JP5272938B2 - Coasting control auxiliary device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coasting control auxiliary device capable of inhibiting coasting control region reduction due to tuning and improving fuel economy. <P>SOLUTION: A variable braking means 5 for variably providing a braking power to the vehicle 10 is provided in the power transmission system following a clutch 3. Coasting control is continued and deceleration braking is carried out by the variable braking means 5 when the plots of an actual accelerator opening degree and a clutch rotation number on the coasting control map come into the hunting dangerous zone C during the coasting control. In addition, the braking power of the deceleration braking is set at the same magnitude as that of engine braking power generated when coasting control is not carried out. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention is directed to a vehicle that performs coasting control in which the clutch provided between the engine and the transmission is disengaged and the engine is idling when the engine is in a no-load state, and the coasting is performed to assist the coasting control. The present invention relates to a control auxiliary device.

  A mechanism (clutch connecting / disconnecting mechanism) that can automatically and manually connect / disconnect a clutch provided between a vehicle engine and a transmission is known (see, for example, Patent Document 1).

  The clutch connecting / disconnecting mechanism will be described with reference to FIG. As shown in FIG. 8, a clutch body 104 is provided between the engine 102 and the transmission 103 of the vehicle, and the clutch body 104 is connected / disconnected by a clutch connection / disconnection mechanism 105.

  In the clutch connecting / disconnecting mechanism 105, a slave cylinder (output system) 106 connected to the clutch body 104 is a master cylinder (pedal system) 108 connected to a clutch pedal 107 and a clutch free controlled by an electronic control unit 109. It is controlled via an intermediate cylinder 111 by two input systems with an actuator (actuator system) 110.

  Conventionally, coasting control is known as control that uses such a clutch connection / disconnection mechanism 105 to improve fuel efficiency (see, for example, Patent Document 2).

  The coasting control improves the fuel efficiency of a vehicle equipped with a mechanism that can automatically connect and disconnect the clutch by automatically disengaging the clutch when a predetermined condition is satisfied and setting the engine speed to idle or a corresponding speed. It is a technique.

  In this coasting control, it is only necessary to be able to automatically cut off the output of the engine to the drive wheel side. Therefore, in addition to the clutch connecting / disconnecting mechanism described above, the same effect can be obtained in a normal torque converter, AT, and AMT system. It is done.

Japanese Patent Laid-Open No. 11-247885 JP 2006-342832 A

  Incidentally, in order to determine the start or end of coasting control, as shown in FIG. 9, coasting control MAP using the accelerator opening and the clutch rotational speed as parameters may be used.

  In FIG. 9, N is a no-load line connecting the accelerator opening and the clutch rotational speed when the engine output and friction (internal resistance) are balanced, and S is a start threshold line for determining the start of coasting control. R and A are a deceleration 0 threshold line and an acceleration 0 threshold line for determining the end of coasting control.

  The coasting control is started when the point (plot point) in which the accelerator opening and the clutch rotational speed are plotted on the coasting control MAP crosses the start threshold line S from the left to the right in FIG. The coasting control continues to run while the plot point is within the area surrounded by the deceleration 0 threshold line R and the acceleration 0 threshold line A, and the plot point moves the deceleration 0 threshold line R from right to left. Or when the acceleration 0 threshold line A is crossed from left to right.

  The threshold lines S, R, and A of the coasting control MAP are determined by tuning based on the no-load line N, and a speed range is set in the coasting control MAP for the tuning.

  Range 1 to Range 4 in FIG. 9 indicates the speed range of the vehicle. Range 1 is assumed to be a general road and is about 35 km / h. Range 2 assumes a dedicated road and is approximately 65 km / h. Range 3 and Range 4 are assumed to be highways, and Range 3 is about 85 km / h, and Range 4 is about 95 km / h. The area above Range 4 is an area where tuning (adjustment) and evaluation cannot be performed in a vehicle to which the map of FIG. 9 is applied. Since the above-mentioned range changes when the vehicle type changes, the assumed speed changes.

  FIG. 10 shows characteristic points during actual coasting control MAP tuning.

  The threshold lines S, R, A and the characteristic points of the coasting control MAP vary depending on the engine mounted and the vehicle characteristics. When tuning the coasting control MAP, tuning is performed so that the dead zone near the no-load line N is taken frequently so that there is no problem.

