Hybrid vehicle control device

Abstract

To provide a control device of a hybrid vehicle which suppress the occurrence of abnormal sound in the time of start of an engine.SOLUTION: A control device of a hybrid vehicle which comprises: a motor being a travel power source; and an engine being a travel power source including a hydraulic lash adjuster that is driven according to the rotation of a cam shaft and a mechanical oil pump that is driven according to the rotation of a crank shaft and supplies lubrication oil to the lash adjuster, comprises: a detection unit which detects the rotation for each unit angle of the cam shaft; a calculation unit which calculates a unit outflow rate being an outflow rate of the lubrication oil from the lash adjuster for each unit angle of the cam shaft during travel by the motor when combustion in the engine stops, and calculates a residual amount of the lubrication oil in the lash adjuster on the basis of a total value of the unit outflow rate; and a start control unit which forcibly starts the engine on the basis of the residual amount.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a control device for a hybrid vehicle. [Background technology]

[0002] When the engine is stopped, lubricating oil inside the hydraulic lash adjuster may leak out, causing abnormal noise when the engine is started. For example, Patent Document 1 discloses adjusting the rotational position of the camshaft to prevent the lubricating oil from leaking out of the lash adjuster. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-198252 Summary of the Invention [Problem to be solved by the invention]

[0004] Hybrid vehicles can run on the motor while the engine is not firing. When running on the motor, road vibrations and the connection between the motor and engine can cause the camshaft to rotate, potentially causing lubricating oil to leak from the lash adjuster. This can result in abnormal engine noise when the engine is started.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a control device for a hybrid vehicle that suppresses the generation of abnormal noise when the engine is started. [Means for solving the problem]

[0006] The above object can be achieved by a control device for a hybrid vehicle including a motor that is a driving power source, and an engine that is a driving power source having a hydraulic lash adjuster that is driven in accordance with the rotation of the camshaft, and a mechanical oil pump that is driven in accordance with the rotation of the crankshaft and supplies lubricating oil to the lash adjuster, the control device including: a detection unit that detects rotation of the camshaft for each unit angle; a calculation unit that calculates a unit outflow amount that is the amount of lubricating oil that flows out of the lash adjuster for each unit angle of the camshaft while combustion in the engine has stopped and the vehicle is being driven by the motor, and calculates the remaining amount of lubricating oil in the lash adjuster based on the total value of the unit outflow amounts; and a start control unit that forcibly starts the engine based on the remaining amount.

[0007] The calculation unit may calculate the unit outflow amount to be smaller as the time during which the camshaft is positioned at a rotational position at which the unit outflow amount is calculated to be other than zero becomes shorter.

[0008] The calculation unit may calculate the unit outflow amount to be smaller as the temperature of the lubricating oil decreases.

[0009] The hybrid vehicle may include another motor connected to the crankshaft, different from the motor, and the engine may have a plurality of lash adjusters, and the calculation unit may include an adjustment unit that calculates the remaining amount for each of the plurality of lash adjusters and drives the other motor to adjust the position of the camshaft to the rotational position where the unit outflow amount from the lash adjuster corresponding to the smallest remaining amount among the plurality of remaining amounts is calculated to be zero.

[0010] The adjustment unit may adjust the position of the camshaft to a range in which the unit outflow rate from all of the lash adjusters is calculated to be zero, the range being closest to a range shifted by 180 degrees from an angle range in which the unit outflow rate from the lash adjuster corresponding to the smallest remaining amount among the plurality of remaining amounts is calculated to be other than zero. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a control device for a hybrid vehicle that suppresses the generation of abnormal noise when the engine is started. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram of a hybrid vehicle. [Figure 2] FIG. 2 is a schematic diagram of the engine. [Figure 3] FIG. 3 is a schematic diagram of a lash adjuster. [Figure 4] FIG. 4 is a flowchart showing an example of noise suppression control executed by the ECU. [Figure 5] FIG. 5A is an example of a map that defines the unit amount of lubricating oil outflow from the lash adjuster according to the rotational position of the camshaft, FIG. 5B is an example of a map that defines a time correction coefficient, and FIG. 5C is an example of a map that defines an oil temperature correction coefficient. DETAILED DESCRIPTION OF THE INVENTION

[0013] [Hybrid vehicle configuration] 1 is a schematic diagram of a hybrid vehicle 1 according to this embodiment. The hybrid vehicle 1 includes an ECU (Electronic Control Unit) 100, an engine 10, a first motor generator (hereinafter referred to as "first MG (Motor Generator)") 14, a second motor generator (hereinafter referred to as "second MG") 15, a PCU (Power Control Unit) 17, a battery 18, a power split mechanism 70, a transmission mechanism 81, a reduction mechanism 82, and drive wheels 83. The engine 10 is a gasoline engine, but is not limited thereto and may be a diesel engine. The engine 10, the first MG 14, and the second MG 15 are power sources for driving the hybrid vehicle 1.

