Start control device

Abstract

To provide a start control device capable of improving acceleration feeling of a driver upon starting a vehicle.SOLUTION: A start control device has: an acquisition unit that acquires a torque required by a vehicle driver and a degree of engagement of a clutch device; and a control unit that controls an engine to assist an engine output torque based on the required torque and the degree of engagement acquired by the acquisition unit upon starting the vehicle in which the clutch device is switched from a disengaged state to an engaged state. When a predetermined condition for terminating the assist is satisfied, the control unit determines whether or not to extend the assist based on the difference between the engine output torque and the required torque.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to a starting control device.

Background Art

[0002] Conventionally, at the start of a vehicle, a starting control device that assists engine torque has been disclosed to suppress engine stall. Here, the starting control device is required to improve the responsiveness of engine control.

[0003] Therefore, for example, Patent Document 1 discloses a vehicle starting control device that improves the starting performance of a vehicle by effectively improving the responsiveness of starting assist control. In this starting control device, starting assist control is performed to increase the engine speed to a target speed according to the accelerator opening and the clutch engagement rate.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, when the assist control is stopped in the starting control device of Patent Document 1, the driver may feel a sense of discomfort in accelerating the vehicle according to the difference between the engine torque and the driver's required torque.

[0006] An object of the present disclosure is to provide a starting control device that improves the driver's acceleration feeling when starting a vehicle.

Means for Solving the Problems

[0007] The starting control device according to the present disclosure includes an acquisition unit that acquires a required torque of a driver of a vehicle and a fastening degree of a clutch device, and controls the engine so as to assist the output torque of the engine based on the required torque and the fastening degree acquired by the acquisition unit when the vehicle starts and the clutch device is switched from a disengaged state to an engaged state. The control unit determines whether to extend the assist based on the difference between the output torque of the engine and the required torque when a predetermined condition for ending the assist is satisfied.

Effect of the Invention

[0008] According to the present disclosure, it is possible to improve the acceleration feeling of the driver when the vehicle starts.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments according to the present disclosure will be described based on the accompanying drawings.

[0011] FIG. 1 shows the configuration of a vehicle equipped with a starting control device according to an embodiment of the present disclosure. This vehicle has an engine 1, and the crankshaft of the engine 1 and the input shaft of the transmission 3 are connected in a disconnectable manner by a clutch device 2. Further, left and right drive wheels are respectively connected to the output shaft of the transmission 3 via a differential gear. The vehicle also has an accelerator pedal 4, a clutch pedal 5, a shift operation device 6, a required torque sensor 7a, a clutch stroke sensor 7b, a shift position sensor 7c, an engine speed sensor 7d, a vehicle speed sensor 7e, and a starting control device 8.

[0012] The engine 1 generates a driving force for running the vehicle by burning fuel, and is composed of, for example, a so-called four-stroke engine that repeats four strokes: an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. Examples of the engine 1 include a diesel engine and a gasoline engine. Further, the engine 1 is not limited to a direct injection engine and may be a premixed combustion engine. Also, the engine 1 may be either a single-cylinder or a multi-cylinder engine.

[0013] The clutch device 2 is disposed between the engine 1 and the transmission 3 and is configured to be switchable between a "disengaged state" in which the transmission of power from the engine 1 to the transmission 3 is interrupted and an "engaged state" in which power is transmitted from the engine 1 to the transmission 3. Specifically, when the driver depresses the clutch pedal 5, the clutch device 2 causes the piston to stroke-move integrally with the push rod by the hydraulic pressure of the working oil supplied from the master cylinder to the release cylinder, and the release fork rotates to press the release bearing, thereby switching from the "engaged state" to the "disengaged state". Further, when the driver releases the clutch pedal 5, the clutch device 2 switches from the "disengaged state" to the "engaged state" by pressing the clutch facing of the clutch disc against the flywheel by the elastic force of the diaphragm spring.

[0014] The transmission 3 is a manual transmission that shifts in response to the operation of a shift operation device 6 provided in the driver's cab and has a plurality of shift gear trains. Specifically, the plurality of shift gear trains are integrally rotatably coupled (gear-in) to the output shaft or the countershaft in response to the operation of the shift operation device 6. The plurality of shift gear trains include, for example, a starting gear train (starting gear stage) such as a low-speed gear train for forward starting (e.g., first speed, second speed) or a reverse gear train for reverse.

