JP2015068169A - Vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To early recover a range to a retreat state even if slip-down occurs in an R-range, and to exactly prevent the jump-put and start, and the abrupt rearward acceleration of a vehicle.SOLUTION: A drive force control unit 20 sets an upper limit vehicle speed Vmax to a vehicle speed which is higher than a vehicle speed Vs at which an engine 2 is stalled when a vehicle slips down in a case that an R-range is selected, sets target acceleration Axt corresponding to an actual vehicle speed V on the basis of a vehicle-speed/target acceleration characteristic in which the target acceleration Axt is set to a value larger than zero in a vehicle speed region which does not exceed the upper limit vehicle speed Vmax, feed-back controls an engine drive force by outputting it to an engine control device 21 on the basis of the target acceleration Axt, on the other hand, sets target deceleration Dect corresponding to the actual vehicle speed V on the basis of a vehicle-speed/target deceleration characteristic in a vehicle speed region which exceeds the upper limit vehicle speed Vmax, and feed-back controls brake hydraulic pressure Pb by outputting it to a brake control device 22 on the basis of the target deceleration Dect.

Description

  In particular, the present invention relates to a vehicle control device that appropriately starts when a reverse range is selected in an automatic transmission vehicle.

  Conventionally, various techniques for ensuring the safety of a vehicle due to an operation error of a driver's shift lever or an erroneous depression of an accelerator pedal have been proposed. For example, in Japanese Patent Application Laid-Open No. 2009-126352 (hereinafter referred to as Patent Document 1), the upper limit acceleration at the time of reverse, which is considered to be highly likely to cause an erroneous operation of the shift lever or an erroneous stepping on the pedal, is set to a low value. A technology of a vehicle travel control device that sets an upper limit acceleration to a higher value as the vehicle speed increases and limits the vehicle acceleration within the upper limit acceleration is disclosed.

JP 2009-126352 A

  However, in the travel control device disclosed in Patent Document 1 described above, the upper limit acceleration is set to a lower value as the speed is lower. Therefore, when the vehicle moves backward with a high gradient, the driving force is temporarily reduced. If the vehicle moves forward due to a shortage, that is, the vehicle slides down, there is a problem that the driving force necessary to recover from the sliding state cannot be obtained until the vehicle reaches a predetermined vehicle speed, and the vehicle cannot recover from the sliding state at an early stage. . Even if the range position is reverse and the vehicle is not in a downhill state, if the driver depresses the accelerator pedal strongly and accidentally, it will be suppressed within the set upper limit acceleration, but the higher the speed, the higher the upper limit acceleration will be. Since it is set, the speed gradually increases in spite of the backward movement, and there is a possibility of jumping backward at a high speed.

  The present invention has been made in view of the above circumstances, and when the range position is in the reverse state, it can return to the retracted state at an early stage even if the sliding occurs, and the backward jump start is suppressed. It is an object of the present invention to provide a vehicle control device that can do the above.

  According to an aspect of the present invention, a vehicle control apparatus sets a target acceleration based on a vehicle speed with reference to a target acceleration map when a range position detecting unit that detects a range position and a reverse range are selected. In a vehicle control device comprising acceleration / deceleration control means for calculating a target engine torque so that the acceleration becomes a target acceleration and engine control means for controlling the engine based on the target engine torque, the target acceleration in the target acceleration map is The upper limit vehicle speed set to a vehicle speed higher than the vehicle speed at which the engine stalls is set to 0, and is set to a positive value that decreases as the vehicle speed increases.

  According to the vehicle control device of the present invention, when the range position is in the reverse state, it is possible to return to the reverse state at an early stage even if the sliding occurs, and to prevent the vehicle from jumping backward and starting. It becomes possible.

