Hybrid vehicle

Abstract

To prevent the deterioration of vehicle fuel efficiency.SOLUTION: A hybrid vehicle comprises an engine which includes a chain tensioner adjusting tensile force of a timing chain and at the same time is connected to a driving wheel, an oil pump which supplies oil to the chain tensioner by using power from the engine, a motor which is connected to the driving wheel, and a control device which controls the engine and the motor so as to travel by switching hybrid travel which uses power of the engine and electrically-driven travel which does not use the power of the engine. The control device executes supply processing that starts the engine and then supplies the oil from the oil pump to the chain tensioner when the engine reversely rotates during electrically driven travel and thereafter, stops the engine.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to hybrid vehicles. [Background technology]

[0002] Conventionally, as this type of hybrid vehicle, there has been proposed a vehicle that includes an engine connected to a drive wheel and having a chain mechanism, an oil pump, and a motor connected to the drive wheel, and that controls the vehicle's driving mode to one of an EV mode in which the engine is stopped while the motor is driven, and a non-EV mode in which the engine is driven to drive (see, for example, Patent Document 1). Here, the chain mechanism includes a drive sprocket attached to the crankshaft, intake side and exhaust side sprockets attached to intake side and exhaust side camshafts, a chain wound around the three sprockets, and a chain tensioner that adjusts the tension of the chain. The oil pump uses power from the engine to supply oil to the chain tensioner, etc. In this hybrid vehicle, when the EV mode is switched to the non-EV mode, a high-pressure process is executed to make the supply pressure of oil supplied to the chain tensioner when the EV duration is equal to or longer than a specified time higher than the supply pressure when the EV duration is less than the specified time. As a result, even if air exists inside the chain tensioner when the EV mode is switched to the non-EV mode, the air can be discharged. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2022-71520 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned hybrid vehicle, when the vehicle switches from EV mode to non-EV mode and the EV duration is equal to or longer than a specified time, the supply pressure of the oil supplied to the chain tensioner is relatively high for a certain period of time, which may lead to a deterioration in fuel economy. The hybrid vehicle of the present disclosure has a primary objective of suppressing the deterioration of the vehicle's fuel economy. [Means for solving the problem]

[0005] The hybrid vehicle of the present disclosure employs the following means to achieve the above-mentioned primary object: The hybrid vehicle of the present disclosure is a hybrid vehicle including an engine having a chain tensioner for adjusting tension of a timing chain and connected to drive wheels, an oil pump for supplying oil to the chain tensioner using power from the engine, a motor connected to the drive wheels, and a control device for controlling the engine and the motor so as to switch between hybrid running using the power of the engine and electric running not using the power of the engine, and the control device executes a supply process for starting the engine and supplying oil from the oil pump to the chain tensioner when the engine rotates in reverse during the electric running, and then stops the engine.

[0006] In the hybrid vehicle disclosed herein, by executing the above-described control, it is possible to prevent air from accumulating in the chain tensioner when switching from electric driving to hybrid driving, and to prevent the need to supply a relatively high pressure to the chain tensioner for a certain period of time in order to bleed the air, thereby preventing a deterioration in the fuel efficiency of the vehicle. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic configuration diagram of a hybrid vehicle 20 according to an embodiment of the present disclosure. [Diagram 2] 2 is a schematic diagram of a main portion of an engine 22 of a hybrid vehicle 20. FIG. [Diagram 3]11 is a flowchart showing an example of a processing routine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] An embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic diagram of a hybrid vehicle 20 according to an embodiment of the present disclosure, and FIG. 2 is a schematic diagram of a main part of an engine 22 of the hybrid vehicle 20. FIG. 2(A) is a schematic diagram of a timing chain mechanism 120 of the engine 22 of the hybrid vehicle 20, and FIG. 2(B) is a schematic diagram of a chain tensioner 130 of the timing chain mechanism 120. As shown in FIG. 1 and FIG. 2, the hybrid vehicle 20 according to the embodiment includes the engine 22, an oil pump 110, an engine electronic control unit (engine ECU) 24, a planetary gear 30, motors MG1 and MG2, inverters 41 and 42, a motor electronic control unit (motor ECU) 40, a battery 50, a battery electronic control unit (battery ECU) 52, a charger 60, and a hybrid electronic control unit (HVECU) 70. The engine ECU 24, the motor ECU 40, the battery ECU 52, and the HVECU 70 are capable of communicating with each other via a shared communication line (CAN bus) 90.

