JP2012031944A - Coasting control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coasting control device capable of preventing a shift change under coasting control without adding a member.SOLUTION: The coasting control device includes: a coasting control executing unit 3 which starts coasting control by disengaging a clutch and reducing the rotational speed of an engine in an operation state where the engine does not work externally; and a coasting time shift change preventing unit 4 which does not engage the clutch when a shift change is carried out under the coasting control.

Description

  The present invention relates to a coasting control device that disengages a clutch during traveling to return an engine to an idle state to reduce fuel consumption, and relates to a coasting control device that can prevent shift switching during coasting control without adding a member.

  In the vehicle, when the accelerator pedal is depressed when the clutch is disengaged, the accelerator is opened and the engine is so-called empty, and the engine speed settles at the engine speed corresponding to the accelerator opening. At this time, the driving force generated by the engine and the engine internal resistance (friction) are balanced, and the engine output torque is zero. That is, the engine does not work at all with respect to the outside, and fuel is wasted. For example, if the engine speed is 2000 rpm, the driver can hear a loud engine sound, so that a considerable amount of fuel is consumed wastefully.

  The state in which the engine does not work to the outside is not limited to the idling when the clutch is disengaged, but also occurs while the vehicle is running. That is, the engine only rotates at an engine speed corresponding to the accelerator opening, as in the case of flying, and does not contribute to acceleration / deceleration of the vehicle. At this time, fuel is consumed only for rotating the engine, which is very wasteful.

  The present applicant performs coasting control (also referred to as fuel consumption traveling control) that disengages the clutch and returns the engine to an idle state to reduce fuel consumption when the engine is rotating but not working to the outside. A coasting control device was proposed (Patent Document 1).

JP 2006-342832 A JP-A-8-67175 JP 2001-304305 A

  When coasting control is started, the clutch is disengaged. Thus, coasting control is control in which the clutch is disengaged even though the driver does not perform clutch operation. On the other hand, before the coasting control device was developed, when the driver wants to shift shift from the current gear stage to another gear stage, the clutch is operated to disengage the clutch and then the shift knob is operated to perform the shift switching. It has become. Of course, shift switching is not possible with the clutch engaged. However, in a vehicle equipped with a coasting control device, since the clutch is disengaged during coasting control, the shift can be easily switched by operating the shift knob.

  However, since coasting control is not performed for the purpose of shift switching, it is irregular and undesirable in terms of control to perform shift switching during coasting control. In particular, if the gear is shifted to a lower gear than the current gear during coasting control when the vehicle speed is high, idle rotation will occur when coasting control ends and the clutch is engaged. If the engine speed is returned to the vehicle speed corresponding to the original gear stage from the number, the load-side speed is larger than the engine speed due to the irregular downshift, so the clutch is engaged. In some cases, the engine may overrun beyond the rated speed, or the tire may not be able to rotate following the vehicle speed and may be locked. Alternatively, when the coasting control is finished and the clutch is to be engaged, if the engine speed is returned to the vehicle speed at the gear stage after the downshift from the idle speed, the target engine speed is If the engine speed exceeds the rated speed, the engine will overrun when the engine speed is increased as intended.

  Therefore, an object of the present invention is to provide a coasting control device that solves the above-described problems and can prevent shift switching during coasting control without adding members.

  In order to achieve the above object, the present invention provides a coasting control execution unit that starts coasting control by disengaging the clutch and lowering the engine speed while the engine is in an operation state where the engine does not work to the outside. A coasting shift switching prevention unit that does not engage the clutch when the shift switching is performed inside is provided.

  The coasting control determination map referred to by the clutch rotational speed and the accelerator opening is provided, and the coasting control execution unit has a plot point of the clutch rotational speed and the accelerator opening on the coasting control determination map within the coasting controllable region. Coasting control when the accelerator pedal operating speed is within a predetermined range and the clutch rotation speed and accelerator opening plot points on the coasting control determination map pass the coasting control threshold line in the accelerator opening decreasing direction. When the accelerator pedal operation speed is out of the predetermined range or the plot point is out of the coasting control possible region, the engine speed may be increased and the coasting control may be terminated with the clutch engaged.

  A coasting shift switching warning unit may be provided that issues a warning when shift switching is performed during coasting control.

  The present invention exhibits the following excellent effects.

  (1) Shift switching during coasting control can be prevented without adding members.

