JP2010084607A - Drive force control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive force control device capable of predicting accelerator pedal displacement by detecting a load to the accelerator pedal and advancing fuel cut start determination. <P>SOLUTION: The drive control device 1 selectively carrying out the supply and stop of fuel to an internal combustion engine 2 which is a drive power source of a vehicle in a state that the internal combustion engine 2 rotates includes an output operation mechanism 4 which operates by receiving an operation force and of which the operation quantity is an output demand quantity, and a fuel stop control means stopping the supply of the fuel to the internal combustion engine 2 when the operation force reaches a predetermined threshold or smaller in a state that fuel is supplied to the internal combustion engine 2 and the vehicle is in travel. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device that controls stop of fuel supply to an internal combustion engine when a reduction in driving force is requested.

  Conventionally, various methods have been employed for fuel cut in internal combustion engines. For example, Patent Document 1 discloses a configuration of an internal combustion engine in which fuel cut is executed when the throttle valve is fully closed. Japanese Patent Application Laid-Open No. 2004-228688 describes a configuration in which a shift or fuel cut is controlled by the accelerator opening (displacement).

Japanese Utility Model Publication No. 2-112946 JP 2001-2335016 A

  The configuration disclosed in Patent Document 1 executes fuel cut control when the throttle valve is fully closed. In such a configuration, the start of fuel cut is delayed until the throttle valve is fully closed. As a result, there is a possibility of impairing the improvement of fuel consumption.

  The configuration shown in Patent Document 2 predicts the future willingness of acceleration / deceleration based on the rate of change of the pedal effort of the accelerator pedal, and the rate of change is increased or decreased. When a predetermined threshold value is exceeded, downshift or upshift is performed assuming that there is a willingness to accelerate or decelerate in the future. Therefore, in the configuration of Patent Document 2, the pedaling force increases or decreases, and the rate of change in the pedaling force in the process is detected or measured. Therefore, the rate of change in the pedaling force is set to a value that establishes the determination of downshift or upshift. It takes time to reach, and there is room for improving control responsiveness.

  The present invention has been made paying attention to the technical problem described above, and detects operating force such as load on an accelerator pedal in order to improve responsiveness of so-called fuel cut control and improve fuel efficiency. Accordingly, it is an object of the present invention to provide a driving force control device that speeds up the fuel cut start determination by pre-reading the driving force reduction request.

  In order to achieve the above object, according to the first aspect of the present invention, fuel can be selectively supplied to and stopped from the internal combustion engine which is a driving force source of the vehicle while the internal combustion engine is rotating. In the driving force control apparatus, in an operating state that receives an operating force and whose operation amount is an output request amount, and in which the internal combustion engine is supplied with fuel and rotates and the vehicle is running, A driving force control device comprising fuel stop control means for stopping the supply of fuel to the internal combustion engine when the operating force becomes a predetermined threshold value or less.

  According to a second aspect of the present invention, in the first aspect of the invention, the fuel stop control means is configured such that the operation force is a threshold value determined in advance in a state where the output request amount by the output operation mechanism is equal to or less than a predetermined request amount. The driving force control device includes means for stopping supply of fuel to the internal combustion engine when the following conditions are met.

  According to a third aspect of the invention, in the first or second aspect of the invention, the operating force is less than or equal to a predetermined threshold value in a state where the internal combustion engine is rotated by being supplied with fuel and the vehicle is running. And further comprising a prohibiting means for prohibiting the fuel stop control means from stopping the fuel supply when the output request amount by the output operation mechanism exceeds a predetermined request amount. It is a driving force control device.

  According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the fuel stop control means is configured to supply fuel to the internal combustion engine when the traveling speed of the vehicle or the rotational speed of the internal combustion engine is equal to or greater than a predetermined value. A driving force control device including means for stopping supply.

  According to the first aspect of the invention, since the fuel stop control means for stopping the supply of fuel to the internal combustion engine when the operating force becomes a predetermined threshold value or less is provided, the operation of the output operation mechanism occurs. Prior to detecting a decrease in driving force, the timing of stopping the supply of fuel can be advanced based on the request, and as a result, fuel efficiency can be improved.

  According to the invention of claim 2, in addition to the effect of the invention of claim 1, when the operation force becomes less than a predetermined threshold in a state where the output request amount by the output operation mechanism is less than the predetermined request amount. Includes means for stopping the supply of fuel to the internal combustion engine, so that the supply of fuel is continued when the driving force is slightly reduced from a predetermined magnitude, and the supply of fuel is stopped separately from this, Fuel consumption can be improved.

  According to the invention of claim 3, in addition to the effect of the invention of claim 1 or 2, the requested output amount by the output operation mechanism when the operating force falls below a predetermined threshold exceeds the predetermined requested amount. In this case, the fuel stop control means further includes a prohibiting means for prohibiting the stop of the fuel supply, so that the driving force does not decrease against the driver's intention, and the drivability is improved.