  As indicated by reference numeral B in FIG. 10, when there is a change point of the no-load line N or when there is a change in the start threshold line S, hunting is likely to occur unless the deceleration 0 threshold line R is changed. That is, in the vicinity of a change in the no-load line N (this is a characteristic of the engine and engine auxiliary equipment), the threshold lines S, R, and A of the coasting control must be changed. The deceleration 0 threshold line R, which is the deceleration side escape from this change point, is susceptible to hunting due to this change, and the coasting control region is slightly narrowed as in the coasting control MAP of FIG. As a result, the fuel efficiency improvement rate in this region (hunting danger region C) is inevitably reduced. In addition, the above-described hunting cannot be suppressed by the accelerator filter or can be achieved by changing the filter, but coasting control in other areas is difficult to enter, and the overall effect is reduced.

  As described above, in the conventional coasting control, the coasting control is not performed in the hunting danger area in order to prevent hunting. ) Decreased, and there was a problem that fuel consumption could not be improved.

  Accordingly, an object of the present invention is to provide a coasting control auxiliary device that can solve the above-described problems, suppress a decrease in the coasting control region due to tuning, and improve fuel efficiency.

  In order to achieve the above object, according to the present invention, an engine mounted on a vehicle and a clutch provided between the engine and a transmission are controlled by a control unit, and the control unit is configured so that the vehicle is running. When the engine is in a no-load state, the clutch is disengaged and coasting control for idling the engine is performed, and the control means determines the start and end of the coasting control, the accelerator opening and the clutch rotational speed. Is determined from the coasting control map using the parameter as a parameter, and a deceleration 0 threshold line is set in the coasting control map to determine the end of the coasting control, and the control means actually executes the coasting control during execution of the coasting control. The points where the accelerator opening and the clutch rotational speed of the engine are plotted on the coasting control map indicate that the deceleration 0 threshold line is shifted from the side where the accelerator opening is large to the side where it is small. A coasting control auxiliary device for ending the coasting control at the time and assisting the coasting control when the engine output and the friction are balanced when tuning the deceleration zero threshold A no-load line in which the accelerator opening and the clutch rotational speed are plotted on the coasting control map is obtained, an offset line obtained by offsetting the no-load line to the side where the accelerator opening is small is obtained, and the coasting control is performed based on the offset line. A hunting danger area where hunting is likely to occur is obtained when the control is executed, and a line obtained by changing the offset line toward the no-load line so that the coasting control ends in the hunting danger area is the deceleration 0 threshold. In the coasting control auxiliary device that is a line, the braking force is variably applied to the vehicle in the power transmission system downstream of the clutch. Variable braking means is provided, and when the coasting control is being executed, the control means plots the actual accelerator opening degree and clutch rotational speed on the coasting control map. When entering, the coasting control is continued and deceleration braking is performed by the variable braking means, and the braking force of the deceleration braking is the same as the engine brake generated when the coasting control is not performed. Is set to

  Preferably, the variable braking means includes a generator attached to the transmission, and braking force adjusting means for adjusting a braking force by adjusting a power generation amount of the generator.

  According to the present invention, it is possible to suppress the decrease of the coasting control region due to tuning and to exhibit an excellent effect that fuel efficiency can be improved.

FIG. 1 is a schematic configuration diagram of a coasting control auxiliary device according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram of the clutch connecting / disconnecting mechanism of the present embodiment. FIG. 3 is a schematic configuration diagram of the controller of the present embodiment. FIG. 4 is a diagram for explaining coasting control of the present embodiment. FIG. 5 is an example of a coasting control map of the present embodiment. FIG. 6 is an example of the lever schedule of this embodiment. FIG. 7 is a diagram for explaining the effect of this embodiment. FIG. 8 is a schematic configuration diagram of a conventional clutch connecting / disconnecting mechanism. FIG. 9 is a diagram for explaining area setting for coasting control. FIG. 10 is a diagram for explaining hunting during coasting control.

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

  The coasting control auxiliary device according to the present embodiment is directed to a vehicle having a relatively small generator (hereinafter referred to as a generator), for example.

  A schematic structure of the vehicle and the coasting control auxiliary device of the present embodiment will be described based on FIGS. 1 to 3.

  As shown in FIG. 1, the vehicle 10 includes an engine 2, a transmission 4 connected to the engine 2 via a clutch 3, and a controller 6 for controlling these devices 2-4.

  The engine 2 is, for example, a multi-cylinder diesel engine. The engine 2 includes a plurality of cylinders 11, an injector 12 for injecting and supplying fuel to each cylinder 11, and an engine speed sensor 13 for detecting the engine speed.

  In the injector 12, the fuel injection amount and the injection timing are controlled by the controller 6. The engine speed sensor 13 is attached to a crankshaft or camshaft (not shown) that forms the output shaft of the engine 2, and transmits the detected value to the controller 6.

