Vehicle control device

Abstract

To provide a control device of a vehicle capable of suppressing leakage of an oil from a breather even when defoaming performance is degraded due to deterioration of the oil.SOLUTION: An electronic control device 90 (control device) of a vehicle 10 including: a differential 22 (power transmission device) disposed on a power transmission path PT between an engine 12 (power source) and a pair of driving wheels 24; and a transaxle case 40 (case) housing the differential 22, storing an oil 60 stirred according to a differential rotating speed Ndif of the differential 22 at a bottom portion and provided with a breather 62 at an upper portion, (a) estimates a deterioration quantity DQ of the oil 60; and (b) determines an operable region of an operation point P represented by an engine rotating speed Ne and a differential rotating speed Ndif so that the oil 60 does not leak out from the breather 62, on the basis of an inclination angle φ of the vehicle 10 as an angle of inclination of a position of the breather 62 to a side close to a liquid level 60s of the oil 60, and the deterioration quantity DQ.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a control device for a vehicle that includes a case that houses a power transmission device, stores oil at the bottom that is stirred according to the rotation speed of the power transmission device, and has a breather attached to the top. [Background technology]

[0002] There is known a vehicle control device that includes a case that houses a differential and an automatic transmission, stores oil at the bottom that is stirred in accordance with the vehicle speed, which corresponds to the rotation speed of the differential, and has a breather attached to the top. For example, the device described in Patent Document 1 is one such device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-114471 Summary of the Invention [Problem to be solved by the invention]

[0004] Patent Document 1 discloses a vehicle control device that estimates the amount of oil deterioration and, when the amount of deterioration reaches or exceeds a predetermined value, prompts the driver to change the oil. However, if such deteriorated oil is used, there is a risk that the oil will leak from the breather due to a decrease in the anti-foaming performance.

[0005] The present invention has been made against the background of the above circumstances, and its purpose is to provide a vehicle control device that can suppress oil leakage from the breather even if the anti-foaming performance is reduced due to oil deterioration. [Means for solving the problem]

[0006] The gist of the present invention is a control device for a vehicle that includes a power source, a pair of drive wheels, a power transmission device provided in a power transmission path between the power source and the pair of drive wheels, and a case that houses the power transmission device, stores oil at the bottom that is stirred according to the rotational speed of the power transmission device, and has a breather attached to the top, and (a) estimates the amount of deterioration of the oil, and (b) sets an operable range of an operating point expressed by the rotational speed of the power source and the rotational speed of the power transmission device based on the amount of deterioration and the inclination angle of the case, which is the angle at which the position of the breather is tilted toward the oil liquid level, so that the oil does not leak from the breather. [Effects of the Invention]

[0007] According to the vehicle control device of the present invention, (a) the amount of deterioration of the oil is estimated, and (b) based on the inclination angle of the case, which is the angle at which the position of the breather is tilted toward the oil level, and the deterioration amount, an operable range of an operating point expressed by the rotational speed of the power source and the rotational speed of the power transmission device is set so that the oil does not leak from the breather. The anti-foaming performance of oil foamed by stirring or the like decreases as the amount of oil deterioration increases. Because the operable range of an operating point expressed by the rotational speed of the power source and the rotational speed of the power transmission device is set so that the oil does not leak from the breather based on the inclination angle of the case and the deterioration amount of the oil, oil leakage from the breather is suppressed even if the anti-foaming performance decreases due to oil deterioration. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a vehicle equipped with an electronic control device according to a first embodiment. [Figure 2] This figure explains the relationship between the distance from the oil level to the breather position and the vehicle's inclination angle, where (a) shows the vehicle in a horizontal state, i.e., not inclined in any direction, (b) shows the vehicle in a state where it is inclined backward, and (c) shows the vehicle in a state where it is inclined forward. [Figure 3] FIG. 4 is a diagram illustrating a method for estimating the deterioration amount of oil. [Figure 4] 10 is a diagram illustrating the relationship between an operable region of an operating point represented by an engine rotation speed and a differential rotation speed, and a tilt angle of a vehicle. FIG. [Figure 5] FIG. 10 is a schematic configuration diagram of a vehicle equipped with an electronic control device according to a second embodiment. [Figure 6] 10 is a diagram illustrating the relationship between the operable region of the operating point represented by the motor rotation speed and the differential rotation speed, and the tilt angle of the vehicle. FIG. [Figure 7] FIG. 10 is a schematic configuration diagram of a vehicle equipped with an electronic control device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, each embodiment of the present invention will be described in detail with reference to the drawings. Note that in each embodiment, the drawings are appropriately simplified or modified, and the dimensional ratios and shapes of each part are not necessarily drawn accurately. [Example]

[0010] FIG. 1 is a schematic diagram of a vehicle 10 equipped with an electronic control device 90 according to the first embodiment.

[0011] In the vehicle 10, a power transmission path PT between an engine 12, which is a power source, and a pair of drive wheels 24 is connected in this order from the engine 12 side to a crankshaft 30, a torque converter 14, a transmission input shaft 32, an automatic transmission 16, a transmission output shaft 34, a final reduction gear 18, and a pair of axles 38, all of which are well-known components. The vehicle 10 also includes a hydraulic control circuit 50 and an electronic control device 90.