It is a block block diagram of the coasting control apparatus of this invention. 1 is a block configuration diagram of a vehicle clutch system to which a coasting control device of the present invention is applied. It is a block diagram of the actuator which implement | achieves the clutch system of FIG. 1 is an input / output configuration diagram of a vehicle to which a coasting control device of the present invention is applied. It is an operation | movement conceptual diagram for demonstrating the outline of coasting control. It is a graph image figure of a coasting control determination map. It is a graph for demonstrating the fuel consumption reduction effect by coasting control. It is a graph of the accelerator opening actually measured in order to create a coasting control determination map, and clutch rotation speed. It is a flowchart which shows the procedure of the shift switching prevention during coasting control in the coasting control apparatus of this invention.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, the coasting control device 1 according to the present invention starts coasting control by disengaging the clutch and lowering the engine rotational speed in an operation state where the engine does not work to the outside. A control execution unit 3 and a coasting shift switching prevention unit 4 that does not engage the clutch when shift switching is performed during coasting control are provided.

  More specifically, the coasting control device 1 performs coasting control based on the coasting control determination map 2 referred to by the clutch rotational speed and the accelerator opening, and the plot points of the clutch rotational speed and the accelerator opening to the coasting control determination map 2. The clutch is disengaged when the accelerator pedal operation speed is within a predetermined range and the plot point of the clutch rotational speed and the accelerator opening passes the coasting control threshold line in the direction of decreasing the accelerator opening. The coasting control is started by lowering the engine speed and the coasting control is terminated when the accelerator pedal operation speed is out of the predetermined range or the plot point is out of the coasting controllable region; A coasting shift switching prevention unit 4 that does not engage the clutch when the shift switching is performed from the gear stage at the start of the coasting control to another gear stage after the coasting control is started.

  Further, the coasting control device 1 performs a shift switching during coasting control, that is, a coasting shift switching warning unit that issues a warning when the shift switching from the gear stage at the start of coasting control to another gear stage is performed after the coasting control is started. 5 is provided.

  The coasting shift switching prevention unit 4 reads and updates the current gear stage output from the shift sensor of the transmission as needed, and coasts the current gear stage when the coasting control execution unit 3 starts coasting control. It is stored as the gear stage at the start of control. Further, the coasting shift switching prevention unit 4 compares the stored gear position at the start of coasting control with the current gear stage to perform shift switching from the gear stage at the time of coasting control start to another gear stage. It is designed to detect the event that it was broken.

  The coasting control determination map 2, the coasting control execution unit 3, the coasting shift switching prevention unit 4, and the coasting shift switching warning unit 5 constituting the coasting control device 1 are mounted on, for example, an ECU (not shown). preferable.

  Each part is demonstrated about the vehicle carrying the coasting control apparatus 1 of this invention.

  As shown in FIG. 2, the vehicle clutch system 101 on which the coasting control device 1 of the present invention is mounted is a system in which a manual type and an automatic type by ECU control are compatible. A clutch master cylinder 103 mechanically coupled to the clutch pedal 102 supplies operating oil to an intermediate cylinder (also referred to as a clutch-free operating cylinder or a switching cylinder) 104 in accordance with a depression / return operation of the clutch pedal 102 by a driver. It is like that. On the other hand, a clutch-free actuator unit 105 controlled by an ECU (not shown) supplies hydraulic oil to the intermediate cylinder 104 in response to a clutch disengagement / contact command. The intermediate cylinder 104 supplies operating oil to the clutch slave cylinder 106. The piston 107 of the clutch slave cylinder 106 is mechanically connected to the movable part of the clutch 108.

  As shown in FIG. 3, the actuator 110 includes a clutch-free actuator 111. The clutch free actuator 111 includes an intermediate cylinder 104 and a clutch free actuator unit 105. The clutch free actuator unit 105 includes a solenoid valve 112, a relief valve 113, and a hydraulic pump 114. In the intermediate cylinder 104, a primary piston 116 and a secondary piston 117 are arranged in series. When the primary piston 116 is stroked by the operating oil from the clutch master cylinder 103, the secondary piston 117 is caused to stroke. . The intermediate cylinder 104 is configured such that the secondary piston 117 is stroked by the operating oil from the clutch-free actuator unit 105. Operating oil is supplied to the clutch slave cylinder 106 in accordance with the stroke of the secondary piston 117. With this configuration, when manual operation is performed, clutch disengagement / engagement is preferentially performed according to manual operation, and when manual operation is not performed, clutch disengagement / engagement according to ECU control is performed.

  The coasting control device 1 of the present invention can also be applied to an automatic clutch system without a manual type.

