JP6094892B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device including an engine, a continuously variable transmission that transmits driving force of the engine to driving wheels, and fuel cut control means that shuts off and restarts fuel supply to the engine.

  In a vehicle equipped with an automatic transmission, when the vehicle is decelerating, fuel cut control is performed to shut off the fuel supply to the engine while slip-controlling the lock-up clutch of the torque converter, and the vehicle is locked up when the vehicle speed falls below a predetermined value. Patent Document 1 or Patent Document 2 below is known in which the clutch is disengaged and the fuel supply is restarted to shift to the idling operation without causing the engine to stall.

Japanese Patent No. 3300906 JP 2007-239724 A

  FIG. 7 is a graph showing the relationship between the vehicle speed and the engine speed from a deceleration running state with a fuel cut to a stop state at a first speed shift stage of a vehicle equipped with a conventional automatic transmission. The engine idling speed is, for example, 700 rpm, and stalls when the engine speed drops below the idling speed. Therefore, the fuel supply is resumed before the engine speed drops below the idling speed (return to fuel cut). Therefore, it is necessary to prevent engine stall by shifting to idling operation.

When the torque converter is provided with a lock-up clutch, the vehicle speed drops to V2, the engine is stalled by disengaging the lock-up clutch at a higher rotational speed than the idling rotational speed and returning to the fuel cut. It is possible to shift to idling operation without any problem.

In this case, the vehicle needs to resume the fuel supply to the engine by fuel cut return well before stopping, but can migrate engines to continue the fuel cut until just before the vehicle stops idling If possible, the fuel consumption of the engine can be further reduced.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to reduce the fuel consumption of the engine by maximally delaying the return from the fuel cut executed when the vehicle is decelerated.

In order to achieve the above object, according to the first aspect of the present invention, an engine, a continuously variable transmission that transmits driving force of the engine to driving wheels, and fuel supply to the engine are shut off and restarted. The continuously variable transmission includes an input shaft connected to the engine, an output shaft connected to the drive wheel, and a speed ratio between the input shaft and the output shaft. And a planetary gear mechanism disposed in parallel with the transmission mechanism between the input shaft and the output shaft, the planetary gear mechanism including a first element connected to the input shaft, A vehicle control device comprising: a second element connected to the output shaft; and a third element connected to an output member of the transmission mechanism via a clutch, wherein the fuel cut control means is a driver Target acceleration indicated by Target acceleration calculating means for calculating the fuel, fuel cut means for cutting off fuel supply to the engine when the vehicle is decelerated when the target acceleration is negative, and the clutch is engaged, and fuel supply to the engine is performed. Target speed ratio calculating means for calculating a target speed ratio of the speed change mechanism for achieving the target acceleration when shut off, and control so that the actual speed ratio of the speed change mechanism matches the target speed ratio. Gear ratio control means for controlling the clutch, clutch control means for holding the clutch engaged until the vehicle stops during control of the actual gear ratio by the gear ratio control means, and fuel to the engine immediately before the vehicle stops There is proposed a vehicle control device comprising fuel cut return means for restarting supply.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the target speed ratio calculating unit is configured to change the speed of the engine so that the engine speed immediately before the vehicle stops coincides with the idling speed. A vehicle control device is proposed, which calculates a target gear ratio of the mechanism.

  According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the clutch control means engages the clutch when a sudden deceleration of the vehicle or a wheel lock is detected. A vehicle control apparatus is proposed in which the fuel cut return means restarts the fuel supply to the engine while releasing the connection.

According to a fourth aspect of the present invention, in addition to the configuration of any one of the first to third aspects, the target gear ratio calculating means is configured such that the engine speed is idling with respect to the current vehicle speed. wherein calculating a target gear ratio of the transmission mechanism so that the rotational speed, when becomes excessive deceleration against targets deceleration in the target gear ratio, the fuel-cut return means the fuel supply to the engine A vehicle control device is proposed which is characterized by restarting.