[0015] The accelerator pedal 4 is arranged to be operable by the driver, and the fuel injection amount or injection timing in the engine 1 is controlled according to the driver's depression amount.

[0016] The clutch pedal 5 is arranged to be operable by the driver and is connected to the clutch device 2 so as to switch between the "disengaged state" and the "engaged state" of the clutch device 2 according to the driver's depression.

[0017] The shift operation device 6 is arranged to be operable by the driver, and the transmission 3 is controlled to shift in response to the driver's operation.

[0018] The required torque sensor 7a detects the depression amount of the accelerator pedal 4. The clutch stroke sensor 7b detects the clutch stroke amount corresponding to the depression amount of the clutch pedal 5. For example, the clutch stroke sensor 7b detects the clutch stroke amount from the movement amount of the rod of the master cylinder connected to the clutch pedal 5. The shift position sensor 7c detects the operation position of the shift operation device 6. The engine speed sensor 7d detects, for example, the rotational speed of the crankshaft connected to the engine 1. The vehicle speed sensor 7e detects, for example, the rotational speed of the propeller shaft. The required torque sensor 7a, the clutch stroke sensor 7b, the shift position sensor 7c, the engine speed sensor 7d, and the vehicle speed sensor 7e each output the detected value to the starting control device 8 that is electrically connected.

[0019] Fig. 2 shows the configuration of the starting control device 8. The starting control device 8 includes an acquisition unit 9, a control unit 10, and a storage unit 11.

[0020] The acquisition unit 9 acquires the driver's required torque (accelerator opening) based on the depression amount of the accelerator pedal 4 detected by the required torque sensor 7a. Also, the acquisition unit 9 acquires the clutch engagement rate (engagement degree) of the clutch device 2 based on the clutch stroke amount detected by the clutch stroke sensor 7b. Further, the acquisition unit 9 acquires the current gear position of the transmission 3 based on the operation position of the shift operation device 6 detected by the shift position sensor 7c. Also, the acquisition unit 9 acquires the rotational speed of the engine 1 based on the rotational speed of the crankshaft detected by the engine speed sensor 7d. Additionally, the acquisition unit 9 acquires the vehicle speed based on the rotational speed of the propeller shaft detected by the vehicle speed sensor 7e.

[0021] When the vehicle starts and the clutch device 2 is switched from the "disengaged state" to the "engaged state", the control unit 10 controls the fuel injection amount or injection timing in the engine 1 so as to assist the output torque of the engine 1 based on the driver's required torque acquired by the acquisition unit 9 and the engagement degree of the clutch device 2. Specifically, the storage unit 11 stores a target rotational speed map that defines the target rotational speed of the engine 1 that changes according to the driver's required torque and the engagement degree of the clutch device 2. For example, the target rotational speed of the engine 1 is set in the target rotational speed map to increase as the driver's required torque increases and to increase as the engagement degree of the clutch device 2 increases.

[0022] When the vehicle starts, the control unit 10 calculates the target engine speed by referring to the target engine speed map stored in the storage unit 11 based on the driver's required torque and the engagement degree of the clutch device 2. Then, the control unit 10 controls the fuel injection amount and the like in the engine 1 so that the engine 1 rotates at the target engine speed. For example, the control unit 10 may perform feedback control on the fuel injection amount in the engine 1 based on the deviation between the target engine speed and the actual engine speed of the engine 1. As a result, when the driver's required torque is insufficient for the target engine speed of the engine 1, the control unit 10 assists the output torque of the engine 1 so as to compensate for the insufficient engine speed (the engine speed increases).

[0023] When a predetermined condition for ending the assist of the engine 1 is satisfied, the control unit 10 determines whether to extend the assist of the output torque of the engine 1 based on the difference between the output torque of the engine 1 and the driver's required torque. For example, the control unit 10 may extend the assist of the engine 1 until the difference between the output torque of the engine 1 and the driver's required torque indicates a value equal to or less than a predetermined value. Note that the predetermined condition may include, for example, the clutch device 2 being in the "engaged state" or the vehicle speed exceeding a predetermined threshold value.

[0024] Note that the starting control device 8 may be composed of one or more processors, and the functions of the control device can also be realized by one or more processors executing a computer program. For example, a reading device of a computer reads the program from a recording medium recording the program for realizing the functions of the starting control device 8 and stores the program in a storage device. Then, a CPU (Central Processing Unit) copies the program stored in the storage device to a RAM (Random Access Memory) and sequentially reads and executes the instructions included in the program from the RAM, whereby the functions of the starting control device 8 can be realized.

