flow of the cooling water for the EGR cooler is switched to the second EGR cooling-water passage.

5. The EGR cooling apparatus according to claim 2, further including a radiator-side water pump placed in the second EGR cooling-water passage, the radiator-side water pump being configured to pressure-feed the cooling water flowing out from the water outlet of the radiator to the EGR cooler,

wherein the control unit turns the radiator-side water pump to an ON state when a flow of the cooling water for the EGR cooler is switched to the second EGR cooling-water passage.

6. The EGR cooling apparatus according to claim 3, further including a radiator-side water pump placed in the second EGR cooling-water passage, the radiator-side water pump being configured to pressure-feed the cooling water flowing out from the water outlet of the radiator to the EGR cooler,

wherein the control unit turns the radiator-side water pump to an ON state when a flow of the cooling water for the EGR cooler is switched to the second EGR cooling-water passage.

7. The EGR cooling apparatus according to claim 1, further including a warm-up state detecting unit to detect a warm-up state of the engine,

wherein the control unit determines whether the engine is in the state during warm-up or in the state after warm-up based on a detection result of the warm-up state detecting unit.

8. The EGR cooling apparatus according to claim 2, further including a warm-up state detecting unit to detect a warm-up state of the engine,

wherein the control unit determines whether the engine is in the state during warm-up or in the state after warm-up based on a detection result of the warm-up state detecting unit.

9. The EGR cooling apparatus according to claim 3, further including a warm-up state detecting unit to detect a warm-up state of the engine,

wherein the control unit determines whether the engine is in the state during warm-up or in the state after warm-up based on a detection result of the warm-up state detecting unit.

10. The EGR cooling apparatus according to claim 4, further including a warm-up state detecting unit to detect a warm-up state of the engine,

wherein the control unit determines whether the engine is in the state during warm-up or in the state after warm-up based on a detection result of the warm-up state detecting unit.

11. The EGR cooling apparatus according to claim 5, further including a warm-up state detecting unit to detect a warm-up state of the engine,

wherein the control unit determines whether the engine is in the state during warm-up or in the state after warm-up based on a detection result of the warm-up state detecting unit.

12. The EGR cooling apparatus according to claim 6, further including a warm-up state detecting unit to detect a warm-up state of the engine,

wherein the control unit determines whether the engine is in the state during warm-up or in the state after warm-up based on a detection result of the warm-up state detecting unit.