Technical field

The present invention concerns a three-way valve. In particular, the three-way valve may be used to control the flow direction of oil or of a cooling fluid in the internal combustion engine of a vehicle, such as a truck. The invention then also concerns a vehicle comprising such a three-way valve.

Background of the invention

In the automotive industry, the cooling circuits and lubricant systems are often provided with three-way valves for controlling the fluid flow. Typically, three-way valves may be used to lead oil or cooling fluid to a heat exchanger when the fluid temperature is too high or too low. To this end, actual three-way valves work with wax or with an electromagnetic assembly. In both cases, there is a mobile part that moves in translation under the effect of wax expansion or electromagnetic force. The amplitude of the mobile part movement depends on the size of the valve.

One major drawback of such valves is that there is a high pressure drop downstream the valve. This high pressure drop partly arises from a significant flow deviation through the valve. Another drawback of such valves is that they are made of several components. This results in a complex manufacturing process and high associated costs.

A simpler solution is known for what concerns two-way valves. In particular, US 2011/0097648 A1 discloses an electromechanical cell, provided with a fluid flow channel. An element is arranged within the fluid flow channel for controlling the fluid flow. This element is a bimetallic strip reducing flow cross section of the channel by a thermally induced change in shape when there is a change of fluid temperature. The bimetallic strip is plate-shaped and fastened by an end to a wall of the channel.

US 3 513 881 discloses a fluid flow regulator comprising a duct through which fluid may flow and two bimetallic sheets disposed against opposite walls of the duct. The bimetallic sheets have a curvature to form a streamlined throat section through which the fluid flows, their curvature becoming straighter as the fluid temperature increases. This results in an increase of the throat section area.

However, nothing exists for three-way valves.

The aim of the present invention is then to propose an improved three-way valve that remedies the abovementioned drawbacks. Summary of the invention

To this end, the invention concerns a three-way valve comprising a first fluid channel, a second fluid channel, and a third fluid channel. According to the invention, the three-way valve includes a closing member that is movable, as a function of the fluid temperature, between a first configuration in which the closing member prevents the fluid from flowing between the first fluid channel and the second fluid channel and a second configuration in which the closing member prevents the fluid from flowing between the first fluid channel and the third fluid channel. Further; the closing member includes at least one bi-material strip.

Further advantageous features of the valve are defined below:

In the first configuration, the closing member does not prevent the fluid from flowing between the first fluid channel and the third fluid channel.

In the second configuration, the closing member does not prevent the fluid from flowing between the first fluid channel and the second fluid channel.

The closing member is movable in a third configuration in which the closing member does not prevent the fluid from flowing between the first fluid channel, the second fluid channel and the third fluid channel.

Said at least one bi-material strip is elongated and comprises two ends, wherein the first end is attached to a non-movable part of the three-way- valve and the second end is movable between the first and the second configuration.

The bi-material strip is arranged in the three-way-valve such that it extends from its first end to its second end in a direction opposite to that of the fluid flow.

Said at least one bi-material strip is deformable depending on the fluid temperature.

Said at least one bi-material strip is designed to bend depending on the fluid temperature towards the first configuration or the second configuration.

The closing member includes only one bi-material strip.

The first fluid channel, the second fluid channel and the third fluid channel are designed with a general Ύ” shape.

Channels are substantially parallel to each other. The second fluid channel and the third fluid channel are separated by a dividing wall, while a first end of the bi-material strip is attached to said dividing wall.

The closing member includes two bi-material strips.

Both bi-material strips are configured such that, in at least one of the first or second configuration, they are bent in the same direction. Both bi-material strips are configured such that, when they are bent in the same direction, they bend following the same curves.

Both bi-material strips are arranged in the three-way valve side by side and are arranged such that, in a rest position where they are not bent, both bi-material strips lie parallel.

Both bi-material strips form between them a duct having approximately the same cross-sections along its length.

The two bi-material strips are identical.

Said at least one bi-material strip is made of at least two different material layers having different thermal expansion coefficients.

Said at least one bi-material strip is a bi-metallic strip made of two different metallic layers, a strip made of a polymer layer and a metallic layer, or a strip made of two different polymer layers.

The first fluid channel, the second fluid channel and the third fluid channel all extend in the same direction.

