GB2513446A

GB2513446A - An improved intercooler for an engine

Info

Publication number: GB2513446A
Application number: GB1402897.1A
Authority: GB
Inventors: Tom Robert George Thompson; David Davies; Peter Ricketts
Original assignee: Ford Global Technologies LLC
Current assignee: Ford Global Technologies LLC
Priority date: 2013-04-18
Filing date: 2014-02-19
Publication date: 2014-10-29
Anticipated expiration: 2034-02-19
Also published as: GB201402897D0; GB2513446B; GB201307053D0; GB2513171B; GB2513171A; GB2513447A; RU152512U1; DE102014105059A1; GB2513447B; GB201402898D0

Abstract

An air-to-air intercooler comprising a charge air inlet 15 and outlet 16, a front face 8 via which ambient air enters the intercooler, a rear face 7 via which ambient air exits the intercooler, and an ambient air flow control device 10 located on the rear face and controlled based upon the temperature of the ambient air exiting the intercooler. The flow control device preferably includes a number of flow control members, for example rotatable slats 11, opened and closed by a single temperature responsive actuator 20 or by individual respective actuators. The front and rear faces may be of a heat transfer unit, which may be a heat transfer matrix. Preferably, the flow control device extends along only part of the length of the heat transfer unit and is positioned at the charge air inlet end. The invention reduces the risk of condensation forming within the intercooler by avoiding overcooling of the charge air.

Description

An Improved Intercooler for an Engine This invention relates to an intercooler for an internal combustion engine and, in particular, to an intercooler for an engine of a motor vehicle.

Forced induction engines such as turbocharged and supercharged engines are configured to compress arrbient air entering the engine in order to increase power. Because compression of the air will cause an increase in temperature of the air it is known to use an intercooler or charge-air cooler to cool the air before it is indicted into the engine thereby increasing the density of the charge air.

is If the humidity of the ambient air is high, condensation in the form of water droplets may form on any internal surface of the intercooler that is cooler than the dew point of the compressed charge air. During certain engine operating conditions such as, for example, hard acceleration these water droplets may be blown out of the intercooler and into the cortustion chambers of the engine resulting in engine misfire, loss of torgue and potential damage to components of the engine.

The formation of such water droplets is often due to over cooling of the charge air when the engine is running at light load due to the need to design the intercooler to sufficiently cool the induction air when operating at maximum load and speed.

It is known from, for example, US Patent US6314950 to provide a cooler flow control device that uses a control system to control the position of flaps located on a front face of the cooler and Patent publication W02008/002265 discloses a cooler flow control device that uses a pneumatic or hydraulic cylinder to move flaps in order to control the flow of ambient air through the cooler.

It Is further known from, for example, Patent publications DE 102009 036 745 and 11S2002/0195090 to provide a cooler flow control device having flaps on a front face of the cooler.

It is an object of the invention to provide an air to air intercooler for an engine in which the risk of the formation of condensation within the intercooler is reduced in a simpler and more cost effective manner and with minimum impact on the underlying performance of the intercooler.

According to a first aspect of the invention there is provided an intercooler for an engine having an inlet end via which charge air enters the intercooler, an outlet end via which charge air exits the intercooler, a front face via which ambient air enters the intercooler, a rear face via which ambient air exits the intercooler and an ambient air flow control device located on the rear face of the intercooler to vary the flow of ambient air through the part of the intercooler it overlies, wherein control of the ambient air flow control device is based upon the temperature of the ambient air exiting the intercooler.

The ambient air flow control device may include one or more flow control members that are moveable between open and closed positions by at least one temperature responsive actuator positioned to react to the temperature of the ambient air exiting the intercooler and the at least one temperature responsive actuator adjusts the position of said one or more flow control members based upon the temperature of the ambient air exiting the intercooler so as to vary the flow of ambient air through the ambient air flow control device.

There may be a number of flow control members and the position of all of the flow control members may be adjusted based upon the temperature of the ambient air exiting the intercooler and opening and closing of all of the flow control members is performed by a single temperature responsive actuator.

