Vehicle control device

Abstract

To provide a controller for a vehicle capable of suppressing an engine stall due to change in a shift range right after starting of an engine.SOLUTION: An ECU starts an engine (step S5) on a predetermined engine start condition (step S3) that a stepping-in quantity of a brake pedal is equal to or larger than a predetermined engine start threshold. The ECU releases a shift lock (step S7) on a predetermined shift lock release condition including a condition (step S6) that the stepping-in quantity of the brake pedal is equal to or larger than a predetermined shift lock release threshold. The shift lock release threshold is set to be larger than the engine start threshold. The ECU preferably releases the shift lock a predetermined time after the stepping-in quantity of the brake pedal reaches the shift lock release value or larger.SELECTED DRAWING: Figure 4

Description

[Technical Field]

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

[0002] Generally, vehicles equipped with an automatic transmission are equipped with a shift lock device that prevents the shift selector from being operated from a shift range that allows the engine to start to another shift range. For example, when the ignition switch is in the ON position and the brake pedal is depressed, the shift lock is released, allowing the shift selector to be operated from a P range or the like to a D range or the like.

[0003] A known example of this type of shift lock device control device is described in Patent Document 1. Patent Document 1 discloses a shift lock control device that prohibits changing the shift position when the engine is started until the transmission is ready. As a result, the device described in Patent Document 1 can prevent the vehicle from becoming immobile or the engine from racing when the engine is started. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-229474 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, when the driver starts the engine and the engine begins to rotate, if the shift lock is released and the shift selector is changed to a driving range such as D range before the engine speed, engine torque, etc. increase and stabilize, the load acting on the engine from the transmission side may cause the engine to stall.

[0006] The technology described in Patent Document 1 uses a brake pedal switch to detect brake pedal depression, and this detection is used as a condition for starting the engine and releasing the shift lock. However, the engine starts and the shift lock is easily released when the brake pedal is depressed relatively lightly without requiring a large amount of force.

[0007] Therefore, with the technology described in Patent Document 1, the driver can easily start the engine and operate the shift selector in succession by simply lightly depressing the brake pedal.If the shift selector is operated to a driving range such as D range immediately after the engine begins to start, the engine has not yet fully exploded and the torque generated is small, so there is a risk of the engine stalling due to the load of the transmission acting on the engine.

[0008] The present invention has been made in consideration of the above-mentioned circumstances, and aims to provide a vehicle control device that can suppress engine stall caused by changing the shift range immediately after starting the engine. [Means for solving the problem]

[0009] In order to achieve the above-mentioned object, the present invention provides a vehicle control device mounted on a vehicle that includes a shift selector operated by a driver to select one of a plurality of shift ranges, and a shift lock unit that performs a shift lock to prevent operation of the shift selector from a shift range that allows the engine to be started to another shift range, the vehicle control device including a brake sensor that detects the amount of depression of the brake pedal, an engine control unit that starts the engine when predetermined engine start conditions are met, including the amount of depression of the brake pedal being equal to or greater than a predetermined engine start threshold, and a shift lock control unit that releases the shift lock by the shift lock unit when predetermined shift lock release conditions are met, including the amount of depression of the brake pedal being equal to or greater than a predetermined shift lock release threshold, wherein the shift lock release threshold is greater than the engine start threshold. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a vehicle control device that can suppress engine stall caused by changing the shift range immediately after starting the engine. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a vehicle equipped with a control device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing a selector module provided in a vehicle equipped with a control device according to an embodiment of the present invention. [Figure 3] FIG. 3 is a diagram showing the correlation between the brake pedal force and the brake stroke in the vehicle control device according to one embodiment of the present invention. [Figure 4] FIG. 4 is a flowchart showing the flow of the shift lock control operation executed by the vehicle control device according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] A vehicle control device according to one embodiment of the present invention is mounted on a vehicle including a shift selector operated by a driver to select one of a plurality of shift ranges, and a shift lock unit that performs a shift lock to prevent operation of the shift selector from a shift range that allows engine start to another shift range, the vehicle control device also including a brake sensor that detects a brake pedal depression amount, an engine control unit that starts the engine when predetermined engine start conditions are met, including the brake pedal depression amount being equal to or greater than a predetermined engine start threshold, and a shift lock control unit that releases the shift lock performed by the shift lock unit when the predetermined shift lock release condition is met, including the brake pedal depression amount being equal to or greater than a predetermined shift lock release threshold, the shift lock release threshold being greater than the engine start threshold. As a result, the vehicle control device according to the one embodiment of the present invention can suppress engine stall caused by changing the shift range immediately after starting the engine. [Example]

[0013] A vehicle control device according to an embodiment of the present invention will now be described with reference to the drawings. Fig. 1 is a schematic diagram of a vehicle 1 equipped with a vehicle control device according to an embodiment of the present invention.