[0009] The oil pump 110 is configured as a mechanical variable displacement oil pump that uses power from the engine 22 to discharge oil into a supply passage 111 and can change its capacity (the amount of oil discharged per rotation of the crankshaft 23) by controlling an adjustment valve. The supply passage 111 is a passage for supplying oil from the oil pump 110 to various parts of the engine 22, such as a cylinder head and a chain tensioner 130 described below.

[0010] The engine 22 includes a throttle valve, an intake valve, an exhaust valve, a fuel injection valve, a spark plug, and a timing chain mechanism 120. The timing chain mechanism 120 includes a drive sprocket 121, an intake side sprocket 122, an exhaust side sprocket 123, a timing chain 124, a fixed guide 125, a swing guide 126, and a chain tensioner 130. The drive sprocket 121 is attached to the crankshaft 23. The intake side and exhaust side sprockets 122, 123 are attached to intake side and exhaust side camshafts for opening and closing the intake and exhaust valves of the engine 22, respectively. The timing chain 124 is wound around the drive sprocket 121, the intake side sprocket 122, and the exhaust side sprocket 123.

[0011] The fixed guide 125 guides the portion of the timing chain 124 between the drive sprocket 121 and the exhaust sprocket 123 from the outer periphery of the timing chain 124. The swing guide 126 guides the portion of the timing chain 124 between the drive sprocket 121 and the intake sprocket 122 from the outer periphery of the timing chain 124. The swing guide 126 includes a guide body 126A, a support protrusion 126B, a rotating shaft 126C, and an abutment protrusion 126D. The guide body 126A extends in a substantially arcuate shape from the drive sprocket 121 toward the intake sprocket 122. The support protrusion 126B protrudes from the end of the guide body 126A on the drive sprocket 121 side to the opposite side to the timing chain 124. The rotating shaft 126C passes through the support protrusion 126B and is fixed to the engine case. This allows the guide body 126A, the support protrusion 126B, and the contact protrusion 126D of the oscillating guide 126 to swing around the rotation shaft 126C. The contact protrusion 126D protrudes from the intake sprocket 122 side to the opposite side to the timing chain 124 beyond the longitudinal center portion of the guide body 126A.

[0012] The chain tensioner 130 adjusts the tension of the timing chain 124 and is disposed on the opposite side of the swing guide 126 from the timing chain 124. The chain tensioner 130 includes a housing 131, a plunger 132, a biasing spring 133, and a check valve mechanism 134. The housing 131 is substantially cylindrical, with one end opening toward the contact protrusion 126D and the other end closed. The inner surface of the housing 131 defines an internal space 131A, an expanded diameter space 131B, and a supply hole 131C. The internal space 131A is a substantially cylindrical space extending from the opening of the housing 131 to the bottom surface. The expanded diameter space 131B is a substantially annular space that circumferentially surrounds the internal space 131A at a substantially central portion in the axial direction of the internal space 131A. Supply hole 131C penetrates from expanded diameter space 131B to the outer circumferential surface of housing 131 and is connected to supply passage 116.

[0013] The plunger 132 has a generally cylindrical shape. The plunger 132 is arranged so as to be movable forward along the internal space 131 and to have a portion protruding from the internal space 131A, and the tip surface of the plunger 132 abuts against the abutment protrusion 126D of the swing guide 126. A hydraulic chamber 130A to which oil is supplied is defined between the base end of the plunger 132 and the internal space 131A. The chain tensioner 130 also functions as an oil damper by the oil supplied to the hydraulic chamber 130A. The inner surface of the plunger 132 defines a first space 132A, a second space 132B, a connection hole 132C, and an introduction hole 132D. The second space 132B, the connection hole 132C, and the first space 132A are arranged in this order from the base end side to the tip end side of the plunger 132. The second space 132B is a generally cylindrical space and is open to the hydraulic chamber 130A. The connection hole 132C is a generally cylindrical space with an inner diameter smaller than the second space 132B and the first space 132A, and is in communication with the second space 132B and the first space 132A. The introduction hole 132D penetrates from the first space 132A to the outer circumferential surface of the plunger 132.

