JP6273776B2 - Driving force limiter - Google Patents

Description

  The present invention relates to a drive force limiting device, and more particularly, a drive that is mounted on a vehicle including a support member that supports a drive mechanism including a drive source with respect to a main body of the vehicle with an elastic force and limits the drive force of the drive mechanism. It relates to a force limiting device.

  The drive mechanism is attached to the main body of the vehicle via an engine mount that constitutes a support member that is supported with an elastic force in order to prevent the vibration from being transmitted to the occupant. When acceleration of the vehicle is required, the driving mechanism increases the driving force. When the driving force by the driving mechanism increases, the driving mechanism is displaced about the drive shaft while deforming the engine mount. For this reason, the drive mechanism cannot transmit all of the drive force to the drive wheels until the displacement of the drive mechanism is settled.

  When the displacement of the drive mechanism is settled and all the drive force of the drive mechanism is transmitted to the drive wheels, the vehicle suddenly accelerates. As described above, the vehicle having the engine mount has reduced drivability such that it does not accelerate immediately even if the accelerator pedal is depressed, and suddenly accelerates after a while.

In particular, when the accelerator pedal is depressed when the vehicle is stopped or decelerated, the displacement of the drive mechanism increases, so the engine mount loses its elastic force before the displacement of the drive mechanism is settled. The so-called “bottom” occurs.
When the bottoming occurs, the driving force consumed for the displacement of the driving mechanism is transmitted to the driving wheels, the vehicle acceleration is overshooted, and drivability is reduced.

In order to suppress such a decrease in drivability, the conventional driving force limiting device is configured so that the driving force of the driving mechanism gradually increases until the displacement of the driving mechanism is settled after the vehicle is requested to accelerate. The output torque of the internal combustion engine was suppressed.
However, in the conventional driving force limiting device, the period and amount of suppression of the output torque of the internal combustion engine are adapted when the vehicle is manufactured in order to suppress variation in drivability. For this reason, the conventional driving force limiting device has increased the number of man-hours for suppressing variation in drivability.

  For example, Patent Document 1 proposes a vibration reduction device for an internal combustion engine provided with an engine mount. The vibration reduction device estimates the load torque of the internal combustion engine and estimates the displacement of the engine mount for the purpose of suppressing the vibration and improving the drivability regardless of the operating state of the internal combustion engine. The load torque of the alternator is set based on the load torque of the engine and the displacement of the engine mount.

Japanese Patent No. 4962447

  However, the one proposed in Patent Document 1 also calculates the displacement of the engine mount due to the load of the internal combustion engine using the equation of motion, so that the characteristics of the engine mount and the output shaft around the internal combustion engine are affected by manufacturing errors and aging degradation. Variations in the moment of inertia caused an increase in the number of man-hours required to suppress drivability variations.

  Accordingly, the present invention has been made to solve such a problem, and an object thereof is to provide a driving force limiting device capable of preventing drivability variation without increasing the number of adaptation steps. .

One aspect of the present invention includes a support member for supporting with a resilient force of the driving mechanism including the driving source with respect to the body of the vehicle, and a torque limiting unit for limiting the output torque of the driving source, the output shaft of the driving mechanism A driving force limiting device for a vehicle, comprising: an output shaft rotational speed sensor for detecting rotational speed; and a wheel speed sensor for detecting rotational speed of driving wheels , wherein the rotational speed detected by the output shaft rotational speed sensor And a displacement for calculating a displacement rate of the drive mechanism relative to the main body of the vehicle in a direction opposite to the traveling direction of the vehicle by a driving force of the drive mechanism from a ratio of the rotation speed detected by the wheel speed sensor It includes a calculation unit, the torque limiting section, from a request for acceleration of the vehicle, until the displacement based on the displacement ratio calculated by the displacement calculating unit no longer increases, the output bets of the driving source It is characterized in that to limit the click.

As described above, according to the above aspect , the displacement rate of the drive mechanism based on the drive force of the drive mechanism is calculated based on the driving state of the vehicle, and the output of the drive source is increased until the displacement based on the calculated displacement rate does not increase. Since the torque is limited, variation in drivability can be prevented without increasing the adaptation man-hours.

In the above aspect , the displacement rate of the drive mechanism is calculated from the rotation speed of the output shaft of the drive mechanism and the rotation speed of the drive wheel as the driving state of the vehicle. The displacement rate of the drive mechanism by the drive force can be calculated.

