WO2005116415A1

WO2005116415A1 - Intake air cooler for a turbocharger-equipped heat engine

Info

Publication number: WO2005116415A1
Application number: PCT/FR2005/001056
Authority: WO
Inventors: Carlos Martins; Michel Potier
Original assignee: Valeo Systemes Thermiques
Priority date: 2004-04-29
Filing date: 2005-04-28
Publication date: 2005-12-08
Also published as: FR2869650B1; FR2869650A1

Abstract

The invention relates to a cooler (2) for the charge air sent to the intake of a heat engine, said cooler (2) being dimensioned such as to be mounted on the engine. The inventive charge air cooler (2) comprises first (10) and second (13) heat exchange bodies which are interconnected by means of a central fluid box (6) and which open into a first lateral fluid box (8) and a second lateral fluid box (9) respectively. The invention is suitable for the diesel engines of motor vehicles.

Description

The invention relates to the field of turbocharger heat engines, in particular for motor vehicles.

It relates more particularly to an intake air circuit for a heat engine provided with a turbocharger, of the type comprising an air duct connecting the turbocharger to the engine intake and a cooler mounted on the air duct for cool the charge air sent to the engine intake. Heat engines used on motor vehicles, and in particular diesel engines, are most often fitted with a turbocharger to improve engine performance.

The turbocharger, driven by engine exhaust gases, produces pressurized air, also called "charge air", which is sent to the engine intake. Thus, a turbocharger heat engine is supplied by pressurized air, unlike the conventional heat engine which is supplied by air at atmospheric pressure.

However, since the air coming from the turbocharger is at a high temperature, it is necessary to cool it before sending it to the engine intake, so that the latter can operate under optimal conditions.

This is the reason why a charge air cooler is used (abbreviated as RAS) which is placed at the outlet of the turbocharger to lower the temperature of the charge air, which in particular makes it possible to increase the density of air and provide more air to the engine for a given air volume.

It is known for this to use a cooler which cools the charge air by heat exchange with a flow of liquid, for example water. Conventionally, such an exchanger comprises an inlet fluid box, a heat exchange body and an outlet fluid box.

It is known that such a charge air cooler is installed on the engine in order to occupy a reduced volume under the engine hood. However, given the low height under the hood, this position requires a cooler of small height, but of large dimensions to ensure efficient heat exchange.

This involves large plates or long tubes forming the heat exchange body, which poses manufacturing problems. In addition, a large exchanger involves large pressure drops, especially when the passage of air is in the direction of the largest dimension of the charge air cooler.

One solution is to reduce the size of this cooler, but this is of course to the detriment of the performance of the latter.

The object of the invention is in particular to overcome this drawback.

It aims in particular to optimize the dimensions of the heat exchange body in order to solve the manufacturing problems and to guarantee the performance of the charge air cooler, by avoiding high pressure drops.

The invention proposes for this purpose a charge air cooler sent to the intake of a heat engine, said cooler being able to have dimensions to be installed on the engine.

According to a main characteristic, said charge air cooler comprises a first and a second heat exchange body connected together by a central fluid box located between the two heat exchange bodies, the first body heat exchange, respectively the second heat exchange body, opening laterally and opposite the central fluid box in a first lateral fluid box, respectively in a second lateral fluid box.

While a conventional charge air cooler comprises a single heat exchange body, the invention provides a heat cooler which, with the same conventional dimensions, comprises two heat exchange bodies in which the flow of the charge air to be cooled is shared. The latter thus make it possible to reduce at least half the size of the plates or tubes of each heat exchange body and thus reduce the pressure losses in each heat exchange body.

Preferably, the lateral fluid boxes are molded from plastics, in particular of the polyamide 6.6 (PA6.6) type, and the two heat exchange bodies comprise a common envelope made of aluminum alloy forming the central fluid box. . Thus, the use of plastic compared to the use of a metal alloy for example of an aluminum alloy for the manufacture of the side fluid boxes makes it possible not only to reduce the cost but also of ease the manufacture of forms more complicated side fluid boxes. The use of plastic is subject to the temperature of the air circulating in the side fluid boxes. According to one possible embodiment, the central fluid box comprises a inlet channel for the charge air opening on either side along its length in the two heat exchange body. Each lateral fluid box is an outlet box for the charge air having passed through the corresponding heat exchange body, each lateral fluid box opening onto an air intake plenum (also called the air intake chamber). 'air) contained in the engine.