It is explanatory drawing which shows schematic structure of the vehicle which concerns on one Embodiment of this invention. It is a functional block diagram of a driving force control unit according to an embodiment of the present invention. 3 is a flowchart of a reverse travel control program according to an embodiment of the present invention. It is explanatory drawing of the detected value of a road surface gradient and true road surface gradient estimation which concerns on one Embodiment of this invention. An example of the vehicle speed-target acceleration / deceleration characteristic according to the embodiment of the present invention is shown, FIG. 5 (a) shows the vehicle speed / target acceleration characteristic, and FIG. 5 (b) shows the vehicle speed / target acceleration characteristic. It is a detailed explanatory view of a vehicle speed-target acceleration characteristic according to an embodiment of the present invention. FIG. 7A shows an example of a vehicle speed-target acceleration / deceleration characteristic different from FIG. 5 according to the embodiment of the present invention, FIG. 7A shows a vehicle speed-target acceleration characteristic, and FIG. 7B shows a vehicle speed-target acceleration characteristic. Show properties. FIGS. 8A and 8B show examples of vehicle speed-target acceleration / deceleration characteristics different from FIGS. 5 and 7 according to the embodiment of the present invention, FIG. 8A shows vehicle speed-target acceleration characteristics, and FIG. 8B shows vehicle speed-target acceleration characteristics. The deceleration characteristics are shown.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In FIG. 1, reference numeral 1 denotes a vehicle, and the driving force by an engine 2 disposed at the front of the vehicle is transmitted from an automatic transmission device (including a torque converter and the like) 3 behind the engine 2 via a transmission output shaft 3a. It is transmitted to the center differential device 4, and is input from the center differential device 4 to the rear wheel final reduction device 8 via the rear drive shaft 5, the propeller shaft 6, and the drive pinion 7, while from the center differential device 4 to the front drive It is input to the front wheel final reduction gear 10 via the shaft 9. Here, the automatic transmission device 3, the center differential device 4, the front wheel final reduction gear device 10 and the like are integrally provided in a case (not shown).

  The driving force input to the rear wheel final reduction device 8 is transmitted to the left rear wheel 12rl through the rear wheel left drive shaft 11rl and to the right rear wheel 12rr through the rear wheel right drive shaft 11rr, while the front wheel final reduction device. The driving force input to 10 is transmitted to the left front wheel 12fl via the front wheel left drive shaft 11fl and to the right front wheel 12fr via the front wheel right drive shaft 11fr.

  Reference numeral 13 denotes a brake drive unit of the vehicle. A master cylinder 15 connected to a brake pedal 14 operated by a driver is connected to the brake drive unit 13. When the driver operates the brake pedal 14, the master cylinder 15 is connected. 15, through the brake drive unit 13, each wheel cylinder of four wheels 12 fl, 12 fr, 12 rl, 12 rr (left front wheel wheel cylinder 16 fl, right front wheel wheel cylinder 16 fr, left rear wheel wheel cylinder 16 rl, right rear wheel wheel cylinder 16 rr) Brake pressure is introduced, which brakes the four wheels.

  The brake drive unit 13 is a hydraulic unit including a pressurizing source, a pressure reducing valve, a pressure increasing valve, and the like, and in response to an input signal from the brake control device 22, each wheel cylinder 16fl, 16fr, 16rl, 16rr is The brake pressure can be introduced independently of each other.

  An engine control device 21 as engine control means for controlling the engine 2 and a brake control device 22 for controlling the brake drive unit 13 are connected to the driving force control unit 20. The driving force control unit 20 is selected by a driver, a vehicle speed sensor 31 that detects a vehicle speed V composed of a multiphase wheel speed sensor that can also determine whether the vehicle is traveling forward or backward. Inhibitor switch 32 as a range position detection means for detecting the range position of the select lever (not shown) (each range position such as drive “D”, reverse “R”, neutral “N”, etc.), detects the road slope value θks Road surface gradient sensor 33, engine speed sensor (not shown), ON / OFF of reverse travel control at the time of reverse start, which will be described later, and the driver selects the upper limit vehicle speed from three types of vehicle speeds in reverse travel control Sensors and switches such as a vehicle speed upper limit setting switch 34 to be set manually are connected. As a means for detecting the range position of the select lever, a signal from a transmission control unit that controls the transmission may be used in place of the inhibitor switch 32.

  Then, when the R range is selected, the driving force control unit 20 calculates the target acceleration Axt and the target deceleration Dect when the R range is selected, so that the engine control device 21 does not exceed the upper limit vehicle speed Vmax. The target engine torque TEt and the target brake hydraulic pressure Pb are output to the brake control device 22.

  Here, the upper limit vehicle speed Vmax is set to a vehicle speed higher than an engine vehicle speed Vs (for example, 10 km / h) that is a vehicle speed at which the engine is stalled when the vehicle is in a sliding state. The target acceleration Axt is calculated from the vehicle speed V with reference to a target acceleration map in which the relationship between the vehicle speed V and the target acceleration Axt is stored. This target acceleration map is set to a positive value so that the characteristic decreases as the vehicle speed V increases and becomes 0 at the upper limit vehicle speed Vmax. On the other hand, the target deceleration Dect is calculated from the target deceleration map according to the vehicle speed V when the vehicle speed V exceeds the upper limit vehicle speed Vmax. Thus, the driving force control unit 20 is provided with a function as acceleration / deceleration control means.

