Vehicle driving force control device

Abstract

Provided is a driving force control device for a vehicle, which can suppress a decrease in accelerator pedal operability while achieving an acceleration required by a driver. A basic acceleration uniquely determined based on an operation amount of an accelerator pedal and a vehicle speed is calculated, and when the required acceleration is greater than a predetermined value determined in advance and the operation speed of the accelerator pedal is greater than a predetermined speed (step S1), the required acceleration is set to a corrected acceleration greater than the basic acceleration, and the driving force is controlled so as to generate the set corrected acceleration (steps S6 to S7).

Description

Technical Field

[0001] The present invention relates to a device for controlling a driving force based on an operation amount of an accelerator pedal. Background Art

[0002] In Patent Document 1, there is described a vehicle control device configured to correct a target acceleration based on an accelerator operation in order to satisfy an acceleration required by a driver. Specifically, the control device described in Patent Document 1 performs correction to increase the target acceleration by multiplying the target acceleration (reference acceleration) in the case where no quick depression is performed by a gain greater than "1" when it is determined that a quick depression of the accelerator pedal has been performed. Further, when the accelerator opening degree becomes small due to an operation such as removing the foot from the accelerator pedal, the target acceleration converges to the reference acceleration according to the accelerator opening degree and the gain, and when the acceleration becomes "0", the target acceleration completely converges to the reference acceleration. Further, it is configured that the gain is determined based on an operation speed of the accelerator pedal, and the relationship between the operation speed of the accelerator pedal and the amplification gain is mapped in advance and stored in an ECU.

[0003] Further, in Patent Document 2, there is described a control device configured to perform driving force control in such a manner that an actual vehicle speed follows a target vehicle speed by obtaining a target acceleration based on an operation speed of an accelerator pedal and obtaining a target vehicle speed based on the target acceleration, thereby compensating for a response delay of the actual vehicle speed with respect to a change in the vehicle speed corresponding to an accelerator operation.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2011-148342

[0007] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2004-276669 Summary of the Invention

[0008] In the control device described in the above-mentioned Patent Document 1, when a quick depression of the accelerator pedal such as a sudden acceleration is performed, the acceleration required by the driver is achieved by performing correction such as multiplying a reference acceleration by a gain. However, the reference acceleration described in Patent Document 1 is uniquely determined based on the operation amount of the accelerator pedal and the vehicle speed. When the reference acceleration is multiplied by a gain, there may be a deviation between the actual required acceleration based on the quick depression and the corrected acceleration obtained by multiplying by the gain, and sometimes the acceleration required by the driver cannot be accurately grasped. In addition, it is configured that the corrected acceleration converges to the reference acceleration in a state where the acceleration is "0", in other words, it is configured to return to the reference acceleration in a state where the acceleration is "0". Therefore, in the region near this acceleration "0", a sudden change occurs due to the switching from the corrected target acceleration to the reference acceleration. Since the region near the acceleration "0" is a stable driving region, the operation frequency of the driver's accelerator pedal becomes the highest. Such a sudden change creates a step (or staircase) in the acceleration, and may even cause discomfort or unpleasantness to the driver. In addition, when such a sudden change occurs in the stable driving region where the operation frequency of the accelerator pedal is high, the operability of the accelerator pedal may be reduced. In addition, such a technical problem also occurs in Patent Document 2.

[0009] The present invention has been completed in view of the above technical problems, and an object thereof is to provide a vehicle driving force control device that can suppress a decrease in the operability of the accelerator pedal while achieving the acceleration required by the driver.

[0010] To achieve the above object, the present invention provides a vehicle driving force control device including a controller that outputs a driving force command signal based on a required acceleration obtained when a driver operates an accelerator pedal, characterized in that the controller is configured to calculate a basic acceleration uniquely determined based on the operation amount of the accelerator pedal and the vehicle speed, and when the basic acceleration is greater than a predetermined value and the operation speed of the accelerator pedal is greater than a predetermined speed, obtain a corrected acceleration obtained by increasing and correcting the basic acceleration, and control the driving force in such a way as to generate the corrected acceleration.

[0011] In addition, in the present invention, it is also possible that the corrected acceleration is calculated based on the basic acceleration and an addition amount of the acceleration with respect to the basic acceleration, and the addition amount of the acceleration is determined by the difference between a dynamic acceleration obtained based on the operation amount of the accelerator pedal, the vehicle speed, and the operation speed of the accelerator pedal and the basic acceleration, and a predetermined control gain.

[0012] In addition, in the present invention, the control gain may also be set according to the operation amount of the accelerator pedal and the vehicle speed, and configured to be set to the maximum gain when the required acceleration is greater than the predetermined value, and set to the minimum gain when the required acceleration is the base acceleration.

[0013] In addition, in the present invention, it may also be configured that when the required acceleration is greater than the base acceleration and less than the predetermined value, the control gain changes continuously according to the required acceleration.

[0014] In addition, in the present invention, the controller may also reduce the control gain according to the operation amount of the accelerator pedal, and when the control gain is reduced and the required acceleration returns from the corrected acceleration to the base acceleration, control the driving force in such a way that the acceleration when returning to the base acceleration is greater than "0".

[0015] In addition, in the present invention, the controller may also obtain the road surface gradient on which the vehicle travels, calculate the required acceleration according to the operation amount of the accelerator pedal, the vehicle speed, and the road surface gradient, and be configured to calculate the added amount of the acceleration using the control gain determined according to the operation amount of the accelerator pedal, the vehicle speed, and the road surface gradient.

[0016] Moreover, in the present invention, the region where the acceleration is "0" when the road surface gradient in the predetermined operation amount of the accelerator pedal is above the predetermined gradient may be larger than the region where the acceleration is "0" when the road surface gradient is less than the predetermined gradient.