[0014] As shown in FIG. 1, the vehicle 1 includes an engine 2, an automatic transmission 3, a torque converter 4, drive wheels 5, a selector module 6, and an ECU (Electronic Control Unit) 10 as an engine control unit and a shift lock control unit.

[0015] The engine 2 is formed with a plurality of cylinders. In this embodiment, the engine 2 is configured to perform a series of four strokes for each cylinder, including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke.

[0016] The automatic transmission 3 changes the speed of the rotation output from the engine 2 and transmits it to the drive wheels 5 via a drive shaft 51 to drive the drive wheels 5. The automatic transmission 3 of this embodiment is configured by, for example, a transmission equipped with a planetary gear mechanism.

[0017] The torque converter 4 is provided between the engine 2 and the automatic transmission 3, and transmits the engine torque input from the engine 2 to the automatic transmission 3 via the working fluid. When the vehicle 1 is stopped, the torque converter 4 amplifies the engine torque input from the engine 2 and transmits it to the automatic transmission 3.

[0018] The selector module 6 includes a shift selector 61, a shift lock unit 62, and a sensor 63. The selector module 6 is provided near the driver's seat of the vehicle 1, and is electrically connected to the ECU .

[0019] The selector module 6 outputs a signal indicating the range selected by the shift selector 61 to the ECU 10. The ECU 10 controls the automatic transmission 3 based on the signal indicating the range input from the selector module 6.

[0020] The shift selector 61 is configured as a shift lever operated by the driver to select one of a plurality of shift ranges. For example, as shown in FIG. 2, the shift selector 61 is operated along a straight-type shift pattern 60 provided on the selector module 6.

[0021] The multiple ranges provided in this embodiment include a parking range (hereinafter referred to as "P range") indicated by "P" in Fig. 2, a reverse range (hereinafter referred to as "R range") indicated by "R" in Fig. 2, a neutral range (hereinafter referred to as "N range") indicated by "N" in Fig. 2, a drive range (hereinafter referred to as "D range") indicated by "D" in Fig. 2, and a manual range (hereinafter referred to as "M range") indicated by "M" in Fig. 2. Fig. 2 shows a state in which the shift selector 61 is positioned in the P range.

[0022] When the P range is selected by the shift selector 61, a neutral state is established in the automatic transmission 3, and a parking brake (not shown) is activated. When the N range is selected by the shift selector 61, a neutral state is established in the automatic transmission 3. In other words, when the P range or N range is selected, the automatic transmission 3 is in a neutral state, and power transmission is cut off inside the automatic transmission 3, and no load is applied to the engine 2 from the automatic transmission 3, which is connected via the torque converter 4.

[0023] In this embodiment, the P range constitutes a shift range that allows starting of the engine 2. Note that the P range and the N range may constitute a shift range that allows starting of the engine 2.

[0024] When the D range or M range is selected by the shift selector 61, a forward gear is formed in the automatic transmission 3. When the R range is selected by the shift selector 61, a reverse gear is formed in the automatic transmission 3. When the D range, M range, or R range is selected, a load from the automatic transmission 3 acts on the engine 2 via the torque converter 4.

[0025] The shift lock unit 62 performs a shift lock that prevents the shift selector 61 from being operated from the P range, which is a shift range that allows starting of the engine 2, to another shift range. In other words, the shift lock unit 62 prohibits the shift selector 61 from moving from the P range to another range.

[0026] A device having the following configuration, for example, can be used as the shift lock unit 62. That is, as shown in Fig. 2, the shift lock unit 62 has a stopper 62A that can protrude onto the movement path of the shift selector 61 between the P range and the R range (hereinafter referred to as "between PR") in the shift pattern 60 of the selector module 6, and a solenoid 62B that causes the stopper 62A to protrude.

[0027] The shift lock unit 62 prevents the shift selector 61 from moving from the P range to another range by causing a stopper 62A to protrude between the PR ranges on the movement path of the shift selector 61 using a solenoid 62B.

[0028] The shift lock unit 62 is provided with a forced release button (not shown) so that the shift lock can be forcibly released even when the battery is dead. When the forced release button is pressed, the stopper 62A moves away from the movement path between PR (the shift lock is released), and the shift selector 61 can be moved.