As an option in this embodiment, the central fluid box comprises a intake air intake manifold and an outlet opening provided with a valve having a movable member displaceable between a position for deflection of the intake air in the engine air intake plenum, in which air is able to circulate from the inlet pipe to the outlet opening without passing through the heat exchange bodies, and a closed position, in which the air is able to circulate from the inlet pipe to the lateral fluid boxes through the heat exchange bodies.

This option allows in particular to choose whether or not to cool either all of the charge air, or part of the charge air, in particular in a so-called "in-line" engine, that is to say that the cylinders of the engine are in line as well as the air intake pipes in the engine included in the charge air intake plenum.

According to another option, the central fluid box includes two charge air inlets and a longitudinal partition defining two parallel channels for charge air inlet, each channel opening along its length in one of the two exchange bodies heat.

This other option is interesting in the case of a so-called V-engine with double turbo, that is to say that the engine cylinders are arranged in a V shape as well as the air intake pipes in the engine and that the engine has two separate air circuits.

According to another possible embodiment, each fluid box side is a charge air inlet box opening into the corresponding heat exchange body, the central fluid box is a charge air outlet box having passed through the heat exchange bodies, the central fluid box opening onto an air intake plenum that the engine contains.

As an option, the two heat exchange bodies are V-shaped, interconnected by the central fluid box.

This option is interesting in the case of a so-called V-shaped motor since it allows not only to adapt to the V-shape of the motor but also to increase the exchange surface of the heat exchange bodies: lateral fluid boxes being fixed to the engine air intake plenum, only the position of the box a _. central fluid can vary in height so as to increase or decrease the area of the heat exchange bodies.

According to another option, the two heat exchange bodies are in the same plane, interconnected by the central fluid box.

In the sense that it is used here, the term "intake" generally designates the intake manifold which receives the charge air and which directs it towards the cylinders of the engine.

In the description which follows, given solely by way of example, reference is made to the appended drawings, in which:

- Figure 1 shows an air intake circuit known from the prior art where the precooled charge air is sent directly to the engine intake;

- Figure 2 is a top view of the charge air cooler integrated in the intake plenum of an in-line engine according to a first embodiment of the invention; - Figure 3 and Figure 4 are respectively a cross-sectional view AA and a longitudinal sectional view BB of the charge air cooler of Figure 2;

- Figure 5 is a top view of the charge air cooler capable of being integrated into the intake plenum of a V-engine according to a second embodiment of the invention;

- Figure 6 and Figure 7 are respectively a longitudinal sectional view C-C of Figure 5 according to a first option and a longitudinal sectional view C-C of Figure 5 according to a second option;

- Figure 8 is a top view of the charge air cooler integrated into the intake plenum of a V-engine according to a third embodiment of the invention;

- Figure 9 is a longitudinal sectional view D-D of Figure 8.

Reference is first made to FIG. 1 which represents a heat engine 40, in particular a diesel engine, intended for a motor vehicle, in particular for a passenger vehicle.

The engine 40 includes an intake manifold 42 (hereinafter called "intake" for simplicity) and an exhaust manifold 44 (hereinafter called "exhaust" for simplicity). The engine 40 is supplied by an intake air circuit comprising an air duct 46 connecting a turbocharger 48 to the intake 42 of the engine. The turbocharger 48 is driven by the engine exhaust gases from the exhaust manifold 44 through the conduit 76 and is supplied by outside air. It produces a flow of pressurized air, called "charge air", which is sent to the intake 42 of the engine. The air duct 46 supplies a charge air cooler 2 (abbreviated as "RAS") which is installed on the engine 40. This cooler has the function of cooling the charge air by heat exchange with the liquid d 'a secondary cooling circuit (not shown). It is therefore an air / water type heat exchanger.

The cooler 2 is installed on the engine 40, which allows it to be connected directly to the air intake plenum (also called the air intake chamber).

