Vehicle control device

Abstract

To provide a vehicle controller improving a driver's operability.SOLUTION: A vehicle controller 1 can switch to an inertia travel mode that does not transmit to a drive shaft 7 power generated by an engine 2. The vehicle controller 1 is provided with: a motor 13 which is rotated by power of the engine 2 and generates power; a battery 14 charging electric power generated by the motor 13; a friction brake device 15 generating a friction brake force to a vehicle; a temperature sensor 16 acquiring the temperature of the friction brake device 15; and a determination part 9A determining the temperature of the friction brake device 15 acquired by the temperature sensor 16. The friction brake device 15 generates a friction brake force when the battery 14 is fully charged with electric power and cancels the inertia travel mode in the case that the temperature of the friction brake device 15 is higher than a prescribed temperature when the battery 14 is fully charged with electric power and in the inertia travel mode.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In recent years, research and development has been conducted into improving fuel efficiency, which contributes to energy efficiency, in order to ensure that more people have access to affordable, reliable, sustainable and advanced energy.

[0003] For example, some vehicles are equipped with a coasting mode (also called inertia mode) to improve fuel economy. This coasting mode has the function of automatically disengaging the clutch, idling the engine, and gradually reducing the vehicle speed when the accelerator pedal is released.

[0004] The coasting driving mode is used on roads with gentle slopes or highways, and is effective in situations where you do not want to use engine braking too much, i.e., when you want to reduce speed gradually.

[0005] For example, Patent Document 1 discloses a technology in which, when a vehicle is faster than a predetermined vehicle speed and satisfies the coasting permission conditions, the clutch connecting the engine output shaft and the transmission input shaft is automatically connected and disconnected to allow the vehicle to coast, and when the vehicle is traveling downhill, for example, the engine brake is activated without coasting to reduce the vehicle speed. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-226701 Summary of the Invention [Problem to be solved by the invention]

[0007] Generally, there are two methods for braking a vehicle: regenerative braking and friction braking. When the vehicle battery is fully charged, it is designed to discharge electricity so that regenerative braking can compensate for the braking force equivalent to engine braking that occurs when the accelerator pedal is released.

[0008] However, when coasting, engine braking is not performed, so electricity cannot be discarded and regenerative braking cannot be performed. As a result, when the battery is fully charged, the electrical energy that could be discarded during normal driving is converted into heat energy from friction braking during coasting, which increases the temperature of the brake friction material and could result in a decrease in braking performance.

[0009] Furthermore, when the battery is fully charged, the selectable gears are limited when changing from coasting to engine braking, but it is necessary to make this functional reduction consistent so that the driver is aware that the brakes are hot.

[0010] The present invention has been made in view of the above-mentioned problems, and has an object to provide a vehicle control device that improves operability for the driver, and ultimately contributes to energy efficiency. [Means for solving the problem]

[0011] (1) A vehicle control device (e.g., a vehicle control device 1 described later) according to the present invention is a vehicle control device that can be switched to a coasting mode in which power generated by a power source (e.g., an engine 2 described later) is not transmitted to a drive shaft (e.g., a drive shaft 7 described later), and includes a generator (e.g., a motor 13 described later) that is rotated by the power of the power source to generate electricity, a battery (e.g., a battery 14 described later) that charges the electricity generated by the generator, a friction brake device (e.g., a friction brake device 15 described later) that generates a friction braking force on the vehicle, a temperature acquisition unit (e.g., a temperature sensor 16 described later) that acquires the temperature of the friction brake device, and a judgment unit (e.g., a judgment unit 9A described later) that judges the temperature of the friction brake device acquired by the temperature acquisition unit, and the friction brake device generates the friction braking force when the battery is fully charged, and when the battery is fully charged and in the coasting mode, the coasting mode is cancelled if the temperature of the friction brake device is higher than a predetermined temperature.

[0012] According to the vehicle control device of the invention (1), whether to cancel the coasting mode is determined based on the temperature of the friction brake device (including the brake caliper and brake fluid pad), and the coasting mode is canceled when the temperature is higher than a predetermined temperature. This allows for a unified feel between the coasting function and the deceleration change function, improving marketability.