[0029] The shift lock unit 62 is not limited to the device having the above-mentioned configuration, and any device having a configuration that can prevent the shift selector 61 from moving in the shift pattern 60 of the selector module 6 may be used.

[0030] The sensor 63 detects the position (shift position) of the shift selector 61 in the selector module 6.

[0031] The ECU 10 is composed of a computer unit having a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), flash memory for storing backup data, etc., input ports, and output ports.

[0032] The ROM of the computer unit stores various constants, various maps, and the like, as well as a program for causing the computer unit to function as the ECU 10.

[0033] That is, the CPU executes the program stored in the ROM using the RAM as a work area, whereby the computer unit functions as the ECU 10 in this embodiment.

[0034] The ECU 10 is electrically connected to various devices such as the engine 2, the automatic transmission 3, and the selector module 6.

[0035] The ECU 10 is connected to a brake sensor 22 that detects the depression amount of a brake pedal 21 (hereinafter also referred to as a brake stroke), and a start operation unit 23 that allows the driver to start the engine 2.

[0036] The brake sensor 22 is composed of a single brake stroke sensor that continuously detects the amount of depression of the brake pedal 21. The brake sensor 22 may be composed of multiple switches arranged at different positions so as to detect the brake pedal 21 at different depression positions.

[0037] The start operating unit 23 is composed of an ignition switch (not shown), and is operated by the driver by inserting and turning the ignition key. The start operating unit 23 has three positions: a START position for starting the engine 2, an ON position for continuing to operate the engine 2, and an OFF position for stopping the engine 2, and any of these positions can be selected by the driver turning the ignition key. The start operating unit 23 may also be composed of a START button for starting the engine 2.

[0038] The ECU 10 starts the engine 2 when predetermined engine start conditions are met, including the depression amount of the brake pedal 21 being equal to or greater than a predetermined engine start threshold. Specifically, the engine start conditions are met when the shift range is in the P range, the depression amount of the brake pedal 21 is equal to or greater than the engine start threshold, and the start operating unit 23 is operated to the START position.

[0039] The ECU 10 releases the shift lock by the shift lock unit 62 when predetermined shift lock release conditions are met, including the depression amount of the brake pedal 21 being equal to or greater than a predetermined shift lock release threshold. More specifically, the shift lock release condition is met when both of the following conditions are met: the start operating unit 23 is in the ON position, and the depression amount of the brake pedal 21 is equal to or greater than the shift lock release threshold.

[0040] In this embodiment, the shift lock release threshold is set to be greater than the engine start threshold, i.e., the brake stroke threshold at which the shift lock release condition is satisfied is set to be greater than the brake stroke threshold at which the engine start condition is satisfied.

[0041] The driver must depress the brake pedal 21 to start the engine 2. However, the engine start condition can be satisfied by depressing the brake pedal 21 to a position equal to or greater than the engine start threshold, which is a relatively small amount. Therefore, the brake operation required to start the engine 2 can be performed lightly and does not impose a burden on the driver. However, to release the shift lock, the driver must further depress the brake pedal 21 to a position equal to or greater than the shift lock release threshold. Therefore, after depressing the brake pedal 21 to a position equal to or greater than the engine start threshold to start the engine 2, the driver can release the shift lock and operate the shift selector 61 to a position such as D range by further depressing the brake pedal 21 to a position equal to or greater than the shift lock release threshold. In other words, after performing a start operation to start the engine 2, further depressing the brake pedal 21 to a position equal to or greater than the shift lock release threshold to release the shift lock in order to operate the shift selector 61 to a position such as D range can ensure time for the engine 2 to be fully started (for the engine 2 to reach a fully developed state). This prevents engine stall, for example, when starting the engine from parking on a slope and starting the vehicle. Furthermore, if the engine stalls on a slope, there is a risk of the vehicle sliding down the slope because the engine's negative pressure cannot be utilized.

[0042] It is preferable that the ECU 10 releases the shift lock a predetermined time after the depression amount of the brake pedal 21 becomes equal to or greater than the shift lock release threshold. In other words, it is preferable to set a predetermined time as a delay time from when the depression amount of the brake pedal 21 becomes equal to or greater than the shift lock release threshold until the shift lock is released. This predetermined time is determined in advance taking into consideration the time required for the engine 2 to start, complete the start, and increase and stabilize the engine speed, engine torque, and the like. This makes it possible to more reliably ensure the time required to complete the start of the engine 2, and to prevent the engine from stalling due to the load from the drivetrain.

