EP3504410A1

EP3504410A1 - Device for cooling an air supercharging system of a heat engine, and air supercharging system equipped with such a device

Info

Publication number: EP3504410A1
Application number: EP17751797.6A
Authority: EP
Inventors: Jean Novati; Marc JAN; Arnaud Dupuis
Original assignee: PSA Automobiles SA
Current assignee: PSA Automobiles SA
Priority date: 2016-08-24
Filing date: 2017-07-11
Publication date: 2019-07-03
Also published as: CN109642490B; WO2018037171A1; FR3055368B1; CN109642490A; FR3055368A1

Abstract

The device (12) according to the invention is suitable for cooling an air supercharging system (1) of a heat engine (2) comprising a thermal turbocharger (10) and a water-cooled electric compressor (11). The device comprises a first cooling circuit (12A) intended to cool the charge air supplied by the system to the heat engine and a second cooling circuit (12B) intended for the water-cooling of the electric compressor. According to the invention, the device comprises a water-air heat exchanger (120) that is shared by the two cooling circuits.

Description

THERMAL ENGINE AIR SUPPLY SYSTEM COOLING DEVICE, AND OVERHEATING SYSTEM

AIR EQUIPPED WITH SUCH A DEVICE

[001] The invention relates generally to the field of the automobile. More particularly, the invention relates to a cooling device for an engine air supercharging system comprising a thermal turbocharger and an electric compressor. The invention also relates to an air supercharging system in which is integrated such a cooling device.

[002] In the context of the reduction of C0 ₂ emissions from motor vehicles, car manufacturers have moved towards the development of smaller-displacement engines equipped with more efficient and responsive new-generation air-boosting systems. These new-generation air-boosting systems are built around a thermal turbocharger and an electric compressor. [003] The conventional thermal turbocharger operating from the energy recovered in the hot exhaust gases of the engine requires for its release sufficient pressure of the exhaust gas. The thermal turbocharger is actually triggered actually only from a certain speed of rotation of the engine causing a rise in pressure of the exhaust gas. The integration of an electric compressor in an air supercharging system makes it possible to overcome this known disadvantage of the turbocharger by extending the operating range of the air supercharging at low speeds.

[004] The implementation under the bonnet of an electric compressor imposes severe constraints on car manufacturers. Indeed, the volume required under the bonnet is important. It is necessary not only to house the electric compressor and the connection and bypass lines to be integrated in the air loop of the engine, but also an additional cooling circuit that may be necessary to cool the electric compressor.

[005] From a certain power, the electric compressor requires more efficient cooling means than a simple air cooling for its electric motor and power electronics associated therewith. The need for a circuit of Water cooling is then required and requires a water-air heat exchanger and a water pump which represent additional costs and a large volume.

[006] The document DE10315779A1 describes a cooling device of a thermal engine air supercharging system. In the current state of the art, it appears necessary to propose a solution facilitating the integration of the electric compressor and its cooling circuit under the engine bonnet of a motor vehicle, and which is less restrictive in terms of congestion and cost.

According to a first aspect, the invention relates to a cooling device of an engine air supercharging system comprising a thermal turbocharger and a water-cooled electric compressor, the device comprising a first cooling circuit for cooling of the charge air supplied by the system to the heat engine and a second cooling circuit for the water cooling of the electric compressor. The device comprises a water-air heat exchanger which is common to both said first and second cooling circuits.

[008] A same water-air heat exchanger is thus used for cooling the supercharged compressed air and for cooling the compressor. The water-to-air heat exchanger does not need to be oversized compared to the one that would be used in an air supercharging system without an electric compressor. The invention therefore provides a large volume gain that facilitates the integration of the electric compressor under the engine hood of the vehicle and allows a significant reduction in costs.

According to a particular characteristic of the device of the invention, the total cooling capacity of the common water-air heat exchanger is dimensioned for the first cooling circuit for cooling the supercharging air supplied to the heat engine when this it is in a high-speed operating zone in which it delivers its maximum power.

According to another particular feature, the common water-air heat exchanger is formed of first and second heat exchange sections in fluid communication and together providing the total cooling capacity of the common water-air heat exchanger. [001 1] According to yet another particular feature, the first cooling circuit uses the first and second heat exchange sections.

According to yet another particular characteristic, the second cooling circuit uses the second heat exchange section. According to yet another particular characteristic, the thermal cooling capacity of the second heat exchange section is sized to cool the electric compressor to just necessary when the electric compressor is activated in a low-speed operating zone of the engine. .