[0012] The engine 12 is a well-known internal combustion engine. An engine control device including a throttle actuator, a fuel injection device, an ignition device, etc. controls the engine torque Te [Nm] output from the engine 12. The engine 12 corresponds to the "power source" in the present invention. Hereinafter, unless otherwise specified, the terms power, driving force, torque, and force are synonymous.

[0013] The torque converter 14 includes a pump wheel connected to the crankshaft 30, a turbine wheel connected to the transmission input shaft 32, and a lock-up clutch LU (not shown) that can directly connect the pump wheel and the turbine wheel. The torque converter 14 is a fluid-type power transmission that can transmit power output from the engine 12 from the crankshaft 30 to the transmission input shaft 32 via a fluid. When the lock-up clutch LU is in a directly connected state, the engine rotation speed Ne [rpm], which is the rotation speed of the engine 12, is the same as the input rotation speed Nin [rpm] of the automatic transmission 16. When the lock-up clutch LU is in a disengaged state, a difference can occur between the engine rotation speed Ne and the input rotation speed Nin by the amount of the differential rotation between the pump wheel and the turbine wheel. The engine rotation speed Ne corresponds to the "rotation speed of the power source" in this invention.

[0014] The automatic transmission 16 is a well-known transmission that changes the rotation of a transmission input shaft 32 and outputs the rotation from a transmission output shaft 34. The automatic transmission 16 is, for example, a stepped transmission that has one of a plurality of gear stages (also referred to as "gear stages") with different speed ratios (also referred to as "gear ratios") γat. The speed ratio γat is the rotational speed ratio (=Nin / Nout) between an input rotational speed Nin and an output rotational speed Nout [rpm]. The input rotational speed Nin is the rotational speed of the transmission input shaft 32, which is the input shaft of the automatic transmission 16, and the output rotational speed Nout is the rotational speed of the transmission output shaft 34, which is the output shaft of the automatic transmission 16.

[0015] The final reduction gear 18 is a device that combines a reduction gear 20 that reduces the speed of the power from the automatic transmission 16 and a differential 22 (also referred to as a "differential gear") that distributes the power to a pair of drive wheels 24. The reduction gear 20 includes an output gear 34a fixed to a transmission output shaft 34, a large reduction gear 36a fixed to a countershaft 36 that is parallel to the transmission output shaft 34 and meshes with the output gear 34a, and a small reduction gear 36b fixed to the countershaft 36 and meshes with a differential ring gear 22r of the differential 22. The large reduction gear 36a has a larger diameter than the output gear 34a, and the small reduction gear 36b has a smaller diameter than the differential ring gear 22r. The differential 22 corresponds to the "power transmission device" in this invention.

[0016] The rotational speed of the differential ring gear 22r is referred to as the differential rotational speed Ndif [rpm]. The output rotational speed Nout is reduced in accordance with the gear ratio α of the reduction gear device 20 and transmitted to the differential 22. The rotational speed ratio between the output rotational speed Nout and the differential rotational speed Ndif (= Nout / Ndif) is referred to as the reduction ratio γslw. The rotational speed ratio γttl between the input rotational speed Nin and the differential rotational speed Ndif (= Nin / Ndif) is the gear ratio γat × the reduction ratio γslw. The differential rotational speed Ndif and the rotational speed ratio γttl correspond to the "rotational speed of the power transmission device" and "rotational speed ratio" in this invention, respectively.

[0017] The torque transmitted from the engine 12 via the automatic transmission 16 and the reduction gear 20 to the differential 22 and then transmitted by the differential 22 to the pair of drive wheels 24 is referred to as the transmission torque Td [Nm] of the differential 22. The output torque Tout [Nm] of the automatic transmission 16 is increased in accordance with the gear ratio α. The power output from the automatic transmission 16 is finally decelerated by the reduction gear 20, whereby the torque is increased and input to the differential 22. The differential 22 distributes the power input from the automatic transmission 16 to the pair of axles 38 and outputs it to the pair of drive wheels 24.

[0018] The torque converter 14, automatic transmission 16, and final reduction gear 18 are housed in a transaxle case 40 (hereinafter simply referred to as "case 40"). The case 40 is attached to the vehicle body. Oil 60 (see FIG. 2) is stored in the bottom of the case 40. The case 40 corresponds to the "case" in this invention.

[0019] A portion of the oil 60 stored at the bottom of the case 40 is scooped up by the gears of the differential 22 (particularly the differential ring gear 22r) and the like, and is used to lubricate the gears and bearings inside the case 40. The oil 60 is stirred by being scooped up by the differential ring gear 22r and the like provided in the differential 22. Furthermore, as the gears of the final reduction gear 18 and the automatic transmission 16 inside the case 40 rotate, the oil 60, which is a lubricating oil, is splashed around. The oil 60 is, for example, ATF (Automatic Transmission Fluid). A breather 62 is attached to the top of the case 40. The breather 62 exhausts air when the pressure inside the case 40 becomes higher than the outside pressure, and takes in air when the pressure inside the case 40 becomes lower than the outside pressure. For example, if the rotation speed of the differential ring gear 22r increases while the vehicle is running and the oil 60 is stirred vigorously, or if the gears of the final reduction gear 18 and the automatic transmission 16 increase in speed and the oil 60 is splashed, the oil 60 is more likely to foam. As will be described later, at relatively high vehicle speeds where the lock-up clutch LU is in a directly-coupled state, the oil 60 is more likely to foam than at relatively low vehicle speeds where the lock-up clutch LU is in a disengaged state.

