Mild hybrid vehicle comprising a low-temperature cooling circuit

Abstract

One aspect of the invention relates to a mild hybrid vehicle (1) comprising a low-temperature cooling circuit (2) that extends through a heat exchanger (3), further comprising an inverter (4) of an electric traction machine, a power battery (5) arranged to supply power to the electric traction machine, a DC-DC converter (6) arranged to recharge a service battery by means of the power battery (5), and a pump (7) arranged to force the cooling fluid to flow in the low-temperature cooling circuit (2), said vehicle (1) being characterized in that the low-temperature cooling circuit (2) includes a first pipe (11) that is connected to the output of the inverter (4) and to the inlet of the heat exchanger (3), said first pipe (11) being opposite a radiator (9) for cooling a heat engine (8), the radiator (9) being arranged in an accessory facade (12) of the vehicle (1).

Description

DESCRIPTION TITLE OF THE INVENTION: SEMI-HYBRID VEHICLE COMPRISING A LOW-TEMPERATURE COOLING CIRCUIT

[0001] The present invention claims priority from French application No. 2212908 filed on 07.12.2022, the content of which (text, drawings and claims) is incorporated herein by reference.

[0002] One aspect of the invention relates to a semi-hybrid vehicle comprising a low-temperature cooling circuit, in particular for a power battery and an inverter of an electric traction machine.

[0003] Such a semi-hybrid vehicle is better known by the acronym MHEV (for “Mild Hybrid Electric Vehicle” in English) and can include a power battery with a voltage of 48V.

[0004] Generally speaking, there are different operating modes for a semi-hybrid vehicle, namely: An electric mode, also sometimes called “ZEV” (Zero Emission Vehicle), in which the vehicle is propelled and / or towed by the electric traction machine without the intervention of a thermal engine; A thermal mode in which the vehicle is towed and / or propelled using only the thermal engine without intervention from the electric traction machine; and A hybrid mode in which the vehicle is towed and / or propelled simultaneously by means of the thermal engine and the electric traction machine.

[0005] In use, the power battery associated with the electric traction machine must not have a temperature higher than a maximum operating temperature. In order to cool the power battery, it is known from the state of the art to equip the vehicle with a low-temperature cooling circuit. When the vehicle is running in electric mode, the circuit Low temperature cooling according to the prior art is the only cooling circuit used to cool the power battery. If the loads on the electric traction machine and the inverter are high, the temperature of the coolant contained in the low temperature cooling circuit increases rapidly until it approaches or reaches an operating limit temperature.

[0006] As described in document FR-A1-3061110, one solution for lowering the temperature of the coolant in the low-temperature cooling circuit is to install a radiator and a thermostat upstream of the radiator in order to control the circulation of the coolant through the radiator. This radiator and thermostat are intended to limit the rise in temperature of the coolant circulating in the low-temperature cooling circuit.

[0007] However, the space available at the front of a semi-hybrid vehicle for the installation of the radiator of the low-temperature cooling circuit is often limited. The installation constraints are increased in the case of a semi-hybrid vehicle with the presence, in addition to the thermal engine, of the electric traction machine, the power components and the power battery. Such a solution is therefore not satisfactory for reasons of both space and cost.

[0008] The aim of the invention is in particular to propose a semi-hybrid type vehicle comprising a low-temperature cooling circuit with reduced bulk.

[0009] In this context, the invention thus relates, in its broadest sense, to a semi-hybrid vehicle comprising a low-temperature cooling circuit passing through a heat exchanger arranged to cool a cooling fluid of the low-temperature cooling circuit, an inverter of an electric traction machine of the semi-hybrid vehicle, a power battery arranged to supply energy to the electric traction machine, a DC-DC converter arranged to recharge a service battery of said semi-hybrid vehicle by means of the power battery, and a pump arranged to force circulation of the cooling fluid in the circuit of low temperature cooling. The semi-hybrid vehicle according to this aspect of the invention is remarkable in that the low temperature cooling circuit comprises a first pipe connected to the output of the inverter and to the input of the heat exchanger, the first pipe being opposite a cooling radiator of a heat engine arranged in an accessory facade of the semi-hybrid vehicle.

[0010] The inverter significantly increases the temperature of the coolant when the vehicle is in an electric driving phase. Thus, the passage of the first pipe opposite the cooling radiator of the thermal engine makes it possible to effectively cool the coolant circulating in the first pipe, and more particularly the coolant leaving the inverter. Thus, the radiator and the thermostat usually installed in the low-temperature cooling circuit of the state of the art are eliminated thanks to this particular arrangement.