[0014] Both the first MG 14 and the second MG 15 function as motors that output torque when supplied with drive power, and as generators that generate regenerative power when torque is applied. Specifically, the first MG 14 and the second MG 15 are AC rotating electric machines. The AC rotating electric machines are, for example, permanent magnet synchronous motors that have rotors with embedded permanent magnets.

[0015] The first MG 14 and the second MG 15 are electrically connected to the battery 18 via the PCU 17. The PCU 17 includes a first inverter that exchanges power with the first MG 14, a second inverter that exchanges power with the second MG 15, and a converter. The converter boosts the power of the battery 18 and supplies it to the first and second inverters, and reduces the power supplied from the first and second inverters and supplies it to the battery 18. The first inverter converts DC power from the converter into AC power and supplies it to the first MG 14, and converts AC power from the first MG 14 into DC power and supplies it to the converter. The second inverter converts DC power from the converter into AC power and supplies it to the second MG 15, and converts AC power from the second MG 15 into DC power and supplies it to the converter. That is, the PCU 17 charges the battery 18 using the regenerative electric power generated in the first MG 14 or the second MG 15, and drives the first MG 14 or the second MG 15 using the electric power charged in the battery 18.

[0016] The battery 18 is made up of a plurality of stacked cells, which are, for example, secondary batteries such as nickel-metal hydride batteries or lithium-ion batteries.

[0017] The power split mechanism 70 mechanically couples the crankshaft of the engine 10, the rotating shaft of the first MG 14, and the output shaft of the power split mechanism 70. The power split mechanism 70 is, for example, a planetary gear mechanism including a sun gear, a planetary carrier, a pinion gear, and a ring gear. The output shaft of the power split mechanism 70 is coupled to a transmission mechanism 81. The rotating shaft of the second MG 15 is also coupled to the transmission mechanism 81. The transmission mechanism 81 is coupled to a speed reduction mechanism 82, and the driving forces of the engine 10, the first MG 14, and the second MG 15 are transmitted to driving wheels 83 via the transmission mechanism 81 and the speed reduction mechanism 82. The power split mechanism 70 is provided with a one-way clutch that limits the rotation direction of the engine 10 to one direction.

[0018] The reduction mechanism 82 is a multi-stage automatic transmission that changes the gear ratio by changing the gear ratio under the control of the ECU 100. In this way, the reduction mechanism 82 switches between a plurality of power transmission states. Note that instead of the reduction mechanism 82, a continuously variable transmission that continuously changes the gear ratio may be used.

[0019] The ECU 100 is an electronic control unit that includes a processing circuit for performing various calculations related to vehicle driving control and a memory that stores control programs and data. The ECU 100 is an example of a control device for the hybrid vehicle 1, and functionally realizes a detection unit, a calculation unit, and a start control unit, which will be described in detail later.

[0020] The ECU 100 receives signals from an ignition switch 91, an oil temperature sensor 92, and a crank angle sensor 93. The ignition switch 91 detects the on / off state of the ignition. The oil temperature sensor 92 detects the temperature of the lubricating oil that lubricates each part of the engine 10. The crank angle sensor 93 detects the engine rotation speed, which is the rotation speed of the crankshaft of the engine 10.

[0021] The ECU 100 switches the driving mode of the hybrid vehicle 1 between a hybrid driving mode and a motor driving mode based on the accelerator operation amount and the charge amount of the battery 18. In the hybrid driving mode, the hybrid vehicle 1 is driven by at least the engine 10. In the motor driving mode, combustion in the engine 10 is stopped and the hybrid vehicle 1 is driven by the second MG 15.

[0022] [Engine outline] Figure 2 is a schematic diagram of the engine 10. The engine 10 is a gasoline engine, but may also be a diesel engine. The engine 10 may be a multi-cylinder engine, such as a four-cylinder engine. Figure 2 shows one cylinder.

