Layout structure for front compartment of hybrid vehicle

A front compartment is provided with an engine, an air cleaner, a radiator, a reservoir tank, a motor unit, an auxiliary battery, and an EFI-ECU. The engine, the reservoir tank, the motor unit and the EFI-ECU are aligned in a vehicle's width direction. The air cleaner and the auxiliary battery are also aligned in the vehicle's width direction. The air cleaner is located in front of the motor unit. The motor unit includes a power control unit and a transaxle. The air cleaner is located in front of the power control unit. The auxiliary battery is located diagonally forward to left of the motor unit.

CROSS-REFERENCE TO RELATED APPLICATION

The present disclosure claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2018-216667, filed on Nov. 19, 2018. The content of the application is incorporated herein by reference in their entirety.

TECHNICAL FIELD

The present disclosure relates to a layout structure of a front compartment of a hybrid vehicle (hereinafter also referred to as a “HV vehicle”).

BACKGROUND

JP2018-001810A discloses a layout structure for protecting a wire harness from damages in an event of a HV vehicle collision. The wire harness connects a power control unit (hereinafter also referred to as a “PCU”) and a hybrid controller (hereinafter also referred to as a “HV controller”). The PCU includes a capacitor that smooths current in a high-voltage battery. The HV controller transmits a discharge command to the PCU to discharge the capacitor in the event of the HV vehicle collision.

The wire harness and the PCU are connected to each other on an upper surface of the PCU and also on a rear side of the HV vehicle. By connecting the wire harness and the PCU in such a position, it is possible to prevent the wire harness from being damaged in the event of the HV vehicle collision.

However, the layout described above emphasizes reliable transmission of the discharge command, and do not directly prevent damages to the PCU as a high-voltage component. Therefore, an improvement from this viewpoint is desired.

The present disclosure addresses the above described problem, and one object of the present disclosure is to provide a technique that is able to prevent the PCU from being damaged in the event of the HV vehicle collision.

SUMMARY

A first aspect is a layout structure for a front compartment of a HV vehicle.

The front compartment is provided with an engine, a transaxle, a PCU, a low-voltage battery, and a vehicle component.

The transaxle is configured to house a motor for traveling.

The PCU is provided on an upper surface of the transaxle.

The PCU is configured to control transmission of power between the motor for traveling and the high-voltage battery.

A stiffness of the vehicle component is lower than that of the PCU.

The engine and the transaxle are aligned in a vehicle's width direction.

The vehicle component and the low-voltage battery are aligned in a vehicle's width direction in front of the PCU.

The vehicle component is located in front of the PCU.

The low-voltage battery is located in an outer side of the HV vehicle than the vehicle component.

A second aspect further has the following feature in the first aspect.

The vehicle component is an air cleaner of the engine.

A third aspect further has the following feature in the first aspect.

The vehicle component is a reservoir tank of coolant for cooling the engine and the PCU.

A fourth aspect further has the following features in the second aspect.

The PCU is integrated with the transaxle on an upper surface of the transaxle.

A control unit which is configured to control the HV vehicle and/or the engine is disposed on an upper surface of the PCU.

A fifth aspect further has the following feature in the third aspect.

The PCU is integrated with the transaxle on an upper surface of the transaxle.

A control unit which is configured to control the HV vehicle and/or the engine is disposed on an upper surface of the PCU.

A sixth aspect further has the following feature in the first aspect.

The vehicle component is a control unit for controlling the HV vehicle and/or the engine.

According to the first aspect, the vehicle component is arranged in front of the PCU while the low-voltage battery is arranged in front of the PCU and also on the outer side of the HV vehicle. Therefore, in a head-on collision of the HV vehicle, collision energy is absorbed by the vehicle component. In a collision at diagonally forward of the HV vehicle, the collision energy is absorbed by the low-voltage battery. In addition, according to the first aspect, the stiffness of the vehicle component is lower than that of the PCU. Therefore, even if the vehicle component absorbing the collision energy goes backward, it is possible to reduce a shock to which the PCU is subjected by contacting with the vehicle component. Therefore, it is possible to prevent the PCU from being damaged in the event of the HV vehicle collision.

According to the second, third or sixth aspect, it is possible to prevent the PCU from being damaged in the event of the HV vehicle collision by the air cleaner, the reservoir tank or the control unit. According to the third aspect, it is possible to lessen a distance between the reservoir tank and the PCU. Therefore, it is possible to shorten a hose for cooling which connects the reservoir tank and the PCU and reduce original cost therefor. According to the sixth aspect, it is possible to lessen the distances between the control unit and the PCU. Therefore, it is possible to shorten a wire harness and reduce the original cost therefor.