Alternatively, there may be a number of flow control members and the position of the flow control members may be adjusted based upon the temperature of the ambient air exiting the intercooler and opening and closing of each of the flow control members is individually performed by a respective temperature responsive actuator.

As yet another alternative there may be several temperature responsive actuators each actuator controlling the position of two or more flow control members.

Each flow control member may be a rotatable slat.

In which case, the position of each flow control member may be adjusted by changing a rotational position of a

rotatable slat.

The front and rear faces may be front and rear faces of a heat transfer unit forming part of the intercooler and through which the charge air flows from an inlet end of the heat transfer unit to an outlet end of the heat transfer unit.

The ambient air flow control device may extend along only part of the length of the heat transfer unit.

The ambient air flow control device may be positioned at the inlet end of the heat transfer unit.

The heat transfer unit may be a heat transfer matrix.

According to a second aspect of the invention there is provided a motor vehicle having an intercooler constructed in accordance with said first aspect of the invention.

The invention will now be described by way of example with reference to the accompanying drawing of which:-Fig.l is a diagrammatic rear view of an intercooler for an engine constructed in accordance with a first aspect of the invention showing an ambient air flow control device in a closed position; Fig.2 is a view similar to Fig.1 but showing the ambient air flow control device in an open position; Fig.3 is a diagrammatic plan view of the intercooler shown in Fig.1; Fig.4 is a diagrammatic plan view of the intercooler shown in Fig.2; Fig.5 is a diagrammatic side view of a motor vehicle constructed in accordance with a second aspect of the invention having an intercooler constructed in accordance with the first aspect of the invention.

Referring firstly to Fig.7 there is shown a motor vehicle 1 having an internal combustion engine 2. An intercooler 5 is connected to an air induction system of the engine 2 by respective supply and return conduits indicated by a single line 3 on Fig.7. Hot charge air from the air induction system passes through passageways formed in the intercooler 5 and is cooled by ambient air through which the motor vehicle 1 is passing as indicated by the arrow D' In some cases an intercooler fan may be provided to maintain an air flow through the intercooler 5 even when the motor vehicle 1 is not moving. The charge air is returned after cooling to the air induction system of the engine 2.

To prevent the formation of condensation within the intercooler 5 an ambient air flow control device 10 is provided on a rear or ambient air downstream side of the intercooler 5. The ambient air flow control device 10 is operable to control or regulate the flow of ambient air through the intercooler 5 and can be of any suitable design.

The ambient air flow control device 10 is preferably located near to an inlet end of the intercooler 5 and extends for only part of the length of the intercooler 5.

When the ambient air flow control device 10 is in an open position, the flow of ambient air through the portion of the intercooler 5 over which it extends is substantially unaffected compared to a case where no ambient air flow control device is used. When the ambient air flow control device 10 is in a closed position, the flow of ambient air through the portion of the intercooler 5 over which it extends is significantly reduced compared to a case where no ambient air flow control device is used and substantially no ambient air can flow through the portion of the intercooler S over which it extends while the ambient air flow control device 10 is in the closed position.

Referring now to Figs.1 to 4 there is shown in more detail an embodiment of the intercooler 5.

The intercooler 5 comprises inlet and outlet end tanks and 16 through which charge air respectively enters and leaves the intercooler 5 as indicated by the arrows VA and "B" and a central body portion 17 supporting an air to air heat transfer unit in the form of heat transfer matrix 6 in which heat transfer from the charge air to the ambient air takes place during use. The heat transfer matrix 6 has a length "L", height "H" and a width "W".

The inlet tank 15 is located at a charge air inlet end of the intercooler 5 and the outlet end tank 16 is located at a charge air ontlet end of the intercooler 5.

As is well known in the art, the heat transfer matrix 6 includes one or more charge air flow passages (not shown) through which the charge air flows in a generally longitudinal direction of the intercooler 5 from an inlet end of the heat transfer matrix 6 to an outlet end of the heat transfer matrix 6 and a plurality of fins (not shown) exposed to the flow of ambient air and conductively connected to the charge air flow passages so as to conduct heat away from the charge air flow passage or passages.