[0013] (2) In the vehicle control device according to the invention of (1), it is preferable to provide a deceleration unit (e.g., ECU 9 and motor 13 described later) having a plurality of deceleration stages that can change the deceleration of the vehicle, and to switch to one of the plurality of deceleration stages when the coasting mode is released.

[0014] According to the vehicle control device of the invention (2), the driver can be made aware of the high thermal load and can shift to a deceleration stage other than the deceleration stage in coasting mode, which allows the driver to visually and sensuously recognize the thermal load, improving marketability.

[0015] (3) In the vehicle control device according to the invention of (1) or (2), a driving condition detection unit (e.g., driving condition detection unit 12 described later) for detecting the driving condition of the vehicle, a reduction unit (e.g., automatic transmission 4 described later) having a plurality of reduction stages capable of changing the deceleration of the vehicle, and a control unit (e.g., control unit 9B described later) for setting a reduction stage among the plurality of reduction stages corresponding to the temperature of the friction brake device, wherein the judgment unit judges whether the vehicle is in a downhill condition based on the detection result of the driving condition detection unit, and the control unit preferably switches to the reduction stage corresponding to the current temperature of the friction brake device when the judgment unit judges that the vehicle is in a downhill condition during the coasting mode.

[0016] When coasting, engine braking is ineffective, so it is necessary to switch to a deceleration gear. When switching to a deceleration gear, the appropriate deceleration gear is changed as needed depending on factors such as the angle of the slope. The vehicle control device according to the invention (3) can determine whether the vehicle is descending a slope, switch to a deceleration gear with an appropriate deceleration, and prevent the temperature of the brake device (brake friction material) from becoming too high.

[0017] (4) In a vehicle control device according to any one of the inventions (1) to (3), the vehicle control device comprises a speed reducer (e.g., an automatic transmission 4 described later) having a plurality of speed reducers that can change the deceleration of the vehicle, and an operation unit (e.g., operation unit 10 described later) that is provided in a steering unit (e.g., steering unit 11 described later) and that can select the coasting mode in response to an operation by the driver, and has a fixed speed change mode that can switch between a plurality of speed reducers based on an operation by the driver, and an automatic speed change mode that can switch between the plurality of speed reducers based on the running state of the vehicle, wherein the speed reducer is switched to a speed reducer having a greater deceleration than the deceleration of a currently selected speed reducer by operation of the operation unit, and in the automatic speed change mode and the coasting mode, when the temperature of the friction brake device is higher than a predetermined temperature, the automatic speed change mode is switched to the fixed speed change mode, and in the fixed speed change mode, when the temperature of the friction brake device is higher than the predetermined temperature, it is preferable that switching to the coasting mode is prohibited.

[0018] According to the vehicle control device of the invention (4), when the temperature of the friction brake device is higher than a predetermined temperature, the vehicle can be made to only operate the fixed speed change mode operated by the driver and cannot be switched to the coasting mode in order to make the driver aware of the need to decelerate. This makes the vehicle more safe, thereby improving its marketability. [Effects of the Invention]

[0019] According to the present invention, it is possible to improve the operability for the driver, which in turn can contribute to energy efficiency. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a schematic diagram showing a configuration of a vehicle control device according to an embodiment of the present invention; [Figure 2] FIG. 4 is a schematic diagram illustrating transitions between multiple reduction gear stages. DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0022] First, the configuration of a vehicle control device 1 according to an embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing the configuration of a vehicle control device 1 according to an embodiment of the present invention.

[0023] 1 is capable of switching from D range, which is a driving mode used during normal driving, to a coasting mode in which power generated by the engine 2 is not transmitted to the pair of left and right drive shafts 7. This vehicle control device 1 has a fixed speed change mode in which multiple reduction gears can be switched based on the driver's operation, and an automatic speed change mode in which multiple reduction gears can be switched based on the driving state of the vehicle.

