JPS63243562A - Transmission control method of vehicle with continuously variable transmission - Google Patents

Abstract

PURPOSE:To prevent overrotation of an engine by maintaining the speed change ratio at the change ratio immediately before the speed change, or controlling it at the change ratio responding to the assumed actual car speed at the time when a sudden deceleration is released, when the rear wheel is suddenly decelerated compared to the actual speed, in the speed change control of a motorcycle in a rough terrain running. CONSTITUTION:In a hydraulic continuously variable transmission TM, a constant injection type hydraulic pump P and a variable capacity type hydraulic motor M are connected each other to composed a hydraulic closed circuit 21. The hydraulic pump P is connected to an input shaft 3 which is driven by an engine E, and the hydraulic motor M is connected to a rear wheel Wr through an output shaft 2 and a chain 14. In this case, a throttle opening sensor Sa, an engine rotation frequency sensor Sb, and a car speed sensor Se are connected to a control device C, which controls the operation of an actuator 28 while reading input signals of these sensors. Therefore, when the rear wheel Wr is decelerated suddenly compared to the actual car speed, the speed of the rear wheel is maintained at the speed change ratio immediately before the speed change, or controlled at the speed change ratio responding to the assumed actual car speed at the time when the sudden deceleration is released.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a vehicle with a continuously variable transmission that can perform appropriate control even when the driving wheels suddenly decelerate compared to the actual vehicle speed. This invention relates to a speed change control method.

[Prior Art] In conventionally known vehicles with continuously variable transmissions, the gear ratio is generally controlled based on engine speed and vehicle speed (see, for example, Japanese Patent Application Laid-Open No. 57-161346). In this case, the vehicle speed is usually represented by the rotational speed of the driven heavy wheels.

[Problems to be Solved by the Invention] By the way, when a continuously variable transmission is installed in a competition motorcycle for running on rough terrain such as a motocross race and the conventional control is performed, the following problems occur. There is.

In other words, if sudden braking is applied during a competition, for example on a slippery road such as mud, the deceleration of the drive wheels will be steeper than the actual change in deceleration of the vehicle body due to excessive braking force or a decrease in the coefficient of friction of the road surface. , the wheels may become locked and run m on the road surface. In this case, although the actual vehicle speed of the vehicle body does not change much, the engine rotation speed and the rotation speed of the driving wheels suddenly decrease, so the gear ratio moves from the Q optimum value to the maximum value side (LOW side). . Therefore, next time the wheels are released from the locked state and the actual vehicle speed (i
Tf Body speed change When the wheel speeds match, the engine overspeeds.

SUMMARY OF THE INVENTION An object of the present invention is to provide a speed change control method for a continuously variable transmission-equipped vehicle that allows the vehicle to run at a speed ratio that matches the actual vehicle speed even in the above-mentioned cases.

[Means for Solving the Problems] The present invention provides a speed change control method for a vehicle with a continuously variable transmission in which a speed ratio is set based on the engine rotational speed and the driving wheel rotational speed representative of the vehicle speed. When the wheels suddenly decelerate from the actual vehicle speed, the gear ratio immediately before the sudden deceleration is maintained, or
The system is characterized by estimating the actual vehicle speed when sudden deceleration is released and controlling the gear ratio according to the estimated actual vehicle speed.

[Function] In the present invention, when the driving wheels suddenly decelerate compared to the actual vehicle speed, the gear ratio is maintained at the speed ratio immediately before the sudden deceleration, or the gear ratio is controlled to the gear ratio according to the estimated actual vehicle speed when the sudden deceleration is released. Therefore, when the speed of the driving wheels and the actual vehicle speed match, a gear ratio suitable for the actual vehicle speed is ensured.

Therefore, overspeeding of the engine is prevented.

[Embodiment 1] Hereinafter, an embodiment in which the present invention is applied to a motorcycle for traveling on rough terrain equipped with a hydraulic continuously variable transmission will be described with reference to the drawings.

Figures 1 and 2 show the entire motorcycle for riding on rough terrain (1
Indicates completion. In the figure, reference numeral 1 indicates a vehicle body frame, E indicates a two-stroke engine supported by the vehicle body frame 1, and TM indicates a continuously variable transmission disposed after engine E.

The continuously variable transmission 'rM in this case is a hydraulic type,
The output shaft 2 and the input shaft (man-powered member) 3 are on the same axis.

Both shafts 2.3 are arranged in the left-right direction of the vehicle body so that they are parallel to the crankshaft 4 of the engine E.
An input shaft 3 is connected to a crankshaft 4 via a chain 5. Further, the continuously variable transmission 'FM is housed in a single casing 6 together with the engine E, chain 5, etc., and only the output shaft 2 is exposed to the outside from the left side of the vehicle body.

Further, Wr is a non-driven front wheel, Wr is a rear wheel to which driving force is transmitted from the engine E, a fuel tank 7 is mounted on the face of the vehicle body frame 1, and a trunk 8 is mounted on the rear seat rail Ia. Fixed.

The front wheel Wf is supported by the lower end of a front fork [0] attached to a head pipe 9 at the front of the vehicle body frame 1.
A handle II is attached on top of the head vibe 9. On the other hand, the rear wheel Wr is supported by the tip of a swing arm 13 that is attached to the vehicle body frame l so as to swing while receiving the reaction force of the suspension 12.
A continuously variable transmission T is connected by a chain 14 placed on the left side of the vehicle body.
It is connected to the output shaft 2 of M.