[0011] A semi-hybrid vehicle is a hybrid vehicle comprising a “small” electric traction machine powered, for example, by 48V or 24V.

[0012] The size and cost of the low temperature cooling circuit according to this aspect of the invention are further reduced.

[0013] In addition to the characteristics which have just been mentioned in the preceding paragraph, the vehicle according to the invention may have one or more additional characteristics among the following, considered individually or in all technically possible combinations.

[0014] According to a non-limiting aspect of the invention, the low-temperature cooling circuit further comprises: A second line connected to the heat exchanger and pump; and A third line connected to the pump and the power battery, the pump being arranged between the thermal engine and a passenger compartment of the semi-hybrid vehicle.

[0015] According to a non-limiting aspect of the invention, the low-temperature cooling circuit further comprises: A fourth line connected to the power battery and the converter; and A fifth line connected to the converter and the inverter.

[0016] According to a non-limiting aspect of the invention, the low temperature cooling circuit is arranged to allow a heat exchange between the cooling fluid contained in the low temperature cooling circuit and the exterior which is: Maximum, the maximum heat exchange being ensured by a first segment of the first pipe connected to the heat exchanger and facing the cooling radiator of the heat engine, a third segment of the second pipe connected to the heat exchanger, a sixth segment of the third pipe connected to the power battery and a seventh segment of the fourth pipe connected to the power battery; Medium, the medium heat exchange being provided by a second segment of the first pipe connected to the inverter, an eighth segment of the fourth pipe connected to the converter, and the fifth pipe; and Minimal, the minimal heat exchange being ensured by a fourth segment of the second pipe connected to the pump, a fifth segment of the third pipe connected to the pump and a ninth segment of the fourth pipe arranged between the seventh segment and the eighth segment of the fourth pipe.

[0017] According to a non-limiting aspect of the invention, maximum heat exchange is ensured by an aluminum conduit wall.

[0018] According to a non-limiting aspect of the invention, the minimal heat exchange is ensured by a rubber conduit wall having a thickness of between 3 mm and 5 mm.

[0019] According to a non-limiting aspect of the invention, the average heat exchange is ensured by a rubber pipe wall having a thickness of between 1 mm and 3 mm.

[0020] According to a non-limiting aspect of the invention, the inverter is thermally isolated from the electric traction machine.

[0021] According to a non-limiting aspect of the invention, the power battery is arranged below the passenger compartment of the semi-hybrid vehicle.

[0022] According to a non-limiting aspect of the invention, the power battery has a voltage of 48V.

[0023] The invention and its various applications will be better understood by reading the following description and examining the accompanying figure.

[0024] [Fig. 1] illustrates, in a schematic manner, a non-limiting exemplary embodiment of a semi-hybrid type vehicle according to the invention.

[0025] More particularly, Figure 1 illustrates a semi-hybrid vehicle 1 equipped with a low-temperature cooling circuit 2 in which a cooling fluid circulates. This cooling fluid is formed by a heat transfer fluid.

[0026] The semi-hybrid vehicle 1 illustrated in Figure 1 further comprises: A heat exchanger 3 arranged to cool the coolant of the low temperature cooling circuit 2, this heat exchanger 3 is also known by the English terminology of Chiller; An inverter 4 of an electric traction machine (not shown) of the semi-hybrid vehicle 1; A power battery 5 arranged to supply energy to said electric traction machine; in a non-limiting manner, the power battery 5 may for example be of the 48V or 24V type; A direct-direct converter 6 (or DC / DC converter) arranged to recharge a service battery (not shown) of the semi-hybrid vehicle 1 by means of the power battery 5; A pump 7 arranged to force circulation of the cooling fluid in the low temperature cooling circuit 2; A thermal engine 8; A radiator 9 for cooling the thermal engine 8; and A 10-seater cabin.

[0027] The low temperature cooling circuit 2 comprises a set of pipes in which the cooling fluid circulates.

[0028] More particularly, the low temperature cooling circuit 2 comprises a first pipe 11 connected to the output of the inverter 4 and to the input of the heat exchanger 3.

[0029] It should be noted that the first pipe 11 is opposite the radiator 9 for cooling the thermal engine 8 arranged in an accessory facade 12 of the semi-hybrid vehicle 1, and in particular is transverse to the air flow passing through the radiator 9, in front of or behind this radiator 9 depending on the direction of air circulation. The accessory facade 12 corresponds to the front face of the semi-hybrid vehicle 1. Thus, when the semi-hybrid vehicle 1 moves, the ambient air and / or the air from the radiator 9 participates in a heat exchange by convection around the wall of the first pipe 11, and therefore in the cooling of the cooling fluid passing through the first pipe 11.