FIG. 1 is a configuration diagram showing a main part of a vehicle equipped with a driving force limiting device according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing the drive mechanism and its supporting member shown in FIG. FIG. 3 is a schematic view showing a state in which the drive mechanism shown in FIG. 1 is displaced with respect to the vehicle body. FIG. 4 is a flowchart showing a driving force limiting operation by the driving force limiting device according to the embodiment of the present invention. FIG. 5 is a graph for explaining the operation of the driving force limiting operation according to the embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, an example in which the driving force limiting device according to the present invention is applied to a front engine / front drive type vehicle will be described.

  As shown in FIG. 1, a vehicle 1 equipped with a driving force limiting device according to an embodiment of the present invention includes an internal combustion engine type engine 2 as a driving source, a transaxle 3, drive shafts 4L and 4R, Drive wheel 5L, 5R and ECU (Electronic Control Unit) 6 are comprised.

  In the present embodiment, the engine 2 is constituted by a so-called horizontal engine in which a crankshaft as its output shaft is arranged in the vehicle width direction of the vehicle 1. The engine 2 includes a four-cycle engine that performs a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke, and performs ignition during the compression stroke and the expansion stroke. The engine 2 may be configured by various types of engines such as an in-line 4-cylinder engine, an in-line 6-cylinder engine, a V-type 6-cylinder engine, a V-type 12-cylinder engine, or a horizontally opposed 6-cylinder engine.

The transaxle 3 includes a transmission 11, an output shaft 12 of the transmission 11, and a differential gear 13. In the present embodiment, the transmission 11 may be configured by various transmissions such as an automatic transmission, a manual transmission, a semi-automatic transmission, a dual clutch transmission, and a continuously variable transmission.
Further, the transmission 11 and the engine 2 integrally constitute a drive mechanism 14. The driving force limiting device according to the present invention can also be applied to a vehicle using a rotating electrical machine as a driving source. In this case, the drive mechanism includes a rotating electrical machine.

  The differential gear 13 rotates integrally with a final gear 16 that meshes with an output gear 15 provided on the output shaft 12 of the transmission 11. Drive shafts 4L and 4R are connected to differential gear 13, and drive wheels 5L and 5R are connected to drive shafts 4L and 4R, respectively. In other words, the power transmitted to the differential gear 13 is transmitted to the drive wheels 5L and 5R via the drive shafts 4L and 4R.

  The output shaft 12 of the transmission 11 is provided with an output shaft rotational speed sensor 20 that detects the rotational speed of the output shaft 12. The drive shafts 4L and 4R are provided with wheel speed sensors 21L and 21R for detecting the rotational speeds of the drive shafts 4L and 4R, that is, the rotational speeds of the drive wheels 5L and 5R, respectively.

  As shown in FIG. 2, the drive mechanism 14 is supported by the main body of the vehicle 1 by a pendulum type support structure. Specifically, the drive mechanism 14 is provided with engine mounts 26 </ b> L and 26 </ b> R that constitute a support member that supports the drive mechanism 14 with elasticity against the main body of the vehicle 1.

  The engine mounts 26 </ b> L and 26 </ b> R are provided at both ends of the drive mechanism 14 in the vehicle width direction of the vehicle 1 and constitute a support member that supports the drive mechanism 14 with respect to the main body of the vehicle 1 with an elastic force. More specifically, the engine mounts 26L and 26R have a line 27 connecting the centers of the engine mounts 26L and 26R passing through the upper part of the drive mechanism 14 in the vehicle height direction of the vehicle 1 and in the vehicle width direction of the vehicle 1. The drive mechanism 14 is provided so as to pass through the center of gravity 28 thereof. The drive mechanism 14 is provided with a torque rod 29 that supports the drive mechanism 14 from the rear of the vehicle 1 in the vicinity of the drive shafts 4L and 4R with respect to the main body of the vehicle 1.

As shown in FIG. 3, when the vehicle 1 is requested to accelerate, the drive mechanism 14 increases the driving force. When the driving force by the driving mechanism 14 increases, the driving mechanism 14 is displaced about the drive shafts 4L and 4R while deforming the engine mounts 26L and 26R.
For this reason, the drive mechanism 14 cannot transmit all the drive force to the drive wheels 5L and 5R until the displacement of the drive mechanism 14 is settled. When the displacement of the drive mechanism 14 is settled, the drive mechanism 14 can transmit all the drive force to the drive wheels 5L and 5R.
In FIG. 3, the engine mounts 26L and 26R are illustrated as modeled coil springs. Further, the drive mechanism 14 indicated by a solid line is shown in a state of being displaced by the driving force of the drive mechanism 14, and the drive mechanism 14 indicated by a two-dot chain line is shown in a state of not being displaced.