[0023] The cylinder head 41 is attached to the top of the cylinder block 40, and a cylinder 40a is formed within the cylinder block 40. A piston 43 is slidably disposed within the cylinder 40a. One end of a connecting rod 50 is connected to the piston 43, and the other end is connected to a crankshaft 52. An oil pan 51 that stores lubricating oil is attached to the underside of the cylinder block 40. The lubricating oil is pumped up by an oil pump 55 and supplied from the oil pan 51 via the main gallery to the cylinder block 40 and cylinder head 41, and is also supplied to the lash adjusters 46i and 46e.

[0024] The cylinder head 41 is provided with an intake port 42i, an exhaust port 42e, an intake valve 45i, an exhaust valve 45e, an intake-side lash adjuster 46i, an exhaust-side lash adjuster 46e, and a spark plug 56. The intake valve 45i opens and closes the intake port 42i. The exhaust valve 45e opens and closes the exhaust port 42e.

[0025] A fuel injection valve 54 is provided in the intake port 42i. When the intake valve 45i opens, a mixture of fuel and air is introduced into the cylinder 40a. The mixture is ignited by a spark plug 56 and burns, causing the piston 43 to reciprocate up and down within the cylinder 40a, rotating the crankshaft 52.

[0026] The lash adjuster 46i, rocker arm 47i, and camshaft 48i are provided to drive the intake valve 45i. The lash adjuster 46e, rocker arm 47e, and camshaft 48e are provided to drive the exhaust valve 45e. The camshaft 48i is provided with a cam 49i. The camshaft 48e is provided with a cam 49e. The camshafts 48i and 48e rotate in conjunction with the crankshaft 52, and each of the camshafts 48i and 48e rotates once while the crankshaft 52 rotates twice. The intake valve 45i is biased in a valve closing direction by a valve spring (not shown) and is opened and closed by the rocker arm 47i and cam 49i. As the camshaft 48i rotates, the cam 49i acts on the rocker arm 47i. The rocker arm 47i swings under the driving force of the cam 49i, pressing against the intake valve 45i to open it. The intake valve 45i is closed by the elastic force of a valve spring. The same applies to the lash adjuster 46e, rocker arm 47e, camshaft 48e, cam 49e, and exhaust valve 45e.

[0027] The intake-side lash adjuster 46i is hydraulic and supports the rocker arm 47i to adjust the clearance between the rocker arm 47i and the intake valve 45i. The same applies to the exhaust-side lash adjuster 46e.

[0028] [Lash adjuster outline] The general configuration of the lash adjuster 46i will be described below. Note that the exhaust-side lash adjuster 46e has the same configuration as the intake-side lash adjuster 46i, so a duplicated description will be omitted. Figure 3 is a general configuration diagram of the lash adjuster 46i. As shown in Figure 3, the lash adjuster 46i includes a body 60 and a plunger 62. The body 60 and plunger 62 are each cylindrical and made of metal. The body 60 has a bottom surface and an open top surface. The plunger 62 is housed in the body 60 and is slidable in the vertical direction relative to the body 60 in the figure. The upper end of the plunger 62 is dome-shaped and comes into contact with the rocker arm 47i.

[0029] A leak passage 63 surrounding the plunger 62 is formed between the inner wall of the body 60 and the outer circumferential surface of the plunger 62. As will be described later, lubricating oil is discharged from the high-pressure chamber 60a to the outside through the leak passage 63.

[0030] A low-pressure chamber 62a that stores lubricating oil is provided inside the plunger 62. The body 60 and the bottom surface of the plunger 62 define a high-pressure chamber 60a below the low-pressure chamber 62a. The high-pressure chamber 60a and the low-pressure chamber 62a can communicate with each other through a communication port 62b in the plunger 62. A supply hole 62c is provided in the plunger 62, and a supply hole 60b is provided in the body 60. Lubricating oil is supplied by the oil pump 55 from the oil pan 51 through the supply holes 60b and 62c to the low-pressure chamber 62a, and is then introduced into the high-pressure chamber 60a.