The air to air heat transfer unit can be of any known type and the invention is not limited to the use of a particular type of air to air heat transfer unit or to the use of a particular type of heat transfer matrix.

2\ri ambient air flow control device 10 is attached to a rear face of the intercooler 5 so as to be located on a downstream side of the heat transfer matrix 6.

In the example shown, the ambient air flow control device 10 is positioned close to the charge air inlet end of the intercooler 5 that is to say, towards the inlet end tank and overlies a portion of the heat transfer matrix 6 at an inlet end of the heat transfer matrix 6. The ambient air flow control device 10 is located on a rear face 7 of the heat transfer matrix 6.

The size of the ambient air flow control device 10 will depend upon a number of factors including, but not limited to, the total heat transfer capacity of the heat transfer matrix 6 and the amount of heat that needs to extracted from the charge air when the engine 2 is operating at low power to prevent condensation occurring. It is not necessary for the ambient air flow control device 10 to extend along the entire length "L" of the heat transfer matrix 6 and an ambient air flow control device 10 that extends for less than half the length "L" of the heat transfer matrix 6 is normally all that is required to prevent condensation from occurring.

In the example shown, the ambient air flow control device 10 extends for approximately one third of the length "I!' of the heat transfer matrix 6.

The ambient air flow control device 10 comprises a frame 13 moveably supporting a number of rotatable louvres or slats 11 and an actuator 20 for moving the slats 11 In the example shown the slats 11 are arranged to extend in a vertical direction but it will be appreciated that they could alternatively be arranged to extend horizontally.

Each of the slats 11 can rotate from a closed position (as shown in Figs.1 and 3) to an open position (as shown in Figs.2 and 4) . In the open position a number of ambient air flow passages 12 are produced between adjacent open slats 11 through which ambient air can flow (Only shown on Figs.2 and 4) All of the slats 11 are in this case mechanically connected together and are moved by a single temperature responsive actuator in the form of a bimetallic strip actuator 20 (only shown on Figs.3 and 4) The bimetallic strip actuator 20 is positioned so as to react to the temperature of the ambient air exiting the heat transfer matrix 6 and so provides a controlling output based upon the temperature of the ambient air impinging against it.

The bimetallic actuator 20 is operable to adjust the rotational position of the slats 11 so as to open the slats 11 (or maintain them fully open if already in the fully open position) when the ambient air out temperature is such that condensation in unlikely to occur and close the slats U (or keep them in the fully closed position) when the ambient air out temperature is such that condensation could occur.

By controlling the rotational position of the slats 11 in this manner maximises engine performance by providing maximum cooling when required while preventing the formation of condensation within the charge air passages of the heat transfer matrix 6 by reducing the cooling effect when the charge temperature is lower.

Although a single actuator is used in the illustrated example, it will be appreciated that there could be a like number of temperature responsive actuators formed by bimetallic actuators as there are slats. With such an embodiment each slat is moved individually by their respective actuator based upon the temperature of the ambient air impinging against it. That is to say, each bimetallic actuator will react individually to the temperature of the ambient air exiting the heat transfer matrix so as to adjust the rotational position of the respective slat to which it is connected. In such a case the bimetallic actuators could be arrange to respond differently to temperature and each slat would open and close based upon a different ambient air out temperature versus position relationship.

As yet another alternative there may be several temperature responsive actuators with each actuator controlling the position of two or more flow control members forming a group of slats. In such a case the bimetallic actuators could be arrange to respond differently to temperature and each group of slats would open and close based upon a different ambient air out temperature versus position relationship.

Operation of the ambient air flow control device 10 is as follows. During operation of the motor vehicle 1 ambient air flows through the heat transfer matrix 6 in the direction of the arrows "D" shown on Figs. 3 and 4.