  As shown in FIG. 4, the vehicle is provided with an ECU 121 that mainly controls a transmission and a clutch, and an ECM 122 that mainly controls an engine. The ECU 121 includes a shift knob switch, a transmission shift sensor, a select sensor, a neutral switch, a T / M rotation sensor, a vehicle speed sensor, an idle switch, a manual changeover switch, a parking brake switch, a door switch, a brake switch, a half-clutch adjustment switch, Input signal lines for the accelerator operation amount sensor, the clutch sensor, and the hydraulic switch are connected. Also connected to the ECU 121 are alarm devices such as speakers, buzzers, display lamps, display screens, motors of the hydraulic pump 114 of the clutch system 101, solenoid valves 112, hill start assist valves, and warning & meter output signal lines. Has been. Although not shown, various input signal lines and output signal lines used for engine control are connected to the ECM 122. The ECM 122 can transmit each signal of the engine speed, the accelerator opening, and the engine speed change request to the ECU 121 via a CAN (Controller Area Network) transmission path.

  The clutch rotational speed used in the present invention is the rotational speed on the driven side of the clutch, and is the same as the rotational speed of the input shaft of the transmission. The clutch rotational speed can be obtained from the input shaft rotational speed detected by an input shaft rotational speed sensor (not shown). Alternatively, the clutch rotational speed can be obtained from the vehicle speed detected by the vehicle speed sensor using the gear ratio of the current gear stage. The clutch rotational speed represents the engine rotational speed corresponding to the vehicle speed.

  The transmission is a transmission that can be shifted manually by a shift knob. When performing automatic shift switching by electronic control, shift switching during coasting control can be prohibited on the control logic. Therefore, the coasting control device 1 of the present invention is effective for a vehicle equipped with a manual shift transmission.

  Hereinafter, the operation of the coasting control device 1 of the present invention will be described.

  The operation concept of coasting control will be described with reference to FIG. The horizontal axis shows time and control flow, and the vertical axis shows engine speed. While the accelerator pedal 141 is largely depressed from the idling state and the accelerator opening degree continues to be 70%, the engine speed 142 increases and the vehicle is accelerated. Assume that a coasting control start condition described later is satisfied when the engine speed 142 is stabilized, the depression of the accelerator pedal 141 is reduced, and the accelerator opening is 35%. By starting coasting control, the clutch is controlled to be disengaged, and the engine speed 142 is controlled to the idle speed. The vehicle will run in coasting control. Thereafter, it is assumed that the accelerator pedal is no longer depressed and the accelerator opening becomes 0% or other coasting control end conditions are satisfied. When the coasting control ends, the engine is controlled to rotate and the clutch is controlled to contact. In this example, since the accelerator opening is 0%, the engine is braked and the vehicle is decelerated.

  If coasting control is not performed, the engine speed remains high as indicated by the broken line during the coasting control execution period, so that fuel is wasted, but coasting control is performed. Thus, during coasting control, the engine speed 142 becomes the idling speed and fuel is saved.

  FIG. 6 shows the coasting control determination map 2 as a graph image.

  The coasting control determination map 2 is a map in which the horizontal axis is the accelerator opening and the vertical axis is the clutch rotational speed. The coasting control determination map 2 can be divided into a minus region MA where the engine output torque is negative and a plus region PA where the engine output torque is positive. The minus region MA is a region where the engine friction is larger than the engine required torque and the engine output torque is negative. The positive region PA is a region where the engine output torque is positive because the engine required torque is larger than the engine friction. The engine output torque zero line ZL, which is the boundary between the minus area MA and the plus area PA, indicates that the engine does not work to the outside as described in the background art, and fuel is wasted.

  In the present embodiment, the coasting control threshold line TL is set slightly to the left of the engine output torque zero line ZL of the coasting control determination map 2 (on the side where the accelerator opening is small). In the coasting control determination map 2, a coasting controllable area CA having a finite width including the coasting control threshold line TL is set between the minus area MA and the plus area PA. In the coasting control determination map 2, a lower limit threshold line UL of the clutch rotational speed is set. The lower limit threshold line UL defines a lower limit threshold value of the clutch rotational speed regardless of the accelerator opening. The lower limit threshold line UL is set slightly above the clutch rotational speed in the idle state as shown in the figure.

The coasting control device 1 starts coasting control when all the following four coasting start conditions are satisfied.
(1) The accelerator pedal operating speed is within the threshold range. (2) In the coasting control determination map 2, the plot points of the clutch rotational speed and the accelerator opening pass the coasting control threshold line TL in the accelerator return direction. The plot point on the control determination map 2 is within the coasting controllable area CA. (4) In the coasting control determination map 2, the clutch rotational speed is equal to or greater than the lower limit threshold line UL.