[0031] The high-pressure chamber 60a is provided with springs 64 and 66, a retainer 68, and a check ball 69. The spring 64 is located on the bottom surface of the body 60 and applies an upward elastic force to the plunger 62 via the retainer 68. In other words, the plunger 62 is urged upward by the spring 64. The spring 66 is located on the bottom surface of the retainer 68 and applies an upward elastic force to the check ball 69. The check ball 69 faces the communication port 62b of the plunger 62 and is urged upward by the spring 66. When the check ball 69 moves away from the communication port 62b, the high-pressure chamber 60a and the low-pressure chamber 62a communicate with each other, allowing lubricating oil to flow from the high-pressure chamber 60a to the low-pressure chamber 62a or from the low-pressure chamber 62a to the high-pressure chamber 60a. On the other hand, when the check ball 69 comes into contact with the communication port 62b, communication between the high-pressure chamber 60a and the low-pressure chamber 62a is blocked.

[0032] When the camshaft 48i shown in FIG. 2 presses the rocker arm 47i, the pressing force is transmitted to the plunger 62 via the rocker arm 47i. As a result, the plunger 62 attempts to enter the body 60. The check ball 69 blocks the communication port 62b, thereby preventing lubricating oil from flowing from the high-pressure chamber 60a to the low-pressure chamber 62a. The increase in hydraulic pressure in the high-pressure chamber 60a prevents the plunger 62 from sinking, and the plunger 62 is pressed against the rocker arm 47i. This prevents clearance from forming between the intake valve 45i and the rocker arm 47i. At this time, the plunger 62 enters the body 60, and the lubricating oil in the high-pressure chamber 60a flows through the leak passage 63 between the inner wall of the body 60 and the outer circumferential surface of the plunger 62 and then flows out of the body 60 via the supply hole 60b. This reduces the amount of lubricating oil in the high-pressure chamber 60a.

[0033] As the camshaft 48i rotates and the pressing force from the rocker arm 47i decreases, the rocker arm 47i attempts to move away from the plunger 62. At this time, the plunger 62 is pushed up by the elastic force of the spring 64 and protrudes from the body 60. This prevents clearance from being generated between the plunger 62 and the rocker arm 47i. At this time, the volume of the high-pressure chamber 60a expands, causing the pressure to decrease, and the check ball 69 moves away from the communication port 62b, causing the lubricating oil in the low-pressure chamber 62a to be sucked into the high-pressure chamber 60a. As a result, the amount of lubricating oil in the high-pressure chamber 60a increases and the amount of lubricating oil in the low-pressure chamber 62a decreases, but the oil pump 55 supplies lubricating oil to the low-pressure chamber 62a via the supply holes 60b and 62c.

[0034] In engine 10 equipped with lash adjusters 46i and 46e configured as described above, combustion in engine 10 stops during driving in the motor driving mode, and thus driving of oil pump 55 stops. As a result, no new lubricating oil is supplied to lash adjusters 46i and 46e. In this state, for example, vibrations from the road surface may cause crankshaft 52 to rotate unintentionally. Furthermore, if hybrid vehicle 1 suddenly accelerates or decelerates, for example, rotation of second MG 15 may be transmitted to crankshaft 52 of engine 10 via power split mechanism 70, causing crankshaft 52 to rotate unintentionally. As a result, camshafts 48i and 48e rotate, causing lash adjusters 46i and 46e to expand or contract, which may result in lubricating oil leaking from lash adjusters 46i and 46e. If the engine 10 is started with insufficient lubricating oil in the lash adjusters 46i and 46e, gaps may form between the lash adjuster 46i and the rocker arm 47i or between the lash adjuster 46e and the rocker arm 47i, which may cause abnormal noise. To prevent this, the ECU 100 executes the following control.

[0035] [Noise suppression control] 4 is a flowchart showing an example of noise suppression control executed by the ECU 100. This control is repeatedly executed at predetermined intervals while the ignition is on. The ECU 100 determines whether the driving mode is set to the motor driving mode (step S1). If the result in step S1 is No, this control is terminated.

[0036] If the answer to step S1 is Yes, the ECU 100 calculates the remaining amount of lubricant in each of the lash adjusters 46i and 46e (step S2). Here, if the engine 10 is a four-cylinder engine and each cylinder is provided with two intake valves 45i and two exhaust valves 45e, a total of four lash adjusters are provided per cylinder. Generally, since the phases of the two cams in each cylinder are the same, the remaining amount of lubricant in the two lash adjusters 46i of each cylinder is considered to be the same, and the remaining amount of lubricant in the two lash adjusters 46e of each cylinder is also considered to be the same. Therefore, the ECU 100 calculates a total of eight remaining amounts of lubricant, including the remaining amount in each lash adjuster 46i of each of the four cylinders and the remaining amount in each lash adjuster 46e of each of the four cylinders. The method for calculating the remaining amount will be described in detail later. The processing in step S2 is an example of processing executed by the calculation unit.