[0017] The driving force control device for a vehicle according to the present invention is configured to perform control to improve acceleration performance when the required acceleration and the operation speed of the accelerator pedal are greater than a predetermined value. Specifically, it is configured that when the required acceleration is greater than the predetermined value and the operation speed of the accelerator pedal is greater than the predetermined speed, for the base acceleration determined according to the accelerator opening and the vehicle speed, find the added amount of the acceleration, and calculate the corrected acceleration as the final required acceleration. Moreover, generate the driving force in such a way as to achieve the corrected acceleration. Thus, compared with the structure described in Patent Document 1 above, for example, the acceleration required by the driver can be generated more accurately.

[0018] In addition, according to the present invention, when the control for improving the acceleration property ends and the acceleration returns from the corrected acceleration to the base acceleration, the acceleration is greater than 0G. Therefore, the sudden change when returning to the base acceleration occurs in the acceleration region greater than 0G. Therefore, when the decreasing acceleration reaches near 0G which is the stable driving region, no sudden change occurs near this 0G. Therefore, the operability of the accelerator pedal near 0G which is the stable driving region becomes good. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 FIG. is a diagram showing the structure of a vehicle and an outline of a control system which are objects of control in the control device of a vehicle according to the present invention.

[0020] Figure 2 FIG. is a diagram for explaining the acceleration characteristics for each accelerator opening.

[0021] Figure 3 FIG. is a flowchart for explaining an example of control in an embodiment of the present invention.

[0022] Figure 4 FIG. is a diagram for explaining a method for determining a control amount reflection rate (control gain).

[0023] Figure 5 FIG. is a diagram for explaining a method for determining a recovery G and a control start G.

[0024] Figure 6 FIG. is a diagram showing an example of a timing chart in the case of executing the control of Figure 3 , and particularly, it is a diagram for explaining an example of the case where the accelerator opening is made constant and the vehicle is accelerated.

[0025] Figure 7 FIG. is a diagram for explaining a change in the control amount reflection rate in the case of executing the control of Figure 6 .

[0026] Figure 8 FIG. is a diagram for explaining the acceleration characteristics in the case of executing the control of Figure 6 .

[0027] Figure 9 FIG. is a diagram for explaining the effects in an embodiment of the present invention.

[0028] Figure 10 FIG. is a diagram for explaining other effects in an embodiment of the present invention.

[0029] Figure 11 FIG. is a diagram showing an example of a timing chart in the case of executing the control of Figure 3 , and particularly, it is a diagram for explaining an example of the case where the accelerator opening is decreased after acceleration.

[0030] Figure 12 is a graph for explaining the change in the control amount reflection rate under the condition of executing the Figure 11 control.

[0031] Figure 13 is a graph for explaining the acceleration characteristics under the condition of executing the Figure 11 control.

[0032] Figure 14 is a graph showing an example of a timing chart of a control example of executing the Figure 3 control, particularly a graph for explaining an example of a case where, after the control of reducing the accelerator opening to increase the acceleration after acceleration ends, the accelerator pedal is further depressed to accelerate again.

[0033] Figure 15 is a graph for explaining the change in the control amount reflection rate under the condition of executing the Figure 14 control.

[0034] Figure 16 is a graph for explaining the acceleration characteristics under the condition of executing the Figure 14 control.

[0035] Figure 17 is a graph showing an example of a timing chart of a control example of executing the Figure 3 control, particularly a graph for explaining an example of a case where, during the execution of the control of increasing the acceleration while releasing the accelerator pedal, the accelerator pedal is further depressed to accelerate again.

[0036] Figure 18 is a graph for explaining the change in the control amount reflection rate under the condition of executing the Figure 17 control.

[0037] Figure 19 is a graph for explaining the acceleration characteristics under the condition of executing the Figure 17 control.

[0038] Figure 20 is a flowchart for explaining other control examples in the embodiments of the present invention.

[0039] Figure 21 is a graph showing an example of a timing chart of a control example of executing the Figure 20 control.

[0040] (Symbol Explanation)

[0041] 1: Driving force source; 2: Front wheel; 3: Rear wheel; 4: Accelerator pedal; 5: Brake pedal; 6: Detection unit; 7: ECU (Electronic control unit); Ve: Vehicle. Detailed Embodiments

[0042] Referring to the accompanying drawings, embodiments of the present invention will be described. In addition, the embodiments shown below are merely examples of cases where the present invention is embodied, and do not limit the present invention.

[0043] The vehicle that can be an object in the present invention is a vehicle having an engine or a motor as a driving force source. However, it can also be an electric vehicle having only a motor as a driving force source, or a hybrid vehicle having an engine and a motor as a driving force source. In addition, the electric vehicle includes a pure electric vehicle (BEV) having only a motor as a driving force source, and a so-called range-extended EV vehicle having an engine for power generation only. Furthermore, it can also be a so-called plug-in type vehicle or a fuel cell vehicle.

[0044] Figure 1 An example of the drive system and the control system of the vehicle Ve that is a control object in the embodiments of the present invention is shown. In Figure 1 the vehicle Ve shown, as main components, there are provided a driving force source (PWR) 1, front wheels 2, rear wheels 3, an accelerator pedal 4, a brake pedal 5, a detection unit 6, and an ECU 7.

[0045] The driving force source 1 is a power source that outputs a driving torque for generating the driving force of the vehicle Ve. The driving force source 1 is, for example, an internal combustion engine such as a gasoline engine or a diesel engine, and is configured to electrically control the adjustment of the output and the operating states such as start and stop. If it is a gasoline engine, the opening degree of the throttle valve, the supply amount or injection amount of fuel, the execution and stop of ignition, and the ignition timing are electrically controlled. Or, if it is a diesel engine, the injection amount of fuel, the injection timing of fuel, or the opening degree of the throttle valve in the EGR (Exhaust Gas Recirculation) system is electrically controlled.

[0046] In addition, the driving force source 1 in the embodiments of the present invention can also be, for example, a permanent magnet type synchronous motor or an induction motor. In this case, the motor has, for example, both the function of a motor that is driven by being supplied with electric power and outputs a motor torque, and the function of a generator that is driven by receiving an external torque and generates electricity. That is, the motor is a motor having a power generation function (so-called motor generator), and electrically controls the switching of the function as a motor and the function as a generator. A battery (both not shown) is connected to the motor via an inverter. Therefore, the motor can be driven as a generator, and the electric energy generated at this time can be stored in the battery. In addition, the electric energy stored in the battery can also be supplied to the motor, and the motor can be driven as a motor to output a motor torque.