  As shown in FIG. 2, the driving force control unit 20 mainly includes a host vehicle acceleration calculation unit 20a, a true road gradient value calculation unit 20b, a forward / reverse determination unit 20c, and an acceleration / deceleration control unit 20d.

  The own vehicle acceleration calculating unit 20a receives the vehicle speed V from the vehicle speed sensor 31, calculates the own vehicle acceleration Ax based on the temporal change (differentiation) of the vehicle speed V, and outputs the calculated vehicle acceleration Ax to the acceleration / deceleration control unit 20d.

  The true road surface gradient value calculation unit 20 b receives the road surface gradient value θks detected from the road surface gradient sensor 33. Then, for example, referring to the map shown in FIG. 4 or the like that has been set in advance, the detected road surface gradient value θks is calculated by taking the road surface gradient value that takes into account the maximum error that can be generated into the true road surface gradient value. (Estimated gradient value) θke is set and output to the acceleration / deceleration control unit 20d.

  Generally, an error is included in the value of the road surface gradient detected by the road surface gradient sensor 33 or the like depending on the loading state of the vehicle. For example, as shown in FIG. 4, when the road surface gradient value θks detected by the road surface gradient sensor 33 or the like, the true road surface gradient value (estimated gradient value θke) estimated at the detected gradient value θ1 is θL (in the figure). , The value on the “θk1” line) to θH (the value on the “θk2” line in the figure) (in the example of FIG. 4, the road gradient is 0 degrees, and the rear of the vehicle 1 is It is a figure when the sign in the case of becoming high is “+”). Therefore, when the shift position is the “R” range position and the detected road surface gradient value θks is θ1, and the true gradient value is θL, the limit of the driving force is too small and the vehicle 1 suddenly moves backward. It will start. On the contrary, when the true gradient value is θH, the limit of the driving force is too large and the vehicle 1 falls down. The true road surface gradient value calculation unit 20b according to the embodiment of the present invention considers the road surface gradient value in consideration of the maximum error that may occur with respect to the detected road surface gradient value θks, that is, on the “θk2” line in FIG. The value (θH) is adopted as the initial value of the estimated gradient value.

  The forward / reverse determination unit 20c receives the vehicle speed V from the vehicle speed sensor 31, determines whether the vehicle 1 is moving forward or backward, and outputs the determination result to the acceleration / deceleration control unit 20d. Thus, the forward / reverse determination unit 20c is provided as a forward / reverse determination unit.

  The acceleration / deceleration control unit 20d receives the vehicle speed V from the vehicle speed sensor 31, receives the shift position selected by the driver from the inhibitor switch 32, and turns ON the reverse travel control at the time of reverse start from the vehicle speed upper limit setting switch 34. An OFF signal and an upper limit vehicle speed, which will be described later in the reverse traveling control selected by the driver, are input, the vehicle acceleration Ax is input from the vehicle acceleration calculation unit 20a, and the estimated gradient is calculated from the true road surface gradient value calculation unit 20b. The value θke is input, and the determination result as to whether the vehicle is moving forward or backward is input from the forward / reverse determination unit 20c.

  When the reverse travel control at the time of reverse start is turned on and the R range is selected, the target acceleration Axt corresponding to the vehicle speed V is set with reference to the target acceleration map (FIG. 5A). In this target acceleration map, a positive target acceleration Axt is set so as to decrease as the vehicle speed V increases and to become 0 at the upper limit vehicle speed Vmax set higher than the engine stall vehicle speed Vs. After calculating the target acceleration Axt, the final target acceleration is calculated according to the deviation between the target acceleration Axt and the actual acceleration Ax, the final target acceleration is multiplied by the vehicle weight, and various running resistances are added to the tire. The target engine torque TEt is calculated by multiplying the torque conversion coefficient such as radius, total gear ratio, torque converter ratio, etc., and output to the engine control device 21. Various running resistances include gradient resistance. The gradient resistance used here is an estimated gradient value θke that does not cause the vehicle 1 to slide down even if the error from the true road surface gradient calculation unit 20b is taken into consideration. It is.