  The clutch 3 is for transmitting and shutting off the power from the engine 2 to the transmission 4, and a clutch body 21 (for example, a wet multi-plate clutch) provided between the engine 2 and the transmission 4, And a mechanism (hereinafter referred to as a clutch connection / disconnection mechanism) 22 for connecting and disconnecting the clutch body 21.

  The clutch body 21 includes a clutch disk 23, a pressure plate 24, a diaphragm spring 25, a clutch cover 26, and a release fork 27. In the clutch body 21, the pressure plate 24 presses the clutch disk 23 against a disk (for example, a flywheel) fixed to the crankshaft by the urging force of the diaphragm spring 25 when connected, and the release disk 27 causes the clutch disk 23 to move to the crankshaft when disconnected. Separated from.

  The clutch connection / disconnection mechanism 22 is basically configured to be automatically connected / disconnected by the controller 6 and to be manually connected / disconnected by the clutch pedal 28.

  More specifically, as shown in FIG. 2, the clutch connecting / disconnecting mechanism 22 is controlled by the master cylinder 29 connected to the clutch pedal 28, the slave cylinder 30 connected to the release fork 27, and the controller 6. And a clutch-free actuator 31. In the illustrated example, when the clutch pedal 28 is depressed, the master cylinder 29 extends. When the slave cylinder 30 is extended, the release fork 27 is operated to the clutch disengagement side.

  The clutch free actuator 31 includes an operating cylinder 32 connected to the master cylinder 29 and the slave cylinder 30 and an actuator unit 33 connected to supply and recover hydraulic pressure to the operating cylinder 32.

  The operating cylinder 32 is formed in a cylindrical shape whose both ends are closed, and a primary piston 35 and a secondary piston 36 are arranged in the axial direction and are movably accommodated therein.

  A pedal system passage 37 communicating with the master cylinder 29 is connected to one end of the operating cylinder 32 (end on the primary piston 35 side, right end in FIG. 2), and the other end (end on the secondary piston 36 side, FIG. 2). An output system passage 38 communicating with the slave cylinder 30 is connected to the left end). A spring 39 is provided between the secondary piston 36 and the left end of the operating cylinder 32 to urge the secondary piston 36 toward the primary piston 35 (right side).

  An intermediate position in the axial direction of the operating cylinder 32 is provided between the primary piston 35 and the secondary piston 36 between the primary piston 35 and the secondary piston 36, and between the primary piston 35 and the secondary piston 36. Is connected to the outflow passage 41 for collecting the hydraulic oil to the actuator unit 33. A hydraulic oil tank 42 is connected to the operating cylinder 32 closer to the secondary piston 36 than the inflow path 40. The hydraulic oil tank 42 is connected to the actuator unit 33 by a recovery path 43.

  The actuator unit 33 includes a hydraulic pump 45 provided in the inflow passage 40 and driven by a motor 44, and a solenoid valve 46 provided in a passage 49 that connects the outflow passage 41 and the recovery passage 43. In the actuator unit 33, 47 is a check valve and 48 is a relief valve. The opening degree of the solenoid valve 46 is continuously controlled (for example, duty control) by the controller 6.

  In this clutch connection / disconnection mechanism 22, when the clutch pedal 28 is depressed, the primary piston 35 of the operating cylinder 32 moves to the left side together with the secondary piston 36 by the hydraulic pressure of the master cylinder 29, and the clutch body 21 operates to the disconnection side. When the opening degree of the solenoid valve 46 is reduced, the secondary piston 36 is moved to the left side by the pressure of the hydraulic pump 45, and the clutch body 21 is operated to the disconnected side.

  On the other hand, when the clutch pedal 28 is returned or the opening degree of the solenoid valve 46 is increased, the secondary piston 36 moves to the right side and the clutch main body 21 operates to the connection side.

  Returning to FIG. 1, the transmission 4 includes an input shaft 51 connected to the clutch 3, an output shaft 52 connected to a propeller shaft (not shown), the input shaft 51, the counter shaft, the main shaft, and the output shaft 52. It has a plurality of gears (not shown) provided, and the shift control is automatically performed by the controller 6.

  The transmission 4 is provided with an input shaft rotational speed sensor 53 for detecting the rotational speed of the input shaft 51 of the transmission 4, and the input shaft rotational speed sensor 53 transmits the detected value to the controller 6.