[0047] The vehicle Ve transmits the driving torque output from the driving force source 1 to the drive wheels to generate a driving force. InFigure 1 shows the structure of a front-wheel drive vehicle in which the front wheels 2 are driving wheels. In addition, the vehicle Ve in the embodiment of the present invention may also be a rear-wheel drive vehicle in which the rear wheels 3 are driving wheels. Alternatively, it may be a four-wheel (all-wheel) drive vehicle in which both the front wheels 2 and the rear wheels 3 are driving wheels. In addition, when an engine is mounted as the power source 1, it may be configured to provide a transmission (not shown) on the output side of the engine, and transmit the driving torque output from the power source 1 to the driving wheels via the transmission.

[0048] In addition, the vehicle Ve is provided with an accelerator pedal 4 for the driver to adjust the driving force and perform an acceleration operation of the vehicle Ve. The accelerator pedal 4 has a generally known structure. By the driver's stepping-on operation and releasing operation, corresponding to the operation amount (stepping-on amount, or accelerator opening or accelerator pedal position) of the accelerator pedal 4, the driving torque output from the power source 1 increases, and the driving force of the vehicle Ve increases. On the contrary, by the stepping-on and releasing of the accelerator pedal 4 (operated to move the accelerator away, or the accelerator opening or accelerator pedal position decreases), corresponding to the operation amount of the accelerator pedal 4, the driving torque decreases, and the driving force of the vehicle Ve decreases. In addition, when a motor is mounted as the power source 1, the motor functions as a so-called regenerative brake, that is, a braking force is generated in the vehicle Ve by the regenerative torque output from the motor. Alternatively, when an engine is mounted as the power source 1, by performing an operation of moving the accelerator away, a so-called engine brake comes into play, and the braking force of the vehicle Ve increases. For example, the frictional torque and pumping loss of the engine become a resistance (braking torque) against the driving torque, and a braking force is generated in the vehicle Ve.

[0049] In addition, in the vehicle Ve, a brake pedal 5 is provided for the driver to adjust the braking force and perform a braking operation of the vehicle Ve. By stepping on the brake pedal 5, a braking device such as a hydraulic disc brake or a drum brake operates to generate a braking force of the vehicle Ve. In addition, the accelerator pedal 4 may also be an operating device capable of driving in a so-called single-pedal mode in which both acceleration and deceleration are controlled according to the operation amount of the pedal by the driver. In this case, it may also be configured to control the accelerator pedal 4 and the brake pedal 5 in conjunction with each other.

[0050] The detection unit 6 acquires various data for controlling each part of the vehicle Ve, and particularly detects various data related to the operation state of the accelerator pedal 4. The detection unit 6 collectively refers to the sensors and devices for detecting such various data. Therefore, the detection unit 6 in the embodiment of the present invention at least includes an accelerator pedal position sensor 6a for detecting the operation amount of the accelerator pedal 4 (i.e., the accelerator pedal position or the accelerator opening). In addition, the detection unit 6 includes a brake stroke sensor 6b for detecting the operation amount of the brake pedal 5 (i.e., the brake pedal stroke or the brake pedal opening), a vehicle speed sensor 6c for detecting the vehicle speed, an acceleration sensor 6d for detecting the acceleration in the front-rear direction of the vehicle Ve, a slope angle sensor 6e for detecting the slope angle of the road surface, and a rotational speed sensor 6f for detecting the rotational speed of the output shaft of the motor or the rotational speed of the output shaft of the engine, etc. Moreover, the detection unit 6 is electrically connected to the ECU 7 and outputs an electric signal corresponding to the detection values of the various sensors and devices as described above to the ECU 7 as detection data.

[0051] The ECU 7 corresponds to the "controller" in the embodiment of the present invention and is an electronic control device mainly composed of, for example, a microcomputer, and is input with various data detected or calculated by the above detection unit 6. In addition, the ECU 7 performs operations using the various input data as described above, as well as the pre-stored data and calculation formulas, etc. Furthermore, it can be configured to output its operation result as a control command signal to control the vehicle Ve.

[0052] Specifically, it acquires data related to the operation state of the accelerator pedal 4 detected by the accelerator pedal position sensor 6a as described above, and calculates the target drive torque of the power source 1 and the target acceleration (or target deceleration) of the vehicle Ve based on the acquired data. Then, it controls the output of the power source 1 according to the calculated target drive torque. That is, it outputs a control command signal for controlling the power source 1. In addition, it controls the driving force and braking force generated in the vehicle Ve corresponding to the operation states of the accelerator pedal 4 or the brake pedal 5 according to the calculated or detected target acceleration and required acceleration. That is, it outputs a control command signal for controlling the driving force and braking force. In addition, Figure 1 shows an example in which one ECU 7 is provided, but multiple ECUs 7 can also be provided, for example, for each device or equipment to be controlled, or for each control content.

[0053] The vehicle Ve configured in this way generally determines the target acceleration of the vehicle Ve according to the operation amount (accelerator opening) of the driver's accelerator pedal 4, and controls the torque of the power source 1 to generate a driving force so as to achieve the target acceleration. In addition, the target acceleration is, for example, as Figure 2As shown, it is pre-mapped in relation to the vehicle speed and stored in the ECU 7. On the other hand, when the driver depresses the accelerator pedal 4 at a speed equal to or higher than a predetermined speed during hard acceleration or in other cases where the acceleration requirement is large, due to inevitable delays, the acceleration required by the driver may sometimes not be generated. Therefore, in the embodiment of the present invention, it is configured that in the case of a relatively large acceleration requirement, according to the driver's accelerator pedal operation, the addition amount of the target acceleration is calculated, and the driving force is controlled in such a way that the corrected target acceleration obtained by adding this addition amount is generated.