In FIG. 1, an ECU 6 is configured by a computer unit having a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an input port, and an output port. ing. A program for causing the computer unit to function as the ECU 6 is stored in the ROM of the ECU 6 together with various control constants, various maps, and the like.
That is, in the ECU 6, when the CPU reads a program from the ROM into the RAM and executes the read program, the computer unit functions as the ECU 6.

In the present embodiment, in addition to the output shaft rotational speed sensor 20 and the wheel speed sensors 21L and 21R, an accelerator opening sensor 31 that detects an accelerator opening representing the opening of the accelerator pedal 30 is provided at the input port of the ECU 6. Various sensors including it are connected.
On the other hand, various control objects such as a throttle valve 32 that adjusts the intake air amount of the engine 2 and an ignition plug 33 that ignites the fuel of the engine 2 are connected to the output port of the ECU 6. The ECU 6 controls various control objects based on information obtained from various sensors.

In the present embodiment, the ECU 6 constitutes a displacement calculating unit 50 that calculates the displacement of the driving mechanism 14 by the driving force of the driving mechanism 14 based on the driving state of the vehicle 1. Specifically, the ECU 6 determines the displacement state of the drive mechanism 14 based on the ratio between the rotational speed Nd detected by the output shaft rotational speed sensor 20 and the rotational speed Nw detected by the wheel speed sensors 21L and 21R. A displacement rate dP to be expressed is calculated.
Here, the ECU 6 calculates an average value of the rotational speed detected by the wheel speed sensor 21L and the rotational speed detected by the wheel speed sensor 21R as the rotational speed Nw.

More specifically, when the gear ratio from the drive mechanism 14 to the differential gear 13, in this embodiment, the gear ratio between the output gear 15 and the final gear 16 is R, the ECU 6 determines the displacement rate dP = Nd / (Nw × R) is calculated. Here, the ECU 6 calculates the displacement rate dP as 1 when the rotational speed Nw is 0.
That is, when the rotational speed Nw is not 0 and the displacement rate dP is 1, this means that the displacement of the drive mechanism 14 due to the driving force of the drive mechanism 14 has been settled. It represents that the drive mechanism 14 is displaced in the direction opposite to the traveling direction of the vehicle 1 by the drive force of the mechanism 14, and when the displacement rate dP is smaller than 1, the drive mechanism is reduced by the decrease of the drive force of the drive mechanism 14. 14 represents that the vehicle 1 is displaced in the traveling direction.

  The ECU 6 configures a torque limiting unit 51 that limits the output torque of the engine 2 on the condition that the vehicle 1 is requested to accelerate. Specifically, the ECU 6 determines that the displacement rate dP is 1 until the displacement of the driving mechanism 14 by the driving force of the driving mechanism 14 does not increase after the depression of the accelerator pedal 30 is detected by the accelerator opening sensor 31. By adjusting the opening degree of the throttle valve 32 until it becomes below, the intake air amount of the engine 2 is adjusted, and the output torque of the engine 2 is set to a predetermined constant increase rate and a predetermined constant value. The output torque of the engine 2 is limited by the torque. Note that the ECU 6 may limit the output torque of the engine 2 by adjusting the ignition timing of the spark plug 33.

  When the displacement rate dP is 1 or less, it indicates that the engine mounts 26L and 26R are starting to be restored, that is, the drive mechanism 14 is starting to be displaced in the traveling direction of the vehicle 1. Here, if the driving force of the driving mechanism 14 is small, the restoring force of the engine mounts 26L and 26R acts in the direction opposite to the direction in which the driving mechanism 14 drives, and the driving force of the driving mechanism 14 decreases.

  For this reason, the ECU 6 releases the restriction on the output torque of the engine 2 and demands the output torque on the condition that the displacement rate dP becomes 1 or less in a state where the output torque of the engine 2 is restricted. The intake air amount of the engine 2 is adjusted so as to be torque (hereinafter simply referred to as “requested torque”). The ECU 6 may adjust the ignition timing of the spark plug 33 so that the output torque of the engine 2 becomes the required torque.

  Further, the ECU 6 has a timer, and when the state where the output torque of the engine 2 is limited continues for a predetermined time or longer, the state where the output torque of the engine 2 is low continues for a long time. Therefore, the restriction on the output torque of the engine 2 is released.

  The driving force limiting operation by the driving force limiting device according to the embodiment of the present invention configured as described above will be described with reference to FIG. The driving force limiting operation described below is executed when depression of the accelerator pedal 30 is detected by the accelerator opening sensor 31.