According to the fifth aspect of the present invention, in addition to the configuration of any one of the first to third aspects, the target speed ratio calculating means is configured such that the engine speed is idling with respect to the current vehicle speed. wherein calculating a target gear ratio of the transmission mechanism so that the rotational speed, wherein when made in the deceleration insufficient for the goal deceleration at the target speed ratio, the brake control means for decelerating the vehicle by means other than the engine brake There is proposed a vehicle control device comprising:

  According to the invention described in claim 6, in addition to the configuration of any one of claims 1 to 5, the fuel cut return means is configured such that when the engine speed falls below the idling speed. A vehicle control device is proposed, which restarts fuel supply to the engine.

  The toroidal transmission mechanism 11 of the embodiment corresponds to the transmission mechanism of the present invention, the output disk 22 of the embodiment corresponds to the output member of the present invention, and the low speed clutch 39 of the embodiment is the clutch of the present invention. The sun gear 44 corresponds to the third element of the present invention, the ring gear 45 of the embodiment corresponds to the second element of the present invention, and the carrier 46 of the embodiment corresponds to the first element of the present invention. The electronic control unit U of the embodiment corresponds to the fuel cut control means of the present invention.

  According to the configuration of the first aspect of the present invention, the vehicle control device shifts the input shaft connected to the engine, the output shaft connected to the drive wheels, and the gear ratio between the input shaft and the output shaft in a stepless manner. And a planetary gear mechanism arranged in parallel with the speed change mechanism between the input shaft and the output shaft, so that the driving force of the engine is circulated between the speed change mechanism and the planetary gear mechanism with the clutch engaged. A geared neutral state in which the driving wheel is stopped while the engine is operating can be realized.

Therefore, when the vehicle is decelerated and the engine is fuel cut by the fuel cut means, the clutch control means engages the clutch and the speed ratio control means controls the speed ratio of the speed change mechanism until just before the vehicle stops. prevent stalling of the engine to maintain the engine speed above idling speed, can be shifted to the idling operation to start the engine by fuel cut operation in the fuel cut recovery Kite stage just before the vehicle stops . This not only maximizes the period during which fuel cuts are performed to save engine fuel consumption, but also maximizes engine brakes to extend the life of the brake pads. .

  Moreover, while the engine is being fuel cut, the target acceleration calculated by the driver is calculated by the target acceleration, and the target transmission ratio is calculated by the target transmission ratio calculation means to achieve the target acceleration. The speed ratio control means controls the actual speed ratio of the speed change mechanism so that it matches the target speed ratio. Therefore, the engine speed can be arbitrarily controlled to adjust the effectiveness of the engine brake. Can be generated to improve the braking feeling.

According to the second aspect of the present invention, the target speed ratio calculating means calculates the target speed ratio of the speed change mechanism so that the engine speed immediately before the vehicle stops coincides with the idling speed, so that the vehicle stops. It is possible to reliably prevent the engine from stalling by maintaining the engine speed equal to or higher than the idling speed until just before .

  According to the third aspect of the present invention, when a sudden deceleration of the vehicle or a wheel lock is detected, the clutch control means disengages the clutch, and the fuel cut return means resumes fuel supply to the engine. Therefore, even when it is difficult to control the speed ratio of the speed change mechanism and the engine speed cannot be controlled to be lower than the idling speed, the shift to the idling operation can be made possible.

According to the fourth aspect of the present invention, the target speed ratio calculating means calculates the target speed ratio of the speed change mechanism so that the engine speed becomes the idling speed with respect to the current vehicle speed, and the target speed ratio is reduced by the target speed ratio. In the case of excessive deceleration with respect to speed, the fuel cut return means resumes fuel supply to the engine, so the deceleration of the vehicle can be reduced by the restarted engine driving force and decelerated at the target deceleration. it can. At this time, if the deceleration of the vehicle is reduced by reducing the speed ratio of the toroidal transmission mechanism and reducing the effectiveness of the engine brake, the engine speed becomes lower than the idling speed and the engine can not shift to idling. It is possible to shift to idling operation by performing fuel cut return before.