  In the present embodiment, the rotational speed of the input shaft 51 of the transmission 4 is the clutch rotational speed (the output-side rotational speed of the clutch body 21). That is, the input shaft rotational speed sensor 53 serves as clutch rotational speed detection means for detecting the clutch rotational speed. For example, the clutch rotational speed may be calculated from the vehicle speed and the gear ratio of the transmission 4. In this case, a detection value of a vehicle speed sensor 76, which will be described later, is used as the vehicle speed, and a gear ratio is calculated from detection values of a shift sensor 72 and a select sensor 73, which will be described later.

  The power from the output shaft 52 of the transmission 4 is transmitted to drive wheels through a propeller shaft, a differential gear, and a drive shaft (not shown) in this order. That is, the above-described clutch 3, transmission 4, propeller shaft (not shown), differential gear, and drive shaft constitute a power transmission system from the engine 2 to the drive wheels.

  The coasting control auxiliary device 1 of the present embodiment is attached to a transmission 4 (that is, a power transmission system subsequent to the clutch 3), a variable braking means 5 for variably applying a braking force to the vehicle 10, and the controller 6 It consists of. The controller 6 serves as control means for executing coasting control and regeneration assist control, which will be described later.

  The variable braking means 5 includes a generator 56 attached to the transmission 4, an inverter 57 serving as a braking force adjusting means for adjusting a braking force by adjusting a power generation amount (also referred to as a regeneration amount) of the generator 56, and the inverter And a battery 58 (power adjustment system) connected to 57.

  The generator 56 and the inverter 57 (control system) are configured as a transmission-integrated (or integrated) compact power generation unit. The generator 56 is a generator (for example, an AC generator) having an output smaller than the output of the engine 2, and is, for example, 10 kW or less. The generator 56 is formed in a size that can be attached to the rear end (the right end in FIG. 1) of the transmission 4.

  More specifically, the gear 60 is fixed to the shaft 59 of the generator 56, the gear 60 meshes with a gear 61 fixed to the output shaft 52 of the transmission 4, and the gear 60 and the gear 61 are interposed therebetween. The generator 56 is connected to the output shaft 52 at a predetermined gear ratio (reduction ratio). A housing 63 that houses the gear 60 and the gear 61 is provided at the rear of the transmission 4, and a generator 56 is attached to the outer surface (rear surface) of the housing 63.

  In the example shown in the figure, a small generator 56 is attached to the rear end of the transmission 4. However, the variable braking means 5 may be anything as long as it can control the output kW (braking force) and apply deceleration. For example, the variable braking means 5 may be a retarder or an alternator. If control is possible, an air conditioner compressor (variable capacity) can also be applied to the variable braking means 5.

  In the case of the generator 56 and the alternator, whether to use the generated electricity as an auxiliary for normal alternator power generation or to release it as heat is determined by cost conversion. If the cost is not met, the electricity generated by the generator 56 may be converted into heat, dissipated and discarded. If it is a retarder, it is released as heat. In any case, since the level is as small as several KW (for example, about 10% or less of the maximum output of the engine 2), the use can be appropriately determined by the vehicle 10.

  The inverter 57 converts the electricity generated by the generator 56 from alternating current to direct current and supplies it to the battery 58, and the electricity charged in the battery 58 is supplied to auxiliary equipment (not shown) of the vehicle 10. The inverter 57 can adjust the current (or voltage) flowing from the generator 56 to the battery 58, and adjusts the regenerative braking force of the generator 56 by adjusting the current (or voltage). The inverter 57 is controlled by the controller 6.

  The controller 6 includes an engine electronic control unit 66 that controls the engine 2 and a transmission electronic control unit 67 that controls the transmission 4.

  The engine electronic control unit 66 is communicably connected to the engine speed sensor 13, an accelerator opening sensor 69 for detecting the depression amount (accelerator opening) of the accelerator pedal 68, the injector 12, and the like. The engine electronic control unit 66 controls the injector 12 so that the detected value of the engine speed sensor 13 becomes a predetermined idling speed during coasting control, which will be described later, and causes the engine 2 to perform idling operation.

  As shown in FIG. 3, various devices 44, 46, 71-86 are communicably connected to the transmission electronic control unit 67.

  More specifically, in FIG. 3, 71 is a shift knob SW (switch), 72 is a shift sensor & select sensor & neutral sensor of the transmission 4, 75 is the input shaft rotational speed sensor (also referred to as T / M rotational sensor), 76 is a vehicle speed sensor, 77 is an idle SW, 78 is a manual switch SW, 79 is a parking brake SW, 80 is a door SW, 81 is a brake SW, 82 is a half-clutch adjustment SW, and 83 is for detecting the stroke of the clutch 3. The clutch sensor 84 is a hydraulic pressure SW provided in the output system passage 38 of the clutch connecting / disconnecting mechanism 22, 85 is a slope start assisting valve, and 86 is a warning & meter.