[0024] Specifically, the vehicle control device 1 includes an engine (power source) 2, a clutch 3, an automatic transmission (reduction unit) 4, a hydraulic circuit 5, a differential mechanism 6, a pair of left and right drive shafts 7, a pair of left and right drive wheels 8, an ECU (Electric Control Unit) 9, an operating unit (shift device, paddle shift) 10 having a plus paddle 10a and a minus paddle 10b, a steering unit 11, a driving condition detection unit 12, a motor 13, a battery 14, a friction brake device 15, a temperature sensor 16, and the like.

[0025] The engine 2 is a power source that generates power for the vehicle. In this embodiment, a hybrid engine is employed that combines a motor 13 with the engine 2, but this is not limiting. The power generated by the hybrid engine is transmitted via a clutch 3, an automatic transmission 4, and a differential mechanism 6 to a pair of left and right drive shafts 7 to which a pair of left and right drive wheels 8 are attached.

[0026] The clutch 3 cuts off the power transmission path that is generated by the hybrid engine and transmitted to the pair of left and right drive shafts 7 in response to the pressure (hydraulic pressure) of the hydraulic oil supplied from the hydraulic circuit 5. When the vehicle is switched to coasting mode, the clutch 3 cuts off the power transmission path that is generated by the hybrid engine and transmitted to the pair of left and right drive shafts 7.

[0027] The automatic transmission 4 adjusts the gear ratio in accordance with the pressure (hydraulic pressure) of the hydraulic oil supplied from the hydraulic circuit 5.

[0028] The hydraulic circuit 5 supplies hydraulic oil pressure (hydraulic pressure) to the clutch 3 and the automatic transmission 4 based on the control of the ECU 9 .

[0029] The differential mechanism 6 distributes the power generated by the hybrid engine and transmitted via the clutch 3 and automatic transmission 4 to a pair of left and right drive shafts 7. A pair of left and right drive wheels 8 are attached to each of the pair of left and right drive shafts 7. The pair of left and right drive wheels 8 convert the power transmitted via the pair of left and right drive shafts 7 into propulsive force for the vehicle.

[0030] The ECU 9 controls the engine 2, motor 13, battery 14, hydraulic circuit 5, etc. based on inputs from the operation unit 10, running condition detection unit 12, temperature sensor 16, etc. The ECU 9 performs various processes by reading and executing computer programs stored in a memory (not shown). Specifically, the ECU 9 includes a determination unit 9A and a control unit 9B.

[0031] The ECU 9 and the motor 13 constitute a reduction unit of this embodiment. The reduction unit of this embodiment has a plurality of reduction stages that can change the deceleration of the vehicle. The plurality of reduction stages includes a first reduction stage that has a larger deceleration than the reduction stage selected in the coasting mode.

[0032] Here, motor 13 generates driving force when the driver depresses the accelerator pedal to accelerate, but acts as a generator when the driver releases his / her foot from the accelerator pedal to decelerate. The force required for this power generation acts as a resistance to the rotation of drive wheels 8, functioning as a regenerative brake. The deceleration unit of this embodiment can change the strength of this regenerative brake in stages by controlling the rotation of motor 13 with ECU 9. Specifically, the deceleration unit of this embodiment can change the deceleration of the vehicle in stages in response to the driver's operation of plus paddle 10a and minus paddle 10b, known as a deceleration selector (described later).

[0033] The determination unit 9A of the ECU 9 determines the temperature of the friction brake device 15 acquired by the temperature sensor 16. That is, the determination unit 9A determines whether the temperature of the friction brake device 15 acquired by the temperature sensor 16 is in a high temperature state. Based on the detection result of the running state detection unit 12, the determination unit 9A determines whether the vehicle is going downhill or other running states of the vehicle.

[0034] The control unit 9B of the ECU 9 controls the operation of the vehicle by setting a reduction gear. This control unit 9B sets a reduction gear from among multiple reduction gears that corresponds to the temperature of the friction brake device 15. Furthermore, when the determination unit 9A determines that the vehicle is going downhill in the coasting mode, the control unit 9B switches to a reduction gear that corresponds to the current temperature of the friction brake device 15. This ensures that the temperature of the friction brake device 15 does not deteriorate the marketability of the friction brake when the vehicle has finished descending the slope. In this case, the reduction gear may be further stored in association with the driving environment (presence or absence of curves, gradient, etc.).