The coasting control device 1 is configured to end coasting control when at least one of the following two coasting termination conditions is satisfied.
(1) The accelerator pedal operating speed is outside the threshold range. (2) The plot point on the coasting control determination map 2 is outside the coasting control possible area CA.

  The operation of the coasting control device 1 according to the coasting control determination map 2, the coasting start condition, and the coasting end condition will be described.

  The coasting control execution unit 3 constantly monitors the accelerator opening based on the accelerator pedal operation amount and the clutch rotational speed obtained from the input shaft rotational speed or the vehicle speed, and displays the accelerator opening on the coasting control determination map 2 of FIG. And plot the clutch rotation speed coordinate point. Coordinate points move over time. At this time, when the coordinate point exists in the coasting controllable area CA, the coasting control execution unit 3 determines whether or not to start coasting control. When the coordinate point does not exist in the coasting controllable area CA, the coasting control execution unit 3 does not determine whether to start coasting control.

  Next, when the coordinate point passes the coasting control threshold line TL in the direction in which the accelerator opening decreases, the coasting control execution unit 3 starts coasting control. That is, the coasting control device 1 controls the clutch to be disengaged and controls the control accelerator opening that the ECM 122 instructs the engine to correspond to the idle. As a result, the clutch is disengaged and the engine is in an idle state.

  As shown in FIG. 6 by the arrow indicating the moving direction of the coordinate point, the direction in which the accelerator opening decreases is the left direction in the figure. Even if the coordinate point passes the coasting control threshold line TL, if the movement direction of the coordinate point has a component in the right direction in the figure, the accelerator opening increases, so the coasting control execution unit 3 performs coasting control. Do not start.

  The coasting control execution unit 3 constantly monitors the accelerator opening and the clutch rotational speed even after starting coasting control, and plots the coordinate points of the accelerator opening and the clutch rotational speed on the coasting control determination map 2. When the coordinate point goes out of the coasting controllable area CA, the coasting control execution unit 3 ends the coasting control.

  With the above operation, when the accelerator pedal is operated to the depression side, coasting control is not started even if the coordinate point of the accelerator opening and the clutch rotational speed passes the coasting control threshold line TL, and the accelerator pedal is Since the coasting control is started when the coordinate point passes the coasting control threshold line TL only when operated on the return side, the driver does not feel uncomfortable.

  The coasting control execution unit 3 does not start coasting control when the coordinate point is below the lower limit threshold line UL (the clutch rotational speed is lower than the lower limit threshold). This is because even if the clutch is disengaged when the engine is in an idle state, many effects of suppressing fuel consumption cannot be expected. Therefore, coasting control execution unit 3 starts coasting control only when the coordinate point exists above the lower limit threshold line UL.

  The fuel consumption reduction effect by coasting control will be described with reference to FIG.

  First, it is assumed that coasting control is not performed. The engine speed changes in the range of 1600 to 1700 rpm from about 30 s to about 200 s, and decreases from about 1700 rpm to about 700 rpm (idle speed) between about 200 s and about 260 s. .

  The engine torque increases from about 30 s to about 100 s, but then starts to decrease and continues to decrease to about 150 s. The engine torque is about 0 Nm from about 150 s to about 160 s and increases between about 160 s and about 200 s, but becomes about 0 Nm at about 200 s. As a result, the period during which the engine torque is approximately 0 Nm is from about 150 s to about 160 s (ellipse B1), from about 200 s to about 210 s (ellipse B2), and from about 220 s to about 260 s (ellipse B3). is there.

  The fuel consumption (no vertical axis scale; for convenience, it is arranged so as to overlap with the engine torque) changes from about 50 s to about 200 s almost accompanying the transition of the engine torque. Even if the engine torque is approximately 0 Nm, the fuel consumption is not zero.

  Here, when coasting control is performed, the engine speed is controlled to the idle speed during a period in which the engine torque is approximately 0 Nm. The graph shows a line (thick solid line) of the engine speed during coasting control so as to be separated from a line (solid line) of the engine speed not performing coasting control. The coasting control was executed three times for ellipses B1, B2 and B3. The fuel consumption amount in the period when the coasting control is performed is lower than the fuel consumption amount when the coasting control is not performed, and it is understood that the fuel consumption is saved.

  Next, a specific setting example of the coasting control determination map 2 will be described.

  As shown in FIG. 8, in order to create the coasting control determination map 2, the characteristics of the accelerator opening and the clutch rotational speed are measured, the horizontal axis is the accelerator opening, and the vertical axis is the clutch rotational speed (= engine rotational speed). ; When the clutch is engaged). Thereby, the actually measured engine output torque zero line ZL can be drawn. The entire left side of the engine output torque zero line ZL is the minus region MA, and the entire right side is the plus region PA.