[0020] The oil 60 stored in the bottom of the case 40 is drawn into an oil pump (not shown). The oil pump may be a mechanical oil pump or an electric oil pump. The oil pump discharges the drawn oil 60 to the hydraulic control circuit 50.

[0021] The hydraulic control circuit 50 supplies oil 60 discharged from the oil pump as lubricating oil for the gears and bearings inside the case 40. After lubricating the gears, bearings, etc., the oil 60 gradually flows down and returns to the bottom of the case 40. The hydraulic control circuit 50 also uses the hydraulic pressure of the oil 60 discharged from the oil pump as the source pressure and supplies adjusted hydraulic pressure to an actuator for establishing a gear position of the automatic transmission 16. The hydraulic control circuit 50 supplies adjusted hydraulic pressure to an actuator that controls the engagement / disengagement state (disconnected state, direct engagement state) of a lock-up clutch LU (not shown) that the torque converter 14 has.

[0022] FIG. 2 is a diagram illustrating the relationship between the distance from the oil level 60s to the position of the breather 62 and the inclination angle φ [deg] of the vehicle 10. (a) shows the vehicle 10 in a horizontal state, i.e., a state where the vehicle 10 is not inclined in any direction. (b) shows the vehicle 10 in a state where the vehicle 10 is inclined backward. (c) shows the vehicle 10 in a state where the vehicle 10 is inclined forward. The inclination angle φ is the angle at which the case 40 is inclined toward the side where the position of the breather 62 approaches the oil level 60s. Because the case 40 is attached to the vehicle body, the inclination angle φ of the vehicle 10 and the inclination angle of the case 40 are the same. The inclination angle φ corresponds to the "inclination angle of the case" in this invention. The position of the breather 62 is the position at which the breather 62 opens within the case 40 for intake and exhaust. The larger the inclination angle φ, the closer the position of the breather 62 is to the oil level 60s. In this embodiment, the breather 62 is attached to the upper part of the case 40, for example, toward the rear of the vehicle. Note that the liquid level 60s of the oil 60 refers to the liquid level 60s when the oil 60 is not foaming (or, if the oil 60 is foaming, it is assumed that the oil is not foaming).

[0023] As shown in Fig. 2(a), when the vehicle 10 is in a horizontal state, the distance from the liquid level 60s of the oil 60 to the position of the breather 62, that is, the height H [m] of the position of the breather 62 with the liquid level 60s of the oil 60 as the reference plane, is the height h0. As shown in Fig. 2(b), when the vehicle 10 is in a state of tilting backward, the height H of the position of the breather 62 with the liquid level 60s of the oil 60 as the reference plane is the height h1 (< h0). As shown in Fig. 2(c), when the vehicle 10 is in a state of tilting forward, the height H of the position of the breather 62 with the liquid level 60s of the oil 60 as the reference plane is the height h2 (> h0). Thus, in this embodiment, as the vehicle 10 tilts backward, the position of the breather 62 approaches the liquid level 60s of the oil 60, and as the vehicle 10 tilts forward, the position of the breather 62 moves away from the liquid level 60s of the oil 60. Therefore, the tilt angle φ has a positive value on the side where the vehicle 10 tilts backward and a negative value on the side where the vehicle 10 tilts forward.

[0024] Returning to Fig. 1, the electronic control unit 90 is configured to include a so-called microcomputer having, for example, a CPU, a RAM, a ROM, an input / output interface, etc. The CPU performs signal processing according to a program stored in the ROM in advance while using the temporary storage function of the RAM to execute various controls of the vehicle 10. For example, the electronic control unit 90 executes operation control of the engine 12, connection / disconnection control of the lock-up clutch LU of the torque converter 14, shift control of the automatic transmission 16, etc., and performs control of the entire vehicle 10 as necessary. Note that the electronic control unit 90 corresponds to the "control device" in the present invention.

[0025] Various signals (for example, the accelerator opening θacc [%] which is the amount of the driver's accelerator operation representing the magnitude of the driver's acceleration operation, the vehicle speed V [km / h], the engine rotational speed Ne, the differential rotational speed Ndif, the tilt angle φ of the vehicle 10, the oil temperature THoil [°C] of the oil 60, etc.) based on the detection values by various sensors (for example, an accelerator opening sensor 70, a vehicle speed sensor 72, an engine rotational speed sensor 74 of the engine 12, a rotational speed sensor 76 of the differential 22, a tilt angle sensor 78, an oil temperature sensor 80, etc.) provided in the vehicle 10 are respectively input to the electronic control unit 90.

[0026] The electronic control device 90 outputs various command signals (e.g., an engine control signal Se for controlling the operation of the engine 12, an LU control signal Slu for controlling the engagement and disengagement of the lock-up clutch LU, and a transmission control signal Sat for controlling the shifting of the automatic transmission 16) to each device (e.g., the engine 12, the hydraulic control circuit 50, etc.) provided in the vehicle 10.

[0027] The electronic control device 90 functionally comprises an engine control unit 90a, a torque converter control unit 90b, a gear change control unit 90c, a deterioration estimation unit 90d, and an operating point setting unit 90e.