According to the fourth or fifth aspect, when the air cleaner or the reservoir tank is arranged in front of the PCU, it is possible to shorten the distance between the control unit and the PCU. Therefore, it is possible to shorten a wire harness and reduce the original cost therefor.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. It should be noted that same signs are attached to same elements in the respective drawings, and duplicate descriptions are omitted.

1. First Embodiment

First, a layout structure of the first embodiment will be explained with reference toFIG. 1andFIG. 2. In the drawings, a F-axis of coordinates represents a vehicle's length direction (i.e., a longitudinal direction) of the HV vehicle. A W-axis of the coordinates represents a vehicle's width direction (i.e., horizontal direction). A H-axis of the coordinates represents a vertical direction.

1.1 Configuration of Main Parts of HV Vehicle

FIG. 1is a schematic top view of a front compartment in a HV vehicle1to which the layout structure according to the first embodiment is applied. InFIG. 1, only main parts highly related to the layout structure is depicted. The HV vehicle1includes an engine10, an air cleaner12, a radiator14, a reservoir tank16, a motor unit20, a high-voltage battery30, an auxiliary battery32, a HV-ECU (hybrid Electronic Control Unit)40, and an EFI-ECU (Electronic Control Unit for engine)42.

The engine10is an internal combustion engine in which thermal energy generated by burning mixed gas is converted into kinetic energy of moving body such as piston, thereby a driving force of the HV vehicle1is outputted. The mixed gas is composed of air taken in from the air cleaner12and fuels supplied to the engine10. Examples of fuel of the engine10include gasoline, light oil, and hydrogen fuel. An output shaft (not shown) of the engine10is connected to a driving force distribution mechanism (not shown) at a vehicle's width direction.

The radiator14forms a part of a circulation system of coolant which cools the engine10and the PCU. The radiator14exchanges heat with the coolant flowing in the circulation system. As temperature of the coolant rises and its volume expands, excess coolant is delivered to the reservoir tank16. As the temperature of the coolant decreases and its volume shrinks, the coolant is returned from the reservoir tank16.

The motor unit20has an electromechanical integral structure in which the PCU and the transaxle (hereinafter also referred to as a “VA”) are directly fastened by screws.FIG. 2is a schematic view of a left lateral face of the motor unit20and its surroundings. As shown inFIG. 2, the motor unit20includes a PCU22and a T/A24. The T/A24includes two motor/generators for driving25and26, a differential gear27and a driving force distribution mechanism. In the following, the motor/generator is also referred to as the “M/G”.

An axis25aof the M/G25, an axis26aof the M/G26and an axis27aof the differential gear27are arranged so as to be triangular when viewed from the vehicle's width direction. With this arrangement, an upper surface24aof the T/A24is lowered forward. The PCU22is fixed an upper surface24a. A bottom surface22aof the PCU22is inclined by same angle as slope angle of the upper surface24a. There is no aperture between the bottom surface22aand the upper surface24a. Unlike the bottom surface22a, an upper surface22bof the PCU22is substantially horizontal. A front face22cof the PCU22is substantially perpendicular.

The PCU22converts DC power of the high-voltage battery30into AC power suitable for driving the M/G25and the M/G26. The driving force distribution mechanism appropriately combines output torque of the engine10, the M/G25and the M/G26, and outputs the combined torque. The combined torque is transmitted to wheels via the differential gear27. The driving force distribution mechanism may distribute the output torque of the engine10to the M/G25and the wheels. In this instance, the HV vehicle1generates power at the M/G25while traveling by the driving force of the engine10. The PCU22converts the AC power generated by the M/G25into the DC power. Regenerative power converted into the DC power is used to charge the high-voltage battery30.

The auxiliary battery32provides power to various auxiliaries. The “auxiliary” is a generic term for a device driven by a low voltage. The “low voltage” means a voltage lower than an output voltage of the high-voltage battery30. That is, the output voltage of the auxiliary battery32is lower than that of the high-voltage battery30. Examples of the auxiliaries include a control circuit implemented in the PCU22, the HV-ECU40, and the EFI-ECU42, respectively.

The HV-ECU40and the EFI-ECU42are microcomputers, each of which includes a CPU (Central Processing Unit), a memory, an input/output buffer, and the like (all of which are not shown). The HV-ECU40receives a state of the high-voltage battery30detected by a power monitoring unit (not shown). The HV-ECU40executes control of the M/G25and the M/G26based on the detected results.

The EFI-ECU42receives values such as intake air amount and coolant temperature from various sensors provided in the engine10, and transmits them to the HV-ECU40. The EFI-ECU42receives from the HV-ECU40output command value and target engine speed of the engine10based on the detected results.