[0037] Next, the ECU 100 determines whether the smallest remaining amount among the calculated remaining amounts is equal to or less than a threshold value (step S3). If the result in step S3 is No, the process in step S2 continues.

[0038] If the answer to step S3 is Yes, the ECU 100 drives the first MG 14 to adjust the rotational positions of the camshafts 48i and 48e via the crankshaft 52 (step S4), as will be described in detail later.

[0039] Next, the ECU 100 determines whether each remaining amount is equal to or less than a threshold value (step S5). The threshold value in step S5 is a value smaller than the threshold value in step S3. The threshold value in step S5 is set to a lower limit value at which abnormal noise due to a decrease in the remaining amount of lubricating oil does not occur when the engine 10 is started. If the result in step S5 is No, the processing from step S2 onwards is executed again.

[0040] If the answer to step S5 is Yes, the ECU 100 starts the engine 10 (step S6). As a result, the engine 10 starts and the oil pump 55 is driven to supply lubricating oil to the lash adjusters 46i and 46e before the remaining amount of oil decreases to the point where abnormal noise occurs. In this way, the generation of abnormal noise when the engine 10 is started is suppressed. The processing of step S6 is an example of processing executed by the start control unit.

[0041] [How to calculate the remaining amount of lubricating oil] Next, a method for calculating the remaining amount of lubricating oil will be described. This calculation method is similar for both the exhaust-side lash adjuster 46e and the intake-side lash adjuster 46i, so the following description will be given using the intake-side lash adjuster 46i as an example.

[0042] Since the engine 10 has four cylinders #1 to #4, the angle range in which the nose of the cam 49i for each cylinder of the camshaft 48i is formed is assumed to be 60 degrees. In this case, the angle ranges of the nose of the cam 49i for each cylinder #1, #3, #4, and #2 are 60 to 120 degrees, 150 to 210 degrees, 240 to 300 degrees, and 330 to 390 degrees. As described above, lubricating oil flows out when the plunger 62 is pushed into the body 60. Therefore, the angle ranges of the camshaft 48i in which lubricating oil flows out from the lash adjusters 46i for each cylinder #1, #3, #4, and #2 are 60 to 90 degrees, 150 to 180 degrees, 240 to 270 degrees, and 330 to 360 degrees.

[0043] A map that defines the unit amount of lubricant outflow Δf from the lash adjuster 46i corresponding to the rotational position of the camshaft 48i is stored in advance in the ROM of the ECU 100. This map is calculated based on experimental results and simulation results. FIG. 5A shows an example of a map that defines the unit amount of lubricant outflow Δf from the lash adjuster 46i corresponding to the rotational position of the camshaft 48i. Here, the unit amount of lubricant outflow Δf is the amount of lubricant outflow from the lash adjuster 46i when the camshaft 48i rotates by a unit angle.

[0044] Here, the unit lubricating oil outflow rate Δf decreases as the time during which the camshaft 48i is positioned at a rotational position where the calculated unit outflow rate Δf is not zero. For this reason, the unit outflow rate Δf is corrected by a time correction coefficient Ct. Figure 5B is an example of a map that defines the time correction coefficient Ct. This map is calculated based on experimental results and simulation results. The maximum value of the time correction coefficient Ct is 1, and it decreases as the time during which the camshaft 48i is positioned at the above-mentioned rotational position decreases.

[0045] Furthermore, the lower the temperature of the lubricating oil when the camshaft 48i is positioned at a rotational position where the unit outflow rate Δf is large, the higher the viscosity of the lubricating oil and the lower the unit outflow rate Δf. For this reason, the unit outflow rate Δf is corrected by an oil temperature correction coefficient Co. Figure 5C is an example of a map that defines the oil temperature correction coefficient Co. This map is calculated based on experimental results and simulation results. The maximum value of the oil temperature correction coefficient Co is 1, and it decreases as the oil temperature when the camshaft 48i is positioned at the above-mentioned rotational position decreases.