  According to the fifth aspect of the present invention, the target speed ratio calculating means calculates the target speed ratio of the speed change mechanism so that the engine speed becomes the idling speed relative to the current vehicle speed, and the target speed ratio is reduced by the target speed ratio. When the deceleration becomes insufficient with respect to the speed, the braking control means decelerates the vehicle by means other than the engine brake, so that it is possible to shift to the idling operation while maintaining the engine speed at the idling speed. The vehicle can be decelerated at the target deceleration.

  According to the sixth aspect of the present invention, the fuel cut return means restarts the fuel supply to the engine when the engine speed falls below the idling speed. When control becomes impossible and the engine speed becomes equal to or lower than the idling speed, the engine can be shifted to idling while preventing the engine from stalling.

The skeleton figure of a continuously variable transmission provided with a toroidal transmission mechanism. The block diagram which shows the circuit structure of an electronic control unit. Graph showing changes in engine speed, overall transmission ratio of continuously variable transmission and transmission ratio of toroidal transmission mechanism (Part 1) Graph showing changes in engine speed, overall transmission ratio of continuously variable transmission and transmission ratio of toroidal transmission mechanism (Part 2) The 1st partial figure of the flowchart of fuel cut control and fuel cut return control. The 2nd partial figure of the flowchart of fuel cut control and fuel cut return control. The graph which shows the relationship between the vehicle speed and engine speed until a vehicle provided with an automatic transmission reaches from a deceleration driving state to a stop state .

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the continuously variable transmission T including the toroidal transmission mechanism 11 includes an input shaft 12, an output shaft 13, a counter shaft 14, and an idle shaft 15 that are arranged in parallel to each other. The crankshaft 16 of the engine E is connected to the input shaft 12 via a damper 17, and the left and right drive wheels are connected to the output shaft 13 via a final drive gear 18, a final driven gear 19, a differential gear D, and drive shafts 20 and 20. W and W are connected.

  The toroidal transmission mechanism 11 disposed on the input shaft 12 includes a first continuously variable transmission mechanism 11F and a second continuously variable transmission mechanism 11R having substantially the same structure, and the first continuously variable transmission mechanism 11F includes the input shaft 12 A substantially cone-shaped input disk 21 fixed to the input shaft 12, a substantially cone-shaped output disk 22 supported on the input shaft 12 so as to be relatively rotatable and slidable in the axial direction, and a pair disposed so as to sandwich the input shaft 12 therebetween. Trunnions 23, 23, a pair of crank-shaped pivot shafts 24, 24 that are rotatably supported at one end by the trunnions 23, 23, and an input disk 21 that is rotatably supported at the other ends of the pivot shafts 24, 24. And a pair of power rollers 25, 25 capable of contacting the output disk 22.

  The surfaces on which the input disk 21 and the output disk 22 abut on the power rollers 25, 25 are formed of toroidal curved surfaces, and when the pair of trunnions 23, 23 move in opposite directions along the trunnion axis that is the axis of their own. The pair of power rollers 25 and 25 tilt around the trunnion shaft, and the contact points of the power rollers 25 and 25 with respect to the input disk 21 and the output disk 22 change.

  The second continuously variable transmission mechanism 11R is disposed substantially in plane symmetry with the first continuously variable transmission mechanism 11F across the drive gear 26, and the output disks of the first and second continuously variable transmission mechanisms 11F and 11R. 22, 22 and the drive gear 26 are integrally formed. However, while the input disk 21 of the first continuously variable transmission mechanism 11F is fixed to the input shaft 12, the input disk 21 of the second continuously variable transmission mechanism 11R is not rotatable relative to the input shaft 12 and moves in the axial direction. The spline coupling is possible, and the hydraulic loader 27 is urged in the axial direction.