[0035] Furthermore, when the battery 14 is fully charged and the vehicle is in the coasting mode, the control unit 9B cancels the coasting mode if the temperature of the friction brake device 15 is higher than a predetermined temperature.

[0036] The above-mentioned predetermined temperature is set because, in conventional reduction gear selectors, degeneration control is performed from a gear position with a high brake load so as to return to D range when the estimated temperature of the friction brake device reaches a predetermined high temperature (a fourth temperature described below). More specifically, the settable gear positions of conventional reduction gear selectors are the first to fifth reduction gear positions when the above-mentioned predetermined temperature is reached, the first to fourth reduction gear positions when a first temperature higher than the above-mentioned predetermined temperature is reached, the first to third reduction gear positions when a second temperature higher than the above-mentioned first temperature is reached, the first to second reduction gear positions when a third temperature higher than the above-mentioned second temperature is reached, and only the first reduction gear position when a fourth temperature higher than the above-mentioned third temperature is reached.

[0037] Furthermore, when the coasting mode is cancelled, the control unit 9B switches to one of a plurality of reduction gears. In this case, the reduction gear may be switched to a reduction gear with a greater deceleration in the automatic speed change mode, or the driver may be notified to switch to a reduction gear with a greater deceleration in the driver selection mode (fixed speed change mode) after the coasting mode is cancelled.

[0038] Furthermore, in the automatic speed change mode and the coasting mode, if the temperature of the friction brake device 15 is higher than a predetermined temperature, the control unit 9B switches from the automatic speed change mode to the fixed speed change mode. Furthermore, in the fixed speed change mode, if the temperature of the friction brake device 15 is higher than a predetermined temperature, the control unit 9B prohibits switching to the coasting mode.

[0039] The operation unit 10 is provided on the steering unit 11, and allows the driver to select the coasting mode. When the coasting mode is selected by operating the operation unit 10, the vehicle transitions to the coasting mode.

[0040] The operating unit 10 is a shift device that can change between multiple reduction gears. The operating unit 10, which is a shift device, has a plus paddle (first operating unit) 10a and a minus paddle (second operating unit) 10b. The plus paddle 10a can be switched to a reduction gear with a smaller deceleration than the currently selected reduction gear. The minus paddle 10b can be switched to a reduction gear with a larger deceleration than the currently selected reduction gear. Operating the plus paddle 10a causes a transition to coasting mode.

[0041] The operating unit 10, which is a shift device, is a paddle shift. When the plus paddle 10a is operated for a first predetermined time, the mode shifts to automatic speed change mode and coasting mode. When the plus paddle 10a is operated for a second predetermined time that is longer than the first predetermined time, the mode shifts to fixed speed change mode and coasting mode.

[0042] In addition, the coasting mode is cancelled by operating the minus paddle 10b.

[0043] In the coasting mode, when the operation state of the minus paddle 10b continues for a first predetermined time, the vehicle is switched to the first reduction gear.

[0044] When the vehicle is traveling at the first reduction gear, if the operation state of either the plus paddle 10a or the minus paddle 10b continues for a second predetermined time that is longer than the first predetermined time, the mode is switched from the fixed speed change mode to the automatic speed change mode.

[0045] The running state detection unit 12 detects the running state of the vehicle and inputs a detection signal of the detected running state of the vehicle to the ECU 9.

[0046] The motor 13 generates electricity by being rotated by the power of the engine 2. On the other hand, the motor 13 also serves as a power source that generates power for the vehicle using the power of the battery 14.

[0047] The battery 14 is charged with the electric power generated by the motor 13 .

[0048] The friction brake device 15 generates a friction braking force on the vehicle. When the battery 14 is fully charged, the friction brake device 15 generates a friction braking force equivalent to regenerative braking / engine braking when the brake pedal is not depressed.

[0049] The temperature sensor 16 acquires the temperature of the friction brake device 15. The temperature sensor 16 converts the acquired temperature of the friction brake device 15 into a signal and inputs it to the ECU 9.