  A coasting control threshold line TL is defined and drawn slightly to the left of the engine output torque zero line ZL. A deceleration zero threshold line TLg is estimated and drawn slightly to the left of the coasting control threshold line TL. An acceleration zero threshold line TLk is estimated and drawn slightly to the right of the engine output torque zero line ZL. A region sandwiched between the deceleration zero threshold line TLg and the acceleration zero threshold line TLk is defined as a coasting controllable region CA. In this example, the lower limit threshold line UL is set to 880 rpm.

  The deceleration zero threshold line TLg and the acceleration zero threshold line TLk are set to such an extent that the driver is difficult to drive. However, since they are problems of human sense, they cannot be quantified by design, so they are tuned with an actual vehicle. The coasting control threshold line TL is set at the center of the deceleration zero threshold line TLg and the acceleration zero threshold line TLk.

  The graph of FIG. 8 created as described above is appropriately digitized (discretized) and written into the storage element, whereby the coasting control determination map 2 that can be used for the arithmetic processing by the coasting control execution unit 3 is obtained.

  Next, prevention of shift switching during coasting control in the coasting control device 1 of the present invention will be described with reference to FIG.

  In step S91, the coasting shift switching prevention unit 4 determines whether the coasting control by the coasting control execution unit 3 is currently being performed. If NO, the process proceeds to the end. If YES, the process proceeds to step S92. The determination in step S91 is NO until the coasting control is started after the coasting control is ended, YES is performed when the coasting control is started, and thereafter, the clutch is engaged and the coasting control is completely ended. Yes.

  In step S92, the coasting shift switching prevention unit 4 stores the coasting control start gear stage stored when the coasting control execution unit 3 starts coasting control and the current gear read from the shift sensor of the transmission. By comparing with the gear, it is determined whether or not shift switching has been performed from the gear at the start of coasting control to another gear. In the case of NO, since the shift switching has not been performed, the process proceeds to the end. In the case of YES, the shift switching has been performed, and thus the process proceeds to step S93.

  In step S93, the coasting shift switching prevention unit 4 performs control so that the clutch is not engaged because the shift switching from the gear stage at the start of the coasting control to another gear stage has been performed. Specifically, even if the coasting control execution unit 3 determines to end coasting control, coasting control is not terminated.

  In step S94, the coasting shift switching warning unit 5 sends a signal to a warning device such as a speaker, a buzzer, a display lamp, and a display screen to warn the driver.

  As a result, when shift switching is performed during coasting control, the clutch is not brought into contact, so that engine overrun and tire lock can be avoided. Thereafter, the driver notices the warning and performs shift switching to return to the gear position at the start of the coasting control, so that the control of the coasting shift switching prevention unit 4 that does not engage the clutch is eliminated, and the determination in the coasting control execution unit 3 It is possible to end coasting control on the street. At this time, since the gear stage returns to the same as when coasting control is started, engine overrun or tire lock does not occur even if the clutch is engaged.

  As described above, according to the coasting control device 1 of the present invention, when shift switching is performed during coasting control, the clutch is not engaged, so that shift switching during coasting control can be prevented. Moreover, the shift sensor and warning device to be used are conventionally provided in the vehicle, and there is no need to add a special member for preventing shift switching. Therefore, there is no cost increase factor, and it is preferable to adopt it for a popular vehicle.

1 coasting control device 2 coasting control determination map 3 coasting control execution unit 4 coasting shift switching prevention unit 5 coasting shift switching warning unit

Claims (3)

A coasting control execution unit that starts coasting control by disengaging the clutch and lowering the engine speed while the engine is in an operation state where the engine does not work to the outside;
A coasting control device comprising: a coasting shift switching prevention unit that does not engage the clutch when shift switching is performed during coasting control. With a coasting control determination map that is referred to by the clutch rotational speed and accelerator opening,
The coasting control execution unit includes the coasting control determination region in which a plot point of the clutch rotational speed and the accelerator opening is within the coasting controllable region, the accelerator pedal operation speed is within a predetermined range, and the coasting control determination When the plot point of the clutch rotation speed and accelerator opening on the map passes the coasting control threshold line in the direction of decreasing the accelerator opening, coasting control is started and the accelerator pedal operation speed is out of the specified range or the plot point 2. The coasting control device according to claim 1, wherein when the engine goes out of the coasting controllable region, the engine speed is increased and the coasting control is terminated by engaging the clutch.   The coasting control device according to claim 1, further comprising a coasting shift switching warning unit that issues a warning when shift switching is performed during coasting control.

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