[0054] Figure 3 FIG. is a flowchart showing an example of this control. First, it is determined whether there is an acceleration intention (step S1). Specifically, it is judged whether the required acceleration G of the driver is greater than a predetermined value α determined in advance and whether the operation speed of the accelerator pedal 4 is greater than a predetermined speed β determined in advance. The judgment as to whether the required acceleration G is greater than the predetermined value α can be made by comparing the acceleration obtained from the map ( Figure 2 ) based on the accelerator opening and the vehicle speed with the predetermined value α. In addition, since the required acceleration G in this step S1 can be calculated based on the map determined in advance as described above, in other words, it can be called the static acceleration. This static required acceleration corresponds to the "basic acceleration Gb" in the embodiment of the present invention. Therefore, in the case where a negative judgment is made in this step S1, that is, in the case where the required acceleration G is equal to or less than the predetermined value α, or in the case where the operation speed of the accelerator pedal 4 is equal to or less than the predetermined speed β, it is judged that there is no intention of acceleration requirement, and the subsequent control is not executed, and the control example shown Figure 3 is temporarily ended.

[0055] Conversely, in the case where an affirmative judgment is made in this step S1, that is, in the case where the required acceleration G is greater than the predetermined value α and the operation speed of the accelerator pedal 4 is greater than the predetermined speed β, it is judged that there is an intention of acceleration requirement, and the acceleration characteristic Gi for realizing the acceleration feeling according to the driver's intention is calculated (step S2). This acceleration characteristic Gi can be called the dynamic acceleration relative to the static acceleration in the above step S1. The required acceleration G in the above step S1 is uniquely determined according to the accelerator opening and the vehicle speed. In contrast, the acceleration characteristic Gi is calculated by taking the operation speed of the accelerator pedal 4 as a parameter in addition to the accelerator opening and the vehicle speed. That is, by adding the operation speed of the accelerator pedal 4, which is a dynamic operation, as a parameter, the driver's acceleration intention can be grasped more accurately.

[0056] Next, upper limit processing and lower limit processing are performed on the acceleration characteristic Gi calculated in step S2 (step S3). As described above, in order to accurately grasp the driver's acceleration intention, the acceleration characteristic Gi is calculated. However, when the acceleration characteristic Gi exceeds the maximum acceleration Gmax that the vehicle Ve can achieve, upper limit processing (correction processing) is required. Specifically, when the acceleration characteristic Gi exceeds the maximum acceleration Gmax of the vehicle Ve, the acceleration characteristic Gi is corrected to the maximum acceleration Gmax. On the other hand, when the acceleration characteristic Gi is below the maximum acceleration Gmax, the value remains unchanged without correction. In addition, the lower limit processing becomes the basic acceleration Gb obtained in step S1.

[0057] Next, the difference Gs (= Gi - Gb) between the basic acceleration Gb and the acceleration characteristic Gi is calculated (step S4). In addition, the difference Gs is multiplied by a control gain (hereinafter also simply referred to as gain) to calculate the acceleration addition amount Gsgain (= Gs × gain) (step S5). These steps S4 and S5 are steps for multiplying the difference Gs between the desired acceleration characteristic Gi and the basic acceleration Gb by the gain, which is the reflection rate as a control amount, to obtain the final addition amount Gsgain. That is, in step S4, the difference is simply obtained, and in step S5, the magnitude of the acceleration to be added to the basic acceleration Gb is obtained. In addition, the gain, which is the reflection rate as a control amount, is obtained according to a pre-determined map, and the specific method for obtaining this gain will be described later.

[0058] Next, the acceleration addition amount Gsgain calculated in step S5 is added to the basic acceleration Gb to calculate the corrected acceleration Gh (step S6). That is, this corrected acceleration Gh becomes the final required acceleration of the driver. When expressed as a calculation formula, it is as follows.

[0059] Gh = Gb + Gsgain

[0060] Next, according to various factors such as the vehicle weight, gear ratio, tire diameter, and driving resistance of the vehicle Ve, the corrected acceleration Gh calculated in step S6 is converted into a driving force and generated as the required driving force (step S7). That is, in order to generate the finally calculated required acceleration, the driving force is determined.

[0061] Then, it is judged whether the gain becomes "0" (step S8). If it is judged that the gain becomes "0", the Figure 3 control example shown ends. That is, if the gain becomes "0", the control to increase the acceleration ends, and it returns to the basic acceleration Gb. On the contrary, if it is judged that the gain is not "0", it returns to step S2, and steps S2 to S8 are repeatedly executed until an affirmative judgment is made in this step S8.

[0062] Here, a method for obtaining a control gain that reflects the response rate as a control quantity will be described. The control gain ranges from 0 to 100% and varies according to the required acceleration. As Figure 4 shown, the response rate of the control quantity of 0% is the point A (hereinafter also referred to as recovery G) where it returns to the basic acceleration Gb, in other words, the point where the driver has no intention of accelerating. In addition, the response rate of the control quantity of 100% is the point B (hereinafter also referred to as control start G) where the control to increase the acceleration feeling starts, in other words, the point where it is judged that the driver has an intention of accelerating. Furthermore, the response rate of the control quantity = 0% is the "minimum gain" in the embodiment of the present invention, and the response rate of the control quantity = 100% corresponds to the "maximum gain" in the embodiment of the present invention. In addition, regarding the reason why the recovery G is set to be greater than 0G, the vicinity of 0G is a stable driving region where the acceleration becomes "0" and is the region where the accelerator pedal 4 is used most frequently. Therefore, good operability (the controllability of the accelerator pedal 4) is desired. Thus, it is configured that by ending the control to increase the acceleration, the acceleration when returning to the basic acceleration Gb is greater than 0G, thereby improving the operability of the accelerator pedal 4 when returning to the basic acceleration Gb.