[0046] Therefore, the unit outflow can be expressed by the following formula: Unit outflow rate = Δf × Ct × Co Here, the unit outflow amount is calculated each time a rotation of the camshaft 48i by a unit angle is detected, and the unit outflow amounts are sequentially added up to calculate the total outflow amount from the lash adjuster 46i. Therefore, the total outflow amount can be expressed as follows: Total outflow = Δf1×Ct1×Co1+Δf2×Ct2×Co2+…Δf n ×Ct n ×Co n The subscripts 1 to n attached to the unit outflow amount Δf, the time correction coefficient Ct, and the oil temperature correction coefficient Co indicate the order in which the camshaft 48i has rotated by a unit angle since calculation of the remaining amount began.

[0047] Therefore, the final remaining amount can be expressed as follows: Residual volume = Volume of low pressure chamber 62a - Total outflow volume The volume of low pressure chamber 62a is stored in advance in the ROM of ECU 100. The remaining amount of lubricant in exhaust-side lash adjuster 46e is calculated in a similar manner. In this manner, the remaining amount of lubricant can be calculated with high accuracy. Note that the calculation of the remaining amount is not limited to the method based on the maps of Figures 5A to 5C, and may also be calculated using an arithmetic expression.

[0048] In this embodiment, because the camshaft 48i rotates in conjunction with the crankshaft 52, the ECU 100 can detect the rotation of the camshaft 48i through a unit angle based on the detection value of the crank angle sensor 93, which detects the rotational position of the crankshaft 52. Furthermore, if a variable valve timing mechanism capable of changing the rotational phase of the camshaft 48i relative to the crankshaft 52 is provided, the ECU 100 detects the rotation of the camshaft 48i through a unit angle based on the detection value of the crankshaft 52 and the rotational phase of the camshaft 48i relative to the crankshaft 52. For example, if the detection resolution of the crank angle sensor 93 is 10 degrees, the ECU 100 can detect the rotation of the camshaft 48i every 5 degrees. The above-described processing by the ECU 100 is an example of processing executed by a detection unit. Furthermore, if a cam angle sensor capable of directly detecting the rotational position of the camshaft 48i or the camshaft 48e is provided, the rotation of the camshaft 48i or the camshaft 48e through a unit angle may be detected based on the detection value of the cam angle sensor.

[0049] [Rotational position adjustment] Next, adjustment of the rotational positions of the camshafts 48i and 48e will be described. By rotating the crankshaft 52 with the first MG 14, the positions of the camshafts are adjusted to rotational positions where the unit outflow rate from the lash adjuster corresponding to the smallest remaining amount among the calculated remaining amounts is calculated as zero. For example, if the remaining amount in the lash adjuster 46i of cylinder #1 is the smallest remaining amount, as shown in Figure 5A, the position of the camshaft 48i is adjusted to outside the range of 60 degrees to 90 degrees.

[0050] The position of the camshaft 48i may be adjusted to a rotational position where the unit outflow rate from each of the lash adjusters 46i for cylinders #1 to #4 is calculated as zero. For example, in the example of Fig. 5A, the position of the camshaft 48i is preferably adjusted to any of the following: greater than 0 degrees and less than 60 degrees, greater than 90 degrees and less than 150 degrees, greater than 180 degrees and less than 240 degrees, or greater than 270 degrees and less than 330 degrees. This also makes it possible to suppress outflow of lubricating oil from other lash adjusters.

[0051] The camshaft may be adjusted to a range in which the unit outflow rate from all lash adjusters is calculated to be zero, the range being closest to a range 180 degrees shifted from the angle range in which the unit outflow rate of the lash adjuster corresponding to the minimum remaining amount is calculated to be other than zero. For example, if the remaining amount in the lash adjuster 46i of cylinder #1 is the minimum remaining amount, it is preferable to adjust the camshaft 48i to either an angle greater than 180 degrees but less than 240 degrees or an angle greater than 270 degrees but less than 330 degrees, the angle being closest to a range of 240 degrees to 270 degrees, which is 180 degrees shifted from the range of 60 degrees to 90 degrees. This makes it possible to prevent the camshaft 48i from rotating again after the position adjustment and causing lubricating oil to leak again from the lash adjuster 46i.

[0052] As described above, since the crankshaft 52 is linked to both the camshafts 48i and 48e, the above-described position adjustment causes both the camshafts 48i and 48e to rotate. Even during this time, the remaining amount is continuously calculated by the lash adjusters 46i and 46e of each cylinder, thereby improving the accuracy of the remaining amount calculation.