[0043] Next, the correlation between the brake pedal force and the brake stroke, and the threshold value of the brake stroke will be described with reference to Fig. 3. In Fig. 3, the vertical axis represents the brake pedal force (the operating force with which the driver presses the brake pedal 21), and the horizontal axis represents the brake stroke (the amount of depression of the brake pedal 21).

[0044] As shown in Fig. 3, the brake stroke thresholds include a shift lock release threshold and an engine start threshold. The shift lock release threshold is set to a value greater than the engine start threshold. The shift lock release threshold and the engine start threshold are set to values ​​greater than the brake stroke when the brake switch is turned on and the brake lamps are illuminated (referred to as the brake switch ON determination threshold in the figure).

[0045] In this embodiment, the brake stroke detected by the brake sensor 22 is not used to control the illumination of the brake lamps. The brake lamps are illuminated when a brake switch provided on the brake pedal 21 is turned on. Also, since it is required that the brake lamps be illuminated with a small brake stroke, it is not possible to set the position of the brake switch so that it is turned on with the same brake stroke as the shift lock release threshold.

[0046] FIG. 3 shows an engine-off brake pedal force that represents the brake pedal force when the engine 2 is off (engine stopped), and an engine-on brake pedal force that represents the brake pedal force when the engine 2 is on (engine running).

[0047] The engine-on brake pedal force increases in proportion to the brake stroke throughout the entire range. On the other hand, the engine-off brake pedal force is the same value as the engine-on brake pedal force until the brake stroke increases and reaches a position just before it reaches the shift lock release threshold, but the slope increases sharply from the position just before it reaches the shift lock release threshold. This is because a brake booster (not shown) that utilizes the negative pressure in the intake system of the engine 2 does not operate when the engine 2 is off. Furthermore, because the brake booster does not operate, the engine-off brake pedal force has an engine-off pedal depression region where increasing the brake pedal force only slightly increases the brake stroke, and once this engine-off pedal depression region is entered, the slope of the engine-off brake pedal force increases sharply.

[0048] The engine-off brake pedal depression region is a region in which the brake pedal force and brake stroke are large, starting from the point where the gradient of the engine-off brake pedal force begins to rapidly increase (the bending point). In this embodiment, the shift lock release threshold is set to the engine-off brake pedal depression region. Therefore, the driver must consciously depress the brake pedal 21 with a large brake force to cause the brake stroke to reach the shift lock release threshold. In other words, the driver attempts to depress the brake pedal 21 to a position above the shift lock release threshold to release the shift lock in order to operate the shifter in D range, etc. However, while the engine 2 has not yet started, a large brake force is required to reach the shift lock release threshold, making it impossible to reach the shift lock release threshold. Therefore, the driver must wait for the engine 2 to start, thereby ensuring time for the engine 2 to complete starting. Once the engine 2 has started, the driver can use the engine's negative pressure to easily perform a depressing operation that exceeds the shift lock release threshold.

[0049] From another perspective, Figure 3 defines the shift lock release brake force required when the engine is on and the shift lock release brake force required when the engine is off as brake pedal forces corresponding to the shift lock release threshold. The shift lock release brake force required when the engine is off is greater than the shift lock release brake force required when the engine is on because the brake booster is not activated. In other words, while the engine 2 has not yet started, a large brake force is required and the shift lock release brake force cannot be reached, so the driver has to wait for the engine 2 to start up, thereby ensuring time for the engine 2 to complete starting. Once the engine 2 has started up, the negative pressure of the engine 2 can be used and the driver can easily apply the shift lock release brake force required when the engine is on.

[0050] The shift lock release threshold may be set to be different when the engine is on and when the engine is off.

[0051] Next, the flow of the shift lock control operation executed by the ECU 10 of this embodiment will be described with reference to FIG.

[0052] As shown in FIG. 4, the ECU 10 determines whether the engine 2 is OFF (stopped) (step S1), and if the engine 2 is ON (operating), ends the current operation.

[0053] If the engine 2 is OFF in step S1, the ECU 10 determines whether the position of the shift selector 61 is in the P range (step S2), and if the position of the shift selector 61 is not in the P range, ends the current operation.

[0054] If the position of the shift selector 61 is in the P range in step S2, the ECU 10 determines whether the braking conditions are met (step S3), and if the braking conditions are not met, ends the current operation. In step S3, the brake stroke is compared with the engine start threshold, and if the brake stroke is equal to or greater than the engine start threshold, the braking conditions are met.

[0055] If the braking conditions are met in step S3, the ECU 10 determines whether the START operation has been performed (step S4), and if the START operation has not been performed, the ECU 10 ends this operation. In step S4, if the start operating unit 23 is operated to the START position, the ECU 10 determines that the START operation has been performed.