However, this installation under the hood of the vehicle implies a low height of the cooler 2 and therefore, to guarantee good performance, a large heat body with large plates or long tubes. These large dimensions imply certain problems such as manufacturing problems or problems of high pressure drop of the air cooler. FIG. 2 illustrates a charge air cooler 2 according to a first embodiment of the invention. This charge air cooler 2 comprises two heat exchange bodies 10 and 13 connected together by a central fluid box 6 and opening out laterally each in a lateral fluid box 8, respectively 9 placed opposite the central fluid box. The charge air to be cooled by this cooler 2 enters according to arrow F5 through an inlet pipe 16 in the central fluid box 6. The heat exchange bodies and the central fluid box are combined in an envelope metal alloy, for example aluminum alloy. The central fluid box 6 is defined by a space between the two heat exchange bodies delimited by this envelope and opening on either side along its length in the channels of the heat exchange bodies. This space is also called an inlet channel. Once entered into the central fluid box, the charge air is directed on one side according to the arrow FI in the channels of the first heat exchange body 10 and the other side according to arrow F2 in the channels of the second heat exchange body.

After passing in the opposite directions on the one hand the channels of the heat exchange body 10 and on the other hand the channels of the heat exchange body 13, the charge air emerges on one side in the box with lateral fluid 8 and on the other side in the lateral fluid box 9.

The lateral fluid boxes 8 and 9 being connected to the air intake plenum 4 of an in-line engine, the charge air circulates from the side fluid boxes 8 and 9 in the air intake plenum 4 according to arrows F3 and F4 before being sent into the air intake pipes 18 of the cylinders of the in-line engine. According to FIG. 2, the air intake plenum 4 of an in-line engine is composed of a tube placed horizontally, opening onto the air intake pipes 18 placed along its length and folded in the horizontal plane at its ends to each receive the end of one of the lateral fluid boxes. Thus, the cooler 2 is placed horizontally under the hood and is connected to the air intake plenum 4 of the in-line engine in the horizontal plane defined by the plane of FIG. 2.

According to a possible option of the invention, the central fluid box 6 comprises an air vacuum valve 20 in the intake air intake pipe 16 in order to create, when this valve is closed, a vacuum air in the engine air intake chamber to allow exhaust gases to enter this air intake chamber. This can be useful for re-burning exhaust gases in the engine cylinders and reducing the emission of harmful gases. It is also possible to provide a deflection valve 15 opening into the air intake plenum 4. This valve 15 comprises a movable member displaceable between a deflection position corresponding to a position opening in which the charge air entering through the intake manifold 16 of the charge air cooler flows into the air intake plenum

4 passing through the open deflection valve 15 and without passing through the two heat exchange bodies 10 and 13 and a closed position in which the air entering the charge air cooler circulates in the central fluid box , then crosses the two heat exchange bodies 10 and 13 before reaching the air intake plenum 4 after crossing the lateral fluid boxes 8 and 9.

This valve 15 can be actuated by a micromotor controlled by a control circuit taking into account the operating parameters of the engine. Thus, by means of this deflection valve 15, the temperature of the charge air on admission to the engine can be regulated. In some cases, for example when it is very cold, the charge air does not need to be cooled. In these cases, the valve 15 is completely open. Each heat exchange body 10 and 13 is formed of parallel channels between them 11 and extending from the central fluid box to the lateral fluid boxes 8 and 9. In these parallel channels, the charge air flows from the central fluid box towards the lateral fluid boxes 8 and 9. These channels 11 are, in known manner, formed on the one hand by straight plates parallel to each other and to the casing of the cooler and extending from the central fluid box to the lateral fluid boxes 8 and 9, and on the other hand by corrugated fins positioned between the straight plates and fixed to them by brazing, each corrugation forming a channel 11 of charge air. Each straight plate defines passages in which a cooling fluid, for example cooling water, circulates, these passages possibly being perpendicular to the channels 11.

The channels 11 in which the charge air circulates can also be defined by parallel fins between them and connected perpendicularly to parallel tubes between them forming a bundle of tubes in which the coolant circulates. These examples of embodiment of channels are not limiting.

References 12 and 14 respectively define the entry according to arrow F6 of the cooling fluid in the charge air cooler 2, and the outlet pipe of the cooling fluid according to arrow F7. The circuit of the coolant of the charge air cooler makes it possible to bathe the channels 11 for circulation of the charge air.