[0053] 4, after executing step S2, it may be determined whether the minimum remaining amount is equal to or less than the threshold without executing steps S3 and S4, and if the determination is negative, step S2 may be executed again, and if the determination is positive, the engine 10 may be started. This type of control is suitable for, for example, a hybrid vehicle equipped with an engine as a driving power source, a motor disposed on a power transmission path from the engine to the drive wheels, and a clutch disposed on the power transmission path between the engine and the motor. This is because, in such a hybrid vehicle, the clutch is disengaged while the vehicle is running in the motor driving mode, making it difficult to adjust the rotational position of the engine crankshaft using the motor.

[0054] In the above embodiment, the power split device 70 is provided with a one-way clutch that limits the rotational direction of the engine 10 to one direction. However, this is not limiting. That is, if the one-way clutch is not provided, the engine 10 can rotate in both directions during running in the motor running mode. In this case, for example, when forward rotation of the camshaft 48i is detected, the map shown in FIG. 5A is used as the map for forward rotation to calculate the unit outflow rate Δf. When reverse rotation of the camshaft 48i is detected, the map for reverse rotation is used to calculate the unit outflow rate Δf. As described above, when the camshaft 48i rotates forward, the angle range of the nose of the cam 49i is 60 to 120 degrees. The angle range of the camshaft 48i in which lubricating oil flows out of the lash adjuster 46i of cylinder #1 is 60 to 90 degrees, in which the plunger 62 is pushed in. In contrast, when the camshaft 48i rotates reversely, the angle range is 90 to 120 degrees, in which the plunger 62 is pushed in. Therefore, the reverse rotation map defines the angle ranges of the camshaft 48i over which lubricating oil flows out from the lash adjusters 46i of cylinders #1, #3, #4, and #2 as 90 to 120 degrees, 180 to 210 degrees, 270 to 300 degrees, and 360 to 390 degrees. By using such maps, the remaining amount of lubricating oil can be calculated.

[0055] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as defined in the claims. [Explanation of symbols]

[0056] 10 Engine 14 First motor generator 15 Second motor generator 46i, 46e lash adjuster 48i, 48e camshaft 52 crankshaft 100 ECU (controller, detector, calculator, start controller)

Claims

1. a motor that is a driving power source; an engine as a driving power source, the engine having a hydraulic lash adjuster that is driven in response to rotation of a camshaft, and a mechanical oil pump that is driven in response to rotation of a crankshaft to supply lubricating oil to the lash adjuster; In a control device for a hybrid vehicle, a detection unit that detects rotation of the camshaft per unit angle; a calculation unit that calculates a unit outflow amount, which is the amount of lubricating oil that flows out from the lash adjuster for each unit angle of the camshaft while combustion in the engine is stopped and the vehicle is running using the motor, and calculates the remaining amount of lubricating oil in the lash adjuster based on the total value of the unit outflow amounts; a start control unit that forcibly starts the engine based on the remaining amount.

2. 2. The control device for a hybrid vehicle according to claim 1, wherein the calculation unit calculates the unit outflow amount to be smaller the shorter the time during which the camshaft is positioned at a rotational position at which the unit outflow amount is calculated to be other than zero.

3. 3. The control device for a hybrid vehicle according to claim 1, wherein the calculation unit calculates the unit outflow amount to be smaller as the temperature of the lubricating oil decreases.

4. the hybrid vehicle includes another motor connected to the crankshaft, the other motor being different from the motor; the engine has a plurality of the lash adjusters, the calculation unit calculates the remaining amount for each of the plurality of lash adjusters, 3. The control device for a hybrid vehicle according to claim 1, further comprising an adjustment unit that adjusts a position of the camshaft to a rotational position where the unit outflow amount from the lash adjuster corresponding to the smallest remaining amount among the plurality of remaining amounts is calculated as zero by driving the other motor.

5. 5. The control device for a hybrid vehicle according to claim 4, wherein the adjustment unit adjusts the position of the camshaft to a range in which the unit outflow rate from all of the lash adjusters is calculated to be zero, the range being closest to a range shifted by 180 degrees from an angle range in which the unit outflow rate from the lash adjuster corresponding to the smallest remaining amount among the plurality of remaining amounts is calculated to be other than zero.

Images