Vehicle control device

Abstract

To provide a vehicle control device capable of reliably protecting a drive-system portion even under a situation where a real gear step is undefined.SOLUTION: When a vehicle speed normal value is not acquired and real gear steps of a manual transmission are undefined, a torque limit map for each of the gear steps is used to calculate a torque limit value for each of the gear steps, and a minimum value of the torque limit value for each of the gear steps is selected as a torque limit value to be used for limiting the torque of a power source. Thereby, when the real gear step is undefined, the torque of the power source is limited using a smallest torque limit value. Accordingly, a drive-system portion can be reliably protected even under the situation where the real gear steps are undefined.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a control device for a vehicle equipped with a manual transmission.

Background Art

[0002] A control device for a vehicle including a power source and a manual transmission that transmits the power of the power source to drive wheels is well known. For example, the gear position determination device described in Patent Document 1 is such a device. Patent Document 1 discloses specifying an actual gear stage, which is the actual gear stage of a manual transmission, based on the ratio of the engine rotation speed as the rotation speed of the power source to the vehicle speed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when a normal value of the vehicle speed is not obtained, the ratio of the rotation speed of the power source to the vehicle speed cannot be appropriately calculated, and the actual gear stage may be indeterminate. On the other hand, it is conceivable to protect the drive system part (synonymous with the power transmission system part) by calculating a torque limit value corresponding to the actual gear stage and performing torque limit of the power source using the torque limit value. However, when the actual gear stage is indeterminate, depending on the torque limit value, sufficient torque limit of the power source may not be able to be performed, and there is a possibility that the drive system part cannot be appropriately protected.

[0005] The present invention has been made against the background of the above circumstances, and an object thereof is to provide a control device for a vehicle that can surely protect a drive system part even in a situation where the actual gear stage is indeterminate.

Means for Solving the Problems

[0006] The gist of the first invention is a control device for a vehicle comprising (a) a power source and a manual transmission for transmitting the power of the power source to drive wheels, the control device including (b) an actual gear stage specifying section for specifying the actual gear stage of the manual transmission based on the ratio of the rotational speed of the power source and the vehicle speed, and (c) a torque limit value calculating section for calculating a torque limit value for limiting the torque of the power source using the actual gear stage specified by the actual gear stage specifying section and a torque limit map predetermined for each gear stage of the manual transmission. (d) When a normal value of the vehicle speed is not acquired and the actual gear stage is indeterminate, the torque limit value calculating section calculates the torque limit value for each gear stage using the torque limit map for each gear stage, and selects the minimum value among the torque limit values for each gear stage as the torque limit value used for limiting the torque of the power source.

Advantages of the Invention

[0007] According to the first invention, when a normal value of the vehicle speed is not acquired and the actual gear stage of the manual transmission is indeterminate, the torque limit map for each gear stage is used to calculate the torque limit value for each gear stage, and the minimum value among the torque limit values for each gear stage is selected as the torque limit value used for limiting the torque of the power source. Thereby, when the actual gear stage is indeterminate, the torque of the power source is limited using the smallest torque limit value. Therefore, the drive system parts can be reliably protected even under the situation where the actual gear stage is indeterminate.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Embodiment

[0010] FIG. 1 is a diagram for explaining the schematic configuration of a vehicle 10 to which the present invention is applied, and is also a diagram for explaining the main parts of the control functions and control systems for various controls in the vehicle 10. In FIG. 1, the vehicle 10 includes an engine 12 as a power source, wheels WH including left and right front wheels 14 and left and right rear wheels 16, and a power transmission device 18. The power transmission device 18 is a drive system part provided in the power transmission path between the engine 12 and the wheels WH, that is, the drive wheels, for transmitting the power of the engine 12 to the wheels WH. The vehicle 10 is a four-wheel drive vehicle capable of distributing torque to the front wheels 14 and the rear wheels 16. The above "left and right" refers to the left and right with respect to the forward direction of the vehicle 10.

[0011] The power transmission device 18 includes a clutch 20, a transmission 22, a transfer 24, a front propeller shaft 26, a front differential 28, a front drive shaft 30, a rear propeller shaft 32, a rear differential 34, a rear drive shaft 36, and the like.