[0063] The point A as the recovery G and the point B as the control start G are determined by the relationship between the required acceleration and the vehicle speed as Figure 5 shown. The line of the recovery G slowly increases as the vehicle speed increases. The reason for this is that as the vehicle speed becomes high, the region where the driver feels the acceleration change becomes large. On the other hand, the line of the control start G decreases as the vehicle speed increases. The reason for this is that the driver is less likely to require an increase in acceleration in the case of high vehicle speed compared to the case of low vehicle speed. Moreover, the region below the recovery G is the region where the response rate of the control quantity is 0%, the region above the control start G is the response rate of the control quantity of 100%, and the region between the recovery G and the control start G is the response rate of the control quantity of 0 to 100%.

[0064] Next, with reference to the timing chart, the changes in the required acceleration and the like in the case of executing the Figure 3 control example will be described. Figure 6 is a diagram showing the timing chart thereof, and shows the changes in the accelerator opening, the required driving force, the response rate (gain) of the control quantity, and the G addition execution flag, respectively. In addition, the Figure 6 shown timing chart shows an example of a state where the accelerator opening is constantly accelerating.

[0065] Specifically, first, the accelerator opening increases, and an increase in acceleration is required (at time point t0). As described in step S1 above, the required acceleration is greater than a predetermined value α, and the operating speed of the accelerator pedal 4 is greater than a predetermined speed β, thereby performing control to increase the acceleration. Therefore, the G addition execution flag becomes ON. Then, with the G addition execution flag becoming ON, the control quantity reflection rate becomes 100%. In addition, in the required acceleration, the dashed line represents the basic acceleration Gb, and the solid line represents the corrected acceleration Gh as the final acceleration.

[0066] Next, from time point t0 to time point t1, the basic acceleration Gb decreases. When the basic acceleration Gb is lower than the line of symbol B as the control start G, the control quantity reflection rate starts to decrease (at time point t1). That is, the control quantity reflection rate starts to drop from 100%, and the acceleration addition amount Gsgain starts to decrease.

[0067] Then, when the basic acceleration Gb further decreases and reaches the line of symbol A as the recovery G, the control quantity reflection rate becomes 0%. That is, the acceleration addition amount Gsgain becomes "0" (at time point t2). Then, with the control quantity reflection rate becoming "0", the G addition execution flag becomes OFF. In addition, as can be understood from this Figure 6 It is configured that the control quantity reflection rate becomes 0% when recovering to the basic acceleration Gb. That is, it is configured that when recovering to the basic acceleration Gb, the addition amount of acceleration converges to "0". In other words, it is configured that when recovering to the basic acceleration Gb, there is no step change in acceleration.

[0068] Then, when the control quantity reflection rate becomes "0", it recovers to the basic acceleration Gb, and when the required acceleration further decreases, the required acceleration becomes near 0G in the stable driving region. However, the acceleration near 0G has already recovered to the basic acceleration Gb, and there is no sudden change in acceleration. That is, in the embodiment of the present invention, by having the recovery G greater than 0G, the operability of the accelerator pedal 4 becomes good.

[0069] In addition, Figure 7 is Figure 6 the change in the control quantity reflection rate in the timing chart shown. As shown by the arrow, at time point t1, the control quantity reflection rate starts to drop from 100%, and at time point t2, the control quantity reflection rate reaches 0%. In addition, in Figure 8 is represented by the relationship with the vehicle speed Figure 6In the timing diagram, for the change in the required acceleration G, at time point t0, the accelerator opening increases, the required acceleration increases, and the control to increase the acceleration starts. Then, as the vehicle speed increases, the required acceleration gradually decreases. The base acceleration Gb crosses the line of symbol B which is the control start G, and the required acceleration reaches the line of symbol A which is the restored G, thus ending the control to increase the acceleration. At this time, the required acceleration reaches the restored G at a point greater than 0G.

[0070] Next, the operation in the embodiment of the present invention will be described. As described above, in the embodiment of the present invention, it is configured to execute the control to increase the acceleration when the required acceleration is large. Specifically, it is configured that when the required acceleration is greater than a predetermined value α and the operation speed of the accelerator pedal 4 is greater than a predetermined speed β, for the predetermined base acceleration Gb, the added amount Gsgain of the acceleration to be added is obtained, and the corrected acceleration Gh as the final acceleration is calculated. Then, the driving force is generated in a manner to achieve the corrected acceleration Gh. Thus, compared with the structure described in Patent Document 1 above, for example, the acceleration required by the driver can be generated more accurately.

[0071] In addition, according to the embodiment of the present invention, the operability of the accelerator operation in the stable driving region near 0G when the required acceleration decreases is improved. Figure 9 It is a diagram comparing the control example (conventional example) of Patent Document 1 above and the embodiment of the present invention. In the conventional example, when the control to increase the acceleration ends and returns to the base acceleration Gb, the acceleration becomes near 0G, and the time change rate (mutation) of the acceleration near this 0G changes. Therefore, the operability of the accelerator pedal 4 decreases. This region near 0G is the stable driving region, so it is the region where the operation frequency of the driver's accelerator pedal 4 is the highest. Therefore, it is desired to suppress the mutation near 0G. In contrast, in the embodiment of the present invention, when the control to increase the acceleration ends and returns to the base acceleration Gb, the required acceleration G is greater than 0G. Then, a mutation change occurs in the acceleration region greater than this 0G, and when the required acceleration reaches near 0G, no mutation change occurs. Therefore, in the embodiment of the present invention, the operability of the accelerator pedal 4 in the stable driving region becomes good.

[0072] In addition, as Figure 10 shown, in the embodiment of the present invention, the added amount Gsgain is calculated based on the difference Gs between the acceleration characteristic Gi and the base acceleration Gb, so the acceleration and driving force that are desired to be achieved can be appropriately generated. For example, as Figure 10As shown, in the conventional example, after the acceleration increases, the acceleration rapidly decreases, causing discomfort to the driver due to the sudden stall. In contrast, in the embodiment of the present invention, it is configured to maintain the acceleration feeling even after the acceleration increases. Therefore, it is possible to suppress the drop in the latter half of the acceleration. As a result, it is possible to generate an acceleration corresponding to the driver's intention. That is, in the embodiment of the present invention, the acceleration addition amount Gsgain can be freely controlled according to the driver's intention, so that the target driving force and acceleration can be generated.