  According to the invention of claim 4, in addition to the effects of the inventions of claims 1 to 3, the means for stopping the supply of fuel to the internal combustion engine when the running speed of the vehicle or the rotational speed of the internal combustion engine is greater than or equal to a predetermined value. Therefore, fuel efficiency can be improved without causing so-called engine stall.

  The best mode for carrying out the invention will be described below. FIG. 1 is a configuration diagram schematically showing an embodiment of a driving force control apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes a driving force control device according to the present invention, which includes a central processing unit (ECU) 3 connected to an engine 2 that is a power source mounted on a vehicle, for example.

  The driving force control device 1 includes an accelerator pedal 4, an accelerator pedal displacement detection device 5, and an accelerator pedal load detection device 6. That is, a value obtained by depressing the accelerator pedal and detecting the depression force by a sensor such as a strain gauge is sent to a central processing unit (ECU) 3. The central processing unit (ECU) 3 inputs vehicle speed (v) and engine speed (Ne) values and is connected to the engine 2 as a power source. The engine 2 includes an electronic throttle 7. The engine 2 is configured to output a driving force to a tire 10 as a driving wheel via a transmission (transmission) 8 and a differential gear 9. A target driving force is calculated based on the accelerator pedal displacement detected by the accelerator pedal displacement detecting device 5, and the effective fuel cut is determined based on the accelerator pedal load detected by the accelerator pedal load detecting device 6.

  A flowchart showing the fuel cut control by the driving force control device 1 is shown in FIG. In the figure, a target driving force based on the accelerator pedal displacement detected by the accelerator pedal displacement detector 5 is calculated (step S1). This can be performed based on a map prepared in advance. Further, the rate of change in the depression force on the accelerator pedal 4 is determined (step S2). If the pedaling force change rate does not fall below a preset threshold value, that is, if a negative determination is made in step S2, the process returns once. On the other hand, if the rate of change in the pedal force with respect to the accelerator pedal 4 is less than the above threshold value, that is, if a positive determination is made in step S2, the routine proceeds to step S3, where the pedal force of the accelerator pedal 4 is determined in advance. It is determined whether it is below the threshold value. If it is determined negative in step S3 because the pedal effort of the accelerator pedal does not fall below the pedaling force threshold value, the process returns. Proceeds to step S4 and starts fuel cut control. The start of the fuel cut control is to start a series of controls (or control routines) such as reading various data and checking signals when actually stopping the fuel supply.

  Then, with the start of fuel cut control, it is determined whether or not the displacement of the accelerator pedal 4 is below another threshold value (step S5). If a negative determination is made in step S5, the process returns once without performing any particular control. On the other hand, if a positive determination is made in step S5, a fuel cut is executed (step S6). That is, the supply of fuel to the engine 2 is stopped.

  FIG. 3 shows a time chart when the control shown in the flowchart of FIG. 2 is executed. In a state where the accelerator pedal 4 is depressed to a predetermined opening, fuel is supplied (injected) to the engine 2 and a driving force corresponding to the accelerator opening is output. In this state, when the depressing force is reduced to return the accelerator pedal 4 (time t1 in FIG. 3), the accelerator opening starts to decrease at time t2. Further, the target driving force is obtained based on the vehicle state such as the vehicle speed and the accelerator opening at that time. Since the actual driving force is controlled to achieve the target driving force, the actual driving force changes with a delay with respect to the target driving force.

  In this process, when the depression force of the accelerator pedal 4 falls below the aforementioned depression force threshold value (at time t3), fuel cut control is started. Immediately after the depressing force of the accelerator pedal 4 becomes almost zero, the accelerator opening falls below the threshold value and becomes almost zero (at time t4), so a fuel cut command is output, and accordingly fuel supply (injection) is performed. It is switched to the OFF state (at time t5).

  On the other hand, as described in Patent Document 1 described above, when the fuel cut control is executed after the throttle valve is fully closed, the control start timing is delayed as shown by the broken line in FIG. (Time t6), the duration of fuel supply is relatively longer than in the case of the present invention. That is, the amount of improvement in fuel consumption is relatively reduced.

  The control based on the depression force of the accelerator pedal 4 can be applied to the shift control in addition to the fuel cut control, and an example thereof will be described next. FIG. 4 is a flowchart for explaining a control example when applied to the downshift control, and calculates a target driving force based on the accelerator pedal displacement detected by the accelerator pedal displacement detector 5 (step S7). . This can be performed based on a map prepared in advance. Further, the rate of change in the pedal force applied to the accelerator pedal 4 is determined, and if it does not exceed the threshold value, that is, if it is negatively determined that the downshift is not required, the routine returns once (step S8). On the other hand, if it is positively determined that a downshift is required that exceeds the threshold value, the process proceeds to step S9, and a shift execution determination is made.