In this embodiment of the invention, the lateral fluid boxes 8 and 9 are advantageously molded from plastic, for example polyamide type 6 PA 6.6 which is an inexpensive plastic. This plastic embodiment of the lateral fluid boxes 8 and 9 is possible insofar as the charge air, after passage through the heat exchange bodies 10 and 13, is at a temperature below the maximum temperature supported by the plastic used to make the lateral fluid boxes 8 and 9. By way of example, this maximum temperature is of the order of approximately 200 ° C.

The use of plastic allows the production of complex molded shapes for the lateral fluid boxes 8 and 9.

Figure 4 shows the charge air cooler 2 in longitudinal section BB. In this embodiment of the invention, the two heat exchange bodies 10 and 13 are in the same plane which is the horizontal plane when the cooler is placed on the engine. The heat exchange body 10, the central fluid box 6 and the heat exchange body 13 are surrounded by the same metal envelope, for example made of aluminum alloy according to the inlet temperatures of the charge air. In the example of FIGS. 2, 3, 4, the same cooling fluid circuit bathes the two heat exchange bodies 10 and 13. It is possible to provide a different cooling circuit for each heat exchange body .

Figures 5, 6 and 7 show a second embodiment of the invention.

Elements identical to those of FIGS. 2 to 4 have been designated by the same reference numerals.

This second embodiment has a charge air cooler for a so-called "V" engine, that is to say for an engine whose cylinders are arranged in a V shape. The charge air cooler of this embodiment is suitable for adapting to this type of engine.

According to Figure 5, the charge air cooler comprises, as before, two heat exchange bodies 10 and 13 connected together by a central fluid box 26 not comprising a bypass valve. This central fluid box comprises a partition 25 along the length of the central fluid box 26 so as to define two parallel air inlet channels, each channel opening along its length into one of the heat exchange bodies 10 and 13. Two air inlet pipes 16-1 and 16-2 are provided for each .channel delimited by the partition of the central fluid box 26. This embodiment makes it possible in particular to balance the air flows entering each of the heat exchange bodies. This embodiment is advantageous, for example in the case of a double-turbo V engine comprising two separate air circuits, a circuit being connected to an air inlet pipe 16.

The heat exchange body 10, respectively 13, opens laterally and opposite the central fluid box on a lateral fluid box 28, respectively 29, comprising outlet pipes 22. These outlet pipes 22 are connected perpendicular to the side fluid boxes. The cooler is suitable for being positioned on the V-engine so that these outlet pipes are placed under the lateral fluid boxes, each outlet pipe 22 fitting onto an air intake pipe of the V-engine.

In this case, the engine air intake plenum is made up of the V-shaped air intake pipes of the engine. As before, a single coolant circuit is provided, fitted with inlet pipes and output 12 and 14, by way of example.

In this second embodiment, the charge air enters the central fluid box 26, opens on either side along its length in each heat exchange body.

10 and 13 to reach each lateral fluid box 28 and 29 and finally enter the air intake plenum of the V-engine via the outlet pipes 22 of the charge air cooler.

For a V engine, it is possible to design a charge air cooler as shown in Figure 6.

In this case, the two heat exchange bodies 10 and 13 are in the same plane.

It is also possible to design a charge air cooler as shown in FIG. 7. In this case, the two heat exchange bodies 10 and 13 form a non-zero angle between them and less than 180 °. This embodiment makes it possible to increase the surface area of the two heat exchange bodies 10 and 13 between the central fluid box and the lateral fluid boxes so as to increase the performance of the charge air cooler. Indeed, the lateral fluid boxes being fixed to the engine air intake plenum, only the position of the central fluid box can vary in height so as to increase or decrease the surface of the heat exchange bodies. In addition, this embodiment allows the shape of the charge air cooler to be adapted to the V shape of the engine.

As in the case of FIGS. 2, 3 and 4, the lateral fluid boxes 28 and 29, comprising the outlet pipes 22 can advantageously be molded in plastic.

The length of the fluid box defines the dimension over which the charge air can enter the channels of the heat exchange bodies from the intake of the charge air.

Figures 8 and 9 describe a third embodiment of the invention. Elements identical to the previous figures are identified by the same reference numeral.