The passage of the ambient air through the heat transfer matrix 6 will cool the charge air as it passes through the heat transfer matrix 6 from the front face 8 of the heat transfer matrix 6 to the downstream or rear face 7 of the heat transfer matrix 6 and the temperature of the ambient air will increase. The increase in ambient air out temperature is used as an indication of the probable charge air temperature in the heat transfer matrix 6 and, in particular, whether the charge air temperature is likely to be low enough to produce a risk of condensation occurring within the charge air passages of the heat transfer matrix 6.

The charge air enters the intercooler 5 via the inlet end tank 15 and exits the intercooler 5 via the outlet end tank 16 as indicated by the arrows "A" and "B".

If the ambient air out temperature is high then it can be inferred that there is no risk of condensation forming and so the ambient air flow control device 10 assumes a fully open state as shown in Figs.2 and 4 in which the flaps 11 are fully open and there is virtually no restriction to ambient air flow.

However, if the ambient air out temperature falls below a certain pre-calibrated temperature there is a risk of -10 -condensation occurring within the charge air flow passages at or near to the outlet end of the heat transfer matrix or within the outlet end tank 16. Cooling of the charge air must therefore be reduced in order to reduce the risk of condensation occurring. The bimetallic actuator 20 is then operable to move or adjust the rotational position of the slats 11 from their respective fully open positions towards their respective closed positions in order to reduce the cooling effect of the heat transfer matrix 6 in the region over which the ambient air flow control device 10 is positioned. If the temperature of the charge air continues to fall or is still too low, the bimetallic actuator 20 will continue to move or adjust the rotational position of the slats 11 towards their respective closed positions until, eventually, all of the slats 11 are in their respective closed positions (as shown in Figs.1 and 3).

In an alternative embodiment (not shown) , the slats 11 are either fully open or fully closed. A mechanism is provided to hold the slats 11 closed against the action of the bimetallic actuator 20 until the ambient air out temperature exceeds a first upper temperature threshold at which point the bimetallic actuator 20 overcomes the mechanism and the slats U will then move rapidly to their respective fully open positions. The slats 11 are then held open by the mechanism until the temperature falls below a second lower temperature threshold at which point the action of the bimetallic actuator 20 overcomes the mechanism and the slats 11 move rapidly to their respective fully closed positions.

When the slats 11 are in their fully closed positions substantially no ambient air can flow through the part of the heat transfer matrix 6 covered by the ambient air flow control device 10. Therefore, when the ambient air flow control device 10 is in a closed state, the effective cooling area of the heat transfer matrix 6 is significantly

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reduced compared to the situation when ambient air flow control device 10 is in an open state. When the ambient air flow control device 10 is in the open state, there is only a small reduction in the cooling area of the heat transfer matrix 6 due primarily to the presence of the frame 13 of the ambient air flow control device 10.

It will be appreciated that the cooling effect of the heat transfer matrix 6 per unit area is considerably higher at the charge air inlet end of the intercooler 5 than it is at the charge air outlet end of the intercooler 5 due to the greater temperature difference at the charge air inlet end of the intercooler 5 compared to the oharge air outlet end of the intercooler 5.

In addition, due to the very high cooling effect of the heat transfer matrix 6 towards the charge air inlet end of the intercooler 5, if the ambient air flow control device 10 were to be positioned close to the charge air outlet end of the intercooler 5 there is a possibility that the charge air could be overcooled that is to say, cooled below the dew point before the charge air reaches the ambient air flow control device 10, thereby risking condensation within the charge air flow passages.

It is therefore advantageous to position the ambient air flow control device 10 at or near to the charge air inlet end of the intercooler 5.

By mounting the ambient air flow device 10 on the rear face 7 of the heat transfer matrix 6 a temperature responsive actuator can se the temperature of the ambient air exiting the heat transfer device to control opening and closing of the ambient air flow control device 10. It will be appreciated by those skilled in the art that, if a temperature responsive actuator is positioned upstream of the heat transfer matrix, the temperature responsive -12 -actuator will only be responsive to the temperature of the ambient air entering the heat transfer matrix 6 and so cannot be used to control the ambient air flow control device 10.

