Hybrid vehicle

Abstract

To provide a new technique capable of quickly expelling air that intrudes into a chain tensioner.SOLUTION: A hybrid vehicle comprises: a travel motor; an internal combustion engine; a hydraulic chain installed on the internal combustion engine; a chain tensioner which adjusts tension on the chain; an oil pump which operates in conjunction with the internal combustion engine and supplies oil to the chain tensioner; and a control device controlling operation of the oil pump in accordance with target hydraulic pressure of the oil pump. The control device sets the target hydraulic pressure to an upper limit value until an elapse of a first predetermined period after a start-up of the internal combustion engine in an EV travel mode. The control device also repeatedly fluctuates the target hydraulic pressure within a range equal to or lower than the upper limit value until an elapse of a second predetermined period after an elapse of the first predetermined period and then sets the target hydraulic pressure to a predetermined standard target value after an elapse of the second predetermined period.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The technology disclosed in this specification relates to hybrid vehicles. [Background technology]

[0002] Patent Document 1 discloses a hybrid vehicle including a driving motor, an internal combustion engine, a chain attached to the internal combustion engine, a hydraulic chain tensioner that adjusts the tension of the chain, an oil pump that operates in conjunction with the internal combustion engine and supplies oil to the chain tensioner, and a control device that controls the operation of the oil pump in accordance with a target oil pressure of the oil pump. [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 hybrid vehicle of Patent Document 1, since the internal combustion engine is stopped during the execution of the EV driving mode, the oil pump that operates in conjunction with the internal combustion engine is also stopped. During the execution of the EV driving mode, the internal combustion engine may rotate slightly in the reverse direction due to the driving force of the driving motor. In this case, a force acts on the chain tensioner, causing the oil filled in the chain tensioner to be discharged, and air may enter the chain tensioner. If the internal combustion engine is started in this state, an abnormal noise will be generated due to the air that has entered the chain tensioner. The control device of Patent Document 1 increases the target oil pressure the longer the EV driving mode has been executed, thereby discharging the air that has entered the chain tensioner earlier.

[0005] This specification provides a new technology that can quickly expel air that has entered a chain tensioner. [Means for solving the problem]

[0006] In a first aspect of the present technology, a hybrid vehicle includes a driving motor, an internal combustion engine, a chain provided on the internal combustion engine, a hydraulic chain tensioner that adjusts tension of the chain, an oil pump that operates in conjunction with the internal combustion engine and supplies oil to the chain tensioner, and a control device that controls operation of the oil pump in accordance with a target oil pressure of the oil pump. The control device sets the target oil pressure to an upper limit value until a first predetermined time has elapsed since the internal combustion engine is started during execution of an EV driving mode, repeatedly increases and decreases the target oil pressure within a range equal to or less than the upper limit value until a second predetermined time has elapsed after the first predetermined time has elapsed, and sets the target oil pressure to a predetermined reference target value after the second predetermined time has elapsed.

[0007] According to the above configuration, the target oil pressure repeatedly rises and falls within a range equal to or less than the upper limit value from the time when the first predetermined time has elapsed until the time when the second predetermined time has elapsed, so that the oil pressure of the oil supplied from the oil pump to the chain tensioner also rises and falls. This makes it easier for air that has entered the chain tensioner to be discharged. Therefore, air that has entered the chain tensioner can be discharged early. As a result, the target oil pressure can be set to a predetermined reference target value early. [Brief description of the drawings]

[0008] [Figure 1] Schematic diagram of a hybrid vehicle 2. [Diagram 2] 2 is a schematic diagram of a chain mechanism 40. FIG. [Diagram 3] FIG. 4 is a time chart showing the target oil pressure of the oil pump 56 after the internal combustion engine 16 is started. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] (Example) (Configuration of Hybrid Vehicle 2) As shown in FIG. 1, the hybrid vehicle 2 includes a vehicle body 10, a pair of drive wheels 12, a pair of driven wheels 14, an internal combustion engine 16, a traction motor 18, a battery 20, and a control device 22. The pair of drive wheels 12 are connected to an output shaft 32 via a differential gear 30. The internal combustion engine 16 includes a crankshaft 16A connected to a planetary gear mechanism 34. The planetary gear mechanism 34 is connected to the output shaft 32. The traction motor 18 is connected to the planetary gear mechanism 34 and is electrically connected to the battery 20. The traction motor 18 is driven by power supplied from the battery 20. The battery 20 is a rechargeable secondary battery, and includes, as an example, a plurality of lithium-ion cells.