[0012] The clutch 20 is, for example, a known dry single-plate friction clutch provided in the power transmission path between the engine 12 and the transmission 22. The transmission 22 is a manual transmission provided in the power transmission path between the engine 12 and the wheels WH. The transmission 22 is, for example, a known synchronized engagement type parallel two-shaft stepped transmission capable of establishing a plurality of gear stages GS with different gear ratios.

[0013] The transfer 24 is connected to the output side of the transmission 22. The transfer 24 transmits the power from the engine 12 transmitted through the transmission 22 to, for example, only the rear wheels 16, or distributes it to each of the front wheels 14 and the rear wheels 16. The power distributed by the transfer 24 is transmitted to the rear wheels 16 via the rear propeller shaft 32, the rear differential 34, the rear drive shaft 36, etc., and is also transmitted to the front wheels 14 via the front propeller shaft 26, the front differential 28, the front drive shaft 30, etc. Therefore, in the transfer 24, a power transmission path for setting the vehicle 10 in a two-wheel drive (= 2WD) state and a power transmission path for setting the vehicle 10 in a 4WD state are selectively formed. Also, the transfer 24 selectively establishes, for example, either the high-speed gear stage H or the low-speed gear stage L to shift the power from the transmission 22 and transmit it to the subsequent stage. Therefore, in the transfer 24, a power transmission path for establishing the high-speed gear stage H and a power transmission path for establishing the low-speed gear stage L are selectively formed.

[0014] The vehicle 10 is provided with an electronic control device 50 including a control device of the vehicle 10 related to various controls. The electronic control device 50 is configured to include a so-called microcomputer provided with, for example, a CPU, a RAM, a ROM, an input / output interface, etc.

[0015] Various signals (for example, engine rotational speed Ne, rear propeller rotational speed Nrp, wheel speed Nw, accelerator opening θacc, dial operation signal OPdial, etc.) based on detection values by various sensors (engine rotational speed sensor 60, rear propeller rotational speed sensor 62, wheel speed sensor 64, accelerator opening sensor 66, drive state changeover dial 68, etc.) provided in the vehicle 10 are respectively supplied to the electronic control device 50. The wheel speed sensor 64 includes a left front wheel speed sensor 64fl, a right front wheel speed sensor 64fr, a left rear wheel speed sensor 64rl, and a right rear wheel speed sensor 64rr.

[0016] The engine rotational speed Ne is the rotational speed of the engine 12. The rear propeller rotational speed Nrp is the rotational speed of the rear propeller shaft 32 and is a signal corresponding to the vehicle speed V. The wheel speed Nw is the rotational speed of the wheels WH, including the left front wheel speed Nwfl and the right front wheel speed Nwfr as the front wheel speed Nwf, which is the rotational speed of the front wheels 14, and the left rear wheel speed Nwrl and the right rear wheel speed Nwrr as the rear wheel speed Nwr, which is the rotational speed of the rear wheels 16. The accelerator opening θacc is a signal corresponding to the acceleration demand amount representing the magnitude of the driver's acceleration operation and is the amount of accelerator operation by the driver.

[0017] The drive state changeover dial 68 is, for example, a dial-type switch manually operated by the driver. The drive state changeover dial 68 has three dial operation positions: a "H-2WD" position for selecting the changeover to the H2 state, a "H-4WD" position for selecting the changeover to the H4 state, and an "L-4WD" position for selecting the changeover to the L4 state. The H2 state, the H4 state, and the L4 state each indicate the state of the transfer 24 (hereinafter referred to as the T / F state). The H2 state is a 2WD state in the high-speed gear stage H, the H4 state is a 4WD state in the high-speed gear stage H, and the L4 state is a 4WD state in the low-speed gear stage L.

[0018] The dial operation signal OPdial is a signal indicating each of the three dial operation positions of the drive state changeover dial 68. For example, when the dial operation position of the drive state changeover dial 68 is set to the "H-2WD" position, the dial operation signal OPdial corresponding to the "H-2WD" position is output. Similarly, at other dial operation positions, the dial operation signal OPdial corresponding to the dial operation position is output.

[0019] Various command signals (such as the engine control command signal Se, the high-low changeover control command signal Shl, the 2WD / 4WD changeover control command signal Stf, etc.) are output from the electronic control unit 50 to each device (such as the engine 12, the transfer 24, etc.) provided in the vehicle 10.