  A time chart for the flowchart shown in FIG. 4 is shown in FIG. As shown in the figure, the accelerator pedal 4 is depressed to increase the accelerator pedal force, but the accelerator opening has not yet increased (at time t7 in FIG. 5). After that, once the accelerator pedaling force exceeds the threshold value, the downshift is executed, and the accelerator pedaling force decreases accordingly. Then, when the accelerator pedal force decreases to a substantially predetermined value, the accelerator opening increases with a delay to a predetermined value (at time t8). At this time, the target driving force is closer to the target driving force than the driving force that has already been subjected to the shift determination based on the displacement of the accelerator opening at the time t8 in the driving force that has been determined based on the accelerator pedaling force at the time t7. Follow the path. That is, drivability is improved.

  Next, FIG. 6 shows a flowchart for upshift control based on the depression force of the accelerator pedal 4. In the figure, a target driving force based on the accelerator pedal displacement detected by the accelerator pedal displacement detector 5 is calculated (step S10). This can be performed based on a map prepared in advance. Further, the rate of change in the pedal force applied to the accelerator pedal 4 is determined, and if it does not fall below the threshold value, that is, if it is determined negatively that the downward upshift is not required, the routine returns once (step S11). On the other hand, if it is determined that an upshift is required, which is below the threshold value, the process proceeds to step S12, and shift execution is determined.

  FIG. 7 shows a time chart for the flowchart shown in FIG. As shown in the figure, at the time when the depression force on the accelerator pedal 4 is decreasing, the accelerator opening still shows a constant value (at time t9 in FIG. 7). At this time, the shift execution determination of the upshift is started, and therefore the engine speed based on the depression force of the accelerator pedal 4 starts to decrease. Immediately after the depression force of the accelerator pedal 4 becomes almost zero, the accelerator opening falls below the threshold value and becomes almost zero (at time t10), so the engine rotation speed is already lower than the engine rotation speed at the accelerator displacement. . That is, fuel consumption can be improved.

  Here, when the relationship between the accelerator pedal displacement and the accelerator pedal depression force is shown in FIG. 8, the value 11 of the accelerator pedal displacement slowly rises with respect to the time axis that is the horizontal axis, and then decreases to a substantially constant value. To maintain. On the other hand, the value 12 of the accelerator pedal depression force gradually increases and then remains almost constant.

  Further, FIG. 9 showing the characteristics of the accelerator pedal 4 indicated by the accelerator pedal displacement and the accelerator pedal depression force shows a value 13 of the accelerator pedal static characteristic and a value 14 of the accelerator pedal dynamic characteristic. The value 13 of the accelerator pedal static characteristic indicates the relationship between the displacement of the accelerator pedal 4 and the load when the accelerator pedal is slowly displaced, and the value 14 of the accelerator pedal dynamic characteristic indicates the displacement of the accelerator pedal 4 when the accelerator pedal 4 is operated quickly. The relationship of load is shown.

  The accelerator pedal 4 described above corresponds to the output operation mechanism of the present invention, the accelerator pedal depression force corresponds to the operation force, and the accelerator pedal load corresponds to the operation amount.

It is a block diagram which shows typically the Example of the driving force control apparatus which concerns on this invention. 3 is a flowchart showing fuel cut control for the driving force control apparatus 1; It is a time chart about the flowchart shown in FIG. It is a flowchart in shift execution judgment about a driving force control apparatus. It is a time chart about the flowchart shown in FIG. It is a flowchart in case of an upshift. It is a time chart about the flowchart shown in FIG. It is a figure which shows the relationship between an accelerator pedal displacement and an accelerator pedal depression force. It is a figure shown by accelerator pedal displacement and accelerator pedal depression force.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Driving force control apparatus, 2 ... Engine, 3 ... Central processing unit (ECU), 4 ... Accelerator pedal, 5 ... Accelerator pedal displacement detection apparatus, 6 ... Accelerator pedal load detection apparatus, 7 ... Electronic throttle, 8 ... Shift Machine (transmission), 9 ... differential gear, 10 ... tire.

Claims (4)

In the driving force control apparatus capable of selectively performing the supply and stop of the fuel to the internal combustion engine which is a driving force source of the vehicle while the internal combustion engine is rotating,
An output operation mechanism that operates upon receiving an operation force and whose operation amount is an output request amount;
A fuel stop control means for stopping the supply of fuel to the internal combustion engine when the operating force becomes a predetermined threshold value or less in a state where the internal combustion engine is rotated by being supplied with fuel and the vehicle is running. And a driving force control device.   The fuel stop control means stops the supply of fuel to the internal combustion engine when the operation force becomes a predetermined threshold value or less in a state where the output request amount by the output operation mechanism is not more than a predetermined request amount. The driving force control apparatus according to claim 1, further comprising means.   In a state where the internal combustion engine is supplied with fuel and rotates and the vehicle is running, the output request amount by the output operation mechanism when the operation force becomes a predetermined threshold value or less is a predetermined request amount. 3. The driving force control apparatus according to claim 1, further comprising a prohibiting unit that prohibits the fuel supply control by the fuel stop control unit when the fuel stop control unit exceeds the limit.   The fuel stop control means includes means for stopping the supply of fuel to the internal combustion engine when the traveling speed of the vehicle or the rotational speed of the internal combustion engine is equal to or greater than a predetermined value. The drive force control apparatus in any one.

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