[0050] Next, a plurality of reduction gear stages in the reduction unit of this embodiment and the transitions therebetween will be described with reference to Fig. 2. Fig. 2 is a schematic diagram illustrating the transitions between a plurality of reduction gear stages.

[0051] As shown in FIG. 2, the multiple reduction stages include a 0th reduction stage which is a reduction stage selected in the coasting mode, a 1st reduction stage which has a deceleration greater than that of the 0th reduction stage which is a reduction stage selected in the coasting mode, a 2nd reduction stage which has a deceleration greater than that of the 1st reduction stage, a 3rd reduction stage which has a deceleration greater than that of the 2nd reduction stage, a 4th reduction stage which has a deceleration greater than that of the 3rd reduction stage, a 5th reduction stage which has a deceleration greater than that of the 4th reduction stage, and a 6th reduction stage which has a deceleration greater than that of the 5th reduction stage.

[0052] In the case of D range, which is the driving mode used during normal driving, when "+ paddle pull" is performed, in which the operation state of the plus paddle 10a continues for a first predetermined time, smart coasting is activated and the mode is switched to automatic shift mode and coasting mode (coasting driving mode), i.e., to stage 0 of the automatic shift mode.

[0053] The expected scenario for using smart coasting is when adjusting the distance to a distant target. Specifically, for example, when there is a distance to the vehicle ahead and you want to gently decelerate to adjust the distance, or when there is a distance to an intersection and you want to gently decelerate to adjust the distance or vehicle speed. In this case, the plus paddle 10a is used to release the deceleration force and gently decelerate, and as will be described later, when accelerating again, the system automatically returns to D range.

[0054] In the case of D range, when "+ paddle prolongation" is performed in which the operation state of the plus paddle 10a continues for a second predetermined time longer than the first predetermined time, fixed coasting is activated and the mode is switched to fixed speed change mode and coasting mode (coasting mode), i.e., to stage 0 of the fixed speed change mode.

[0055] Fixed coasting is expected to be used in situations where you want to expand the deceleration control range using the accelerator operator and improve acceleration control (for example, when you are following another vehicle in a traffic jam and want to gently decelerate to adjust the distance between vehicles because the gap is narrow, or when you want to drive easily from a steady speed downhill without the vehicle accelerating or decelerating due to the gradient).

[0056] In the case of smart coasting, when "-paddle pulling" is performed in which the operation state of the minus paddle 10b continues for a first predetermined time, the coasting mode is released and the mode is switched to the second reduction stage of the automatic shift mode.

[0057] In the case of smart coasting, when "extended paddle pull" is performed, in which the operation state of the minus paddle 10b continues for a second predetermined time, the coasting mode is released, the automatic shift mode is switched to the fixed shift mode, and the mode transitions to the second stage of the fixed shift mode.

[0058] In the case of smart coasting, when the accelerator operation detection unit detects the driver's operation of the accelerator operator, the coasting mode is cancelled and the shift is made to the D range.

[0059] In the case of fixed coasting, when "-paddle pulling" is performed in which the operation state of the minus paddle 10b continues for a first predetermined time, the coasting mode is released and the mode is switched to the first stage of the fixed speed change mode.

[0060] In the case of fixed coasting, when "extended paddle pull" is performed in which the operation state of the minus paddle 10b continues for a second predetermined time, the coasting mode is released and the mode is switched from the fixed shift mode to the automatic shift mode, transitioning to the first stage of the automatic shift mode.

[0061] According to the vehicle control device 1, the coasting driving mode and the reduction gear are operated as a single function, and the coasting driving mode is degenerated, specifically, the coasting mode is degenerated in the order of coasting degeneration, the sixth reduction gear which has the greatest deceleration, the fifth reduction gear which has the next greatest deceleration, and so on, thereby improving the operability for the driver.

[0062] Furthermore, the vehicle control device 1 determines whether to cancel the coasting mode based on the temperature of the friction brake device (including the brake calipers and brake fluid pads) 15, and cancels the coasting mode if the temperature is higher than a predetermined temperature. This allows for a sense of unity between the coasting function and the deceleration change function, improving marketability.

