Low temperature cooling device for internal combustion engine

Patent metadata

Field	Value
Publication number	US-10260461-B2
Application number	US-201615572139-A
Country	US
Kind code	B2
Filing date	Apr 14, 2016
Priority date	May 7, 2015
Publication date	Apr 16, 2019
Grant date	Apr 16, 2019

Abstract

A low temperature cooling device applied to an internal combustion engine includes an EGR device, a low temperature coolant circuit, a prediction unit predicting whether an EGR cooler falls into a state where a cooling performance falls short according to at least one of an operating state of an internal combustion engine and an outside air environment while a control that dehumidifies an EGR gas by cooling the EGR gas in the EGR cooler is performed, and a control unit performing at least one of a first increase control that increases a flow rate of a coolant flowing into the EGR cooler, a second increase control that increases an air rate of a radiator fan cooling a radiator, and an inhibition control that inhibits the EGR gas from flowing back when the prediction unit predicts that the EGR cooler falls into the state where the cooling performance falls short.

First claim

The invention claimed is:

1. A low temperature cooling device for an internal combustion engine, comprising:
an EGR device returning a part of an exhaust gas of an internal combustion engine to an intake passage as an EGR gas;
a low temperature coolant circuit circulating a coolant through an intercooler cooling an intake gas of the internal combustion engine, an EGR cooler cooling the EGR gas, and a radiator;
a prediction unit predicting whether the EGR cooler falls into a state where a cooling performance falls short according to at least one of an operating state of the internal combustion engine and an outside air environment while a control that dehumidifies the EGR gas by cooling the EGR gas in the EGR cooler is performed; and
a control unit performing at least one of a first increase control that increases a flow rate of the coolant flowing into the EGR cooler, a second increase control that increases an air rate of a radiator fan cooling the radiator, and an inhibition control that inhibits the EGR gas from flowing back when the prediction unit predicts that the EGR cooler falls into the state where cooling performance falls short.

2. The low temperature cooling device for the internal combustion engine according to claim 1 , wherein:
the prediction unit predicts that the EGR cooler falls into the state where cooling performance falls short when predicting that a temperature of the coolant flowing into the EGR cooler exceeds an allowable upper limit value.

3. The low temperature cooling device for the internal combustion engine according to claim 1 , wherein:
the prediction unit predicts that the EGR cooler falls into the state where cooling performance falls short when the internal combustion engine reaches a predetermined decelerating operation.

4. The low temperature cooling device for the internal combustion engine according to claim 1 , wherein:
the prediction unit uses at least one of a speed of the internal combustion engine, a load of the internal combustion engine, a flow rate of the EGR gas, and a temperature of the coolant which has passed through the EGR cooler as the operating state of the internal combustion engine.

5. The low temperature cooling device for the internal combustion engine according to claim 1 , wherein:
the prediction unit uses at least one of an outside air temperature and an outside air humidity as the outside air environment.

6. The low temperature cooling device for the internal combustion engine according to claim 1 , wherein:
the control unit performs the inhabitation control to inhibit the EGR gas from flowing back when neither the first increase control that increases the flow rate of the coolant flowing into the EGR cooler nor the second increase control that increases the air rate of the radiator fan is enabled.

7. The low temperature cooling device for the internal combustion engine according to claim 1 , wherein:
When the control unit performs the inhabitation control to inhibit the EGR gas from flowing back by inhibiting the EGR gas from flowing back, the control unit inhibits the EGR gas from flowing back until a predetermined time elapses or until a period during which a temperature of the coolant flowing into the EGR cooler is at or above a predetermined value is completed.

8. The low temperature cooling device for the internal combustion engine according to claim 1 , further comprising:
a separator separating and collecting a condensate water in the EGR gas which has passed through the EGR cooler; and
an EGR heater heating the EGR gas which has passed through the separator.

Assignees

• Denso Corp

Inventors

• Minami Keitarou
• Miyagawa Masashi
• Ichihara Hideaki

Classifications

• F02M26/06

  Low pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust downstream of the turbocharger turbine and reintroduced into the intake system upstream of the compressor · CPC title

• F02M26/24

  with two or more coolers · CPC title

• F02M26/28

  with liquid-cooled heat exchangers · CPC title

• F01P7/16

  by thermostatic control · CPC title

• F02M26/33 Primary

  controlling the temperature of the recirculated gases · CPC title