  As a result, the power rollers 25, 25 are clamped between the input disk 21 and the output disk 22 of the second continuously variable transmission mechanism 11R, and the power between the input disk 21 and the output disk 22 of the first continuously variable transmission mechanism 11F. The rollers 25, 25 are pinched to generate a pinching pressure that suppresses slipping between the input disks 21, 21 and output disks 22, 22 and the power roller 25.

  When the pair of trunnions 23, 23 of the first continuously variable transmission mechanism 11F are driven in opposite directions by a hydraulic actuator (not shown), the power rollers 25, 25 are tilted in the direction of arrow a in FIG. The contact point moves radially outward with respect to the input shaft 12, and the contact point with the output disk 22 moves radially inward with respect to the input shaft 12, so that the rotation of the input disk 21 is increased and output is performed. The gear ratio is continuously reduced by being transmitted to the disk 22. On the other hand, when the power rollers 25, 25 are tilted in the direction of arrow b in FIG. 1, the contact point with the input disk 21 moves radially inward with respect to the input shaft 12, and the contact point with the output disk 22 is input. Since it moves radially outward with respect to the shaft 12, the rotation of the input disk 21 is decelerated and transmitted to the output disk 22, and the gear ratio increases continuously.

  The operation of the second continuously variable transmission mechanism 11R is the same as the operation of the first continuously variable transmission mechanism 11F described above, and the first and second continuously variable transmission mechanisms 11F and 11R perform the transmission operation in synchronization. Therefore, the driving force input from the crankshaft 16 of the engine E to the input shaft 12 is steplessly shifted at an arbitrary speed ratio within the speed ratio range of the toroidal speed change mechanism 11 and is output from the drive gear 26.

  A driven gear 33 that meshes with the drive gear 26 is fixed to the auxiliary shaft 14, and a first gear 35 that is fixed to a first sleeve 34 that is relatively rotatably fitted to the auxiliary shaft 14 is attached to the output shaft 13. It meshes with the fixed second gear 36. The first gear 35 can be coupled to the driven gear 33 via a high-speed clutch 37.

  Further, a second sleeve 38 is fitted to the sub shaft 14 so as to be relatively rotatable, and the second sleeve 38 can be coupled to the sub shaft 14 via a low speed clutch 39. A third gear 40 fixed to the input shaft 12 meshes with a fourth gear 41 fixed to the idle shaft 15, and the fourth gear 41 meshes with a fifth gear 42 supported relatively rotatably on the second sleeve 38. . The planetary gear mechanism 43 disposed on the countershaft 14 includes a sun gear 44 fixed to the second sleeve 38, a ring gear 45 fixed to the first sleeve 34, and a carrier fixed to the fifth gear 42. 46 and a plurality of pinions 47 that are rotatably supported by the carrier 46 and mesh with the sun gear 44 and the ring gear 45.

  Next, the shifting operation of the continuously variable transmission T having the above-described configuration will be described.

In the high speed mode in which the high speed clutch 37 is engaged and the low speed clutch 39 is disengaged, the rotation of the input shaft 12 is toroidal transmission mechanism 11 → drive gear 26 → driven gear 33 → high speed clutch 37 → first sleeve 34 → It is transmitted to the differential gear D through the path of the first gear 35 → second gear 36 → output shaft 13 → final drive gear 18 → final driven gear 19 to drive the vehicle forward. By changing the gear ratio of the toroidal transmission mechanism 11 steplessly, the total gear ratio between the engine E and the differential gear D can be changed steplessly.

  At this time, in the planetary gear mechanism 43, the carrier 46 connected to the input shaft 12 through the third gear 40, the fourth gear 41, and the fifth gear 42 rotates, but the low-speed clutch 39 is disengaged. Since the sun gear 44 can freely rotate, the ring gear 45 can also freely rotate, and no driving force is transmitted via the planetary gear mechanism 43.