[0030] In order to optimize this cooling, the first pipe 11 may comprise a first segment 13 opposite the radiator 9 and connected to the heat exchanger 3 ensuring maximum heat exchange between the cooling fluid contained in the first segment 13 and the exterior. To ensure this maximum heat exchange, the first segment 13 may comprise an aluminum pipe wall.

[0031] Furthermore, the first pipe 11 may comprise a second segment 14 connected to the inverter 4 ensuring an average heat exchange (in other words in accordance with that ensured by the pipes of the state of the art) between the cooling fluid contained in the second segment 14 and the exterior.

[0032] To ensure this average heat exchange, the second segment 14 may comprise a rubber conduit wall having a thickness of between 1 mm and 3 mm, typically 2 mm.

[0033] The low-temperature cooling circuit 2 further comprises a second pipe 15 connected to the heat exchanger 3 and to the pump 7. It should be noted that the pump 7 is arranged between the heat engine 8 and the passenger compartment 10 of the semi-hybrid vehicle 1.

[0034] The second pipe 15 may comprise a third segment 16 connected to the heat exchanger 3 ensuring maximum heat exchange between the cooling fluid contained in the third segment 16 and the exterior. To ensure this maximum heat exchange, the third segment 16 may comprise an aluminum pipe wall.

[0035] The second pipe 15 may comprise a fourth segment 17 connected to the pump 7 ensuring a minimal heat exchange between the cooling fluid contained in the fourth segment 17 and the outside. To ensure this minimal heat exchange, the fourth segment 17 may comprise a rubber pipe wall having a thickness of between 3 mm and 5 mm, typically 4 mm. This significant thickness makes it possible to prevent the heat generated by the heat engine 8 from being transferred to the cooling fluid passing through the fourth segment 17.

[0036] The low-temperature cooling circuit 2 further comprises a third pipe 18 connected to the pump 7 and the power battery 5.

[0037] The third pipe 18 may comprise a fifth segment 19 connected to the pump 7 ensuring a minimal heat exchange between the cooling fluid contained in the fifth segment 19 and the exterior. To ensure this minimal heat exchange, the fifth segment 19 may comprise a rubber pipe wall having a thickness of the order of 4 mm. This significant thickness makes it possible to prevent the heat generated by the heat engine 8 from being transferred to the cooling fluid passing through the fifth segment 19.

[0038] The third pipe 18 may comprise a sixth segment 20 connected to the power battery 5 ensuring maximum heat exchange between the cooling fluid contained in the sixth segment 20 and the exterior. To ensure this maximum heat exchange, the sixth segment 20 may comprise an aluminum pipe wall.

[0039] The low temperature cooling circuit 2 also comprises a fourth pipe 21 connected to the power battery 5 and to the converter 6.

[0040] The fourth pipe 21 may comprise a seventh segment 22 connected to the power battery 5 ensuring maximum heat exchange between the fluid cooling contained in the seventh segment 22 and the exterior. To ensure this maximum heat exchange, the seventh segment 22 may include an aluminum conduit wall.

[0041] Furthermore, the fourth pipe 21 may comprise an eighth segment 23 connected to the converter 6 ensuring an average heat exchange between the cooling fluid contained in the eighth segment 23 and the exterior.

[0042] To ensure this average heat exchange, the eighth segment 23 may comprise a rubber conduit wall having a thickness of the order of 2 mm.

[0043] In addition, the fourth pipe 21 may comprise a ninth segment 24 arranged between the seventh segment 22 and the eighth segment 23. The ninth segment 24 ensures minimal heat exchange between the cooling fluid it contains and the exterior. To ensure this minimal heat exchange, the ninth segment 24 may comprise a rubber pipe wall having a thickness of the order of 4 mm.

[0044] The low temperature cooling circuit 2 also comprises a fifth pipe 25 connected to the converter 6 and to the inverter 4.

[0045] The fifth pipe 25 can provide an average heat exchange between the cooling fluid it contains and the exterior. For this purpose, the fifth pipe 25 can comprise a rubber pipe wall having a thickness of the order of 2 mm.

[0046] It is appropriate that two segments of the same pipe, for example the first segment 13 and the second segment 14 of the first pipe 11 can be connected to each other via a crimping.

[0047] In order to improve the cooling of the coolant, the inverter 4 may be thermally insulated from the electric traction machine. For this purpose, the inverter 4 may comprise a plastic casing thermally insulating it from the electric traction machine.