Here, a housing of the motor unit20is made of aluminum die casting, while the air cleaner12and reservoir tank1are made of resins. Cases of the HV-ECU40and EFI-ECU42are also made of resins. That is, stiffness of these vehicle component is lower than that of the housing of the motor unit20.

1.2 Layout Structure

As shown inFIG. 1, the front compartment FC is provided with the engine10, the air cleaner12, the radiator14, the reservoir tank16, the motor unit20, the auxiliary battery32, and the EFI-ECU42. The high-voltage battery30and the HV-ECU40are provided on a compartment other than the front compartment FC. The high-voltage battery30is provided, for example, on a rear compartment of the HV vehicle1. The HV-ECU40is provided, for example, in a chamber of the HV vehicle1.

In the front compartment FC, the engine10, the reservoir tank16, the motor unit20and the EFI-ECU42are aligned in the vehicle's width direction. The air cleaner12and the auxiliary battery32are also aligned in the vehicle's width direction. The air cleaner12and the auxiliary battery32are located in front of the motor unit20. More specifically, the air cleaner12is located in front of the motor unit20. The motor unit20and the auxiliary battery32do not overlap in the vehicle's width direction. The auxiliary battery32is located diagonally forward to left of the motor unit20. That is, the auxiliary battery32is located in front of the motor unit20and in an outer side of the HV vehicle1.

As shown inFIG. 2, the air cleaner12is located in front of the front face22c. That is, the air cleaner12is not located in front of the T/G24but is located in front of the PCU22. The EFI-ECU42is also located in a leftward direction of the left lateral face22dof the PCU22. That is, the EFI-ECU42is not located in the leftward direction of the T/G24but is located in that of the PCU22.

According to the layout structure shown inFIG. 1andFIG. 2, the air cleaner12is arranged in front of the PCU22. Therefore, in an event of a head-on collision of the HV vehicle1, the air cleaner12is impacted earlier than the PCU22. Therefore, collision energy is absorbed by the air cleaner12thereby the PCU22is protected. Also, as described above, the stiffness of the air cleaner12is lower than that of the housing. Therefore, even if the collided air cleaner12goes backward, it is possible to reduce a shock to which the PCU22is subjected by contacting with the air cleaner12.

According to the layout structure shown inFIG. 1andFIG. 2, the auxiliary battery32is also located in the outer side of the HV vehicle1than the motor unit20. Therefore, even if the collided auxiliary battery32goes backward in the event of the head-on collision, it does not interfere with the PCU22. Further, in a collision at diagonally forward of the HV vehicle1, the auxiliary battery32is impacted earlier than the PCU22. Therefore, the collision energy is absorbed by the auxiliary battery32thereby the PCU22is protected.

According to the layout structure shown inFIGS. 1 and 2, further, the EFI-ECU42is also arranged in the leftward direction of the PCU22. As described above, the stiffness of the EFI-ECU42is lower than that of the housing. Therefore, in a collision at the left lateral face of the HV vehicle1, the collision energy is absorbed by the EFI-ECU42thereby the PCU22is protected.

As described above, according to the layout structure shown inFIG. 1andFIG. 2, it is possible to prevent the PCU22from being damaged when the HV vehicle1collides. Therefore, it is possible to ensure security in the PCU22as a high voltage component.

2. Second Embodiment

Next, the layout structure relating to a second embodiment of the present disclosure will be described with reference toFIGS. 0.3 and 4. Note that the descriptions overlapping with those in the first embodiment are omitted as appropriate.

2.1 Layout Structure

FIG. 3is a schematic top view of the front compartment in a HV vehicle2to which the layout structure according to the second embodiment is applied.FIG. 4is a schematic view of the left lateral face of the motor unit20and its surroundings. The layout structure according to the second embodiment differs from that according to the first embodiment in positions of the air cleaner12and the reservoir tank16.

That is, as shown inFIG. 3, the air cleaner12is aligned in vehicle's width direction with the engine10and the motor unit20. The reservoir tank16is aligned in the auxiliary battery32in the vehicle's width direction. The reservoir tank16is also located in front of the motor unit20. Further, as shown inFIG. 4, the reservoir tank16is located in front of the front face22c. That is, the reservoir tank16is not located in front of the T/G24but is located in front of the PCU22.

According to the layout structure shown inFIG. 3andFIG. 4, it is possible to obtain advantageous effects equivalent to those obtained by the layout structure according to the first embodiment. That is, in the event of the head-on collision of the HV vehicle2, the collision energy is absorbed by the reservoir tank16thereby the PCU22is protected.

In addition, even if the collided reservoir tank16goes backward in the event of the head-on collision, it is possible to reduce the shock to which the PCU22is subjected by contacting with the reservoir tank16. Further, in a side collision at the left lateral face, the collision energy is absorbed by the EFI-ECU42thereby the PCU22is protected.