[0073] Thus, in the embodiment of the present invention, the addition amount Gsgain of the acceleration can be controlled according to the driver's accelerator pedal operation, so it is not limited to the example of the state where the accelerator opening is constantly accelerating as described above. Figure 6 The control can be applied to multiple driving scenarios. Hereinafter, an example of applying it to the multiple driving scenarios will be described using a timing chart. Figure 3 Figure 3

[0074] Figure 11 FIG. is an example showing the timing chart, showing the changes in various parameters such as the required acceleration in the case where the driver releases the accelerator pedal 4 after acceleration. In addition, the changes in the parameters from the time point t0 to the time point t2 are substantially the same as those in the example of Figure 6 So the same parts will be briefly described.

[0075] First, as the accelerator opening increases, the required acceleration increases, and the G addition execution flag becomes ON, thereby executing the control to increase the acceleration (time point t0). In addition, by executing the control to increase the acceleration, the control amount reflection rate becomes 100%.

[0076] Next, from the time point t0 to the time point t1, the basic acceleration Gb decreases. When the basic acceleration Gb is lower than the line of the symbol B as the control start G, the control amount reflection rate starts to decrease (time point t1). That is, the control amount reflection rate starts to decrease from 100%, and the acceleration addition amount Gsgain starts to decrease. In addition, at this time point t1, the accelerator opening starts to decrease, and the change rate of the required acceleration G to decrease also becomes larger.

[0077] Then, when the accelerator opening and the basic acceleration Gb further decrease and reach the line of the symbol A as the recovery G, the control amount reflection rate becomes 0%. That is, the acceleration addition amount Gsgain becomes "0" (time point t2). Then, by the control amount reflection rate becoming "0", the G addition execution flag becomes OFF. In addition, at this time point t2, the required acceleration is restored to the basic acceleration Gb in such a way that no change in acceleration (step of acceleration) occurs, and this recovery G is greater than 0G.

[0078] Next, when the control quantity reflection rate becomes "0" and returns to the basic acceleration Gb, and further reduction in acceleration is required, the required acceleration becomes near 0G, which is the stable driving region. However, the acceleration near 0G has already returned to the basic acceleration Gb, and there is no abrupt change in acceleration (from time point t2 to time point t3). That is, by restoring G to be greater than 0G, the operability of the accelerator pedal 4 becomes good.

[0079] Then, when the accelerator opening further decreases to near "0" (time point t3), the required acceleration becomes a negative value. That is, the vehicle Ve brakes.

[0080] In addition, Figure 12 is Figure 11 the change of the control quantity reflection rate in the timing chart as shown by the arrow. At time point t1, the control quantity reflection rate starts to decrease from 100%. At time point t2, the control quantity reflection rate reaches 0%. At time point t3, it remains 0%. Additionally, in Figure 13 is represented by the relationship with the vehicle speed Figure 11 the change of the required acceleration G in the timing chart. At time point t0, the accelerator opening increases, the required acceleration increases, and the control to increase the acceleration starts. Then, as the vehicle speed increases, the required acceleration gradually decreases, and the basic acceleration Gb crosses the line of symbol B which is the control start G. Furthermore, when the accelerator pedal is released and the accelerator opening decreases, according to this change in the accelerator opening, the required acceleration G decreases, and the decreased required acceleration G crosses the line of symbol A which is the restoration G, becoming a negative acceleration. In addition, at the time point when the required acceleration G reaches the restoration G, the control to increase the acceleration ends.

[0081] Next, referring to the timing chart, the changes of each parameter when the control example of Figure 3 is applied to the situation where after releasing the accelerator pedal 4 and ending the control to increase the acceleration, the accelerator pedal 4 is further depressed again to accelerate are described. In addition, regarding the changes of each parameter, the parts that are the same as those in the above Figure 6 and Figure 11 are omitted or simplified for description. Figure 14 is the figure showing the timing chart. First, from time point t0 to time point t2, it is the same as the example of the timing chart of Figure 11 , that is, the control to increase the acceleration according to the increase of the accelerator opening is executed. After that, through the decrease of the accelerator opening and the basic acceleration Gb, the required acceleration G returns to the basic acceleration Gb (from time point t0 to time point t2). Then, the accelerator opening further decreases, and the required acceleration G becomes a negative value (time point t3).

[0082] When the accelerator pedal 4 is depressed again from this state, an increase in the required acceleration G is demanded (from time point t3 to time point t4). The required acceleration from time point t3 to time point t4 is set as the base acceleration Gb. In addition, afterwards, if the accelerator pedal 4 is further depressed and exceeds the line of the control start symbol B, the control to increase the acceleration is executed again.

[0083] In addition, Figure 15 is Figure 14 the change in the control amount reflection rate in the timing chart as shown by the arrow. At time point t1, the control amount reflection rate starts to decrease from 100%. At time point t2, the control amount reflection rate reaches 0%. Since the acceleration is negative at time point t3 and the required acceleration G increases but does not reach the control start symbol B at time point t4, the control amount reflection rate remains 0%. In addition, in Figure 16 is represented by the relationship with the vehicle speed Figure 14 the change in the required acceleration G in the timing chart. At time point t0, the accelerator opening increases, the required acceleration increases, and the control to increase the acceleration starts. Then, as the vehicle speed increases, the required acceleration gradually decreases, and the base acceleration Gb crosses the line of the symbol B as the control start G. Furthermore, when the accelerator pedal is released and the accelerator opening decreases, according to the change in the accelerator opening, the required acceleration G decreases, and the decreased required acceleration G crosses the line of the symbol A as the restoration G, ending the control to increase the acceleration. After that, the accelerator opening further decreases, the required acceleration G becomes a negative acceleration, but by further depressing the accelerator pedal again, the required acceleration G reaches the restoration G.