[0014] The biasing spring 133 is disposed between the bottom surface of the internal space 131A and the bottom surface of the second space 132B, and biases the plunger 132 toward the contact projection 126D of the swing guide 126. The check valve mechanism 134 is disposed in the second space 132B and attached to the bottom surface of the second space 132B. When the oil pressure in the first space 132A is higher than the oil pressure in the second space 132B, the check valve mechanism 134 allows the oil to flow from the first space 132A to the second space 132B via the connecting hole 132C, and when the oil pressure in the first space 132A is equal to or lower than the oil pressure in the second space 132B, the check valve mechanism 134 restricts the oil to flow from the second space 132B to the first space 132A via the connecting hole 132C.

[0015] The engine ECU 24 includes a microcomputer having a CPU, a ROM, a RAM, a flash memory, an input / output port, and a communication port. The engine ECU 24 receives inputs such as the crank angle θcr of the crankshaft 23 from the crank position sensor 23a, and the rotational positions (cam angles θci, θco) of the intake and exhaust camshafts that open and close the intake and exhaust valves from the cam position sensor 23c. The engine ECU 24 outputs control signals to the throttle valve, fuel injection valve, spark plug, and adjustment valve of the oil pump 110. The engine ECU 24 calculates the rotation speed Ne based on the crank angle θcr.

[0016] The sun gear of the planetary gear 30 is connected to the rotor of the motor MG1, the ring gear is connected to a drive shaft 37 connected to drive wheels 39a, 39b via a differential gear 38, and the carrier is connected to the crankshaft 23 of the engine 22 via a damper 28. The motors MG1, MG2 are configured as, for example, synchronous generator motors. The rotor of the motor MG2 is connected to the drive shaft 37. The inverters 41, 42 are connected to a power line 54 together with a battery 50. The motors MG1, MG2 are rotated by the motor ECU 40 controlling the switching of a plurality of switching elements of the inverters 41, 42. The motor ECU 40 includes a microcomputer similar to the engine ECU 24. The motor ECU 40 receives inputs such as rotational positions θm1, θm2 of the rotors of the motors MG1, MG2 from rotational position sensors 43a, 44a. The motor ECU 40 outputs control signals to the inverters 41, 42. The motor ECU 40 calculates the rotation speeds Nm1, Nm2 of the motors MG1, MG2 based on the rotational positions θm1, θm2.

[0017] The battery 50 is configured as, for example, a lithium ion secondary battery or a nickel-metal hydride secondary battery. The battery ECU 52 includes a microcomputer similar to the engine ECU 24. The battery ECU 52 receives the voltage Vb and current Ib of the battery 50 from a voltage sensor and a current sensor. The battery ECU 52 calculates the charge ratio SOC of the battery 50 based on an integrated value of the current Ib. The charger 60 is connected to a power line 54, and is configured to be able to charge the battery 50 using power from the external power source when a power plug 62 is connected to an external power source such as a household power source or a commercial power source.

[0018] The HVECU 70 includes a microcomputer, similar to the engine ECU 24. The HVECU 70 receives inputs such as a start signal from a start switch 80, the operating position of a shift lever 81 (shift position SP) from a shift position sensor 82, the depression amount of an accelerator pedal 83 (accelerator opening Acc) from an accelerator pedal position sensor 84, the depression amount of a brake pedal 85 (brake pedal position BP) from a brake pedal position sensor 86, and a vehicle speed V from a vehicle speed sensor 87. The HVECU 70 outputs a control signal to the charger 60.

[0019] In the hybrid vehicle 20 of the embodiment, when the system is stopped and the vehicle is parked at a charging point such as a home or a charging station, when the power plug 62 is connected to an external power source, the charger 60 is controlled so that the battery 50 is charged using electric power from the external power source, and external charging is performed. Then, when the system is started after external charging, the hybrid vehicle 20 runs in a CD mode (Charge Depleting) before the power storage ratio SOC of the battery 50 reaches or falls below the threshold value Shv, and runs in a CS (Charge Sustaining) mode until the system is stopped after the power storage ratio SOC reaches or falls below the threshold value Shv. The CD mode is a mode in which electric driving (EV driving) is prioritized over hybrid driving (HV driving) so as to reduce the power storage ratio SOC of the battery 50, and the CS mode is a mode in which EV driving and HV driving are used in combination so as to maintain the power storage ratio SOC of the battery 50 within a management range including a target ratio SOC* (for example, the threshold value Shv). EV driving is driving that does not use the power of the engine 22, and HV driving is driving that uses the power of the engine 22.

