KR20200023726A - Cooling system of hybrid electric vehicle - Google Patents

Abstract

A cooling system for a hybrid vehicle is disclosed. An engine cooling circuit for cooling the engine generating power with cooling water; A heating element cooling circuit cooling the heating element generating heat during operation; And a connection line for selectively connecting the cooling water of the engine cooling circuit and the cooling water of the heating element cooling circuit to be selectively alternating current, thereby extending the operating area of the EGR cooler, and promptly cooling and improving fuel efficiency.

Description

COOLING SYSTEM OF HYBRID ELECTRIC VEHICLE}

The present invention relates to a cooling system of a hybrid electric vehicle (HEV), and more particularly, to a cooling system of a hybrid vehicle in which an engine cooling circuit and a power electronics (PE) component cooling circuit are selectively connected and disconnected. will be.

In the conventional engine cooling system of a general vehicle, the engine is cooled by using coolant, that is, the coolant cooled by heat exchange with external air is pumped by a water pump to supply the engine to cool the engine, and the engine is cooled. The coolant can be circulated back to the radiator to cool down or flowed into an exhaust gas recirculation (EGR) cooler to cool the recycle exhaust and then to the water pump.

In order to construct an optimal cooling circuit in such a cooling water circulation circuit, an integrated thermal management module or a thermostat that controls the flow direction of the cooling water is applied.

On the other hand, in addition to the engine cooling system, the hybrid vehicle additionally installs a separate cooling circuit for cooling electric components, eg, PE (Hybrid Starter and Generator) and HPCU (Hybrid Power Control Unit), which are heat generating components. It is becoming.

That is, the cooling water is pumped from the reservoir tank to the HSG to cool the cooling water, the cooling water to cool the HSG is supplied to a low-temperature radiator to cool the cooling water through heat exchange with outside air, and the cooled cooling water is supplied to the HPUC to supply the HPCU. There is an additional heating component cooling circuit that cools and then circulates it back to the reservoir tank.

The heating component cooling circuit and the engine cooling circuit constitute a separate cooling circuit without sharing the cooling water.

However, in the two-circuit cooling method of the conventional hybrid vehicle as described above, the EGR gas EGR cooler is cooled by heat exchange with the coolant, and after the engine warms up, the temperature of the coolant rises to 90 degrees or more. In addition, the temperature of the EGR gas cooled by heat-exchanging in the high-temperature cooling water and the EGR cooler is also increased to at least 90 degrees.

When the high-temperature EGR gas is combined with the intake air flowing into the engine through another path as described above, the intake volume efficiency of the intake air is reduced, thereby reducing the fuel efficiency improvement effect and knocking may occur in the engine. .

Matters described in this Background section are intended to enhance the understanding of the background of the invention, and may include matters other than the prior art already known to those skilled in the art.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a cooling system of a hybrid vehicle capable of enlarging the operating area of the EGR cooler and improving the heating and fuel economy.

According to an aspect of the present invention, there is provided a hybrid vehicle cooling system including: an engine cooling circuit configured to cool an engine generating power with coolant; A heating element cooling circuit cooling the heating element generating heat during operation; And it may include a connection line for selectively connecting the cooling water of the engine cooling circuit and the cooling water of the heating element cooling circuit selectively.

The engine cooling circuit includes: a first radiator cooling the cooling water through heat exchange with outside air; A water pump connected to the first radiator to pump and supply the cooling water cooled by the first radiator; An engine cooled by receiving the pumped coolant from the water pump; An EGR cooler connected to the engine to exchange the supplied coolant and the EGR gas so as to receive the coolant cooled by the engine; A heater connected to the EGR cooler to exchange heat with the cooling water discharged from the EGR cooler; And it may include a water pump for supplying the pumped cooling water discharged from the heater.

The engine may be equipped with an integrated thermal management module for allowing the coolant discharged from the engine to flow to the EGR cooler or to the first radiator according to the temperature of the coolant.