  On the other hand, when the vehicle speed V exceeds the upper limit vehicle speed Vmax, the target deceleration Dect corresponding to the actual vehicle speed V is obtained by referring to a target deceleration map (FIG. 5B) corresponding to the preset vehicle speed V. Set. Then, the final target deceleration is calculated according to the deviation between the target deceleration Dect and the actual acceleration (deceleration) Ax, the brake hydraulic pressure Pb is calculated from the final target deceleration, and output to the brake control device 22. . In order to improve drivability, the target deceleration Dect may be corrected to a lower value as the estimated gradient value θke is lower, for example, according to the estimated gradient value θke.

  As described above, in the embodiment of the present invention, the target acceleration map decreases as the vehicle speed V increases and becomes 0 at the upper limit vehicle speed Vmax. Even if the pedal is stepped on strongly, even if the limit of the driving force is weak due to an error in the estimated gradient value or the like, the rearward jumping out can be suppressed. Even if the vehicle is lowered due to insufficient driving force due to an error in the estimated gradient value or the like, the upper limit vehicle speed Vmax is set higher than the engine stall vehicle speed Vs, and the target acceleration Axt is equal to the vehicle speed V. Since it is set to a positive value so that it decreases with increasing and becomes 0 at the upper limit vehicle speed Vmax, it is possible to effectively prevent sliding down. That is, for example, as shown by the broken line in FIG. 6, if the target acceleration Axt in the target acceleration map is set to 0 at a value Vmaxa lower than the stall vehicle speed Vs (characteristic 2), at a vehicle speed V lower than Vmaxa, If the accelerator pedal is depressed, it is possible to prevent sliding down. However, if a slip occurs at a vehicle speed V greater than Vmaxa, the target acceleration Axt becomes 0 even if the driver depresses the accelerator pedal, and the vehicle continues to fall from Vmaxa to the engine speed Vs that leads to engine stall. , You will not be able to recover from that state. On the other hand, in the present invention, the positive target acceleration Axt is set so as to be 0 at the upper limit vehicle speed Vmax set higher than the stall vehicle speed Vs, so that it is possible to recover from the slip-down state. Further, in the present invention, the target acceleration Axt is set to decrease as the vehicle speed V increases, in other words, the target acceleration Axt is set to increase as the vehicle speed V decreases. Therefore, as the vehicle recovers from the slip, that is, as the vehicle decelerates, the target acceleration Axt increases, so that the target engine torque TEt increases abruptly and it is possible to recover quickly from the slip state. If the vehicle speed V does not recover from the slipped-down state and the vehicle speed V exceeds the engine stalled vehicle speed Vs, engine stall occurs. At that time, the reverse travel control is forcibly turned off (released), so the slippage is reduced. It will be. Such a situation is normally not considered in the normal state of the system, but is considered to be a system abnormality such as a failure of the road surface gradient sensor, so the driver is notified of the abnormal state.

  Next, the reverse travel control executed by the driving force control unit 20 will be described with reference to the flowchart of FIG. This reverse travel control program is executed when the reverse travel control at the time of reverse start is turned on and the R range is selected.

  First, in step (hereinafter abbreviated as “S”) 101, the vehicle acceleration calculation unit 20a calculates the vehicle acceleration Ax.

  Next, in S102, the true road surface gradient value calculation unit 20b calculates the true road surface gradient value (estimated gradient value) θke.

  Next, it progresses to S103 and the upper limit vehicle speed Vmax selected by the driver is read.

  Next, in S104, the target acceleration Axt corresponding to the vehicle speed V is set with reference to the target acceleration map.

  Next, the process proceeds to S105, where a target deceleration Dect corresponding to the vehicle speed V is set with reference to the target deceleration map.

  Next, proceeding to S106, the final target acceleration is calculated according to the deviation between the target acceleration Axt and the actual acceleration Ax. Then, the target engine torque TEt is calculated by multiplying the final target acceleration by the vehicle weight, adding various running resistances, and then multiplying by a torque conversion coefficient such as tire radius, total gear ratio, torque converter ratio, etc. Output to the device 21.

  In step S107, the final target deceleration is calculated according to the deviation between the target deceleration Dect and the actual acceleration (deceleration) Ax, and the brake fluid pressure Pb is calculated from the final target deceleration. 22 and exit the program.