One feature of the invention is that the temperatllre sensed for controlling operation of the ambient air flow control device is the cutlet temperature of the ambient air, this temperature is used because it is possible to infer or estimate whether condensation is likely to occur within the intercocler based upon this temperature and use a simple temperature responsive mechanism to control the operation of the ambient flow control device.

Although in the examples shown the ambient air flow control device extends for less than half of the length of the heat transfer matrix it overlies it will be appreciated that it could extend for the entire length of the heat transfer matrix if required.

Although, preferably, the ambient air flow control device covers the entire height of the heat transfer matrix for the length of the heat transfer matrix it overlies this need not be the case and the ambient air flow control device could have a height less than the height of the adjacent heat transfer matrix.

One advantage of using a temperature responsive actuator such as a bimetallic strip actuator is that the actuator is simple in construction and therefore relatively inexpensive to manufacture compared to a powered actuator.

In addition, no additional sensors or control apparatus is required and the bimetallic actuator does not need to be further calibrated once initial calibration has taken place.

One advantage of locating the ambient air flow control device on the rear face of the intercooler is that, if the -13 -control linkage fails during use, the pressure of the ambient air flowing through the intercooler will tend to open the rotatable slats. This is particularly so if the slats are mounted asymmetrically relative to the axis of rotation.

Although the flow control members are described above with respect to rotatable slats it will be appreciated that other types of flow control members could be used such as for example one or more slideable slats or one or more rotary disc valves or any other suitable type of flow control member.

It will be appreciated by those skilled in the art that although the invention has been described by way of example with reference to one or more embodiments it is not limited to the disclosed embodiments and that alternative embodiments could be constructed without departing from the scope of the invention as defined by the appended claims.

Claims

-14 -Claims 1. An intercooler for an engine having an inlet end via which charge air enters the intercooler, an outlet end via which charge air exits the intercooler, a front face via which ambient air enters the intercooler, a rear face via which ambient air exits the intercooler and an ambient air flow control device located on the rear face of the intercooler to vary the flow of ambient air through the part of the intercooler it overlies, wherein control of the ambient air flow control device is based upon the temperature of the ambient air exiting the intercooler.
2. An intercooler as claimed in claim 1 in which the ambient air flow control device includes one or more flow control members that are moveable between open and closed positions by at least one temperature responsive actuator positioned to react to the temperature of the ambient air exiting the intercooler wherein the at least one temperature responsive actuator adjusts the position of said one or more flow control merters based upon the temperature of the ambient air exiting the intercooler so as to vary the flow of ambient air through the ambient air flow control device.
3. An intercooler as claimed in claim 2 wherein there are a number of flow control members and the position of all of the flow control members is adjusted based upon the temperature of the ambient air exiting the intercooler and opening and closing of all of the flow control members is performed by a single temperature responsive actuator.
4. An intercooler as claimed in claim 2 wherein there are a number of flow control members and the position of the flow control members is adjusted based upon the temperature of the ambient air exiting the intercooler and opening and closing of each of the flow control members is individually performed by a respective temperature responsive actuator.

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5. An intercooler as claimed in any of claims 2 to 4 wherein each flow control member is a rotatable slat.
6. An intercooler as claimed in claim 5 wherein the position of each flow control member is adjusted by changing a rotational position of a rotatable slat.
7. An intercooler as claimed in any of claims 1 to 6 wherein the front and rear faces are front and rear faces of a heat transfer unit forming part of the intercooler and through which the charge air flows from an inlet end of the heat transfer unit to an outlet end of the heat transfer unit.
8. An intercooler as claimed in claim 7 wherein the ambient air flow control device extends along only part of the length of the heat transfer unit.
9. An intercooler as claimed in claim 8 wherein the ambient air flow control device is positioned at the inlet end of the heat transfer unit.
10. An intercooler as claimed in any of claims 7 to 9 6 or in claim 7 wherein the heat transfer unit is a heat transfer matrix.
11. A motor vehicle having an intercooler as claimed in any of claims 1 to 10.
12. An intercooler for an engine substantially as described herein with reference to the accompanying drawing.
13. A motor vehicle substantially as described herein with reference to the accompanying drawing.