[0028] The engine control unit 90a controls the engine torque Te so as to realize a drive demand amount for the vehicle 10 based on the accelerator opening θacc and the vehicle speed V, for example, while the vehicle is running.

[0029] The torque converter control unit 90b controls the engagement / disengagement state of the lock-up clutch LU of the torque converter 14. The torque converter control unit 90b disengages the lock-up clutch LU when the vehicle speed is relatively low, such as when the vehicle starts, and directly engages the lock-up clutch LU when the vehicle speed is relatively high.

[0030] The shift control unit 90c determines whether to shift the automatic transmission 16 using, for example, a shift map, and executes shift control as necessary. The shift map is a predetermined relationship having shift lines for determining whether to shift the automatic transmission 16 on a two-dimensional coordinate system using, for example, accelerator opening θacc and vehicle speed V as variables. In the shift map, the output rotation speed Nout or the like may be used instead of the vehicle speed V, and the required drive torque Trdem [Nm] or the throttle valve opening θth [%] or the like may be used instead of the accelerator opening θacc.

[0031] The deterioration estimation unit 90d estimates the deterioration amount DQ of the oil 60. The deterioration amount DQ is an index that indicates the degree of deterioration of the oil 60. FIG.

[0032] The deterioration estimation unit 90d estimates the deterioration amount DQ by sequentially accumulating a multiplication value ΔDQ (=k×Td×Ndif) obtained by multiplying the product of the transmission torque Td and the differential rotation speed Ndif by a predetermined coefficient k predetermined according to the oil temperature THoil of the oil 60 at every predetermined sampling time Δt with respect to time t [sec] while the vehicle is traveling. The deterioration amount DQ is zero when the oil 60 is first used (for example, when the oil 60 is first used in the vehicle 10 or when the oil 60 is changed in the vehicle 10). The deterioration amount DQ is accumulated by the multiplication value ΔDQ until the oil 60 is changed. The sampling time Δt is a sampling time (= time interval) predetermined experimentally or by design so that the estimation error of the deterioration amount DQ is within an acceptable range. The predetermined coefficient k is a coefficient related to the deterioration amount DQ and is predetermined experimentally or by design. As shown in Fig. 3, a predetermined coefficient k (such as k0 to k7) is predetermined for each temperature range of the oil temperature THoil. The predetermined coefficient k is set to a larger value as the oil temperature THoil increases. The larger the deterioration amount DQ, the more deteriorated the oil 60 is.

[0033] The relationship between the transmission torque Td and the output torque Tout is such that once one of them is determined, the other is determined based on the gear ratio α. The transmission torque Td can be calculated based on the gear ratio α of the reduction gear device 20 and the output torque Tout. In calculating the multiplication value ΔDQ, for example, the output torque Tout may be used instead of the transmission torque Td. The relationship between the differential rotation speed Ndif and the output rotation speed Nout is such that once one of them is determined, the other is determined based on the reduction ratio γslw. The differential rotation speed Ndif can be calculated based on the reduction ratio γslw and the output rotation speed Nout. In calculating the multiplication value ΔDQ, for example, the output rotation speed Nout may be used instead of the differential rotation speed Ndif. When the output torque Tout is used instead of the transmission torque Td, or the output rotation speed Nout is used instead of the differential rotation speed Ndif, the predetermined coefficient k is changed accordingly, for example.

[0034] The deterioration amount DQ is estimated according to the magnitude of the transmission torque Td because, as the transmission torque Td increases, the load on the gears increases, making the oil 60 more likely to become contaminated due to wear on the gear tooth surfaces, etc., and therefore increasing the deterioration amount DQ. The deterioration amount DQ is estimated according to the magnitude of the differential rotation speed Ndif because, as the differential rotation speed Ndif increases, the gears rotate faster, increasing the frequency of wear on the gear tooth surfaces, making the oil 60 more likely to become contaminated, and therefore increasing the deterioration amount DQ. The deterioration amount DQ is estimated according to a predetermined coefficient k that is determined according to the oil temperature THoil of the oil 60 because, for example, as the oil temperature THoil of the oil 60 increases, the viscosity of the oil 60 decreases, reducing the thickness of the oil film that lubricates the gears, making the oil 60 more likely to become contaminated due to wear on the gear tooth surfaces, etc., and therefore increasing the deterioration amount DQ.

[0035] For example, at time t1, a multiplication value ΔDQ_t1 is obtained by multiplying the deterioration amount DQ immediately before time t1 by a predetermined coefficient k corresponding to the transmission torque Td, differential rotation speed Ndif, and oil temperature THoil at time t1. At time t2 (= t1 + Δt), a multiplication value ΔDQ_t2 is obtained by multiplying the deterioration amount DQ at time t1 by a predetermined coefficient k corresponding to the transmission torque Td, differential rotation speed Ndif, and oil temperature THoil at time t2. At time t3 (= t2 + Δt), a multiplication value ΔDQ_t3 is obtained by multiplying the deterioration amount DQ at time t2 by a predetermined coefficient k corresponding to the transmission torque Td, differential rotation speed Ndif, and oil temperature THoil at time t3.

[0036] The operating point setting unit 90e sets an operable region of the operating point P expressed by the engine rotation speed Ne and the differential rotation speed Ndif. The operable region is set on a two-dimensional coordinate system of the engine rotation speed Ne and the differential rotation speed Ndif.