[0010] As shown in FIG. 2, the hybrid vehicle 2 further includes a chain mechanism 40. The chain mechanism 40 includes a crank sprocket 42, an intake side cam sprocket 44, an exhaust side cam sprocket 46, a chain 48, a fixed guide 50, a swing guide 52, a hydraulic chain tensioner 54, and an oil pump 56. The crank sprocket 42 is attached to the crankshaft 16A. The intake side cam sprocket 44 is attached to an intake side camshaft (not shown). The exhaust side cam sprocket 46 is attached to an exhaust side camshaft (not shown). The chain 48 is stretched across the crank sprocket 42, the intake side cam sprocket 44, and the exhaust side cam sprocket 46. The fixed guide 50 guides the chain 48 between the crank sprocket 42 and the exhaust side cam sprocket 46. The fixed guide 50 is fixed to the internal combustion engine 16. The swingable guide 52 guides the chain 48 between the crank sprocket 42 and the intake cam sprocket 44. The swingable guide 52 is attached to the internal combustion engine 16 so as to be swingable.

[0011] The chain tensioner 54 is in contact with the outer surface of the oscillating guide 52. The chain tensioner 54 adjusts the tension of the chain 48 and also functions as an oil damper. An oil pump 56 is connected to the chain tensioner 54. The oil pump 56 is linked to the crankshaft 16A. The oil pump 56 operates in conjunction with the internal combustion engine 16 (more specifically, the crankshaft 16A) to supply oil to the chain tensioner 54. The chain tensioner 54 is filled with oil supplied from the oil pump 56.

[0012] The control device 22 in Fig. 1 includes a CPU and memories such as a ROM and a RAM. The control device 22 executes various processes according to programs stored in the memory. The control device 22 determines a target oil pressure for the oil pump 56, and controls the operation of the oil pump 56 according to the determined target oil pressure. The control device 22 controls the oil pressure of the oil supplied from the oil pump 56 by controlling the operation of an adjustment valve (not shown). The control device 22 is capable of executing an EV driving mode in which the internal combustion engine 16 is stopped and the driving motor 18 is driven, and an HEV driving mode in which the internal combustion engine 16 is driven.

[0013] A specific case executed by the hybrid vehicle 2 of this embodiment will be described with reference to Fig. 3. In the time chart of Fig. 3, the vertical axis indicates the target hydraulic pressure [kPa]. Before time T0, the hybrid vehicle 2 is executing the EV driving mode.

[0014] At time T0, the internal combustion engine 16 starts while the EV driving mode is being executed. That is, the hybrid vehicle 2 switches from a state in which the EV driving mode is being executed to a state in which the HEV driving mode is being executed. In this case, the control device 22 determines that the internal combustion engine 16 has started, and sets the target oil pressure to an upper limit value P1. The upper limit value P1 is the maximum oil pressure that the oil pump 56 can discharge. The control device 22 maintains the target oil pressure at the upper limit value P1 until a first predetermined time (e.g., 5 seconds) has elapsed since the internal combustion engine 16 started.

[0015] When time T1 arrives, the control device 22 determines that a first predetermined time has elapsed since the internal combustion engine 16 was started, and repeatedly increases and decreases the target oil pressure within a range equal to or less than the upper limit value P1 until a second predetermined time (e.g., 5 seconds) has elapsed since the first predetermined time has elapsed. Specifically, the control device 22 repeatedly increases and decreases the target oil pressure within a range between the upper limit value P1 and a predetermined reference target value P2. In this embodiment, the control device 22 first gradually decreases the target oil pressure from the upper limit value P1 to the reference target value P2. Thereafter, the control device 22 repeatedly executes a process of gradually increasing the target oil pressure from the reference target value P2 to the upper limit value P1, and a process of gradually decreasing the target oil pressure from the upper limit value P1 to the reference target value P2.