Thanks to the invention, there is no need for wax or electromagnetic element to close the valve when the fluid temperature increases. The bi-material strip automatically deforms as a function of the fluid temperature and closes the appropriate channel among the second and the third channel. The construction of the valve is then easier and cheaper than that of thermostatic valves working with wax or solenoid valves. In addition, there is less pressure drop downstream of the valve.

The invention also concerns a vehicle comprising a three-way valve as described above.

Brief description of the drawings

The invention will be better understood from reading the following description, given solely by way of two non-limiting example and with reference to the appended drawings, which are schematic depictions, in which:

- Figure 1 represents a first embodiment of a three-way valve according to the invention,

- Figure 2 represents a second embodiment of a three-way valve according to the invention, and

- Figure 3 represents a vehicle comprising the three-way valve according to the first or the second embodiment. Detailed description of example embodiments of the invention

Figure 1 represents a first embodiment of a three-way valve 1 , comprising a first fluid channel 2, a second fluid channel 4 and a third fluid channel 6.

Typically, the fluid may be a cooling fluid of a thermal engine cooling circuit (not represented) or oil circulating in a lubricant system (not represented). Therefore, and as shown on figure 3, the three-way valve 1 may be boarded on a vehicle 3.

Preferably, the first fluid channel 2 is an inlet channel and the fluid channels 4 and 6 are outlet channels. This means that, in normal use conditions, the fluid enters the channel 2 and escapes from the channel 4 and/or 6.

For example, and as shown on figure 3, the first fluid channel 2 of the three-way valve 1 may be connected to a fluid tank 100, the fluid channel 4 may be connected to a heat exchanger 102 and the fluid channel 6 may be connected to the lubricant circuit or to the cooling circuit 104. Accordingly, while the fluid is cold, it flows through the valve 1 from the tank 100 to the cooling circuit of to the lubricant circuit 104. However, when the fluid temperature is too high, the fluid is progressively deviated towards the fluid channel 4, i.e. towards the heat exchanger 102 in order to be cooled.

Advantageously, the first fluid channel 2, the second fluid channel 4 and the third fluid channel 6 all extend in the same direction, so as to avoid as much as possible flow deviation(s) and fluid pressure drop downstream of the valve 1. This means that channels 2, 4 and 6 are substantially parallel to each other. Inside the valve the first fluid channel 2, the second fluid channel 4 and the third fluid channel 6 are preferably designed with a general“Y” shape.

The three-way valve 1 includes a closing member 8 that is movable, as a function of the fluid temperature, between a first configuration in which the closing member 8 prevents the fluid from flowing between the first fluid channel 2 and the second fluid channel 4 and a second configuration in which the closing member 8 prevents the fluid from flowing between the first fluid channel 2 and the third fluid channel 6.

On figure 1 , the first configuration is represented by a thick line and the second configuration is represented by a thin line.

In the example, in the first configuration, the closing member 8 does not prevent the fluid from flowing between the first fluid channel 2 and the third fluid channel 6. In the second configuration, the closing member 8 does not prevent the fluid from flowing between the first fluid channel 2 and the second fluid channel 4.

The closing member 8 includes at least one bi-material strip. In the first embodiment of figure 1 only one bi-material strip is provided. Preferably, the bi-material strip 8 is deformable as a function of the fluid temperature. Preferably the bi-material strip 8 is a bi- metallic strip made of two different metallic layers.

The bi-material strip 8 may include two bonded metallic plates made of different materials, i.e. materials with a different expansion coefficient. For example, one of the metallic plates may be in copper, while the other may be in steel. Therefore, when the fluid temperature changes, one of the bonded plates expands or retracts more than the other and the bi-material strip bends in one or the other direction, depending on whether the fluid temperature increases or decreases.

In a variant, the bi-material strip 8 can be a strip made of a polymer layer and a metallic layer, or can be a strip made of two different polymer layers having different expansion coefficients.

When the bi-material strip 8 deforms, it takes up a curved shape providing the advantage of smoothly guiding the flow of fluid towards fluid channel 4 or 6 and thus of limiting pressure drop downstream of the valve 1.

Advantageously, the closing member 8 is movable in a third configuration in which the closing member 8 does not prevent the fluid from flowing between the first fluid channel 2, the second fluid channel 4 and the third fluid channel 6. In this third configuration, the fluid channels 2, 4 and 6 are then all connected with each other. This third configuration is represented by a dotted line on figure 1.