[0084] Next, referring to the timing chart, the changes in each parameter when the control example of Figure 3 is applied to the case where the accelerator pedal 4 is further depressed again to accelerate during the process of the control amount reflection rate decreasing by releasing the accelerator pedal 4 will be described. In addition, regarding the changes in each parameter, the parts the same as the timing charts of the above Figure 6 , Figure 11 , and Figure 14 will be omitted or simplified for description. Figure 17 is the figure showing the timing chart. First, the control to increase the acceleration according to the increase in the accelerator opening is executed (from time point t0 to time point t1).

[0085] Next, since the base acceleration Gb is lower than the line of B as the control start and the control amount reflection rate decreases from 100%, it is controlled between 0 and 100% (time point t2). Therefore, at this time point t2, the acceleration addition amount Gsgain decreases, and the difference Gs from the above base acceleration Gb becomes smaller.

[0086] Next, when the accelerator pedal 4 is depressed again from this state, the accelerator opening increases, and correspondingly, the required acceleration G also increases (from time point t2 to time point t3). When this required acceleration crosses the line B which is the start of control, the control quantity reflection rate becomes 100% again (time point t3). In addition, during the execution of this Figure 17 control, the G addition execution flag becomes ON at time point t0, and thereafter, since the required acceleration G does not return to the basic acceleration Gb, the flag remains in the ON state.

[0087] In addition, Figure 18 is Figure 17 the change of the control quantity reflection rate in the timing chart as shown. As indicated by the arrow, at time point t1, the control quantity reflection rate starts to decrease from 100%, and at time point t2, the control quantity reflection rate decreases to around 0%. When the accelerator pedal 4 is further depressed again, at time point t3, it reaches 100% again. In addition, in Figure 19 it shows the change of the required acceleration G in the timing chart of Figure 17 in relation to the vehicle speed. At time point t0, the accelerator opening increases, the required acceleration increases, and the control to increase the acceleration starts. Then, as the vehicle speed increases, the required acceleration gradually decreases. At time point t1, the basic acceleration Gb crosses the line B which is the symbol for the start of control G. Furthermore, when the accelerator pedal is released and the accelerator opening decreases, according to this change in the accelerator opening, the required acceleration G decreases (time point t2). By further depressing the accelerator pedal again from this state, it crosses the line B which is the symbol for the start of control again (time point t3).

[0088] Next, other control examples in the embodiments of the present invention will be described. In the above Figure 3 control example, it is configured to use the required driving force obtained based on the accelerator opening and the vehicle speed, and the operation speed of the accelerator pedal 4 as parameters to determine whether there is an acceleration intention and execute the control to increase the acceleration. On the other hand, when the road surface on which the vehicle Ve is traveling is not a flat road but a climbing road with a road surface gradient of a predetermined value or more, it is preferable to consider the road surface gradient to generate the driving force. When generating the same driving force on the climbing road surface as on the flat road surface, although for example the driver's acceleration intention disappears, the control to increase the acceleration may sometimes be executed. Therefore, in the embodiments of the present invention, it is configured to detect the road surface gradient in addition to the accelerator opening, the vehicle speed, and the operation speed of the accelerator pedal 4, and execute the control to increase the acceleration.

[0089] Figure 20 is a flowchart showing an example of this control. In addition, regarding the control content of each step, the structure other than the control considering the road surface gradient is the same as the above Figure 3Since the control content is the same, its description is omitted or simplified.

[0090] First, it is determined whether there is an intention to accelerate (step S100). This step S100 is substantially the same as step S1 in the Figure 3 control example, and it is judged whether the required acceleration G of the driver is greater than a predetermined value α determined in advance and whether the operation speed of the accelerator pedal 4 is greater than a predetermined speed β determined in advance. In the judgment of whether the required acceleration G is greater than the predetermined value α, in addition to the accelerator opening and the vehicle speed, the road surface gradient is also used as a parameter. In addition, the required acceleration G in this step S100 is a static acceleration corresponding to the above-mentioned basic acceleration Gb. When a negative judgment is made in this step S100, that is, when the required acceleration G is equal to or less than the predetermined value α, or when the operation speed of the accelerator pedal 4 is equal to or less than the predetermined speed β, it is judged that there is no intention of acceleration requirement, and the subsequent control is not executed, and the process is temporarily ended Figure 20 the control example shown.

[0091] On the contrary, when an affirmative judgment is made in this step S100, that is, when the required acceleration G is greater than the predetermined value α and the operation speed of the accelerator pedal 4 is greater than the predetermined speed β, it is judged that there is an intention of acceleration requirement, and the acceleration characteristic Gi for realizing the acceleration feeling according to the driver's intention is calculated (step S200). This step S200 is substantially the same as step S2 in the Figure 3 control example, and this acceleration characteristic Gi is a dynamic acceleration relative to the static acceleration in the above step S100. The required acceleration G in the above step S100 is uniquely determined according to the accelerator opening, the vehicle speed, and the road surface gradient. In contrast, in addition to the accelerator opening, the vehicle speed, and the road surface gradient, the operation speed of the accelerator pedal 4 is also used as a parameter to calculate the acceleration characteristic Gi. That is, by adding the operation speed of the accelerator pedal 4, which is a dynamic operation, as a parameter, the driver's acceleration intention can be grasped more accurately.

[0092] Next, upper limit processing and lower limit processing are performed on the acceleration characteristic Gi calculated in step S200 (step S300). It is the same as Figure 3The step S3 of the control example is substantially the same. As described above, in order to accurately grasp the driver's acceleration intention, the acceleration characteristic Gi is calculated. However, when the acceleration characteristic Gi exceeds the maximum acceleration Gmax that the vehicle Ve can achieve, upper limit processing (correction processing) is required. Specifically, when the acceleration characteristic Gi exceeds the maximum acceleration Gmax of the vehicle Ve, the acceleration characteristic Gi is corrected to the maximum acceleration Gmax. On the other hand, when the acceleration characteristic Gi is below the maximum acceleration Gmax, it is maintained without correction. In addition, the lower limit processing becomes the basic acceleration Gb obtained in step S1. Further, the maximum acceleration Gmax is obtained based on the vehicle speed and the road surface gradient at 100% accelerator opening.