According to yet another particular characteristic, the first and second cooling circuits respectively comprise first and second water pumps.

According to another aspect, the invention also relates to a thermal engine air supercharging system comprising a thermal turbocharger and a water-cooled electric compressor, and in which is integrated a cooling device as briefly described herein. -Dessous. Other advantages and features of the present invention will appear more clearly on reading the description below of a particular embodiment of the invention with reference to the accompanying drawings, in which: FIG. a block diagram showing a particular embodiment of an air supercharging system of the invention equipped with its cooling device; and Figs.2A and 2B are views of principle showing the architecture and operation of a water-air heat exchanger integrated in the cooling device according to the invention.

Referring to Fig.1, it is now described in detail the general architecture of an air supercharging system 1 according to the invention.

The air supercharging system 1 essentially comprises a thermal turbocharger 10, an electric compressor 1 1 cooled by water, a cooling device 12, and various ancillary elements of the air loop. supplying air such as an air filter 13, air lines 14, and a branch line 15 equipped with a solenoid valve 150 for the electric compressor 1 1.

The system 1 equips a heat engine 2 and is connected thereto at the air intake distributor 20, through a throttle valve 21, and at the exhaust manifold 23 and the line of the engine. exhausting gases, through a gas propeller 100 of the turbocharger 10.

Also referring to Figs.2A and 2B, is now described in detail the cooling device 12 according to the invention.

The cooling device 12 comprises a first cooling circuit 12A (Fig.1) and a second cooling circuit 12B (Fig.1) which share a common water-air heat exchanger 120. The heat exchanger 120 has first and second heat exchange sections 120A and 120B that are in fluid communication. These first and second sections 120A and 120B, shown in detail in Figs.2A and 2B, are shown in solid and hatched lines, respectively. The first cooling circuit 12A is dedicated to the cooling of the supercharging air, whether it comes from the compression performed by an air propeller 101 (Fig.1) of the turbocharger 10 or that produced by an air propeller 1 10 (Fig.1) of the compressor 1 1. As known, such a cooling of the charge air allows a better filling of the cylinders of the heat engine 2. This first cooling circuit 12A is established through the common water-air heat exchanger 120 and also uses an exchanger thermal air-water 121 and a first water pump 122A. The pump 122A forces the cooling water circulation through the air-water exchanger 121 to cool the charge air and through the exchanger 120. The calories from the charge air are extracted from it. in the exchanger 121 and transferred to the cooling water of the circuit 12A. The cooling water then releases its calories into the ambient air at the level of the common exchanger 120.

The second cooling circuit 12B is a cooling device dedicated to the compressor 1 1, and more precisely its electric motor 1 1 1 and the power electronics associated therewith. This second cooling circuit 12B is established through the common water-air heat exchanger 120 and uses a second water pump 122B which forces the circulation of the cooling water through channels arranged in an engine casing 1 1 1 to cool the latter and through the exchanger 120. The calories extracted from the engine 1 1 1 and its associated electronics are released into the ambient air at the exchanger 120.

The cooling device 12 according to the invention has an architecture called here "in two independent cooling circuits." This architecture has the advantage of allowing differential control of water flow rates through the first and second water pumps 122A and 122B.

In the cooling device 12 according to the invention, the common water-air heat exchanger 120 does not need to be oversized compared to the water-air heat exchanger which would be used in a supercharging system. of air without electric compressor.

Indeed, the operating zone of the heat engine 2 requiring a cooling of the compressor 1 1 is different from that for which was dimensioned the water-air heat exchanger 120. The water-air heat exchanger 120 is dimensioned in full cooling capacity for a high-speed operating zone of the engine 2, that is to say, when the turbocharger 10 is active. The dimensioning of the exchanger 120 is made on the point of maximum power of the heat engine, that is to say in a high-speed operating zone thereof, to evacuate sufficient calories for the cooling of the engine. supercharged compressed air. The electric compressor 1 1 needs to be cooled only when it is used, that is to say in a low-speed operating zone of the engine 2 in which the turbocharger 10 is not active. .