The heating element cooling circuit pumps the coolant stored in the reservoir tank by the electric water pump to supply the HSG to cool the HSG, and the coolant that cools the HSG flows into the second radiator to be cooled by heat exchange with outside air, and the second Cooling water cooled in the radiator may be configured to be supplied to the HPCU to cool the HPCU and then returned to the reservoir tank.

The second radiator may be a low temperature radiator which is a low temperature which is relatively low temperature compared with the first radiator.

The connection line may include a first connection line connecting the HPCU and the EGR cooler such that the cooling water discharged from the HPCU is supplied to the EGR cooler; And a second connection line connecting the heater and the reservoir tank so that the engine coolant discharged from the heater flows into the reservoir tank.

The first connection line is provided with a first valve for selectively supplying the cooling water of the heating element cooling circuit discharged from the HPCU to the EGR cooler side or the reservoir tank side;

The first connection line comprises a first connector connecting the cooling line between the engine and the EGR cooler and the first connection line;

The second connection line is provided with a second valve for selectively supplying the cooling water of the engine cooling circuit discharged from the heater to the water pump side or the reservoir tank side;

The second connection line may include a second connector connecting the cooling line between the HPCU and the reservoir tank and the second connection line.

A first temperature sensor is installed at an inlet side of the EGR cooler of the first connection line to sense a temperature of the coolant discharged from the HPCU and introduced into the EGR cooler; The second temperature sensor for detecting the temperature of the cooling water flowing into the HPCU may be installed at the inlet side of the HPCU.

A controller for controlling the flow direction of the coolant through the first valve and the second valve may be further provided according to the coolant temperature detected by the first temperature sensor and the second temperature sensor.

The controller controls the first valve so that the coolant flows through the first valve to the EGR cooler when the temperature of the coolant flowing into the HPCU sensed by the second temperature sensor is lower than a predetermined temperature. The cooling water passing through the control unit may control the second valve to flow to the reservoir tank.

The first connector and the second connector may be T "shaped.

The controller, when the temperature of the coolant flowing into the EGR cooler sensed by the first temperature sensor is greater than or equal to a predetermined temperature, controls the first valve so that the coolant flows through the first valve to the reservoir tank, Cooling water passing through the second valve may control the second valve to flow to the water pump.

According to the cooling system of the hybrid vehicle according to the embodiment of the present invention as described above, since the EGR cooler and the heater are connected in series on the cooling water circulation passage in the engine cooling circuit, the heating element is cooled separately from the cooling water of the engine cooling circuit. The EGR cooler can be operated with cooling water in the circuit, which allows for rapid heating and widening the operating range of the EGR cooler.

In addition, the HPCU is disposed between the rear end of the second radiator at a relatively low temperature and the front end of the EGR cooler, and thus cooling efficiency may be improved because the cooling water is supplied to the HPCU to cool the HPCU at the lowest temperature of the cooling water in the cooling circuit.

In addition, even when the engine coolant flow stops on the conventional engine cooling circuit, by circulating the cooling water of the heating element cooling circuit toward the EGR cooler and the heater, it is possible to achieve faster heating and enlargement of the operating area of the EGR cooler than in the prior art.

In addition, conventionally, after the engine warms up, the cooling water of the engine is raised to a high temperature (about 90 degrees to 120 degrees), and the temperature of the EGR gas decreases as the high temperature engine cooling water flows into the EGR cooler to cool the EGR gas. However, in the present invention, as the low-temperature cooling water cooling the HPCU is introduced into the EGR cooler to cool the EGR gas, the density of the mixer flowing into the engine together with the EGR gas can be increased, and thus, the mixer. The fuel efficiency of the vehicle can be improved by increasing the volumetric efficiency and reducing engine knocking.

In addition, since the EGR cooler can be operated by introducing the coolant circulating in the heating element cooling circuit during the warm-up of the engine, the fuel efficiency improvement region can be expanded by shortening the operating time of the EGR cooler.