According to these figures, the charge air cooler comprises, as before, two heat exchange bodies 10 and 13 interconnected by a central air box 36 and laterally each comprising a lateral air box 38, 39 located opposite of the central fluid box. The charge air cooler is provided with a coolant circuit comprising an inlet pipe 12 and an outlet pipe 14 for the coolant. As before, it is possible to provide a separate cooling circuit for each heat exchange body 10 and 13.

In this third embodiment, the two lateral air boxes 38 and 39 each each comprise a charge air inlet pipe 30, 31. The charge air entering the side air boxes 38 and 39 passes through the channels of the heat exchange bodies 10 and 13 according to arrows F14 and F15 then opens into the central air box 36. The central air box 36 is provided with an outlet pipe 32 directed downwards, this is i.e. to the engine once cooler 2 is installed on the engine.

This outlet pipe 32 is provided with a vacuum valve

35 controlled so as to create, when this valve is closed, a vacuum to allow the exhaust gases to enter the air intake chamber of the engine.

The outlet pipe 32 opens onto a pipe 34 connecting the charge air cooler to the air intake pipes of the V-engine.

Thus, the charge air arriving in the central air box 36 is directed in the tube 34 towards the air intake pipes of the engine.

As before, it is possible to produce the lateral air boxes 38 and 39 in plastic, for example of the PA6.6 type, provided that the charge air at the inlet of the cooler 2 is at a temperature below the maximum temperature. supported by the plastic forming the lateral fluid boxes 38 and 39, for example 200 °.

The invention finds an application to the engines of motor vehicles, and in particular to passenger vehicles.

Claims

claims

1. Cooler (2) of charge air sent to the intake (42) of a heat engine (40), characterized in that it comprises a first and a second heat exchange body (10,13 ) interconnected by a central fluid box (6, 26, 36) located between the two heat exchange bodies, the first heat exchange body (10), respectively the second heat exchange body (13), opening laterally and opposite the central fluid box in a first lateral fluid box (8, 28, 38), respectively in a second lateral fluid box (9, 29, 39).

2. Cooler according to claim 1, characterized in that the ^' lateral fluid boxes (8, 9; 28, 29; 38, 39) are molded from plastics, in particular of the PA66 type, and in that the two bodies d heat exchange (10, 13) comprises a common envelope of aluminum alloy forming the central fluid box (6, 26, 36).

3. Cooler according to one of claims 1 and 2, characterized in that the central fluid box (6, 26) comprises a inlet channel for the charge air opening on either side along its length in the two heat exchange bodies (10, 13), each lateral fluid box (8, 9; 28, 29) is a charge air outlet box having passed through the corresponding heat exchange body ( 10,13), each lateral fluid box opening onto an air intake plenum (4) that the engine includes.

4. Cooler according to claim 3, characterized in that the central fluid box (6) comprises a intake air intake manifold (16) and an outlet opening provided with a valve (15) having a member movable movable between a deflection position of the charge air in the engine air intake plenum (4), in which the air is able to flow from the inlet pipe (16) to the outlet opening without passing through the heat exchange bodies, and a closed position, in which the air is able to flow from the inlet pipe ( 16) to the lateral fluid boxes (8,9) passing through the heat exchange bodies (10,13).

5. Cooler according to claim 3, ^' characterized in that the central fluid box (26) comprises two charge air inlets and a longitudinal partition defining two parallel channels for entering the charge air, each channel opening along its length in one of the two heat exchange bodies (10,13).

6. Cooler according to one of claims 1 and 2, characterized in that each lateral fluid box (38,39) is a box for the intake of the charge air opening into the corresponding heat exchange body ( 10,13), the central fluid box (36) is a charge air outlet box having passed through the heat exchange bodies, the central fluid box (36) opening onto a plenum (34) d intake of air from the engine (40).

7. Cooler according to one of claims 3 to 5, characterized in that the two heat exchange bodies (10, 13) are V-shaped, interconnected by the central fluid box (26) .

8. Cooler according to one of claims 1 to 4 and 6, characterized in that the two heat exchange bodies (10,

13) are in the same plane, interconnected by the central fluid box (6, 26, 36).

9. Cooler according to one of the preceding claims wherein said cooler (2) has dimensions to be installed on the engine (40).