[0025] Next, the operation of the present embodiment will be described with reference to the flowchart of FIG. 3.

[0026] First, as shown in FIG. 1, when the driver operates the accelerator pedal 4, the required torque sensor 7a detects the depression amount of the accelerator pedal 4. Also, when the driver operates the clutch pedal 5, the clutch stroke sensor 7b detects the clutch stroke amount corresponding to the depression amount of the clutch pedal 5. Then, the required torque sensor 7a and the clutch stroke sensor 7b output the detected depression amount of the accelerator pedal 4 and the clutch stroke amount to the starting control device 8.

[0027] Also, the shift position sensor 7c outputs the detected operation position of the transmission operation device 6 to the starting control device 8. Also, the engine speed sensor 7d outputs the detected rotational speed of the crankshaft to the starting control device 8. Also, the vehicle speed sensor 7e outputs the detected rotational speed of the propeller shaft to the starting control device 8.

[0028] As shown in FIG. 2, the detection data output from the required torque sensor 7a, the clutch stroke sensor 7b, the shift position sensor 7c, the engine speed sensor 7d, and the vehicle speed sensor 7e is input to the acquisition unit 9 of the starting control device 8. Thereby, in step S1, the acquisition unit 9 acquires the required torque of the vehicle driver based on the depression amount of the accelerator pedal 4 detected by the required torque sensor 7a, and acquires the engagement degree of the clutch device 2 based on the clutch stroke amount detected by the clutch stroke sensor 7b.

[0029] Also, the acquisition unit 9 acquires the current gear stage of the transmission 3 based on the operation position of the transmission operation device 6 detected by the shift position sensor 7c. Also, the acquisition unit 9 acquires the rotational speed of the engine 1 based on the rotational speed of the crankshaft detected by the engine speed sensor 7d, and acquires the vehicle speed based on the rotational speed of the propeller shaft detected by the vehicle speed sensor 7e. The acquisition unit 9 outputs the acquired data such as the required torque of the driver, the engagement degree of the clutch device 2, the gear stage of the transmission 3, the rotational speed of the engine 1, and the vehicle speed to the control unit 10.

[0030] When the control unit 10 inputs the acquisition data acquired by the acquisition unit 9, at step S2, it determines whether it is the time of starting of the vehicle in which the clutch device 2 is switched from the "disengaged state" to the "engaged state".

[0031] Specifically, the control unit 10 may determine whether the vehicle is stopped based on the speed of the vehicle acquired by the acquisition unit 9 or the gear position of the transmission 3. For example, as shown in FIG. 4, the control unit 10 can determine that the vehicle is stopped when the gear position of the transmission 3 is neutral at time t0.

[0032] Here, the control unit 10 may be preset with a first mode in which the output torque of the engine 1 is feedback-controlled in a common setting (a common setting for normal control and assist control) throughout the driving of the engine 1, and a second mode in which the output torque of the engine 1 is feedback-controlled in a setting dedicated to the start of the vehicle (a setting dedicated to assist control). Then, when the control unit 10 determines that the vehicle is stopped, it normally controls the engine 1 to maintain a predetermined idling speed based on the first mode.

[0033] Further, when the control unit 10 determines that the vehicle is stopped, it determines whether the clutch device 2 has been switched to the "disengaged state" based on the engagement degree of the clutch device 2 acquired by the acquisition unit 9, and determines whether the transmission 3 has been gear-engaged in the starting gear position of the transmission 3 based on the gear position of the transmission 3 acquired by the acquisition unit 9. Here, the control unit 10 can determine that the vehicle has started when the clutch device 2 is switched to the "disengaged state" (the clutch pedal is depressed) and gear-engaged in the starting gear position at time t1. At this time, the control unit 10 repeats the determination of step S2 until it determines that the vehicle has started.

[0034] When the control unit 10 determines that the vehicle has started moving, it proceeds to step S3 and starts the assist control in the first mode. For example, the control unit 10 can perform feedback control on the fuel injection amount in the engine 1 based on the deviation between the target rotational speed and the actual rotational speed of the engine 1. Specifically, the control unit 10 calculates the target rotational speed R1 of the engine 1 by referring to the target rotational speed map stored in the storage unit 11 based on the required torque (accelerator opening) of the driver and the engagement degree of the clutch device 2. Then, the control unit 10 performs assist control on the output torque T1 of the engine 1 so as to add the assist torque T2 corresponding to the difference between the target rotational speed R1 and the actual rotational speed R2 of the engine 1.