First, the ECU 6 starts limiting the output torque of the engine 2 (step S1). Next, the ECU 6 sets an initial value of the timer and starts a countdown (step S2). Next, the ECU 6 determines whether or not the timer value has become 0 (step S3).
If it is determined that the timer value is not 0, the ECU 6 determines whether or not the displacement rate dP of the drive mechanism 14 is greater than 1 (step S4). That is, the ECU 6 determines whether or not the output torque of the engine 2 is increased by the depression of the accelerator pedal 30 and the drive mechanism 14 starts to be displaced. On the other hand, when determining that the displacement rate dP is not greater than 1, the ECU 6 returns the driving force limiting operation to step S3.

  If it is determined that the displacement rate dP is greater than 1, the ECU 6 determines whether or not the timer value is 0 (step S5). If it is determined that the timer value is not 0, the ECU 6 determines whether the displacement rate dP is 1 or less (step S6). That is, the ECU 6 determines whether or not the displacement of the drive mechanism 14 due to the drive force of the drive mechanism 14 has stopped increasing. On the other hand, when determining that the displacement rate dP is not 1 or less, the ECU 6 returns the driving force limiting operation to step S5.

  If it is determined in step S6 that the displacement rate dP is 1 or less, or if it is determined in step S3 or S5 that the timer value has become 0, the ECU 6 limits the output torque of the engine 2. Release (step S7). When the restriction on the output torque of the engine 2 is released, the ECU 6 increases the output torque of the engine 2 so as to become the required torque (step S8), and ends the driving force restriction operation.

The operation of the driving force limiting operation described above will be described with reference to FIG. FIG. 5 shows an example in which the accelerator pedal 30 is depressed when the engine 2 is idling.
In FIG. 5, the horizontal axis represents time, and the vertical axis represents the accelerator opening, whether the engine 2 output torque is limited, the timer value, the displacement of the drive mechanism 14, the displacement rate dP of the drive mechanism 14 from the top in the figure. And the output torque of the engine 2 is shown. Moreover, the output torque of the engine 2 shown with a broken line has shown the request torque.

  When the depression of the accelerator pedal 30 is detected by the accelerator opening sensor 31 at time t1, the limit of the output torque of the engine 2 is started, and the countdown of the timer set with the initial value is started. Further, the output torque of the engine 2 increases as the accelerator pedal 30 is depressed.

  At time t <b> 2, the drive mechanism 14 starts to be displaced due to an increase in the output torque of the engine 2, so that the displacement rate dP of the drive mechanism 14 becomes greater than 1. When the drive mechanism 14 is not displaced at time t3 and the displacement rate dP becomes 1 or less, the restriction on the output torque of the engine 2 is released, and the output torque of the engine 2 becomes the required torque from time t3 to time t4. To increase.

  As described above, the present embodiment calculates the displacement of the driving mechanism 14 by the driving force of the driving mechanism 14 based on the driving state of the vehicle 1, and the output torque of the engine 2 until the calculated displacement does not increase. Therefore, variation in drivability can be prevented without increasing the man-hours for adaptation.

  Although the embodiments of the present invention have been disclosed above, it is obvious that those skilled in the art can make modifications without departing from the scope of the present invention. All such modifications and equivalents are intended to be included in the claims recited in the claims.

1 vehicle 2 engine (drive source)
4L, 4R Drive shaft 6 ECU (displacement calculation unit, torque limiting unit)
11 Transmission 12 Output shaft 14 Drive mechanism 20 Output shaft rotation speed sensor 21L, 21R Wheel speed sensor 26L, 26R Engine mount (support member)
50 Displacement calculator 51 Torque limiter

Claims (1)

A support member that supports a drive mechanism including a drive source with respect to the main body of the vehicle with an elastic force;
A torque limiting unit for limiting the output torque of the drive source,
An output shaft rotational speed sensor for detecting the rotational speed of the output shaft of the drive mechanism;
A wheel speed sensor for detecting the rotational speed of the drive wheel, and a vehicle driving force limiting device comprising:
From the ratio of the rotational speed detected by the output shaft rotational speed sensor and the rotational speed detected by the wheel speed sensor, the vehicle in the direction opposite to the traveling direction of the vehicle by the driving force of the drive mechanism is determined. A displacement calculator for calculating a displacement rate of the drive mechanism relative to the main body ;
The torque limiting unit limits the output torque of the driving source until the displacement based on the displacement rate calculated by the displacement calculating unit does not increase after the vehicle is requested to accelerate .

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