[0063] Furthermore, the vehicle control device 1 can make the driver aware that the thermal load is high, and can shift to a deceleration stage with a deceleration rate other than that in coasting driving mode. This allows the driver to visually and sensuously recognize the thermal load, improving marketability.

[0064] When coasting, engine braking is ineffective, so it is necessary to switch to a deceleration gear. When switching to a deceleration gear, the appropriate deceleration gear is changed as needed depending on factors such as the angle of the slope. The vehicle control device 1 determines whether the vehicle is descending a slope, and switches to a deceleration gear with an appropriate deceleration, preventing the temperature of the brake device (brake friction material) 15 from becoming too high.

[0065] Also, according to the vehicle control device 1, when the temperature of the friction brake device 15 is higher than a predetermined temperature, in order to make the driver aware of deceleration, it is possible to set only the fixed shift mode operated by the driver and prevent it from being switched to the coasting mode. As a result, safety can be made conscious, and the product quality is improved.

[0066] Note that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within the scope that can achieve the object of the present invention are included in the present invention.

Explanation of Signs

[0067] 1 Vehicle control device 2 Engine (power source) 3 Clutch 4 Automatic transmission 5 Hydraulic circuit 6 Differential mechanism 7 Drive shaft 8 Driving wheel 9 ECU (deceleration unit) 9A Judgment unit 9B Control unit 10 Operation unit (shift device, paddle shift) 10a Plus paddle (first operation unit) 10b Minus paddle (second operation unit) 11 Steering unit 12 Travel state detection unit 13 Motor (generator, deceleration unit) 14 Battery 15 Friction brake device 16 Temperature sensor (temperature acquisition unit)

Claims

1. A control device for a vehicle that can be switched to a coasting mode in which power generated by a power source is not transmitted to a drive shaft, a generator that generates electricity by being rotated by the power of the power source; a battery that charges the power generated by the generator; a friction brake device that generates a friction braking force on the vehicle; a temperature acquisition unit that acquires a temperature of the friction brake device; a determination unit that determines the temperature of the friction brake device acquired by the temperature acquisition unit, the friction brake device generates the friction braking force when the battery is fully charged, A vehicle control device that, when the battery is fully charged and in the coasting mode, if the temperature of the friction brake device is higher than a predetermined temperature, cancels the coasting mode and transmits the power generated by the power source to the drive shaft.

2. a deceleration unit having a plurality of deceleration stages that can change the deceleration of the vehicle; The vehicle control device according to claim 1 , wherein when the coasting mode is cancelled, the vehicle is switched to one of the plurality of reduction gear stages.

3. a running state detection unit that detects a running state of the vehicle; a deceleration unit having a plurality of deceleration stages capable of changing the deceleration of the vehicle; a control unit that sets a reduction gear corresponding to a temperature of the friction brake device among the plurality of reduction gears, the determination unit determines whether the vehicle is traveling downhill based on the detection result of the traveling state detection unit; 2. The vehicle control device according to claim 1, wherein the control unit switches to a reduction gear corresponding to a current temperature of the friction brake device when the determination unit determines that the vehicle is traveling downhill during the coasting mode.

4. a deceleration unit having a plurality of deceleration stages capable of changing the deceleration of the vehicle; an operation unit that is provided in a steering unit and that can select the coasting mode in response to an operation by a driver; A fixed speed change mode that allows switching between multiple reduction stages based on driver operation; an automatic transmission mode capable of switching between the plurality of reduction gear stages based on a running state of the vehicle, the speed reducer is switched to a speed reducer having a greater deceleration than the deceleration of a currently selected speed reducer by operating the operating unit, When the temperature of the friction brake device is higher than the predetermined temperature in the automatic speed change mode and the coasting mode, the mode is switched from the automatic speed change mode to the fixed speed change mode, 2. The vehicle control device according to claim 1, wherein switching to the coasting mode is prohibited in the fixed speed change mode when the temperature of the friction brake device is higher than the predetermined temperature.