[0035] At this time, the target rotational speed R1 of the engine 1 is calculated such that the actual rotational speed R2 of the engine 1 increases from the idling rotational speed in response to an increase in the engagement degree of the clutch device 2 (transition from the "disengaged state" to the "engaged state"). For this reason, before the time t2 when no required torque from the driver is generated (the accelerator pedal 4 is not depressed), the control unit 10 generates the assist torque T2 so that the actual rotational speed R2 of the engine 1 increases in response to an increase in the engagement degree of the clutch device 2. Thereby, the control unit 10 can increase the actual rotational speed R2 of the engine 1 according to the target rotational speed R1. Also, the control unit 10 can increase the actual rotational speed R2 of the engine 1 to a predetermined value or more before the clutch device 2 is completely engaged, and can suppress engine stall.

[0036] When the control unit 10 increases the actual rotational speed R2 of the engine 1 to a predetermined value or more at time t2, it controls the output torque T1 of the engine 1 to maintain the actual rotational speed R2 at the predetermined value based on the deviation between the target rotational speed R1 and the actual rotational speed R2 of the engine 1. For this reason, when the required torque T3 of the driver is input, the control unit 10 controls the output torque T1 of the engine 1 so that the assist torque T2 decreases in response to an increase in the required torque T3.

[0037] Subsequently, at step S4, the control unit 10 determines whether a predetermined condition for ending the assist of the engine 1 is satisfied. For example, the control unit 10 may determine that the predetermined condition is satisfied when the clutch device 2 is in a complete "engaged state" or when the vehicle speed exceeds a predetermined threshold value. The control unit 10 repeats the determination at step S4 until the predetermined condition is satisfied. Here, it is assumed that the control unit 10 determines at time t3 that a predetermined condition for ending the assist of the engine 1 is satisfied.

[0038] Thus, even when a predetermined condition for ending the assist of the engine 1 is satisfied, there is a possibility that a large difference D exceeding a predetermined value may occur between the output torque T1 of the engine 1 and the driver's required torque T3. In such a case, if the assist of the engine 1 is ended, the driver may feel a sense of discomfort in the acceleration of the vehicle according to the difference D between the output torque T1 and the required torque T3. For example, the driver may feel a flatness, dullness, response delay, or drop in the acceleration of the vehicle.

[0039] Therefore, when a predetermined condition for ending the assist of the output torque T1 of the engine 1 is satisfied, the control unit 10 proceeds to step S5 and determines whether to extend the assist of the output torque T1 of the engine 1 based on the difference D between the output torque T1 of the engine 1 and the driver's required torque T3. For example, the control unit 10 may determine whether to extend the assist of the output torque T1 of the engine 1 based on whether the difference D between the output torque T1 of the engine 1 and the driver's required torque T3 is less than or equal to a predetermined value. The predetermined value can be set, for example, based on the evaluation of the acceleration feeling of the passengers.

[0040] When the control unit 10 determines not to extend the assist of the output torque T1 of the engine 1 (determines that the difference D is less than or equal to the predetermined value), it proceeds to step S7 and ends the assist of the output torque T1 of the engine 1. Then, the control unit 10 controls the output torque T1 of the engine 1 based on the driver's required torque T3.

[0041] On the other hand, when the control unit 10 determines that the assist of the output torque T1 of the engine 1 is to be extended (determines that the difference D exceeds a predetermined value), the control unit 10 extends the assist of the output torque T1 of the engine 1. That is, the control unit 10 performs assist control on the output torque T1 of the engine 1 so as to add an assist torque T2 corresponding to the deviation between the target rotational speed R1 and the actual rotational speed R2 of the engine 1. Thereby, the starting control device 8 can suppress the sense of decrease in the output torque T1 and improve the driver's acceleration feeling when the vehicle starts.

[0042] At this time, the control unit 10 can switch from the first mode to the second mode and perform assist control on the engine 1 in the second mode. Here, the assist torque T2a in the second mode is set to decrease more gently than the assist torque T2 in the first mode in response to an increase in the driver's required torque T3. For example, by making the gain of the feedback control in the second mode smaller than that in the first mode, the assist torque T2a in the second mode can be decreased gently. Thereby, when the control unit 10 switches from the first mode to the second mode, the control unit 10 can suppress a step from occurring in the output torque of the engine 1 and smoothly connect the output torque of the engine 1. For this reason, the starting control device 8 can surely improve the driver's acceleration feeling when the vehicle starts.