[0020] Next, the operation of the hybrid vehicle 20 of the embodiment, particularly the operation during EV driving, will be described. FIG. 3 is a flowchart showing an example of a processing routine executed by the HVECU 70. This routine is executed repeatedly during EV driving. When this routine is executed, the HVECU 70 first determines whether the engine 22 has rotated in reverse (step S100). Here, whether the engine 22 has rotated in reverse can be determined using the crank angle θcr of the crankshaft 23, or the cam angles θci, θco of the intake and exhaust camshafts. When it is determined that the engine 22 is not rotating in reverse, this routine is terminated.

[0021] When it is determined in step S100 that the engine 22 has rotated in the reverse direction, the engine 22 is started (step S110), a predetermined time (for example, about several seconds) is awaited (step S120), the engine 22 is stopped (step S130), and this routine is terminated. When the engine 22 rotates in the reverse direction, the oil pump 110 rotates in the reverse direction, and the oil in the chain tensioner 130 may be drained, causing air to be mixed into the chain tensioner 130. In this embodiment, taking this into consideration, the engine 22 is cranked and started by the motor MG1, and the oil pressure supplied to the chain tensioner 130 by controlling the adjustment valve of the oil pump 110 while the engine 22 is operating at an idle is set to the maximum oil pressure. Note that the operating state of the engine 22 and the oil pressure supplied to the chain tensioner 130 are not limited to this. By such control, the oil pump 130 rotates forward to supply oil into the chain tensioner 130, and if air is mixed in the chain tensioner 130, the air can be discharged outside the chain tensioner 130. The predetermined time is determined in advance by experiment, analysis, etc. as the time required to bleed air from the chain tensioner 130. From the above, when switching from EV driving to HV driving, it is possible to suppress air from accumulating in the chain tensioner 130 and suppress the need to supply a relatively high pressure to the chain tensioner 130 for a certain period of time to bleed air. As a result, it is possible to suppress deterioration of the fuel efficiency of the vehicle. In particular, since it is expected that EV driving will continue for a certain period of time in the CD mode, it is easy for a certain amount of air to accumulate in the chain tensioner 130, and therefore the control of this embodiment is useful.

[0022] In the hybrid vehicle 20 of the present embodiment described above, when the engine 22 rotates in reverse during EV running, the engine 22 is started and a supply process is executed to supply oil from the oil pump 110 to the chain tensioner 130, and then the engine 22 is stopped. This prevents the need to supply a relatively high pressure to the chain tensioner 130 for a certain period of time to bleed air from within the chain tensioner 130 when transitioning from EV running to HV running, and prevents a deterioration in fuel efficiency of the vehicle.

[0023] In the above-described embodiment, the hybrid vehicle 20 is equipped with the variable displacement oil pump 110, but it may be equipped with a fixed displacement oil pump and a valve that is provided in a supply passage that connects the oil pump and the chain tensioner and is capable of adjusting the oil pressure. Also, the hybrid vehicle 20 is configured to be capable of external charging, but it may be configured not to be capable of external charging.

[0024] In the above-described embodiment, the hybrid vehicle 20 is configured to include the engine 22 having the chain tensioner 130, the oil pump 110, the planetary gear 30, and the motors MG1, MG2. However, the present invention is not limited to this, and any configuration may be used as long as it includes an engine having a chain tensioner that adjusts the tension of the timing chain and connected to driving wheels, an oil pump that uses power from the engine to supply oil to the chain tensioner, and a motor connected to the driving wheels.

[0025] The above describes embodiments for implementing the present disclosure, but the present disclosure is not limited to these embodiments, and it goes without saying that the present disclosure can be implemented in various forms without departing from the gist of the present disclosure. [Industrial Applicability]

[0026] The present disclosure is applicable to the hybrid vehicle manufacturing industry and the like. [Explanation of symbols]

[0027] 20 hybrid vehicle, 22 engine, 23 crankshaft, 24 engine ECU, 40 motor ECU, 70 HVECU, 110 oil pump, 111 supply passage, 124 timing chain, 130 chain tensioner, MG2 motor.

Claims

[Claim 1] A hybrid vehicle comprising: an engine having a chain tensioner for adjusting tension of a timing chain and connected to drive wheels; an oil pump for supplying oil to the chain tensioner using power from the engine; a motor connected to the drive wheels; and a control device for controlling the engine and the motor so as to switch between hybrid driving using the power of the engine and electric driving not using the power of the engine, When the engine rotates in reverse during the electric traveling, the control device starts the engine, executes a supply process to supply oil from the oil pump to the chain tensioner, and then stops the engine. Hybrid car.

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