[0020] The engine control command signal Se is a signal for controlling the engine 12. The high-low shift control command signal Shl is a signal for controlling the shift between the high-speed gear stage H and the low-speed gear stage L in the transfer 24. The 2WD / 4WD shift control command signal Stf is a signal for controlling the shift between the 2WD state and the 4WD state in the transfer 24.

[0021] The electronic control unit 50 includes a drive control unit 52, an actual gear stage specifying unit 54, and a torque limit value calculating unit 56 in order to realize various controls in the vehicle 10.

[0022] The drive control unit 52 calculates a required value of the engine torque Te, that is, a required engine torque Tedem, based on, for example, the accelerator opening θacc. The drive control unit 52 outputs an engine control command signal Se for controlling the engine 12 so as to realize the required engine torque Tedem.

[0023] The drive control unit 52 controls the switching of the drive mode of the vehicle 10 based on the dial operation signal OPdial. The drive mode of the vehicle 10 includes, for example, an H2 drive mode, an H4 drive mode, and an L4 drive mode. The H2 drive mode is a drive mode that enables traveling in the H2 state in the T / F state. The H4 drive mode is a drive mode that enables traveling in the H4 state in the T / F state. The L4 drive mode is a drive mode that enables traveling in the L4 state in the T / F state.

[0024] When the dial operation signal OPdial is a dial operation signal corresponding to the "H-2WD" position of the drive state switching dial 68, the drive control unit 52 outputs a high-low shift control command signal Shl for controlling the transfer 24 to the high-speed gear stage H and a 2WD / 4WD shift control command signal Stf for controlling the transfer 24 to the 2WD state. Similarly, for other dial operation signals OPdial, control corresponding to the dial operation signal OPdial is performed.

[0025] The actual gear stage specifying unit 54 specifies the actual gear stage G Sr of the transmission 22 based on the NV ratio (=Ne / V), which is the ratio of the engine rotational speed Ne to the vehicle speed V. The NV ratio is represented by, for example, the ratio of the engine rotational speed Ne to the rear propeller rotational speed Nrp, i.e., the integrated gear ratio GRt (=Ne / Nrp). The actual gear stage specifying unit 54 specifies the actual gear stage G Sr by applying the integrated gear ratio GRt to a predetermined NV ratio table. The NV ratio table has, for example, a predetermined relationship for the region of the integrated gear ratio GRt for each of the actual gear stages G Sr. The integrated gear ratio GRt includes the gear ratio of the high-speed side gear stage H or the gear ratio of the low-speed side gear stage L of the transfer 24. Therefore, the NV ratio table includes, for example, an NV ratio table for the high-speed side gear stage H and an NV ratio table for the low-speed side gear stage L. The actual gear stage specifying unit 54 specifies the actual gear stage G Sr using the NV ratio table for the high-speed side gear stage H in the H2 drive mode and the H4 drive mode, while specifying the actual gear stage G Sr using the NV ratio table for the low-speed side gear stage L in the L4 drive mode.

[0026] The torque limit value calculating unit 56 calculates a torque limit value Telim for limiting the engine torque Te using the actual gear stage G Sr specified by the actual gear stage specifying unit 54 and a torque limit map MAP predetermined for each gear stage GS of the transmission 22. The torque limit map MAP has, for example, a predetermined relationship for the torque limit value Telim with respect to the engine rotational speed Ne. The torque limit value calculating unit 56 calculates the torque limit value Telim by applying the engine rotational speed Ne to the torque limit map MAP.

[0027] The drive control unit 52 controls the engine 12 within the range of the engine torque Te with the torque limit value Telim calculated by the torque limit value calculating unit 56 as the upper limit value. Thereby, even when the drive system parts to be protected and the torque limit value Telim differ for each gear stage GS of the transmission 22, the drive system parts can be protected.

[0028] Here, the drive system parts to be protected and the torque limit value Telim may be different for each T / F state of the H2 state, H4 state, and L4 state. Therefore, the torque limit map MAP is determined in advance, for example, for each gear stage GS for each T / F state.