[0037] 4 is a diagram illustrating the relationship between the operable range of the operating point P, expressed by the engine rotation speed Ne and the differential rotation speed Ndif, and the tilt angle φ of the vehicle 10. Regardless of whether the lock-up clutch LU is in a direct-coupled state or not, the engine rotation speed Ne is the same as or approximately the same as the input rotation speed Nin. Therefore, when setting the operable range, for example, the input rotation speed Nin may be used instead of the engine rotation speed Ne. When setting the operable range, for example, the output rotation speed Nout may be used instead of the differential rotation speed Ndif. The operating point P corresponds to the "operating point expressed by the rotation speed of the power source and the rotation speed of the differential" in this invention.

[0038] For example, the operable range is set for each division of the tilt angle φ. When the tilt angle φ is between angles φ1 and φ2 (>φ1), the operable range is set on the lower rotation speed side of boundary line BL1. When the tilt angle φ is between angles φ2 and φ3 (>φ2), the operable range is set on the lower rotation speed side of boundary line BL2. When the tilt angle φ is between angles φ3 and φ4 (>φ3), the operable range is set on the lower rotation speed side of boundary line BL3. In this way, as the tilt angle φ increases, the range in which operation is prohibited on the high rotation speed side of at least one of the engine rotation speed Ne and the differential rotation speed Ndif in the operable range expands, that is, the operable range is restricted. This restriction on the operable range suppresses foaming of the oil 60. The operable range is determined and stored in advance for each division of the tilt angle φ experimentally or by design so as to suppress foaming of the oil 60 and prevent the oil 60 from leaking from the breather 62. In the operable range, operation at the high rotational speed side of the differential rotational speed Ndif is limited because the rotational speed of the differential ring gear 22r is reduced, thereby suppressing the agitation of the oil 60. In the operable range, operation at the high rotational speed side of the engine rotational speed Ne, i.e., the input rotational speed Nin, is limited because the input rotational speed Nin is reduced, thereby suppressing the splashing of the oil 60 caused by the gears rotating in the automatic transmission 16 and the final reduction gear 18. As a result, foaming of the oil 60 is suppressed, making it less likely for the oil 60 to leak from the breather 62.

[0039] For example, if the tilt angle φ is less than a predetermined value φ_jdg, the operable range is not limited, and if the operable range is limited when the tilt angle φ is equal to or greater than the predetermined value φ_jdg, the operating point setting unit 90e limits the operable range as shown in Figure 4, provided that the tilt angle φ is equal to or greater than the predetermined value φ_jdg.

[0040] The engine control unit 90a, the torque converter control unit 90b, and the transmission control unit 90c respectively control the engine 12, the torque converter 14, and the automatic transmission 16 so that the operating point P is included within the operable range set by the operating point setting unit 90e.

[0041] Next, the control function of the electronic control device 90 when the operable area is reduced will be described with reference to Fig. 4. When the operable area is reduced, this is the same as when the limit of the operable area is expanded.

[0042] For example, suppose that while the vehicle is traveling, the tilt angle φ is between angles φ1 and φ2, and the operating point P is operating at operating point p0, but then the tilt angle φ changes to angles φ3 and φ4, narrowing the operable region to the shaded region. In this case, if it is possible to lower the rotational speed ratio γttl by shifting the automatic transmission 16 to the higher side (i.e., the side with a smaller gear ratio γat), the output rotational speed Nout corresponding to the differential rotational speed Ndif is maintained while the automatic transmission 16 is shifted to the higher side, and the operation at operating point p0 is switched to the operating point p1. If it is not possible to shift the automatic transmission 16 to the higher side, i.e., if it is not possible to lower the rotational speed ratio γttl, the differential rotational speed Ndif is lowered while maintaining the gear ratio γat, and the operation at operating point p0 is switched to the operating point p2.

[0043] According to this embodiment, (a) the deterioration amount DQ is estimated, and (b) based on the tilt angle φ and the deterioration amount DQ, an operable region of the operating point P represented by the engine rotation speed Ne and the differential rotation speed Ndif is set so that the oil 60 does not leak from the breather 62. The defoaming performance of the oil 60 foamed by stirring or the like decreases as the deterioration amount DQ increases. Because the operable region of the operating point P represented by the engine rotation speed Ne and the differential rotation speed Ndif is set based on the tilt angle φ of the vehicle 10 and the deterioration amount DQ so that the oil 60 does not leak from the breather 62, leakage of the oil 60 from the breather 62 is suppressed even if the defoaming performance decreases due to deterioration of the oil 60.

[0044] According to this embodiment, the deterioration amount DQ is estimated by sequentially accumulating a multiplication value ΔDQ obtained by multiplying the product of the transmission torque Td and the differential rotation speed Ndif by a predetermined coefficient k that is determined in advance according to the oil temperature THoil of the oil 60 at every predetermined sampling time Δt. By accumulating the multiplication value ΔDQ in this manner, the deterioration amount DQ can be accurately estimated. This makes it possible to accurately estimate the deterioration of the anti-foaming performance due to deterioration of the oil 60, thereby suppressing leakage of the oil 60 from the breather 62 when the anti-foaming performance is reduced due to deterioration of the oil 60.