  The engine electronic control unit 66 and the transmission electronic control unit 67 are communicably connected to each other by a CAN 87 (vehicle-mounted network). For example, the CAN 87 communicates signals such as the engine speed, the accelerator opening, and the engine speed change request between the engine electronic control unit 66 and the transmission electronic control unit 67.

  The controller 6 according to the present embodiment performs coasting control for disengaging the clutch 3 and idling the engine 2 when the engine 2 is in a no-load state while the vehicle 10 is traveling. The controller 6 determines the start and end of the coasting control from a map (hereinafter referred to as coasting control MAP) using the accelerator opening and the clutch rotational speed as parameters.

  Next, the operation of the coasting control auxiliary device 1 of the present embodiment will be described based on FIGS. 4 to 6.

  First, coasting control will be described.

  In general, the engine 2 has an internal friction that prevents the engine 2 from rotating, and the internal friction acts as a resistance against the engine 2 in an operating state. The internal friction basically increases as the engine speed increases, and at a certain engine speed, the internal friction is the same as the output obtained by fuel combustion.

  At this engine speed, the output obtained by combustion is used only for maintaining the rotation of the engine 2, and the substantial output from the engine 2 to the drive wheel side (transmission 4 side) is 0 or Near zero. That is, the engine 2 is in a no-load state. In this no-load state, since the output of the engine 2 is almost zero, even if the engine 2 is disconnected from the power transmission system, there is no influence on the drive wheel side and the vehicle speed does not change.

  Therefore, coasting control is such that when the output of the engine 2 becomes substantially 0, the clutch 3 is disconnected to disconnect the engine 2 from the power transmission system, and the engine 2 is rotated at a predetermined idling speed. As a result, the fuel injection amount required to maintain the rotation of the engine 2 is reduced to reduce fuel consumption.

  An example of coasting control operation will be described with reference to FIG.

  As shown in FIG. 4, at time t0, the accelerator opening is 70%, and the engine speed increases from time t0 and the vehicle 10 is accelerated.

  At time t1, the accelerator pedal 68 is returned, the accelerator opening becomes 35%, and the coasting control start condition is satisfied. Thereby, coasting control is started and executed from time t1.

  From time t1 to time t2, the engine speed becomes the idling speed, the clutch 3 is disconnected, and the vehicle 10 coasts (coasts).

  At time t2, the coasting control end condition is satisfied. In the illustrated example, the accelerator opening is 0%, or the coasting condition cancellation condition (for example, end condition 1 described later) is satisfied. As a result, coasting control is terminated, and rotation matching control for connecting the clutch 3 is started.

  When the rotational speed of the engine matches the rotational speed of the input shaft 51 of the transmission 4, the clutch 3 is connected. As a result, the engine brake acts to decelerate the vehicle 10 and reduce the engine speed.

  Thus, the controller 6 starts coasting control when a predetermined start condition is satisfied, and ends coasting control when a predetermined end condition (prohibition condition) is satisfied during execution of the coasting control.

  The start condition and end condition of coasting control will be described with reference to FIG.

  FIG. 5 shows a coasting control MAP used to determine the start and end of coasting control, which is digitized and stored in storage means (not shown) of the controller 6. In the coasting control MAP, the vertical axis represents the clutch rotational speed, and the horizontal axis represents the accelerator opening.

  Each threshold line for determining the start and end of coasting control is set in the coasting control MAP, and the controller 6 controls the accelerator opening detected by the accelerator opening sensor 69 and the input shaft on the coasting control MAP. The clutch rotational speed detected by the rotational speed sensor 53 is plotted, and the plotted points (hereinafter referred to as plot points) are compared with each threshold line.

  More specifically, in the coasting control MAP of FIG. 5, the symbol N is a no-load line. The no-load line N obtains in advance an accelerator opening degree and a clutch rotational speed (engine rotational speed) when the output of the engine 2 and the friction are balanced by an experiment or the like, and the obtained accelerator opening degree and clutch rotational speed are coasting controlled. It is set by plotting on MAP.

  The symbol S is a starting threshold line. The start threshold line S is a threshold line for determining the start of coasting control, and coasting control is performed when the plot point straddles the start threshold line S from the side where the accelerator opening is small to the large side. Be started. The start threshold line S is set by offsetting (shifting, shifting) the no-load line N to the side where the accelerator opening is small (the side where the accelerator pedal 68 is returned) and performing tuning described later.