[0048] Furthermore, the heat exchanger 3 is arranged to cool the coolant of a high-temperature cooling circuit (not shown) that the semi-hybrid vehicle 1 comprises. The cooling radiator 9 is part of this high temperature cooling circuit. The high temperature cooling circuit is used, in particular, to cool the temperature of the heat engine 8.

[0049] The various aspects of the invention mentioned above have numerous advantages. Among these, we can cite: Improve the cooling of the coolant in a low-temperature cooling circuit by installing the first pipe on the accessories front, and more particularly opposite the thermal engine cooling radiator; and - Reduce the cost and size of the low-temperature cooling circuit by removing the radiator usually fitted to this type of low-temperature cooling circuit.

Claims

CLAIMS

1. Semi-hybrid vehicle (1) comprising a low-temperature cooling circuit (2) passing through a heat exchanger (3) arranged to cool a cooling fluid of said low-temperature cooling circuit (2), an inverter (4) of an electric traction machine of said semi-hybrid vehicle (1), a power battery (5) arranged to supply energy to said electric traction machine, a DC-DC converter (6) arranged to recharge a service battery of said semi-hybrid vehicle (1) by means of said power battery (5), and a pump (7) arranged to force a circulation of said cooling fluid in said low-temperature cooling circuit (2), said semi-hybrid vehicle (1) being characterized in that said low-temperature cooling circuit (2) comprises a first pipe (11) connected at the output of said inverter (4) and at the inlet of said heat exchanger (3),said first pipe (11) being opposite a radiator (9) for cooling a thermal engine (8) arranged in an accessory facade (12) of said semi-hybrid vehicle (1).,

2. Semi-hybrid vehicle (1) according to the preceding claim, characterized in that the low-temperature cooling circuit (2) further comprises: - A second pipe (15) connected to the heat exchanger (3) and to the pump (7); and - A third pipe (18) connected to said pump (7) and the power battery (5), said pump (7) being arranged between the heat engine (8) and a passenger compartment (10) of said semi-hybrid vehicle (1).

3. Semi-hybrid vehicle (1) according to the preceding claim, characterized in that the low-temperature cooling circuit (2) further comprises: - A fourth pipe (21) connected to the power battery (5) and to the converter (6); and A fifth line (25) connected to said converter (6) and to the inverter (4).

4. Semi-hybrid vehicle (1) according to the preceding claim, characterized in that the low-temperature cooling circuit (2) is arranged to allow a heat exchange between the cooling fluid contained in the low-temperature cooling circuit (2) and the exterior which is: - Maximum, said maximum heat exchange being ensured by a first segment (13) of the first pipe (11) connected to the heat exchanger (3) and opposite the radiator (9) for cooling the heat engine (8), a third segment (16) of the second pipe (15) connected to said heat exchanger (3), a sixth segment (20) of the third pipe (18) connected to the power battery (5) and a seventh segment (22) of the fourth pipe (21) connected to said power battery (5); - Means, said average heat exchange being provided by a second segment (14) of said first pipe (11) connected to the inverter (4), an eighth segment (23) of the fourth pipe (21) connected to the converter (6), and the fifth pipe (25); and - Minimal, said minimal heat exchange being ensured by a fourth segment (17) of said second pipe (15) connected to said pump (7), a fifth segment (19) of said third pipe (18) connected to said pump (7) and a ninth segment (24) of said fourth pipe (21) arranged between said seventh segment (22) and said eighth segment (23) of said fourth pipe (21).

5. Semi-hybrid vehicle (1) according to the preceding claim, characterized in that the maximum heat exchange is ensured by an aluminum conduit wall.

6. Semi-hybrid vehicle (1) according to any one of claims 4 or 5, characterized in that the minimum heat exchange is ensured by a rubber conduit wall having a thickness of between 3 mm and 5 mm.

7. Semi-hybrid vehicle (1) according to any one of claims 4 to 6, characterized in that the average heat exchange is ensured by a rubber conduit wall having a thickness of between 1 mm and 3 mm. [Claim s] Semi-hybrid vehicle (1) according to any one of the preceding claims, characterized in that the inverter (4) is thermally insulated from the electric traction machine.

9. Semi-hybrid vehicle (1) according to any one of the preceding claims, characterized in that the power battery (5) is arranged below the passenger compartment (10) of the semi-hybrid vehicle (1).

10. Semi-hybrid vehicle (1) according to any one of the preceding claims, characterized in that the power battery (5) has a voltage of 48V.

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