[0093] Next, the difference Gs (= Gi - Gb) between the basic acceleration Gb and the acceleration characteristic Gi is calculated (step S400). Additionally, the difference Gs is multiplied by a gain to calculate the acceleration addition amount Gsgain (= Gs × gain) (step S500). This step S400 and step S500 are the same as Figure 3 steps S4 and S5 of the control example, so detailed description is omitted.

[0094] Next, the acceleration addition amount Gsgain calculated in step S500 is added to the basic acceleration Gb to calculate the corrected acceleration Gh (step S600). This is the same as Figure 3 step S6 of the control example, that is, this corrected acceleration Gh becomes the final required acceleration of the driver.

[0095] Next, based on various factors such as the vehicle weight, gear ratio, tire diameter, and driving resistance of the vehicle Ve, the corrected acceleration Gh calculated in step S600 is converted into a driving force, and the required driving force is generated (step S700). This is the same as Figure 3 step S7 of the control example, that is, the driving force for generating the finally calculated required acceleration is determined.

[0096] Then, it is judged whether the gain becomes "0" (i.e., whether the control amount reflection rate becomes 0%) (step S800). If it is judged that the gain becomes "0", the Figure 20 shown control example ends. This is the same as Figure 3 step S8 of the control example, that is, if the gain becomes "0", the control to increase the acceleration ends, and it returns to the basic acceleration Gb. On the contrary, if it is judged that the gain is not "0", it returns to step S200, and steps S200 to S800 are repeatedly executed until an affirmative judgment is made in this step S800.

[0097] In this way, in Figure 20In the control example, it is configured to set the required acceleration in consideration of the road surface gradient. Figure 21 This is a timing chart comparing the case of executing control to increase the acceleration without considering the road surface gradient (conventional example) and the case of executing control to increase the acceleration considering the road surface gradient. In Figure 21 In the conventional example shown on the left side of the drawing paper of , at time point t10', the accelerator opening is increased, the G addition execution flag becomes ON, and the control to increase the acceleration starts. Next, starting from time point t11', the road surface gradient starts to increase from 0%, and at time point t12', the road surface gradient becomes γ%. Then, during the transition period from time point t12' to t13', the required acceleration crosses the 0G line at the γ% uphill slope, and at time point t13', it returns to the basic acceleration Gb. That is, during the transition period between time points t12' and t13', although the acceleration intention disappears, at time point t13' which is a deceleration region, it returns to the basic acceleration Gb. Therefore, it becomes a control that does not conform to the driver's acceleration intention.

[0098] In contrast, in Figure 21 In the embodiment of the present invention shown on the right side of the drawing paper of , at time point t10, the accelerator opening is increased, the G addition execution flag becomes ON, and the control to increase the acceleration starts. Next, starting from time point t11, the road surface gradient starts to increase from 0%, and at time point t12, the road surface gradient becomes γ%. Then, it is configured to return to the basic acceleration Gb at time point t12 when the road surface gradient becomes γ%. That is, on the uphill road surface, when the acceleration of the vehicle Ve becomes 0G, it is determined that the acceleration intention disappears. In other words, in the operation amount of the predetermined accelerator pedal 4, the region where the acceleration becomes "0" in the case of having a road surface gradient (above the predetermined gradient) is larger than the region where the acceleration becomes "0" in the case of having no road surface gradient (less than the predetermined gradient). In this way, in the embodiment of the present invention, by considering the resistance amount of the road surface gradient and correcting the return to the basic acceleration Gb according to the situation of the flat road surface, it is possible to perform control corresponding to the driver's acceleration intention. That is, it is possible to appropriately perform the control of the driving force corresponding to the driver's acceleration intention.

Claims

1. A driving force control device for a vehicle, comprising a controller that outputs a driving force command signal based on a required acceleration obtained when a driver operates an accelerator pedal, characterized in that the controller is configured to calculate a basic acceleration uniquely determined by the operation amount of the accelerator pedal and the vehicle speed, when the basic acceleration is greater than a predetermined value and the operation speed of the accelerator pedal is greater than a predetermined speed, obtain a corrected acceleration obtained by increasing and correcting the basic acceleration, and control the driving force in such a way as to generate the corrected acceleration, the corrected acceleration is calculated based on the basic acceleration and the added amount of acceleration relative to the basic acceleration, configured to determine the added amount of acceleration by the difference between the dynamic acceleration and the basic acceleration and a predetermined control gain, and the dynamic acceleration is obtained based on the operation amount of the accelerator pedal, the vehicle speed, and the operation speed of the accelerator pedal.

2. The driving force control device for a vehicle according to claim 1, characterized in that the control gain is set based on the operation amount of the accelerator pedal and the vehicle speed, configured to be set to the maximum gain when the required acceleration is greater than the predetermined value, and set to the minimum gain when the required acceleration is the basic acceleration.

3. The driving force control device for a vehicle according to claim 1, characterized in that configured to, when the required acceleration is greater than the basic acceleration and less than the predetermined value, the control gain continuously varies according to the required acceleration.

4. The driving force control device for a vehicle according to claim 2 or 3, characterized in that the controller reduces the control gain according to the operation amount of the accelerator pedal, and when the control gain is reduced and the required acceleration is restored from the corrected acceleration to the basic acceleration, controls the driving force in such a way that the acceleration when restored to the basic acceleration is greater than "0".

5. The driving force control device for a vehicle according to claim 1, characterized in that the controller obtains the road surface gradient on which the vehicle travels, calculates the required acceleration based on the operation amount of the accelerator pedal, the vehicle speed, and the road surface gradient, configured to calculate the added amount of acceleration using a control gain determined based on the operation amount of the accelerator pedal, the vehicle speed, and the road surface gradient.

6. The driving force control device for a vehicle according to claim 5, characterized in that the region where the acceleration is "0" when the road surface gradient in the predetermined operation amount of the accelerator pedal is above the predetermined gradient is larger than the region where the acceleration is "0" when the road surface gradient is less than the predetermined gradient.

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