In addition, the heating performance is limited by the delay of the temperature rise of the engine coolant when heating the engine conventionally, in the present invention, the heater is disposed in the rear end of the HPCU and the EGR cooler, the heat absorption of the HPCU and the EGR cooler Since the temperature of the cooling water is increased by the exhaust heat recovery, the heating can be performed at an early stage, and thus the heating performance can be improved.

Since these drawings are for reference in describing exemplary embodiments of the present invention, the technical spirit of the present invention should not be construed as being limited to the accompanying drawings.
1 is a configuration diagram of a cooling circuit of a cooling system of a hybrid vehicle according to an exemplary embodiment of the present invention.
2 is an explanatory view of the operation of the separate cooling of the cooling system of the hybrid vehicle according to an embodiment of the present invention.
3 is an explanatory view of the operation during the combined cooling of the cooling system of the hybrid vehicle according to an embodiment of the present invention.

DETAILED DESCRIPTION Embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily practice the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In order to clearly describe the present invention, parts irrelevant to the description are omitted, and like reference numerals designate like elements throughout the specification.

Hereinafter, a cooling system of a hybrid vehicle according to an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Referring to FIG. 1, a cooling system of a hybrid vehicle according to an exemplary embodiment of the present invention includes an engine cooling circuit 10 that cools an engine that burns fuel to generate power of a vehicle with cooling water, and generates heat during operation. The heating element may include a heating element cooling circuit 20 for cooling a power electronics (PE) component such as a hybrid starter and generator (HSG) and a hybrid power control unit (HPCU).

The engine cooling circuit includes a water pump 12 connected with the first radiator 11 to pump and supply the first radiator 11 that cools the cooling water through heat exchange with the outside air, and the cooling water cooled by the first radiator 11. ), An engine 13 that is cooled by receiving the pumped coolant from the water pump 12, and the coolant and EGR (Exhaust Gas Recirculation) connected and supplied to the engine 13 to receive the coolant that cools the engine 13. The EGR cooler 14 for cooling the EGR gas by heat-exchanging with the gas, and the EGR cooler 14 for cooling the EGR gas from the EGR cooler 14 flows into the water pump 12 again. It is connected with the water pump 12 via the heater HTR 15.

Meanwhile, in order to allow the coolant discharged from the engine to flow into the EGR cooler 14 or to flow into the first radiator 11 according to the temperature of the coolant cooling the engine 13, the flow direction of the coolant is controlled. Integrated thermal management module 16 may be installed in the engine (13).

The heating element cooling circuit 20, the electric water pump (EWP) 22 of the cooling water stored in the reservoir tank 21 is pumped and supplied to the HSG (Hybrid Starter and Generator; 23) to supply the HSG (23) Cooling water to cool the HSG 23, is supplied to the second radiator 24 and cooled by heat exchange with the outside air, and then supplied to the HPCU (Hybrid Power Control Unit) to cool the HPCU and then again It is made of a structure that returns to the reservoir tank (21).

The second radiator 24 may be a relatively low-temperature cooling water flow compared to the first radiator (11).

The outlet of the HPCU is provided with a first valve 30 having three ports and capable of flowing in three directions (3-way), the first port of the first valve 30 is connected to the HPCU 25 And a first inflow port into which the coolant cooling the HPCU 25 is introduced, and the second port is a first outflow port through which the coolant cooling the HPCU 25 is supplied to the EGR cooler 14. The third port serves as a second outlet port for allowing the cooling water cooling the HPCU 25 to be returned to the reservoir tank 21.

In the cooling water flow path between the engine 13 and the EGR cooler 14, a first connector 31 having a generally “T” shape is installed, and the first valve 30 and the first connector 31 are connected to each other. By being connected in communication, the coolant discharged from the HPCU 25 may be supplied to the EGR cooler 14 through the first valve 30 and the first connector 31 to cool the EGR gas.