Further, according to the layout structure shown inFIG. 3andFIG. 4, it is possible to shorten a distance between the reservoir tank16and the PCU22. Therefore, it is possible to shorten a hose for cooling which connects the reservoir tank16with the PCU22and reduce original cost for the hose.

Next, the layout structure according to a third embodiment of the present disclosure will be described with reference toFIG. 5andFIG. 6. Note that the descriptions overlapping with those in the first embodiment are omitted as appropriate.

3.1 Layout Structure

FIG. 5is a schematic top view of the front compartment in a HV vehicle3to which the layout structure according to the third embodiment is applied.FIG. 6is a schematic view of a left lateral face of the motor unit20and its surroundings. The layout structure according to the third embodiment differs from that according to the first embodiment in positions of the air cleaner12, the HV-ECU40and the EFI-ECU42.

That is, as shown inFIG. 5, the air cleaner12is positioned diagonally forward to right of the engine10. Also, the HV-ECU40and the EFI-ECU42are aligned in the auxiliary battery32in the vehicle's width direction. These ECUs are also located in front of the motor unit20. As shown inFIG. 6, these ECUs are located in front of the front face22c. That is, these ECUs are not located in front of the T/G24but is located in front of the PCU22.

According to the layout structure shown inFIG. 5andFIG. 6, it is possible to obtain advantageous effects equivalent to those obtained by the layout structure according to the first embodiment. That is, in the event of the head-on collision of the HV vehicle3, the collision energy is absorbed by the HV-ECU40and the EFI-ECU42thereby the PCU22is protected. In addition, even if the collided HV-ECU40and EFI-ECU42go backward in the event of the head-on collision, it is possible to reduce the shock to which the PCU22is subjected by contacting with these ECUs.

Further, according to the layout structure shown inFIGS. 5 and 6, it is possible to shorten the distances between the EFI-ECU42and the engine10. In addition, since the HV-ECU40is provided in the front compartment FC, it is possible to shorten the distance between the two ECUs and the distance between the HV-ECU40and the PCU22. Therefore, it is possible to shorten the wire harness and reduce the original cost for the wire harness.

Next, the layout structure according to a fourth embodiment of the present disclosure will be described with reference toFIG. 7andFIG. 8. Note that the descriptions overlapping with those in the first embodiment are omitted as appropriate.

4.1 Layout Structure

FIG. 7is a schematic top view of the front compartment in a HV vehicle4to which the layout structure according to the fourth embodiment is applied.FIG. 8is a schematic view of the left lateral face of the motor unit20and its surroundings. The layout structure according to the fourth embodiment differs from that according to the first embodiment in positions of the HV-ECU40and the EFI-ECU42.

That is, as shown inFIG. 7, the HV-ECU40and the EFI-ECU42are provided above the motor unit20. As shown inFIG. 8, these ECUs are aligned above the upper surface22b. Such an arrangement is realized by a reduction in the vertical length due to the structure of the motor unit20(i.e., the electromechanical integral structure).

According to the layout structure shown inFIG. 7andFIG. 8, in addition to the advantageous effects by the layout structure according to the first embodiment, the following effects are obtained. That is, according to the layout structure shown inFIG. 7andFIG. 8, it is possible to shorten the distance between the EFI-ECU42and the engine10. In addition, since the HV-ECU40is provided in the front compartment FC, it is possible to shorten the distance between the HV-ECU40and the EFI-ECU42and the distance between the HV-ECU40and the PCU22. Therefore, it is possible to shorten the wire harness and reduce the original cost for the wire harness.

5. Other Embodiments

In the layout structures according to the first to fourth embodiments, the motor unit20having the electromechanical integral structure is assumed. However, in the layout structures according to the first to third embodiments, the PCU22and the VA24may be connected via a bracket.

Further, in the third embodiment, the HV-ECU40and the EFI-ECU42are disposed in front of the PCU22. However, only the HV-ECU40may be disposed in front of the PCU22while the EFI-ECU42may be disposed in the leftward direction of the left lateral face22d. Only the EFI-ECU42may be disposed in front of the PCU22while the HV-ECU40may be disposed in the leftward direction of the left lateral face22d. When the HV-ECU40or the EFI-ECU42is disposed in the leftward direction of the left lateral face22d, a protective effect of the PCU22in the side collision at left lateral face is expected.

6. Correspondence Between Embodiments and Aspects

In the embodiments described above, any one of the air cleaner12, the reservoir tank16, the HV-ECU40, and the EFI-ECU42corresponds to the “vehicle component” of the first aspect. The auxiliary battery32corresponds to the “low-voltage battery” of the first aspect. The HV-ECU40and the EFI-ECU42correspond to the “control unit” of the fourth to sixth aspect.