  In the low speed mode in which the high speed clutch 37 is disengaged and the low speed clutch 39 is engaged, the rotation of the input shaft 12 is toroidal transmission mechanism 11 → drive gear 26 → driven gear 33 → secondary shaft 14 → low speed clutch 39 → 2 is transmitted to the sun gear 44 of the planetary gear mechanism 43 through the path of the sleeve 38, and the rotation of the input shaft 12 is transferred to the carrier 46 of the planetary gear mechanism 43 through the path of the third gear 40 → the fourth gear 41 → the fifth gear 42. Therefore, the driving force of the engine E is differentially transmitted from the ring gear 45 of the planetary gear mechanism 43 through the first sleeve 34 → the first gear 35 → the second gear 36 → the output shaft 13 → the final drive gear 18 → the final driven gear 19. Output to gear D.

  At this time, if the speed ratio of the toroidal transmission mechanism 11 that shifts the rotation of the input shaft 12 and transmits it to the sun gear 44 is controlled to a predetermined value, the rotational speed of the ring gear 45 becomes zero and the driving force is transmitted to the differential gear D. The geared neutral state is realized. When the gear ratio of the toroidal transmission mechanism 11 is changed in one direction from this geared neutral state, the ring gear 45 can be rotated in one direction to drive the vehicle forward at a low speed, and the gear ratio of the toroidal transmission mechanism 11 can be changed in the other direction. When the speed is changed to, the ring gear 45 rotates in the other direction, and the vehicle can travel backward at a low speed.

  In this way, when the vehicle is stopped in the geared neutral state in the low speed mode, the driving force of the engine E circulates through the toroidal transmission mechanism 11 and the planetary gear mechanism 43, so that the engine E is in the operating state without stopping. The engine speed at that time can be arbitrarily adjusted by controlling the gear ratio of the toroidal transmission mechanism 11.

  Next, the circuit configuration of the electronic control unit U that controls the fuel cut and the fuel cut return of the engine E will be described with reference to FIG. The electronic control unit U includes target acceleration calculation means M1, fuel cut means M2, target speed ratio calculation means M3, speed ratio control means M4, clutch control means M5, fuel cut return means M6, and braking control means M7.

  The target acceleration calculation means M1 calculates the target acceleration of the vehicle from the amount of operation of the accelerator pedal and the brake pedal by the driver and the running state of the vehicle (vehicle speed, road surface inclination, acceleration, steering angle, engine speed, etc.). . The fuel cut means M2 is a fuel that cuts off the fuel supply to the engine E in order to reduce the fuel consumption of the engine E when the target acceleration calculated by the target acceleration calculation means M1 is a negative value (target deceleration). Perform a cut.

When the vehicle speed gradually decreases during the fuel cut, the continuously variable transmission T is switched to the low speed mode with the high speed clutch 37 disengaged and the low speed clutch 39 engaged. In this low speed mode, the relationship between the vehicle speed and the engine speed can be arbitrarily adjusted by controlling the gear ratio of the toroidal speed change mechanism 11, so that the engine speed during fuel cut, that is , the effectiveness of the engine brake is adjusted. can do. Based on this principle, the target speed ratio calculating means M3 calculates the target speed ratio of the toroidal speed change mechanism 11 for achieving the target deceleration calculated by the target acceleration calculating means M1.

  FIG. 3 shows the engine speed (see the solid line) from the decelerated running state with fuel cut to the stop state, the overall transmission ratio of the continuously variable transmission T (see the broken line), and the transmission ratio of the toroidal transmission mechanism 11 (see FIG. Change with reference to the chain line). The overall transmission ratio of the continuously variable transmission T is a transmission ratio of the entire continuously variable transmission T including the toroidal transmission mechanism 11 and the planetary gear mechanism 43.