  Symbol A is an acceleration zero threshold line. The acceleration 0 threshold line A is a threshold line for determining the end of coasting control, and during execution of coasting control, the plot point moves the acceleration 0 threshold line A from the side where the accelerator opening is small to the large side. Coasting control is terminated when straddling. The acceleration 0 threshold line A is set by offsetting the no-load line N to the side where the accelerator opening is large (the side where the accelerator pedal 68 is depressed) and tuning.

  Symbol R is a deceleration 0 threshold line. The deceleration 0 threshold line R is a threshold line for determining the end of coasting control, and during execution of coasting control, the plot point moves the deceleration 0 threshold line R from the side where the accelerator opening is large to the small side. Coasting control is terminated when straddling. The deceleration 0 threshold line R is set by offsetting the no-load line N to the side where the accelerator opening is smaller than the starting threshold line S (the side where the accelerator pedal 68 is returned) and tuning.

  Reference symbol L is a coasting control lower limit line. The coasting control lower limit line L is a line that defines the lower limit of the clutch rotational speed at which coasting control is executed, and is a straight line with a constant clutch rotational speed (referred to as a clutch rotational speed threshold). The clutch rotational speed threshold is set near the idling rotational speed described above and higher than the idling rotational speed. That is, even when the clutch 3 is disengaged in the vicinity of the idling speed, the fuel consumption reduction effect is small, so the clutch 3 is not disengaged (that is, coasting control is not performed).

  In the following description, the area on the side (right side) where the accelerator opening is larger than the acceleration 0 threshold line A is the acceleration area, and the area between the acceleration 0 threshold line A and the deceleration 0 threshold line R is coasting control. The area on the side (left side) where the accelerator opening is smaller than the deceleration area and the deceleration 0 threshold line R is referred to as a deceleration area.

  The starting conditions for coasting control are the following four.

  Start condition 1 The operating speed of the accelerator pedal 68 is within a predetermined threshold range.

  Starting condition 2 The plot points of the accelerator opening degree and the clutch rotational speed passed through the starting threshold line S of the coasting control MAP in the return direction of the accelerator pedal 68.

  Starting condition 3 The plot points of the accelerator opening and the clutch rotational speed are within the coasting control possibility region of the coasting control MAP.

  Start condition 4 The clutch rotational speed is equal to or greater than the clutch rotational speed threshold (the plot point is equal to or greater than the coasting control lower limit line L).

  When all of these start conditions 1 to 4 are satisfied, the controller 6 starts coasting control.

  The coasting control end conditions are the following two.

  End condition 1 The operating speed of the accelerator pedal 68 is outside the threshold range.

  Termination condition 2 The plot points of the accelerator opening and the clutch rotational speed are outside the coasting control possibility region of the coasting control MAP.

  The controller 6 of the present embodiment basically ends coasting control when the termination condition 1 or the termination condition 2 is satisfied, but a hunting danger area described later even if the plot point is outside the coasting control possibility area. When in C, coasting control is continued.

  That is, when the coasting control is executed, the controller 6 continues the coasting control when the actual accelerator opening degree and the clutch rotational speed plotted on the coasting control MAP enter the hunting danger region C and is variable. Regenerative assist control is performed in which deceleration braking by the braking means 5 is performed and the braking force of deceleration braking is set to the same magnitude as the engine brake generated when coasting control is not performed.

  Here, the hunting danger region C is obtained by tuning the deceleration 0 threshold line R.

  Next, an example of threshold line tuning will be described with reference to FIG.

  As indicated by reference numeral T1 in FIG. 5, the starting threshold line S is tuned so that the clutch rotational speed changes to the side (left side) away from the no-load line N in the region near 2000 rpm (medium speed region). That is, the engine 2 of the present embodiment has a region where combustion is unstable near the engine speed of 2000 rpm to 2200 rpm, and therefore, the range of coasting control is widened to deal with.

  Further, as indicated by reference numeral T2, the start threshold line S is tuned so as to change to the side (right side) approaching the no-load line N in the region near 2400 rpm (high-speed region). This is because the accelerator operation amount becomes small at high speed, and the operability is lowered unless the width for entering the coasting control is narrowed.

  Next, as indicated by reference numeral T3, the acceleration 0 threshold line A changes so that the clutch rotational speed changes to the side (right side) away from the no-load line N in the region (low speed region) near 1200 rpm to about 1500 rpm. It is tuned. That is, in the region where the speed is lower than that of the exclusive road, the accelerator opening increases by 10% or more at the time of reacceleration, so that the coasting control possibility region can be slightly expanded to the acceleration region side.