[0045] According to this embodiment, when the operable range is narrowed, if the automatic transmission 16 can be shifted to the higher gear, the output rotation speed Nout corresponding to the differential rotation speed Ndif is maintained and the automatic transmission 16 is shifted to the higher gear. If the automatic transmission 16 cannot be shifted to the higher gear, the output rotation speed Nout is reduced while maintaining the gear ratio γat. If the automatic transmission 16 can be shifted to the higher gear, the output rotation speed Nout is maintained, so that the vehicle speed V does not change unintentionally, thereby reducing the driver's discomfort. Even if the anti-foaming performance of the oil 60 deteriorates, leakage of the oil 60 from the breather 62 is reduced, and if the automatic transmission 16 can be shifted to the higher gear, the driver's discomfort is reduced. [Example]

[0046] 5 is a schematic diagram of a vehicle 110 equipped with an electronic control device 190 according to a second embodiment. This embodiment is substantially the same as the configuration of the vehicle 10 in the first embodiment described above, but differs mainly in that the engine 12 and the electronic control device 90 in the first embodiment are replaced with an electric motor MG and an electronic control device 190, respectively. Therefore, the following description will focus on the parts that differ from the first embodiment, and parts that are substantially the same in function as the first embodiment will be denoted by the same reference numerals and will not be described as appropriate.

[0047] In the vehicle 110, a power transmission path PT between the electric motor MG, which is a power source, and a pair of drive wheels 24 is connected in this order from the electric motor MG side to an electric motor output shaft 130, a final reduction gear 18, and a pair of axles 38, all of which are well-known configurations. The vehicle 110 also includes a hydraulic control circuit 150, an inverter 156, and an electronic control device 190. The vehicle 110 does not include the torque converter 14 and the automatic transmission 16 that are included in the vehicle 10 of the first embodiment. The rotational speed ratio γttl (=Nmg / Ndif) between the electric motor rotational speed Nmg [rpm], which is the rotational speed of the electric motor MG, and the differential rotational speed Ndif is the same as the reduction ratio γslw in the first embodiment. The electric motor rotational speed Nmg corresponds to the "rotational speed of the power source" in this invention.

[0048] The electric motor MG is, for example, a rotating electric machine having both an electric motor function and a generator function, and is a so-called motor generator. The electric motor MG may be a rotating electric machine without a generator function as long as it has an electric motor function. The electric motor MG corresponds to the "power source" in the present invention. The hydraulic control circuit 150 has substantially the same configuration as the hydraulic control circuit 50 in the first embodiment, but does not have the function of supplying regulated hydraulic pressure to actuators that control the shifting of the automatic transmission 16 or the engagement and disengagement of the lock-up clutch LU. The inverter 156 is provided between the electric motor MG and a battery (not shown) and is a power supply circuit that converts direct current to alternating current and vice versa under the control of the electronic control device 190. The electric motor torque Tmg [Nm] output from the electric motor MG is controlled by the inverter 156, which is controlled by the electronic control device 190.

[0049] The electronic control device 190 is configured to include, for example, a so-called microcomputer, similar to the electronic control device 90 in the first embodiment, and executes various controls of the vehicle 110. For example, the electronic control device 190 executes operation control of the electric motor MG, and controls the entire vehicle 110 as necessary. The electronic control device 190 corresponds to the "control device" in the present invention. The electronic control device 190 receives various signals (e.g., accelerator opening θacc, vehicle speed V, electric motor rotation speed Nmg, inclination angle φ of the vehicle 110, oil temperature THoil, etc.) based on detection values ​​from various sensors (e.g., accelerator opening sensor 70, vehicle speed sensor 72, rotation speed sensor 174 of the electric motor output shaft 130, inclination angle sensor 78, oil temperature sensor 80, etc.) provided in the vehicle 110. The electronic control device 190 outputs various command signals (e.g., electric motor control signal Smg for controlling the operation of the electric motor MG, etc.) to various devices (e.g., inverter 156, etc.) provided in the vehicle 110.

[0050] The electronic control device 190 functionally comprises an electric motor control unit 190a, a deterioration estimation unit 190d, and an operating point setting unit 190e.

[0051] While the vehicle is traveling, the motor control unit 190a controls the motor torque Tmg to realize a drive demand for the vehicle 110 based on, for example, the accelerator opening θacc and the vehicle speed V. The deterioration estimation unit 190d estimates the deterioration amount DQ. The estimation method of the deterioration amount DQ in the deterioration estimation unit 190d is the same as the estimation method in the deterioration estimation unit 90d in the first embodiment. The transmission torque Td can be calculated based on the gear ratio α of the reduction gear 20 and the motor torque Tmg. In calculating the multiplication value ΔDQ, for example, the motor torque Tmg may be used instead of the transmission torque Td. The differential rotation speed Ndif can be calculated based on the reduction ratio γslw and the motor rotation speed Nmg. In calculating the multiplication value ΔDQ, for example, the motor rotation speed Nmg may be used instead of the differential rotation speed Ndif. The operating point setting unit 190e sets an operable region of the operating point P represented by the motor rotation speed Nmg and the differential rotation speed Ndif. It should be noted that once one of the electric motor rotation speed Nmg and the differential rotation speed Ndif is determined, the other is determined based on the reduction gear ratio γslw. Therefore, the operable region is essentially set on a one-dimensional coordinate system. The operating point P corresponds to the "operating point expressed by the rotation speed of the power source and the rotation speed of the power transmission device" in this invention.