[0056] If the START operation is performed in step S4, the ECU 10 starts the start of the engine 2 (step S5).

[0057] Next, the ECU 10 determines whether the brake stroke amount is less than a threshold value (step S6). In this step S6, the brake stroke is compared with the shift lock release threshold value to determine whether the brake stroke is less than the shift lock release threshold value (brake stroke<threshold value) or is equal to or greater than the shift lock release threshold value (brake stroke≧threshold value).

[0058] If the brake stroke amount is less than the threshold value in step S6 (YES in step S6), the ECU 10 continues the shift lock (step S7) and ends the current operation.

[0059] If the brake stroke amount is equal to or greater than the threshold value in step S6 (NO in step S6), the ECU 10 releases the shift lock (step S8) and ends the current operation.

[0060] As described above, the vehicle control device according to this embodiment includes the brake sensor 22 that detects the depression amount of the brake pedal 21. The ECU 10 starts the engine when predetermined engine start conditions are met, including the depression amount of the brake pedal 21 being equal to or greater than a predetermined engine start threshold. The ECU 10 releases the shift lock by the shift lock unit 62 when predetermined shift lock release conditions are met, including the depression amount of the brake pedal 21 being equal to or greater than a predetermined shift lock release threshold. The shift lock release threshold is set to be greater than the engine start threshold.

[0061] As a result, after the driver depresses the brake pedal 21 to a level equal to or greater than the engine start threshold to start the engine 2, the driver further depresses the brake pedal 21 until the level is equal to or greater than the shift lock release threshold to release the shift lock and operate the shift range to a driving range such as D range. Therefore, further depression of the brake pedal 21 to release the shift lock is required after the engine 2 has started to start.

[0062] Therefore, the time required for the engine 2 to complete starting and for the engine speed, engine torque, etc. to increase and stabilize can be secured between the time the engine 2 starts to start and the time the shift lock is released.

[0063] As a result, engine stall caused by a change in the shift range immediately after the engine 2 is started can be suppressed.

[0064] In the vehicle control device according to this embodiment, the brake sensor 22 is composed of a single brake stroke sensor that detects the amount of depression of the brake pedal 21 in a stepless manner.

[0065] This makes it possible to detect whether the depression amount of the brake pedal 21 is equal to or greater than the engine start threshold or the shift lock release threshold by using a single brake stroke sensor.

[0066] In the vehicle control device according to this embodiment, the brake sensor 22 may be made up of a plurality of switches arranged at different positions so as to detect the brake pedal 21 at different depression positions.

[0067] This allows the brake sensor to be constructed using an inexpensive switch, thereby reducing manufacturing costs.

[0068] In the vehicle control device according to this embodiment, it is preferable that the ECU 10 releases the shift lock after a predetermined time has elapsed since the depression amount of the brake pedal 21 becomes equal to or greater than the shift lock release threshold.

[0069] This ensures that a predetermined time is always ensured between when the engine 2 is started and when the shift lock is released, so that the time required for the engine 2 to complete starting and for the engine speed, engine torque, etc. to increase and stabilize can be more reliably ensured.

[0070] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0071] 1 vehicle 2 engines 10 ECU (engine control unit, shift lock control unit) 21 Brake pedal 22 Brake sensor 61 Shift selector 62 Shift lock section

Claims

1. a shift selector operated by a driver to select one of a plurality of shift ranges; a shift lock unit that performs a shift lock to prevent the shift selector from being operated from a shift range that allows the engine to be started to another shift range, a brake sensor that detects the amount of depression of the brake pedal; an engine control unit that starts the engine when a predetermined engine start condition is met, including the depression amount of the brake pedal being equal to or greater than a predetermined engine start threshold; a shift lock control unit that releases the shift lock by the shift lock unit when a predetermined shift lock release condition is met, including the depression amount of the brake pedal being equal to or greater than a predetermined shift lock release threshold, A vehicle control device, wherein the shift lock release threshold is greater than the engine start threshold.

2. 2. The vehicle control device according to claim 1, wherein the brake sensor is a single brake stroke sensor that detects the amount of depression of the brake pedal in a stepless manner.

3. 2. The vehicle control device according to claim 1, wherein the brake sensor comprises a plurality of switches arranged at different positions so as to detect different depression positions of the brake pedal.

4. 4. The vehicle control device according to claim 1, wherein the shift lock control unit releases the shift lock after a predetermined time has elapsed since the depression amount of the brake pedal becomes equal to or greater than the shift lock release threshold.

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