[0043] Also, by providing the first mode and the second mode separately, with respect to the first mode that performs feedback control with a common setting (a common setting for normal control and assist control) throughout the driving of the engine 1, it is possible to easily set the second mode that performs feedback control with a setting dedicated to the start of the vehicle (a setting dedicated to assist control).

[0044] Subsequently, in step S6, the control unit 10 determines whether the difference D between the output torque T1a of the engine 1 and the driver's required torque T3 is equal to or less than a predetermined value. The control unit 10 repeats the determination in step S6 until the difference D between the output torque T1a of the engine 1 and the driver's required torque T3 indicates that it is equal to or less than the predetermined value. Thereby, the starting control device 8 can suppress the occurrence of a step in the output torque of the engine 1 and can surely improve the driver's acceleration feeling when the vehicle starts.

[0045] Note that the predetermined value may be set to the same value as at the time of the determination in step S5. Further, the predetermined value may be set to zero where the output torque T1a of the engine 1 and the driver's required torque T3 match.

[0046] When the control unit 10 determines at time t4 that the difference D between the output torque T1a of the engine 1 and the driver's required torque T3 is equal to or less than the predetermined value, the control unit 10 proceeds to step S7 and ends the assist of the output torque T1 of the engine 1. Thereby, the control unit 10 controls the output torque T1 of the engine 1 based on the driver's required torque T3. At this time, the control unit 10 may switch from the second mode to the first mode.

[0047] According to the present embodiment, the acquisition unit 9 acquires the driver's required torque T3 of the vehicle and the engagement degree of the clutch device 2. Further, when the vehicle starts and the clutch device 2 is switched from the disengaged state to the engaged state, the control unit 10 controls the engine 1 to assist the output torque T1 of the engine 1 based on the required torque T3 acquired by the acquisition unit 9 and the engagement degree of the clutch device 2. Then, when a predetermined condition for ending the assist is satisfied, the control unit 10 determines whether to extend the assist based on the difference between the output torque T1 of the engine 1 and the required torque T3. For this reason, the starting control device 8 can improve the driver's acceleration feeling when the vehicle starts.

[0048] Note that in the above embodiment, the shift operation device 6 is configured by a manual transmission, but it may be configured by an automatic transmission.

[0049] In addition, each of the above embodiments merely shows an example of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner by these. That is, the present invention can be implemented in various forms without departing from the gist or its main features. For example, the disclosure regarding the shape, number, etc. of each part described in the above embodiments is merely illustrative and can be appropriately changed and implemented.

Industrial Applicability

[0050] The starting control device according to the present disclosure can be used for a device that assists the output torque of an engine.

Explanation of Signs

[0051] 1 Engine 2 Clutch device 3 Transmission 4 Accelerator pedal 5 Clutch pedal 6 Shift operation device 7a Required torque sensor 7b Clutch stroke sensor 7c Shift position sensor 7d Engine speed sensor 7e Vehicle speed sensor 8 Starting control device 9 Acquisition unit 10 Control unit 11 Storage unit D Difference R1 Target rotation speed R2 Actual rotation speed t0~t4 Time T1,T1a Output torque T2,T2a Assist torque T3 Required torque

Claims

1. An acquisition unit that acquires a required torque of a vehicle driver and a degree of engagement of a clutch device; A control unit that controls the engine to assist the output torque of the engine based on the required torque and the degree of engagement acquired by the acquisition unit when the vehicle starts and the clutch device is switched from a disengaged state to an engaged state; and The control unit is a starting control device that determines whether to extend the assist based on the difference between the output torque of the engine and the required torque when a predetermined condition for ending the assist is satisfied.

2. The starting control device according to claim 1, wherein when the control unit extends the assist, the control unit ends the assist when the difference between the output torque of the engine and the required torque indicates a value equal to or less than a predetermined value, and controls the engine based on the required torque.

3. A first mode for assisting the output torque of the engine and a second mode for gradually decreasing an assist torque for assisting the output torque of the engine more gently than the first mode in response to an increase in the required torque are preset. The engine is controlled in the first mode before the predetermined condition is satisfied, and the engine is controlled in the second mode after the extension of the assist. The starting control device according to claim 1.

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