An EGR cooler inlet side of the first connection line 32 connecting the first valve 30 and the first connector 31 is discharged from the HPCU 25 to detect the coolant temperature flowing into the EGR cooler. 1 temperature sensor 33 may be installed.

Meanwhile, a second connector 35 having a generally “T” shape is also installed in the coolant flow path 34 connecting the HPCU 25 and the reservoir tank 21, and the second connector 35 is provided with a second connector 35. The coolant discharged from the HPCU 25 and the coolant discharged from the heater 15 are joined at the second connector 35 by being connected to the heater 15 through a connection line 36, and thus, the reservoir tank 21 is connected to the heater 15. Can be returned to.

A second valve 37 is also provided at the discharge port of the heater 15 to allow flow in three directions (3-way), and the coolant discharged from the heater 15 is provided in the second valve 37. Through the appropriate control of the) may be introduced into the water pump 12 or the reservoir tank 21 through the second connector (35).

Meanwhile, a second temperature sensor 38 may be installed at the inlet side of the HPCU 25 in the cooling water flow path connecting between the second radiator 24 and the HPCU 25.

The first and second temperature sensors 33 and 38 and the first and second valves 30 and 37 are connected to a controller (not shown) to detect the coolant temperature detected by the first and second temperature sensors 33 and 38. Is input to the controller, and the controller applies a control signal to the first and second valves 30 and 37 according to the coolant temperature input from the first and second temperature sensors 33 and 38 to control the first and second valves. It is possible to control the flow direction of the cooling water flowing through the (30,37).

Referring to FIG. 2, the engine cooling circuit 10 and the heating element cooling circuit 20 are separated from each other, so that the PE parts cooling and the engine cooling are performed separately.

That is, when the temperature of the cooling water discharged from the HPCU 25 is detected by the first temperature sensor 33, for example, 70 degrees or more, the heating element cooling circuit 20 for optimal cooling of the HPCU 25. The HPCU 25 is cooled by the cooling water circulating in the bay, and the engine 13 and the EGR cooler 14 are cooled by only the cooling water circulating in the engine cooling circuit 10.

In the engine cooling circuit 10, the coolant cooling the engine 13 is discharged through the integrated thermal management module 16, and then flows into the EGR cooler 15 to cool the EGR cooler 15, and the EGR cooler 15. The cooling water having cooled down is introduced again to the water pump 12 by switching the flow path of the second valve 37 provided at the discharge port side of the heater 15 after passing through the heater 15.

The flow path switching of the second valve 37 may be performed by a control signal of the controller that detects the coolant temperature through the first temperature sensor 33.

On the other hand, in the heating element cooling circuit 20, cooling water cooled by heat exchange with external air in the second radiator 24 is supplied to the HPCU 25 to cool the HPCU 25, and to cool the HPCU 25. Is returned to the reservoir tank 21 via the first valve 30 and the first connector 35.

At this time, when the coolant temperature detected by the first temperature sensor 33 is 70 degrees or more, the controller applies a control signal to the first valve 30 so that a flow path passing through the first valve 30 is stored in the reservoir tank ( 21) to control the connection.

The coolant stored in the reservoir tank 21 is supplied to the HSG 23 by the operation of the electric water pump 22, cools the HSG 23, and then flows into the second radiator 24 to be cooled.

As such, when the cooling water temperature discharged from the HPCU 25 is 70 degrees or more, the heating element cooling circuit 20 is not mixed with the cooling water of the engine cooling circuit 10 for optimal cooling of the HPCU 25 and the HSG 23. It will cycle through the bay.

On the other hand, when the coolant temperature flowing into the HPCU 25 is detected by the second temperature sensor 38, when the temperature is less than 70 degrees, for example, when the engine is warmed up, the coolant of the engine cooling circuit 10 And the cooling water of the heating element cooling circuit 20 are circulated through the engine cooling circuit 10 and the heating element cooling circuit 20.