In the example of FIG. 3, the overall speed change ratio indicated by the broken line is maintained constant until the vehicle speed decreases to V, during which the engine speed indicated by the solid line gradually decreases, and when the vehicle speed reaches V, the engine speed is It becomes idling rotation speed (for example, 680 rpm). Until the vehicle speed decreases from V to zero, the overall speed ratio gradually decreases, so that the engine speed is maintained at the idling speed. The overall gear ratio becomes infinite (geared neutral state) immediately before the vehicle speed becomes zero and the vehicle stops. The transmission ratio of the toroidal transmission mechanism 11 indicated by a chain line is maintained constant until the vehicle speed decreases to V, and gradually decreases until the vehicle speed decreases from V to zero.

  Therefore, during the fuel cut, the gear ratio control means M4 controls the gear ratio of the toroidal transmission mechanism 11 so that the actual gear ratio matches the target gear ratio calculated by the target gear ratio calculation means M3, and during that time clutch control is performed. The means M5 maintains the low speed clutch 39 in the engaged state, and as shown in FIG. 3, even if the vehicle speed decreases to V and the engine speed reaches the idling speed, the vehicle speed becomes zero from there. Until this time, the engine speed can be maintained at idling speed.

As a result, in the past, when the engine speed reached the idling speed at the vehicle speed V, the fuel cut could not be prevented unless the fuel cut was restored, but the fuel cut was continued until just before the vehicle stopped. Immediately before the engine stops, the fuel cut can be returned by the fuel cut return means M6 to reduce the fuel consumption, and the engine E can be shifted to idling without stalling.

  The braking control means M7, when controlled to the target speed ratio calculated by the target speed ratio calculating means M3, cannot achieve the target deceleration calculated by the target acceleration calculating means M1, for example, braking force other than engine braking, for example, automatic braking The target deceleration is achieved by operating the device and the regenerative braking device.

  In the example of FIG. 3, the characteristic line of the engine speed is bent at the vehicle speed V, and the characteristic line of the overall transmission ratio and the transmission ratio of the toroidal transmission mechanism 11 is also bent at the vehicle speed V accordingly. Then, the characteristic line of the engine speed is linear, and the characteristic line of the overall transmission ratio and the transmission ratio of the toroidal transmission mechanism 11 is also a curved line close to a straight line. In this way, by preventing sudden changes in the engine speed, it is possible not only to prevent sudden changes in the braking force of the engine brake and eliminate the sense of discomfort of the occupant, but also to arbitrarily control the engine speed. By adjusting the effectiveness of the engine brake, it is possible to increase the braking feeling by generating the deceleration intended by the driver.

  The function of the electronic control unit U described above will be described in more detail based on the flowcharts of FIGS. 5 and 6.

  First, in step S1, when the low speed clutch 39 is engaged by the clutch control means M5 and the continuously variable transmission T is in a low speed mode in which a geared neutral state can be realized, in step S2, an accelerator pedal or a brake is set by the driver. The operation amount of the pedal is read, and the vehicle running state such as the vehicle speed, the road surface inclination, the acceleration, the steering angle, and the engine speed is read in step S3, and the operation amount and the vehicle running state are set by the target acceleration calculating means M1 in step S4. Based on this, the target acceleration of the vehicle is calculated.

If the target acceleration is a positive value in the subsequent step S5, the toroidal transmission mechanism 11 of the continuously variable transmission T is controlled to shift as usual in a step S6. When the target acceleration in step S5 is decelerating the vehicle to a negative value (target deceleration), the fuel consumption by performing the fuel-cut to cut off the fuel supply to the engine E by Fuyueruka' to manual stage M2 in step S7 Reduce the amount.

When the wheel is locked in the subsequent step S8, or when a sudden deceleration that cannot control the transmission ratio of the toroidal transmission mechanism 11 occurs, it is determined that the transmission ratio control of the toroidal transmission mechanism 11 is not in time, and fuel cut is continued. In step S9, the low speed clutch 39 is disengaged by the clutch control means M5, and in step S10, fuel supply to the engine E is resumed by the fuel cut return means M6 to return to the fuel cut. . Thereby, even when the control of the transmission ratio of the toroidal transmission mechanism 11 becomes difficult and the engine speed cannot be controlled so as not to fall below the idling speed, the shift to the idling operation can be made possible.