[0052] FIG. 6 is a diagram illustrating the relationship between the operable region of the operating point P, which is expressed by the electric motor rotation speed Nmg and the differential rotation speed Ndif, and the tilt angle φ of the vehicle 110. As shown in FIG.

[0053] For example, the operable area is set for each division of the tilt angle φ. When the tilt angle φ is between angles φ1 and φ2, the operable area is set on the lower rotation speed side of boundary point BP1. When the tilt angle φ is between angles φ2 and φ3, the operable area is set on the lower rotation speed side of boundary point BP2. When the tilt angle φ is between angles φ3 and φ4, the operable area is set on the lower rotation speed side of boundary point BP3. In this way, as the tilt angle φ increases, the range in which operation on the high rotation speed side of the electric motor rotation speed Nmg and the differential rotation speed Ndif in the operable area is prohibited expands, i.e., the operable area is restricted.

[0054] Next, the control function of electronic control unit 190 when the operable region is reduced will be described with reference to FIG.

[0055] For example, suppose that while the vehicle is traveling, the tilt angle φ is between angles φ1 and φ2 and the operating point P is operating at operating point p0, but the tilt angle φ changes to angles φ3 and φ4, narrowing the operable region. In such a case, the motor rotation speed Nmg (and the differential rotation speed Ndif) is reduced, and operation is switched from operation at operating point p0 to operation at operating point p2. The vehicle 110 does not have the automatic transmission 16 as in the first embodiment. Therefore, the vehicle 110 cannot reduce the rotation speed ratio γttl, and the differential rotation speed Ndif is reduced while keeping the rotation speed ratio γttl the same.

[0056] According to this embodiment, (a) the deterioration amount DQ is estimated, and (b) based on the tilt angle φ and the deterioration amount DQ, the operable region of the operating point P expressed by the electric motor rotation speed Nmg and the differential rotation speed Ndif is set so as to prevent the oil 60 from leaking from the breather 62. As a result, similar to the first embodiment described above, even if the anti-foaming performance of the oil 60 deteriorates due to deterioration of the oil 60, the oil 60 is prevented from leaking from the breather 62.

[0057] According to this embodiment, the degradation amount DQ is estimated by sequentially accumulating the multiplication value ΔDQ, as in the above-described embodiment 1. This provides the same effects as in embodiment 1.

[0058] According to this embodiment, when the operable region is reduced, it is not possible to reduce the rotational speed ratio γttl, so the differential rotational speed Ndif is reduced while keeping the rotational speed ratio γttl the same. [Example]

[0059] 7 is a schematic diagram of a vehicle 210 equipped with an electronic control device 190 according to a third embodiment. This embodiment is substantially the same as the configuration of the vehicle 110 in the second embodiment described above, except that an axle 238 and a reduction gear 220 are provided instead of the pair of axles 38 and the final reduction gear 18 in the second embodiment. Therefore, the following description will focus on the parts that differ from the second embodiment, and parts that are substantially the same in function as the second embodiment will be denoted by the same reference numerals and will not be described as appropriate.

[0060] The vehicle 210 does not have the differential 22 that the vehicle 110 in the second embodiment had. The axle 238 is, for example, a single rotating shaft connecting one of a pair of drive wheels 24 to the other. The reduction gear 220 has substantially the same configuration as the reduction gear 20 in the second embodiment. The reduction gear 220 has an output gear 34a, a reduction gear 36a, and a reduction pinion gear 36b, and the reduction pinion gear 36b meshes with a gear 220g fixed to the axle 238. The reduction pinion gear 36b has a smaller diameter than the gear 220g. The reduction gear 220 corresponds to the "power transmission device" in the present invention. A portion of the oil 60 stored at the bottom of the case 40 is scooped up by the gear 220g and the like provided in the reduction gear 220 and used to lubricate the gears and bearings in the case 40. The rotational speed Ngear of the gear 220g corresponds to the "rotational speed of the power transmission device" in the present invention.

[0061] The vehicle 210 does not have the differential 22, and therefore cannot appropriately impart a rotational speed difference to the pair of drive wheels 24 as in the vehicle 110 in the second embodiment. For example, the vehicle 210 is a vehicle that runs on a pre-laid track.

[0062] According to this embodiment, the same effects as those of the second embodiment described above can be achieved.

[0063] It should be noted that the above-described embodiments are merely examples of the present invention, and the present invention can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art, without departing from the spirit of the present invention.

[0064] The "power source" in the present invention is the engine 12 in the first embodiment and the electric motor MG in the second and third embodiments, but is not limited to this. For example, the "power source" may be both an engine and an electric motor.

[0065] In the first embodiment described above, the vehicle 10 includes the differential 22. However, the present invention is not limited to this, and the vehicle 10 may not include the differential 22, as in the third embodiment. In the first, second, and third embodiments described above, the vehicles 10, 110, and 210 include the reduction gears 20 and 220, respectively. However, the vehicles 10, 110, and 210 do not necessarily include the reduction gears 20 and 220. For example, in the third embodiment, the rotational speed ratio (=Nmg / Ngear) between the electric motor rotational speed Nmg and the rotational speed Ngear of the gear 220g may be "1." In this embodiment, the gear 220g itself corresponds to the "power transmission device" in the present invention. The "power transmission device" in the present invention may be any device that is housed in the case 40, is provided in the power transmission path PT, and stirs the oil 60 stored in the bottom of the case 40 in accordance with the rotational speed of the gear.