  Next, as indicated by reference numeral T4, the deceleration 0 threshold line R is tuned so that the clutch rotational speed changes to the side away from the no-load line N (left side) in the region near 1200 rpm-1800 rpm (low speed region). Is done. In other words, the coasting control possibility region is expanded to the deceleration region side because the influence of the coasting control to the deceleration region is less affected by the traffic flow in the region slower than the exclusive road.

  Furthermore, the deceleration 0 threshold line R of the present embodiment is tuned to prevent hunting, and a hunting danger area C is obtained during the tuning.

  Specifically, when tuning the deceleration 0 threshold line R, the no-load line N is first offset to the side where the accelerator opening is smaller to obtain an offset line (not shown). Next, an area where hunting is likely to occur when the coasting control is executed based on the offset line (hunting danger area C) is obtained by a running test or the like. Next, a line in which the offset line is changed closer to the no-load line N so as to end coasting control in the hunting danger region C is obtained, and the obtained line is set as a deceleration 0 threshold line R.

  In the example shown in the figure, the area where the clutch speed is around 2100 rpm and the accelerator opening is about 20% to about 40% and the area where the clutch speed is around 3200 rpm and the accelerator opening is about 55% to about 70% are hunting hazards. It becomes area C. This hunting danger area C is a coasting area reduced to prevent hunting, and is determined by the characteristics of the engine 2 and the auxiliary machine characteristics.

  As an example of hunting, the hunting danger area C is an area close to the no-load line N, but unlike other areas, the driver expects (predicts) that a minute engine brake acts on the vehicle.

  However, when coasting control is performed in the hunting danger region C, the clutch 3 is disengaged by coasting control, so that the engine brake does not act. Therefore, the driver feels a sense of incongruity and performs a return operation and a depression operation of the accelerator pedal 68. With this operation, the plot point repeatedly enters and exits the coasting control possibility region, and hunting occurs.

  Conventionally, engine braking is applied to the vehicle 10 by stopping coasting control in the hunting danger region C, thereby preventing hunting.

  On the other hand, in this embodiment, coasting control is continued by applying the braking force by the generator 56 instead of engine braking to prevent hunting.

  That is, the dangerous hunting region C is a deceleration region, and coasting control can be applied if the vehicle can be slightly decelerated.

  Therefore, when the plot point enters the hunting danger region C during execution of the coasting control, the controller 6 of the present embodiment turns the generator 56 while applying the coasting control to apply resistance. At this time, the power generation amount (regeneration amount) of the generator 56 is a value calculated from the accelerator opening, the clutch rotational speed, and the lever schedule.

  More specifically, the controller 6 controls the inverter 57 to set the braking force of the deceleration braking by the regeneration of the generator 56 to the same magnitude as the engine brake generated when it is assumed that coasting control is not performed. To do.

  Next, calculation of the regeneration amount by the generator 56 will be described based on FIG.

  FIG. 6 is a lever schedule of the engine 2, where the vertical axis represents the engine torque and the horizontal axis represents the engine speed. Line 10% -line 100% in the figure shows the relationship between engine speed and engine torque at each accelerator opening.

  During the coasting control, the engine speed becomes the idling speed. Therefore, when calculating the regeneration amount (braking force), the clutch speed (input shaft speed in the example) is used instead of the engine speed. The detection value of the number sensor 53) is used.

  The regenerative amount is calculated by calculating the torque according to the lever schedule in FIG. 6 from the accelerator opening in the hunting danger area C (in the regenerative area) and the clutch rotational speed in FIG. 3, and W = engine rotational speed Ne (rpm) × engine torque It can be calculated by Te (Nm) × 2π / 60.

  For adjustment, it is easy to tune by multiplying a coefficient (example: a) and adding a constant (example: b). For example, the calculation formula is W = a × Ne (rpm) × Te (Nm) × 2π / 60 + b.

  This lever schedule is obtained by experiments or the like and is stored in advance as a map in storage means (not shown) of the controller 6. For example, the controller 6 reads the engine torque from the lever schedule based on the detection values of the accelerator opening sensor 69 and the input shaft rotational speed sensor 53 so that the braking force of the generator 56 matches the read engine torque. The inverter 57 is controlled.

  Thus, according to the coasting control auxiliary device 1 of the present embodiment, it is possible to suppress a decrease in the coasting control region due to tuning and improve fuel efficiency.