  In step S8, when there is no sudden deceleration in which the wheel lock or the transmission ratio of the toroidal transmission mechanism 11 cannot be controlled, the toroidal transmission mechanism capable of achieving the target deceleration by the target transmission ratio calculation means M3 in step S11. After calculating the target gear ratio of 11, the throttle valve is closed in step S12. In the low speed mode in which the low speed clutch 39 is engaged, the engine speed can be arbitrarily adjusted by controlling the gear ratio of the toroidal speed change mechanism 11, so that the target braking speed can be adjusted by adjusting the effectiveness of the engine brake. In addition, the engine speed can be controlled so as not to fall below the idling speed.

  In subsequent step S13, the speed ratio of the toroidal transmission mechanism 11 is a value at which the engine speed exceeds the idling speed at the current vehicle speed, and in step S14, the vehicle deceleration is sufficient for the target deceleration, and in step S16. If the deceleration of the vehicle is not excessive and the engine speed is not equal to or less than the idling speed in step S21, the process returns to step S1 until the vehicle stops in step S23.

  If the deceleration of the vehicle is insufficient with respect to the target deceleration in step S14 while the vehicle speed gradually decreases by repeating this loop, the target speed ratio of the toroidal transmission mechanism 11 is set to the LOW side in step S15. By increasing the engine speed by increasing the engine speed, the braking force of the engine brake can be increased to increase the deceleration of the vehicle, and the deceleration of the vehicle can be matched with the target deceleration.

  If the speed ratio of the toroidal speed change mechanism 11 is the current vehicle speed and the engine speed is lower than the idling speed in step S13, the engine E stalls without shifting to the idling operation even when the fuel cut is restored. Since there is a possibility, the gear ratio of the toroidal transmission mechanism 11 is maintained at the current value by the gear ratio control means M4 in step S18. As apparent from FIGS. 3 and 4, in order to maintain the engine speed at the idling speed, it is necessary to gradually reduce the speed ratio of the toroidal transmission mechanism 11 indicated by the chain line in accordance with the decrease in the vehicle speed. By maintaining the gear ratio without decreasing it, the engine speed can be increased and maintained above the idling speed.

  If the vehicle deceleration is sufficient with respect to the target deceleration in step S19, the process proceeds to step S16. If not, the process proceeds to step S20 and the braking control means M7 (see FIG. 2). For example, the vehicle deceleration can be matched with the target deceleration by operating the automatic brake to brake the vehicle.

  If the deceleration of the vehicle becomes excessive before the vehicle stops in step S16, the fuel supply to the engine E is restarted and the fuel cut is resumed in step S17, so that the engine E is restarted and idling. The engine braking is terminated and the vehicle deceleration can be properly maintained. Further, when the engine speed has decreased below the idling speed for some reason in step S21, it is possible to shift to the idling operation while preventing the engine E from stalling by returning to the fuel cut in step S22.

  If the route of step S17 or step S22 is not passed until the last stage where the vehicle stops in step S23, the fuel cut period can be extended to the maximum to reduce fuel consumption.

Since the target deceleration becomes zero immediately before the vehicle stops, the deceleration of the vehicle becomes excessive in step S16, the fuel cut is restored in step S17, and the engine E shifts to idling operation. In the following step S16, since the engine E has already been idling, the vehicle will not decelerate too much. In the following step S21, since the engine E has already been idling, the engine speed will not be less than the idling speed. proceeds to step S23 in order, vehicles terminates this routine to stopped in step S23.

With the above control, it becomes possible to continue the fuel cut when the vehicle is decelerating until just before the vehicle stops. The engine E by the fuel cut is used while maximizing the engine brake and extending the life of the brake pad. The fuel consumption saving effect is further enhanced.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, the speed change mechanism of the present invention is not limited to the toroidal speed change mechanism 11 of the embodiment, and may be any speed change mechanism such as a belt type continuously variable transmission mechanism or a crank type continuously variable transmission mechanism.