[0029] FIG. 2 is a diagram showing an example of a torque limit map MAP for each gear stage GS for each T / F state. (a) of FIG. 2 is an example of a torque limit map MAP (such as "gs1l4_map", "gs6h4_map", etc.) for each gear stage GS for each T / F state stored in the electronic control device 50, and shows a case where the transmission 22 is a six-speed forward transmission, for example. (b) of FIG. 2 shows an example of "gs3h4_map" which is a torque limit map MAP selected when the T / F state is the H4 state and the gear stage GS is the third-speed gear stage, for example. The a, b, c, d, e, f, g, h of the torque limit value Telim may be the same value, different values, or, for example, only a may be a restricted value. Also, the torque limit map MAP may be a map represented by two-dimensional coordinates with, for example, the engine rotational speed Ne as the X-axis and the torque limit value Telim as the Y-axis, or may be a map linearly interpolated by the a, b, c, d, e, f, g, h of the torque limit value Telim.

[0030] The torque limit value calculation unit 56 acquires the T / F state based on, for example, the high-low switching control command signal Shl and the 2WD / 4WD switching control command signal Stf. The torque limit value calculation unit 56 selects the torque limit map MAP used for calculating the torque limit value Telim from among the torque limit maps MAP for each gear stage GS for each T / F state based on the acquired T / F state and the actual gear stage GSr specified by the actual gear stage specifying unit 54. The torque limit value calculation unit 56 calculates the torque limit value Telim using the selected torque limit map MAP.

[0031] Incidentally, if a normal value of the vehicle speed V is not obtained, the NV ratio may not be calculated appropriately, and the actual gear stage GSr may be indeterminate. In this case, for example, it is conceivable to regard the gear stage GS as the first gear stage and perform torque limitation of the engine 12 with the torque limitation value Telim calculated using the torque limitation map MAP for the first gear stage. However, when the actual gear stage GSr is a gear stage GS different from the first gear stage, if the torque limitation value Telim for the other gear stage GS is smaller than the torque limitation value Telim for the first gear stage, sufficient torque limitation may not be achieved, and there is a risk that the drive system parts cannot be protected appropriately.

[0032] Therefore, when a normal value of the vehicle speed V is not obtained and the actual gear stage GSr is indeterminate, the torque limitation value calculation unit 56 calculates the torque limitation value Telim for each gear stage GS (that is, for all gear stages GS) using the torque limitation map MAP for each gear stage GS, and selects the minimum value among the torque limitation values Telim for each gear stage GS as the torque limitation value Telim to be used for limiting the engine torque Te. At this time, as the torque limitation map MAP for each gear stage GS, among the torque limitation maps MAP for each gear stage GS for each T / F state, the torque limitation map MAP for each gear stage GS corresponding to the acquired T / F state is used.

[0033] The actual gear stage identification unit 54 determines whether or not it is a case where a normal value of the vehicle speed V is not obtained and the actual gear stage GSr is indeterminate. When the vehicle speed sensor, for example, the rear propeller rotation speed sensor 62 is abnormal, or when the vehicle speed V is an extremely low vehicle speed at which detection is difficult due to the accuracy of the vehicle speed sensor, for example, when the rear propeller rotation speed Nrp is an extremely low rotation speed, a normal value of the vehicle speed V is not obtained. In other words, the actual gear stage identification unit 54 determines whether or not the actual gear stage GSr can be calculated. For example, the actual gear stage identification unit 54 determines whether the vehicle speed sensor is normal based on whether the vehicle speed sensor abnormality flag is off. Also, the actual gear stage identification unit 54 determines whether the vehicle speed V is equal to or higher than a predetermined detectable vehicle speed. The actual gear stage identification unit 54 determines whether or not the actual gear stage GSr can be calculated based on whether the vehicle speed sensor is normal and whether the vehicle speed V is equal to or higher than the detectable vehicle speed.

[0034] FIG. 3 is a flowchart for explaining the main part of the control operation of the electronic control device 50, and is a flowchart for explaining the control operation for reliably protecting the drive system part even under the situation where the actual gear stage GSr is indefinite, and is repeatedly executed, for example.