  That is, by performing the regenerative braking calculated as shown in FIG. 6 above, an inflection point is created on the deceleration zero threshold line R (point) even in coasting control with the engine 2 having a change point on no-load. Coasting control can be performed without any problem.

  Since the deceleration 0 threshold line R can be straightened, the operational stability of coasting control is improved. This is because the end of coasting control appears in proportion to the clutch rotational speed and the accelerator opening, so that the driver can easily understand the behavior of the vehicle 10 during coasting control, thereby improving controllability.

  In addition, since the variable braking means 5 is composed of the small generator 56, the cost can be reduced.

  That is, in the case of a parallel hybrid vehicle (HEV) having a motor generator, the above-described regenerative assist control can be operated without any problem, but the installation of a full HEV system is useless in order to operate a small area. The generator 56 is sufficient because there is only regeneration (deceleration).

  Next, based on FIG. 7, the effect by the coasting control auxiliary apparatus 1 of this embodiment is demonstrated.

  The graph of FIG. 7 is an effect prediction on a dedicated road (an empty car dedicated road). In FIG. 7, the left vertical axis represents the engine speed, the right vertical axis represents the vehicle speed, and the horizontal axis represents time.

  The symbol NE is a line indicating a change in engine speed, and the symbol V is a line indicating a change in vehicle speed. Reference numeral CC indicates a region only for coasting control (a region in which coasting control is executed when coasting control is terminated in the hunting danger region C). Symbol AC indicates a region of coasting control + regeneration assist control (region in which regeneration assist control is executed).

  As shown in FIG. 7, in the present embodiment, the distance (time) for traveling by reducing the engine speed to the idling speed is increased by the amount of the region AC in which the regeneration assist control is executed. Therefore, the fuel injection amount is reduced and the fuel efficiency is improved.

  In the example of FIG. 7, the fuel efficiency is improved by 7.8% when only coasting control is performed and when coasting control is not performed. On the other hand, in the case of this embodiment, it is estimated that a 10.1% fuel consumption improves compared with the case where coasting control is not performed.

  Thus, it can be seen that application of the present embodiment increases and stabilizes the coasting control region slightly, so that fuel efficiency can be further improved.

  In addition, this invention is not limited to the above-mentioned embodiment, Various modifications and application examples can be considered.

  For example, in the above-described embodiment, the variable braking means is configured by the generator and the inverter, but is not limited thereto. For example, the variable braking means may be constituted by an alternator, and in that case, a regulator provided in the alternator serves as a braking force adjusting means.

1 coasting control auxiliary device 2 engine 3 clutch 4 transmission 5 variable braking means 6 controller (control means)
10 Vehicle 56 Generator 57 Inverter (braking force adjusting means)

Claims (2)

An engine mounted on the vehicle and a clutch provided between the engine and the transmission are controlled by the control means,
The control means performs coasting control that disengages the clutch and idles the engine when the engine is in a no-load state while the vehicle is running, and the control means starts and ends the coasting control. Is determined from the coasting control map using the accelerator opening and the clutch rotational speed as parameters,
In the coasting control map, a deceleration 0 threshold line for determining the end of the coasting control is set, and the control means sets the actual accelerator opening and the clutch rotational speed during execution of the coasting control. When the point plotted on the coasting control map crosses the deceleration 0 threshold line from the side with a large accelerator opening to the side with a small accelerator opening, the coasting control is terminated and the coasting control assistance for assisting the coasting control A device,
When tuning the deceleration zero threshold line, a no-load line is obtained by plotting on the coasting control map the accelerator opening and the clutch rotational speed when the engine output and the friction are balanced, and the no-load line is An offset line offset to the smaller opening is obtained, a hunting danger area where hunting is likely to occur when the coasting control is executed based on the offset line, and the coasting control ends in the hunting danger area. In the coasting control auxiliary device in which the offset line is changed to the side approaching the no-load line as the deceleration 0 threshold line,
A variable braking means for variably applying a braking force to the vehicle is provided in a power transmission system subsequent to the clutch,
While the coasting control is being executed, the control means continues the coasting control when the actual accelerator opening and the clutch rotational speed plotted on the coasting control map enter the hunting danger region. In addition, the coasting control is characterized in that deceleration braking is performed by the variable braking means, and the braking force of the deceleration braking is set to the same magnitude as the engine brake generated when the coasting control is not performed. Auxiliary device.   The coasting control auxiliary device according to claim 1, wherein the variable braking means includes a generator attached to the transmission, and braking force adjusting means for adjusting a braking force by adjusting a power generation amount of the generator.

Images