[0016] When time T2 arrives, the control device 22 determines that the second predetermined time has elapsed after the first predetermined time has elapsed, and sets the target hydraulic pressure to the reference target value P2.

[0017] The reason why the target oil pressure is repeatedly increased and decreased within a range equal to or less than the upper limit value P1 after the internal combustion engine 16 starts during the EV driving mode will be described. In the hybrid vehicle 2, since the oil pump 56 is connected to the crankshaft 16A, the oil pump 56 is stopped during the EV driving mode. During the EV driving mode, the internal combustion engine 16 may rotate slightly in the reverse direction due to the driving force of the traveling motor 18. In this case, a force acts on the chain tensioner 54, causing the oil filled in the chain tensioner 54 to be discharged, and air may enter the chain tensioner 54. If the internal combustion engine 16 is started in this state, an abnormal noise will be generated due to the air that has entered the chain tensioner 54. By repeatedly increasing and decreasing the target oil pressure within the range of the upper limit value P1 after the internal combustion engine 16 starts, the oil pressure of the oil supplied from the oil pump 56 to the chain tensioner 54 also fluctuates up and down. This allows the air that has entered the chain tensioner 54 to be discharged early. For this reason, the control device 22 repeatedly increases and decreases the target hydraulic pressure within a range equal to or less than the upper limit value P1.

[0018] As described above, the hybrid vehicle 2 includes the traction motor 18, the internal combustion engine 16, the chain 48 provided on the internal combustion engine 16, the hydraulic chain tensioner 54 that adjusts the tension of the chain 48, the oil pump 56 that operates in conjunction with the internal combustion engine 16 and supplies oil to the chain tensioner 54, and the control device 22 that controls the operation of the oil pump 56 in accordance with the target oil pressure of the oil pump 56. The control device 22 sets the target oil pressure to an upper limit value P1 until a first predetermined time has elapsed since the internal combustion engine 16 started while the EV driving mode is being executed, repeatedly raises and lowers the target oil pressure within a range equal to or less than the upper limit value P1 until a second predetermined time has elapsed after the first predetermined time has elapsed, and sets the target oil pressure to a predetermined reference target value P2 after the second predetermined time has elapsed.

[0019] According to the above configuration, since the target oil pressure repeatedly rises and falls within a range equal to or less than the upper limit value P1 from the time the first predetermined time has elapsed until the time the second predetermined time has elapsed, the oil pressure of the oil supplied from the oil pump 56 to the chain tensioner 54 also rises and falls. In this case, air that has entered the chain tensioner 54 is more easily discharged. Therefore, air that has entered the chain tensioner 54 can be discharged early. As a result, the target oil pressure can be set to the predetermined reference target value P2 early. [Explanation of symbols]

[0020] 2: hybrid vehicle, 10: vehicle body, 12: drive wheel, 14: rolling wheel, 16: internal combustion engine, 16A: crankshaft, 18: driving motor, 20: battery, 22: control device, 30: differential gear, 32: output shaft, 34: planetary gear mechanism, 40: chain mechanism, 42: crank sprocket, 44: intake cam sprocket, 46: exhaust cam sprocket, 48: chain, 50: fixed guide, 52: oscillating guide, 54: chain tensioner, 56: oil pump

Claims

[Claim 1] A hybrid vehicle, A driving motor; An internal combustion engine; A chain provided in the internal combustion engine; a hydraulic chain tensioner for adjusting the tension of the chain; an oil pump that operates in conjunction with the internal combustion engine and supplies oil to the chain tensioner; a control device that controls an operation of the oil pump in accordance with a target oil pressure of the oil pump; Equipped with The control device includes: The target hydraulic pressure is set to an upper limit value until a first predetermined time has elapsed since the internal combustion engine was started while the EV driving mode was being executed, The target hydraulic pressure is repeatedly increased and decreased within a range equal to or less than the upper limit value during the period from the lapse of the first predetermined time until the lapse of a second predetermined time. After the second predetermined time has elapsed, the target hydraulic pressure is set to a predetermined reference target value. Hybrid vehicle.

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