In the example, considering that the closing member 8 is initially in the third configuration, the closing member 8 moves from the third configuration to the first configuration when the fluid temperature increases and from the third configuration to the second configuration when the fluid temperature decreases. The third configuration is an intermediate configuration between the first configuration and the second configuration.

Preferably, the fluid channels 2, 4 and 6 are of rectangular section and the bimaterial strip 8 is of rectangular shape and has a width that is identical to that of the fluid channels section. The width is measured along a direction that is perpendicular to the plane of figure 1.

In the example, the bi-material strip 8 has an elongated shape and has a first end 80 which is attached to a fixed part 10 of the valve 1. Typically, the end 80 may be welded, bolted or glued to the fixed part 10. The bi-material strip 8 has also a second end 82 opposite to the first one 80 which is a free end, i.e. which moves in a direction substantially perpendicular to the length of the strip 8 when the strip is moving as a function of the fluid temperature. The second fluid channel 4 and the third fluid channel 6 are preferably separated by a dividing wall and the first end 80 is preferably attached to said dividing wall. The resulting structure is very simple regarding its design.

The bi-material strip is arranged in the three-way-valve such that it extends from its first end 80 to its second end 82 in a direction opposite to that of the fluid flow. Due to this configuration, the fluid upstream from the bi-material strip 8 exerts a pressure on the bimaterial strip 8 that tends to maintain the bi-material strip 8 in the first or second configuration.

In a variant, the fluid channels 2, 4 and 6 may be of round or oval section. In this case a flexible terminal portion made for instance of flexible polymer can be provided at thee free end 82 of the bi-material strip 8. According to this variant, the added flexible terminal portion is designed to deform in a transverse direction to conform to the round or oval shape of the section in order to seal the corresponding channel 4 or 6.

Figure 2 represents a second embodiment of a three-way valve 1. The elements of the valve 1 that are identical or similar to that of the valve represented on figure 1 keep their numeral reference. In addition, for conciseness purpose, only the differences with respect to the first embodiment are described hereafter.

In the embodiment of figure 2, the closing member 8 includes two bi-material strips 8.1 and 8.2. Typically, the bi-material strips 8.1 and 8.2 have one fixed end that is attached to a fixed part 10 of the valve using screws 12. Obviously, other fixing means may be envisaged (glue, welding, bolts, etc.).

Preferably, the two bi-material strips 8.1 and 8.2 are made of the same materials. Preferably, the two bi-material strips 8.1 and 8.2 are arranged in the three-way valve 1 side by side and such that, in a rest position where they are not bent, both bi-material strips 8.1 and 8.2 lie parallel to each other. Typically, the strips 8.1 and 8.2 are identical and comprise each of them at least two layers with different thermal expansion coefficients. Therefore, when the bi-material strips 8.1 and 8.2 deform, they take up the same curved shape providing the advantage of forming a curved duct with a constant cross-section along its length. Then, the fluid is smoothly guided between the first fluid channel 2 and the first fluid channel 4 and pressure drop downstream of the valve 1 is limited.

In this embodiment, the bi-material strip 8.2 of the closing member 8 prevents the fluid from flowing between the first fluid channel 2 and the second fluid channel 4 in the first configuration and the bi-material strip 8.1 of the closing member 8 prevents the fluid from flowing between the first fluid channel 2 and the third fluid channel 6 in the second configuration. In the first configuration, the bi-material strip 8.1 of the closing member 8 does not prevent the fluid from flowing between the first fluid channel 2 and the third fluid channel 6. In the second configuration, the bi-material strip 8.2 of the closing member 8 does not prevent the fluid from flowing between the first fluid channel 2 and the second fluid channel 4.

As in the first embodiment, the closing member 8 is movable in a third configuration in which it does not prevent the fluid from flowing between the first fluid channel 2, the second fluid channel 4 and the third fluid channel 6. As in the first embodiment, on figure 2, the first configuration is represented by thick lines, the second configuration is represented by thin lines and the third configuration is represented by dotted lines.

In the example, considering that the closing member 8 is initially in the first configuration, the closing member 8 moves from the first configuration to the second configuration when the fluid temperature increases. The third configuration is an intermediate configuration between the first configuration and the second configuration.

The features of the two described embodiments and non-represented alternative embodiments may be combined together so as to generate new embodiments of the invention.