[0066] In the first embodiment described above, the "automatic transmission" in the present invention is a stepped transmission, but is not limited to this. For example, the "automatic transmission" may be a well-known continuously variable transmission.

[0067] In the first, second, and third embodiments described above, the breather 62 is attached to the upper portion of the case 40, closer to the rear of the vehicle. However, this is not limiting. For example, the breather 62 may be attached to the upper portion of the case 40, closer to the front of the vehicle. In this embodiment, the position of the breather 62 approaches the oil level 60s as the vehicle 10, 110, or 210 tilts forward, and the position of the breather 62 moves away from the oil level 60s as the vehicle 10, 110, or 210 tilts backward. Therefore, the inclination angle φ has a positive value on the side where the vehicle 10, 110, or 210 tilts forward, and a negative value on the side where the vehicle 10, 110, or 210 tilts backward. For example, the breather 62 may be attached to the center of the upper portion of the case 40, not closer to the front or rear of the vehicle. In this embodiment, if the position of the breather 62 approaches the oil level 60s regardless of whether the vehicle 10, 110, 210 tilts forward or backward, the tilt angle φ will be a positive value on both the side on which the vehicle 10, 110, 210 tilts forward and the side on which the vehicle 10, 110, 210 tilts backward. When the vehicle 10, 110, 210 tilts forward and when it tilts backward, the operating point setting units 90e, 190e respectively set the operable ranges of the operating point P.

[0068] In the above-described first, second, and third embodiments, the deterioration amount DQ is estimated by sequentially accumulating a multiplication value ΔDQ obtained by multiplying the product of the transmission torque Td and the differential rotation speed Ndif by a predetermined coefficient k determined in advance according to the oil temperature THoil of the oil 60 for each predetermined sampling time Δt. However, the method for estimating the deterioration amount DQ is not limited to this. For example, the deterioration amount DQ may be simply estimated by sequentially accumulating a multiplication value obtained by multiplying either the transmission torque Td or the differential rotation speed Ndif by a predetermined coefficient k determined in advance according to the oil temperature THoil of the oil 60 for each predetermined sampling time Δt. Alternatively, the deterioration amount DQ may be simply estimated based on the elapsed time since the start of use of the oil 60 and the cumulative driving time.

[0069] In the first embodiment described above, when the operable region is reduced, if the automatic transmission 16 can be shifted to a higher gear, the output rotation speed Nout is maintained and shifted to a higher gear, and if the automatic transmission 16 cannot be shifted to a higher gear, the output rotation speed Nout is reduced while the gear ratio γat is maintained, but the present invention is not limited to this. The point is that it is sufficient if the operating point P is controlled to be within the operable region. [Explanation of symbols]

[0070] 10, 110, 210: vehicle, 12: engine (power source), 16: automatic transmission, 22: differential (power transmission device), 24: pair of drive wheels, 40: transaxle case (case), 60: oil, 60s: fluid level, 62: breather, 90, 190: electronic control device (control device), 220: reduction gear (power transmission device), DQ: deterioration amount, k: specified coefficient, MG: electric motor (power source), Ne: engine rotation speed (rotation speed of power source), Ndif: differential rotation speed (rotation speed of power transmission device), Ngear: rotation speed (rotation speed of power transmission device), Nmg: electric motor rotation speed (rotation speed of power source), P: operating point, PT: power transmission path, THoil: oil temperature, Td: transmission torque, γttl: rotation speed ratio (rotation speed ratio), ΔDQ: multiplication value, Δt: sampling time, φ: tilt angle (tilt angle of case)

Claims

1. A control device for a vehicle including a power source, a pair of drive wheels, a power transmission device provided in a power transmission path between the power source and the pair of drive wheels, and a case that houses the power transmission device, stores oil at the bottom that is stirred in accordance with the rotation speed of the power transmission device, and has a breather attached to an upper part, Estimating the deterioration amount of the oil; Based on the inclination angle of the case, which is the angle at which the position of the breather is inclined toward the oil surface, and the deterioration amount, an operable region of an operating point expressed by the rotation speed of the power source and the rotation speed of the power transmission device is set so that the oil does not leak from the breather. A vehicle control device characterized by:

2. The deterioration amount is estimated by sequentially integrating a product of a transmission torque of the power transmission device and a rotational speed of the power transmission device and a predetermined coefficient determined in advance according to an oil temperature of the oil at each predetermined sampling time.

2. The vehicle control device according to claim 1.

3. When the operable range is reduced, if it is possible to reduce the rotational speed ratio between the rotational speed of the power source and the rotational speed of the power transmission device, the rotational speed ratio is reduced while maintaining the rotational speed of the power transmission device, and if it is not possible to reduce the rotational speed ratio, the rotational speed of the power transmission device is reduced while maintaining the rotational speed ratio the same.

3. The vehicle control device according to claim 1 or 2.

4. When the rotational speed ratio of the power transmission device is reduced while maintaining the rotational speed of the power transmission device, an automatic transmission provided between the power source and the power transmission device in the power transmission path is shifted to a high speed side.

4. The vehicle control device according to claim 3.

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