[0035] In FIG. 3, first, in step S10 corresponding to the function of the torque limit value calculation unit 56 (hereinafter, steps are omitted), the T / F state (H2 state, H4 state, L4 state) is acquired. However, in the case of a vehicle without switching of the T / F state, it is treated as, for example, the H4 state by default. Next, in S20 corresponding to the function of the actual gear stage identification unit 54, it is determined whether the vehicle speed sensor is normal. If the determination in this S20 is affirmative, then in S30 corresponding to the function of the actual gear stage identification unit 54, it is determined whether the vehicle speed V is equal to or higher than the detectable vehicle speed. If the determination in this S30 is affirmative, then in S40 corresponding to the function of the actual gear stage identification unit 54, the actual gear stage GSr is identified based on the NV ratio (= engine rotational speed Ne / vehicle speed V). Next, in S50 corresponding to the function of the torque limit value calculation unit 56, the torque limit map MAP used for calculating the torque limit value Telim is selected from among the torque limit maps MAP for each gear stage GS for each T / F state. Next, in S60 corresponding to the function of the torque limit value calculation unit 56, the torque limit value Telim is calculated using the selected torque limit map MAP. Incidentally, the engine torque Te that can be tolerated by the drive system part has been obtained experimentally or by design, and when torque limitation is not required, the maximum torque value is set as the torque limit value Telim. On the other hand, if the determination in the above S20 is negative, or if the determination in the above S30 is negative, then in S70 corresponding to the function of the torque limit value calculation unit 56, the torque limit map MAP for each gear stage GS for each T / F state (for example, the torque limit map MAP for each gear stage GS in the acquired T / F state) is used to calculate the torque limit value Telim for each gear stage GS. Next, in S80 corresponding to the function of the torque limit value calculation unit 56, the minimum value among the torque limit values Telim for each gear stage GS is selected. Next to the above S60, or next to the above S80, in S90 corresponding to the function of the torque limit value calculation unit 56, it is determined whether the torque limit value Telim calculated in the above S60 or the above S80 is larger than the previous torque limit value Telim.If the determination in S90 is negative, in S100 corresponding to the function of the torque limit value calculation unit 56, the torque limit value Telim calculated in S60 or S80 is determined as the current torque limit value Telim. If the determination in S90 is affirmative, in S110 corresponding to the function of the torque limit value calculation unit 56, the torque limit value Telim obtained by adding a predetermined sweep value to the previous torque limit value Telim is determined as the current torque limit value Telim. If the determination in S90 is affirmative, it is determined that there is a sudden change in torque in the acceleration direction, and as time passes, the torque limit value Telim is swept (gradually increased) toward the torque limit value Telim calculated in S60 or S80 so as not to cause a sudden change in torque.

[0036] As described above, according to this embodiment, when a normal value of the vehicle speed V is not obtained and the actual gear stage GSr is set to be indefinite, the torque limit map MAP for each gear stage GS is used to calculate the torque limit value Telim for each gear stage GS, and the minimum value among these torque limit values Telim for each gear stage GS is selected as the torque limit value Telim used for restricting the engine torque Te. Thereby, when the actual gear stage GSr is set to be indefinite, the engine torque Te is restricted using the smallest torque limit value Telim. Therefore, the drive system part can be reliably protected even under a situation where the actual gear stage GSr is indefinite.

[0037] As described above, the embodiments of the present invention have been described in detail with reference to the drawings, but the present invention is also applicable in other aspects.

[0038] For example, in the above-described embodiment, the vehicle 10 may be provided with an electric motor in addition to or instead of the engine 12 as a power source. Also, although the rear propeller rotation speed Nrp is exemplified as a signal corresponding to the vehicle speed V, the vehicle speed V may be calculated based on the wheel speed Nw. Further, the present invention can be applied even if the vehicle 10 is a 2WD vehicle.

[0039] The above is merely one embodiment, and the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art.

Explanation of Reference Numerals

[0040] 10: Vehicle 12: Engine (power source) 14: Front wheel (driving wheel) 16: Rear wheel (driving wheel) 22: Transmission (manual transmission) 50: Electronic control unit (control unit) 54: Actual gear stage specifying unit 56: Torque limit value calculating unit WH: Wheel (driving wheel)

Claims

[Claim 1] A control device for a vehicle including a power source and a manual transmission that transmits power from the power source to drive wheels, an actual gear position determination unit that determines an actual gear position of the manual transmission based on a ratio between a rotation speed of the power source and a vehicle speed; a torque limit value calculation unit that calculates a torque limit value for limiting the torque of the power source by using the actual gear position identified by the actual gear position identification unit and a torque limit map that is predetermined for each gear position of the manual transmission; and A vehicle control device characterized in that, when a normal value of the vehicle speed is not obtained and the actual gear stage is uncertain, the torque limit value calculation unit calculates the torque limit value for each gear stage using the torque limit map for each gear stage, and selects the minimum value of the torque limit values ​​for each gear stage as the torque limit value to be used for limiting the torque of the power source.

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