That is, when the coolant temperature sensed by the second temperature sensor 38 is less than 70 degrees, the controller applies a control signal to the first valve 30, and the coolant that has passed through the first valve 30 is removed. The first connector 31 is introduced into the EGR cooler 14, and the cooling water cooling the HSG 15 by applying a control signal to the second valve 37 is passed through the second valve 37. Circulate through reservoir 35 to reservoir tank 21.

The coolant stored in the reservoir tank 21 is again pumped by the operation of the electric water pump 23 and supplied to the HSG 23 to cool the HSG 23, and the coolant that cools the HSG 23 is the second radiator 24. ) Is cooled through heat exchange with the outside air and then supplied to the HPCU 25 to cool the HPCU 25.

In the engine cooling circuit 10, since the EGR cooler 14 and the heater 15 are connected in series on the cooling water circulation passage, the cooling water of the heating element cooling circuit 20 is separate from the cooling water of the engine cooling circuit 10. The furnace EGR cooler 14 is operated, and the heater 15 is passed through, thereby enabling rapid heating and expanding the operating region of the EGR cooler 14.

That is, the amount of cooling water in the heating element cooling circuit 20 is lower than the amount of cooling water in the engine cooling circuit 10, and the heating and the EGR cooler can be quickly heated up by the flow rate control by the controller of the electric water pump 22. It can shorten the operation time.

The HPCU 25 is disposed between the rear end of the second radiator 24 (cooling water outlet end) of the relatively low temperature and the front end (cooling water inlet end) of the EGR cooler 14, which is the temperature of the coolant in the cooling circuit. Since the coolant is supplied to the HPCU 25 in the low state to cool the HPCU 25, the cooling efficiency can be improved.

In addition, even when the engine cooling water flow stops on the engine cooling circuit 10 by the operation of the conventional integrated thermal management module 16, the cooling water of the heating element cooling circuit 20 is transferred to the EGR cooler 14 and the heater ( By circulating to 15), heating and expansion of the operating area of the EGR cooler 25 can be achieved faster than before.

In addition, conventionally, after the engine warms up, the coolant of the engine is raised to a high temperature (about 90 degrees to 120 degrees), and the high-temperature engine coolant flows into the EGR cooler 14 to cool the EGR gas. In the present invention, there is a limit to the temperature decrease of the present invention. However, in the present invention, the low-temperature cooling water cooling the HPCU 25 is introduced into the EGR cooler 14 to cool the EGR gas. Compared to this, the fuel efficiency of the vehicle can be improved by increasing the volumetric efficiency of the mixer and reducing engine knocking.

In the warm-up of the engine, a delay in the increase of the coolant temperature of the engine is conventionally used. When the coolant temperature is 60 degrees or less, the operation of the EGR cooler is delayed by preventing the inflow of the coolant to the EGR cooler to prevent condensate generation inside the EGR cooler. However, in the present invention, the temperature is rapidly increased by circulating the heating element cooling circuit 20. Engine coolant (The coolant circulating in the heating element cooling circuit can be heated up quickly by controlling the circulation of the heating element due to the rapid circulation operation control of the electric water pump. EGR cooler can be operated by inflow of EGR cooler during warm-up This can enlarge the fuel efficiency improvement area.

In addition, in the case of utilizing the engine cooling water for heating in the past, there is a limit of heating performance due to a delay in the temperature rise of the engine cooling water, but in the present invention, the heater 15 is disposed at the rear end of the HPCU 25 and the EGR cooler 14, The heat generation absorption of (25) and the recovery of the exhaust heat from the EGR cooler 14 increase the temperature of the cooling water so that the heating can be performed early, so that the heating performance can be improved.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

10: engine cooling circuit
11: radiator 1
12: water pump
13: engine
14: EGR cooler
15: heater
16: integrated thermal management module
20: heating element cooling circuit
21: reservoir tank
22: electric water pump
23: HSG
24: 2nd radiator
25: HPCU
30: first valve
31: end connections
33: first temperature sensor
35: end connections
37: second valve
38: second temperature sensor