As there is no overlap between these two operating zones of the engine, at high and low speed, the integration of the compressor 1 1 with its water cooling does not affect the dimensioning of full capacity. The cooling device 12 according to the invention can therefore have a water-air heat exchanger 120 having the same volume of space that would be used if the system 1 did not include the compressor. electric 1 1 and the second cooling circuit 12B. With particular reference to Figs.2A and 2B, it is now described in detail the first and second modes of operation of the water heat exchanger- air 120 respectively corresponding to the operating zones at high speed and low speed of the engine 2.

In the first mode of operation shown in Fig.2A, the engine 2 operates at high speed and the electric compressor 1 1 is not active. It is then only necessary to cool the charge air supplied by the turbocharger 10. In this first mode of operation of the exchanger 120, the pump 122B is not activated (sign "X" in Fig.2A) and there is therefore no water circulation in the electric compressor 1 1. There is then obtained a circulation of water in the cooling circuit 12A with all the cooling capacity of the exchanger 120 which is used. The flow of water through the heat exchange sections 120A and 120B is shown in Fig. 2A by the solid arrows. The cooling water circulates throughout the tubular structure of the exchanger 120 to cool the charge air at the exchanger 121.

In the second mode of operation shown in Fig.2B, the engine 2 operates at low speed, the turbocharger 10 is not active and the charge air is supplied by the electric compressor 1 1. It is then necessary to cool the charge air supplied by the electric compressor 1 1 and also to cool the compressor 1 1 itself (electric motor 1 1 and associated power electronics). In this second mode of operation of the exchanger 120, the 122B and 122A pumps are both activated. A flow of water is then obtained in the two cooling circuits 12A and 12B. In Fig.2B, the flow of water through the heat exchange sections 120A and 120B is shown by solid arrows for the first cooling circuit 12A and by dashed arrows for the second circuit. 12B. In this second mode of operation of the exchanger 120, the heat exchange section 120B is sized to cool the electric compressor 1 1 just necessary when it is activated. In this way, the heat exchange section 120B retains a maximum capacity for cooling the water entering the air-water heat exchanger 121 so as to lower the temperature of the charge air at the level of the exchanger 121.

The architecture of the exchanger 120 according to the invention offers the advantage of being able to be designed so as to provide each of the circuits 12A and 12B a capacitance of water cooling adapted to their needs, and without the need to use an actuator such as a solenoid valve.

Of course, the invention is not limited to the particular embodiment which has been described here by way of example. Those skilled in the art, according to the applications of the invention, may make various modifications and variations that fall within the scope of the appended claims.

Claims

1. Cooling device (12) of an air supercharging system (1) of a heat engine (2) comprising a thermal turbocharger (10) and a water-cooled electric compressor (1 1), characterized in that the device comprises a first cooling circuit (12A) for cooling the charge air supplied by said system (1) to the heat engine (2), a second cooling circuit (12B) for cooling said electric compressor (1 1), and a water-air heat exchanger (120) which is common to both said first and second cooling circuits (12A, 12B).

2. Device according to claim 1, characterized in that the total cooling capacity of said common water-air heat exchanger (120) is dimensioned for said first cooling circuit (12A) for cooling the supercharging air supplied to said heat engine ( 2) when the latter is in a high-speed operating zone in which it delivers its maximum power.

3. Device according to claim 2, characterized in that said common water-air heat exchanger (120) is formed of first and second heat exchange sections (120A, 120B) in fluid communication and together providing said total cooling capacity of the common water-air heat exchanger (120).

4. Device according to claim 3, characterized in that said first cooling circuit (12A) uses said first and second heat exchange sections (120A, 120B).

5. Device according to claim 3 or 4, characterized in that said second cooling circuit (12B) uses said second heat exchange section (120B).

6. Device according to any one of claims 3 to 5, characterized in that the thermal cooling capacity of said second heat exchange section (120B) is dimensioned to cool said electric compressor (1 1) just needed when the electric compressor (1 1) is activated in a low-speed operating zone of said engine (2).

7. Device according to any one of claims 1 to 6, characterized in that said first (12A) and second (12B) cooling circuits respectively comprise first (122A) and second (122B) water pumps.

An air supercharging system (1) for a heat engine (2) comprising a thermal turbocharger (10) and a water-cooled electric compressor (1 1), characterized in that it is equipped with a cooling device cooling device (12) according to one of claims 1 to 7.

9. A combustion engine equipped with a motor vehicle, characterized in that it is equipped with an air supercharging system (1) according to claim 8.

10. Motor vehicle characterized in that it comprises a heat engine equipped (2, 1) according to claim 9.