  Thus, according to the embodiment of the present invention, when the R range is selected, the upper limit vehicle speed Vmax is set to a vehicle speed higher than the vehicle speed Vs at which the engine 2 stalls when the vehicle slides down, and the upper limit is set. A target acceleration Axt corresponding to the actual vehicle speed V is set based on the target acceleration characteristic corresponding to the vehicle speed V in which the target acceleration Axt is set to a value larger than 0 in a vehicle speed region that does not exceed the vehicle speed Vmax, and the target acceleration Axt is set. Based on the target deceleration characteristic corresponding to the vehicle speed V, in the vehicle speed region exceeding the upper limit vehicle speed Vmax, the target deceleration corresponding to the actual vehicle speed V is output to the engine control device 21 based on feedback control of the engine driving force. Dect is set and output to the brake control device 22 based on the target deceleration Dect to feedback control the brake fluid pressure Pb. For this reason, even in the R range, even if a slippage occurs, the vehicle can return to the retracted state at an early stage, and the driving force of the backward start can be appropriately limited to jump out and start backward, It is possible to reliably prevent sudden acceleration.

  In the embodiment of the present invention, as shown in FIG. 5, the target acceleration map is set to have the same characteristics when moving backward and moving forward (sliding down state). For example, as shown in FIGS. Alternatively, a target acceleration map having different characteristics for reverse travel and forward travel may be set.

  In the example of FIG. 7A, the target acceleration (broken line) at the time of forward movement is set to a higher value than the target acceleration (solid line) at the time of backward movement based on a constant vehicle speed. The upper limit vehicle speed Vmaxf of the target acceleration is also set to a value higher than the upper limit vehicle speed Vmaxr of the target acceleration during reverse travel. That is, when it is determined that the vehicle is moving forward during the R range, the vehicle 1 is in the falling state, so that the target acceleration is set high in order to quickly return from the sliding state.

  In the example of FIG. 7B, the forward target deceleration (broken line) and the reverse target acceleration (solid line) set corresponding to the forward target acceleration and the reverse target acceleration shown in FIG. ) And the target deceleration is set to be gradually increased from the respective upper limit vehicle speeds Vmaxf and Vmaxr.

  Also, in the example of FIG. 8A, the target acceleration (broken line) at the time of forward movement is set to a higher value than the target acceleration (solid line) at the time of backward movement based on a constant vehicle speed. The upper limit vehicle speed Vmaxf of the target acceleration at the time and the upper limit vehicle speed Vmaxr of the target acceleration at the time of reverse travel are set to the same value. In the example of FIG. 8A as well as in FIG. 7A, when it is determined that the vehicle is in the forward state during the R range, it is a case where the vehicle 1 is falling down. In order to recover, the target acceleration is set high.

  In the example of FIG. 8B, the forward target deceleration (broken line) and the reverse target acceleration (solid line) set corresponding to the forward target acceleration and the reverse target acceleration shown in FIG. ) And the target deceleration is set to be gradually increased from the upper limit vehicle speed Vmaxf (Vmaxr).

  In the embodiment of the present invention, the upper limit vehicle speed Vmax is shown as an example that can be arbitrarily set from among three types by the driver, but may be a preset (one type) fixed value, or It can be set from two types, or can be selected more analogly.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Engine 3 Automatic transmission 12fl, 12fr, 12rl, 12rr Wheel 13 Brake drive part 16fl, 16fr, 16rl, 16rr Wheel cylinder 20 Driving force control unit 20a Own vehicle acceleration calculation part 20b True road surface gradient value calculation part 20c Before and after Advance determination part (forward / reverse determination means)
20d Acceleration / deceleration control unit (acceleration / deceleration control means)
21 Engine control device (engine control means)
22 Brake control device 31 Vehicle speed sensor 32 Inhibitor switch (range position detection means)
33 Road surface gradient sensor 34 Vehicle speed upper limit setting switch

Claims (2)

Range position detecting means for detecting the range position;
When the reverse range is selected, an acceleration / deceleration control unit that sets a target acceleration based on the vehicle speed with reference to the target acceleration map and calculates a target engine torque so that the actual acceleration becomes the target acceleration, and the target engine torque In a vehicle control device comprising engine control means for controlling the engine based on
The target acceleration in the target acceleration map is set to 0 at the upper limit vehicle speed set to a vehicle speed higher than the vehicle speed at which the engine stalls, and is set to a positive value that decreases as the vehicle speed increases. Vehicle control device. It has a forward / reverse determination means for determining whether the vehicle is moving forward or backward,
The target acceleration map includes a target acceleration map for forward travel and a target acceleration map for reverse travel, and the vehicle moves forward based on the determination result of the forward / reverse travel of the vehicle when the reverse range is selected by the range position detecting means. 2. The vehicle control apparatus according to claim 1, wherein the target acceleration map at the time of forward movement is referred to when the vehicle is moving forward, and the target acceleration map at the time of backward movement is referred to when the vehicle is moving backward. .

Images