  The toroidal transmission mechanism 11 of the embodiment is of a double cavity type, but may be of a single cavity type.

  In the planetary gear mechanism 43 of the embodiment, the carrier 46 is the first element, the ring gear 45 is the second element, and the sun gear 44 is the third element. However, the selection of the first to third elements is limited thereto. It is not a thing.

11 Toroidal transmission mechanism (transmission mechanism)
12 Input shaft 13 Output shaft 22 Output disk (output member)
39 Low-speed clutch (clutch)
43 planetary gear mechanism 44 sun gear (third element)
45 Ring gear (second element)
46 Carrier (first element)
E engine T continuously variable transmission U electronic control unit (fuel cut control means)
W driving wheel M1 target acceleration calculating means M2 fuel cut means M3 target gear ratio calculating means M4 gear ratio control means M5 clutch control means M6 fuel cut return means M7 braking control means

Claims (6)

An engine (E), a continuously variable transmission (T) for transmitting the driving force of the engine (E) to driving wheels (W), and a fuel cut control means for shutting off and restarting fuel supply to the engine (E) (U),
The continuously variable transmission (T) includes an input shaft (12) connected to the engine (E), an output shaft (13) connected to the drive wheels (W), the input shaft (12), and A transmission mechanism (11) that changes the transmission ratio between the output shafts (13) steplessly, and the transmission mechanism (11) arranged in parallel between the input shaft (12) and the output shaft (13). A planetary gear mechanism (43),
The planetary gear mechanism (43) includes a first element (46) connected to the input shaft (12), a second element (45) connected to the output shaft (13), and the speed change mechanism (11). And a third element (44) connected to the output member (22) via a clutch (39),
The fuel cut control means (U) includes target acceleration calculation means (M1) for calculating a target acceleration instructed by the driver, and fuel supply to the engine (E) when the vehicle decelerates when the target acceleration is a negative value. The speed change mechanism for achieving the target acceleration when the fuel cut means (M2) and the clutch (39) are engaged and the fuel supply to the engine (E) is cut off. Target speed ratio calculating means (M3) for calculating the target speed ratio of (11), speed ratio control means (M4) for controlling the actual speed ratio of the speed change mechanism (11) to coincide with the target speed ratio; A clutch control means (M5) for holding the clutch (39) in an engaged state until the vehicle stops during the control of the actual speed ratio by the speed ratio control means (M4), and the engine immediately before the vehicle stops. ( ) Control device for a vehicle, characterized in that it comprises a fuel-cut return means (M6) to resume the fuel supply to the. The target speed ratio calculating means (M3) calculates the target speed ratio of the speed change mechanism (11) so that an engine speed immediately before the vehicle stops coincides with an idling speed. The vehicle control device according to claim 1.   When sudden deceleration of the vehicle or wheel lock is detected, the clutch control means (M5) disengages the clutch (39), and the fuel cut return means (M6) returns to the engine (E). The vehicle control device according to claim 1, wherein the fuel supply is restarted. The target speed ratio calculating means (M3), the engine rotational speed for the current vehicle speed and calculates a target speed ratio of the transmission mechanism so that the idling speed (11), the goal is the target gear ratio 4. The fuel cut return means (M6) restarts the fuel supply to the engine (E) when the deceleration becomes excessive with respect to the deceleration. The vehicle control device according to Item. The target speed ratio calculating means (M3), the engine rotational speed for the current vehicle speed and calculates a target speed ratio of the transmission mechanism so that the idling speed (11), the goal is the target gear ratio The braking control means (M7) for decelerating the vehicle by means other than engine braking when the deceleration becomes insufficient with respect to the deceleration is provided. Vehicle control device. The fuel cut return means (M6) restarts fuel supply to the engine (E) when the engine speed falls below the idling speed. The vehicle control device according to claim 1.

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