Claims (12)

An engine cooling circuit for cooling the engine generating power with cooling water;
A heating element cooling circuit cooling the heating element generating heat during operation; And
A connection line selectively connecting the cooling water of the engine cooling circuit and the cooling water of the heating element cooling circuit to be selectively exchanged;
Hybrid vehicle cooling system comprising a.
The method of claim 1,
The engine cooling circuit,
A first radiator cooling the cooling water through heat exchange with the outside air;
A water pump connected to the first radiator to pump and supply the cooling water cooled by the first radiator;
An engine cooled by receiving the pumped coolant from the water pump;
An EGR cooler connected to the engine to exchange the supplied coolant and the EGR gas so as to receive the coolant cooled by the engine;
A heater connected to the EGR cooler to exchange heat with the coolant discharged from the EGR cooler for indoor heating of the vehicle; And
Cooling system of a hybrid vehicle comprising a.
The method of claim 2,
The engine is a cooling system of a hybrid vehicle, characterized in that the cooling water discharged from the engine according to the temperature of the coolant flows to the EGR cooler or an integrated thermal management module for flowing to the first radiator.
The method of claim 3,
The heating element cooling circuit pumps the coolant stored in the reservoir tank by the electric water pump to supply the HSG to cool the HSG, and the coolant that cools the HSG flows into the second radiator to be cooled by heat exchange with outside air, and the second Cooling water cooled in the radiator is supplied to the HPCU cooling the HPCU and then back to the reservoir tank structure of the hybrid vehicle cooling system, characterized in that consisting of.
The method of claim 4, wherein
The second radiator is a cooling system of a hybrid vehicle, characterized in that a low temperature radiator is a low temperature relatively low temperature compared to the first radiator.
The method of claim 4, wherein
The connection line
A first connection line connecting the HPCU and the EGR cooler to supply the cooling water discharged from the HPCU to an EGR cooler; And
A second connection line connecting the heater and the reservoir tank so that the engine coolant discharged from the heater flows into the reservoir tank;
Cooling system of a hybrid vehicle comprising a.
The method of claim 6,
The first connection line is provided with a first valve for selectively supplying the cooling water of the heating element cooling circuit discharged from the HPCU to the EGR cooler side or the reservoir tank side;
The first connection line includes a first connector connecting the cooling line between the engine and the EGR cooler and the first connection line;
The second connection line is provided with a second valve for selectively supplying the cooling water of the engine cooling circuit discharged from the heater to the water pump side or the reservoir tank side;
And the second connection line comprises a second connector connecting the cooling line between the HPCU and the reservoir tank and the second connection line.
The method of claim 7, wherein
A first temperature sensor is installed at an inlet side of the EGR cooler of the first connection line to sense a temperature of the coolant discharged from the HPCU and introduced into the EGR cooler;
And a second temperature sensor for sensing a temperature of the coolant flowing into the HPCU is installed at an inlet side of the HPCU.
The method of claim 8,
And a controller for controlling a flow direction of the coolant through the first valve and the second valve according to the coolant temperature detected by the first temperature sensor and the second temperature sensor. .
The method of claim 9,
The controller controls the first valve so that the coolant flows through the first valve to the EGR cooler when the temperature of the coolant flowing into the HPCU sensed by the second temperature sensor is lower than a predetermined temperature. Cooling system passing through the control system for controlling the second valve to be flowed to the reservoir tank.
The method of claim 7, wherein
Cooling system of a hybrid vehicle, characterized in that the first connector and the second connector is T "shaped.
The method of claim 9,
The controller, when the coolant temperature flowing into the EGR cooler sensed by the first temperature sensor is above a predetermined temperature, the controller controls the first valve so that the coolant flows through the first valve to the reservoir tank, Cooling system passing through the second valve is the cooling system of the hybrid vehicle, characterized in that for controlling the second valve to flow to the water pump.

Images