In this way, in this motorcycle, by using the chain 5.14 as the power transmission means, the crankshaft 4.
, the human power shaft 3, the output shaft 2, and the rear wheel Wr of the continuously variable transmission TM,
All of them are rotated in the same direction as indicated by the arrows.

In addition, numeral 15 is an air cleaner, 16 is an exhaust pipe, 17 is an accelerator grip, and 18 is a cradle lever.

Next, the 413 pressure circuit of the power transmission system will be explained with reference to FIG. In the figure, the hydraulic continuously variable transmission TM includes a constant discharge ni type 411 pressure pump P and a variable displacement hydraulic motor M connected to each other so as to form a hydraulic closed circuit 21. P is connected to the input shaft 3 driven by the engine E, and the 40-pressure motor M is connected to the output shaft 2.
and is connected to the rear wheel Wr via a chain (transmission device ξ) 14.

The hydraulic closed circuit 21 includes a 411 path 21a that connects the discharge port of the hydraulic pump P and the suction port of the hydraulic motor M, and an H path 21b that connects the discharge port of the hydraulic motor M and the suction port of the i+b pressure pump P. It is equipped with

In addition, the discharge port of the replenishment pump F driven by the human power shaft 3 is connected to the Nli oil supply path 22 in these oil passages 21a and 21b.
and are connected via check valves 23 and 24, and 'A
11 Hydraulic oil pumped up from tank T
It is designed to be supplied to the hydraulic closed circuit 21 via the l path 22. Furthermore, a relief valve 25 for keeping the oil pressure of the hli oil supply path 22 constant is connected in the middle of the replenishment oil path 22.

In addition, both Ab paths 21a and 2Ib of 'A11 pressure closed circuit 2I
are connected via a clutch valve 26 that is operated in response to manual operation. This clutch valve 26 has an opening that short-circuits both oil passages 21a and 2Ib, and an opening that short-circuits both oil passages 21a and 2Ib.
, 2Ib is used, and a throttle valve is used which has an intermediate position and can switch between an opening degree that shuts off between 2Ib and 2Ib. When the clutch valve 26 is short-circuited, differential oil is not supplied to the hydraulic motor M, and the power between the hydraulic pump P and the hydraulic motor M is cut off. Further, when the clutch valve 26 is cut off, the hydraulic pump P and the hydraulic motor M
Since the hydraulic oil circulates between the two, driving force is transmitted and the vehicle is in a running state. The former state is the so-called clutch disengaged state, and the latter state is the clutch engaged state. Furthermore, when the opening degree of the clutch valve 26 reaches an intermediate position, the circulation of the hydraulic oil is changed to the hydraulic closed circuit 21 according to the opening degree.
This occurs within the clutch, resulting in a half-clutch condition.

Further, the hydraulic motor M is provided with an operating member 27 for adjusting its capacity. This operating member 27 is connected to an actuator 28, and the operation of the actuator 28 is controlled by a control means C consisting of a computer.

In this case, the control means C includes a throttle opening sensor Sa that detects the throttle opening of the engine E, and an engine rotational speed Ne that detects the rotational speed Ne of the engine E, that is, the rotational speed of the input shaft 3. The sensor sb and the rear wheel (which represents the vehicle speed)
A vehicle speed sensor Sc that detects the rotational speed of the drive wheel) Wr and a gear ratio detection sensor Se that detects the operating position of the actuator 28, that is, the gear ratio e, are connected, and the control means C controls these sensors Sa, Sb, The operation of the actuator 28 is controlled based on the procedure shown in FIG. 4 while reading the human power signals from Sc and Se.

By the way, in the control means C, a reference acceleration V+ is set and stored in advance as a control condition for speed change control. This reference acceleration Ql is the maximum negative wheel rotational acceleration when the two-wheeled motorcycle described above is running on a road surface and the wheels are not locked when sudden braking is applied. In other words, this is the limit value of negative acceleration during normal driving. This acceleration limit value is stored in the control means C as an electrical signal. Therefore, if the rear wheel W exceeds this reference acceleration of 91,
If it is detected that the rotational speed of the vehicle r has suddenly decreased, it can be determined that the rear wheels Wr are locked and the vehicle speed is rapidly decelerating from the actual vehicle speed. Note that the rotational acceleration ♀ of the rear wheel Wr is determined by the temporal change in the rotational speed V, that is, Q = (V n −v n−+)/(T
n −T n−+). However, T n T il-, = T (constant).

Further, a set value Vl is set and stored as a vehicle speed signal, and a set time T1 is also stored.

In FIG. 4, the control procedure of the control means C will be explained as follows.
First, initialization is performed in step S1, and then step S
2. In S3, the signals Ne and ■ from the engine speed sensor sb and the vehicle speed sensor Sc are sequentially read. Next, in step S4, it is determined whether the wheel acceleration Q is smaller than 0, that is, whether or not the vehicle is decelerating. 9ku0
If so, it is further determined in step S5 whether 9≦91,
In other words, it is determined whether the rear wheels Wr are decelerating more rapidly than the actual vehicle speed. When Q≦'J1, the rear wheels are locked, and in that case, the process advances to step S6.

In step S6, the previously read vehicle speed VF is the set value V1.
It is determined whether the If it is not equal to or greater than the set value Vt, the process advances to step S7 to perform normal control. In step S7, the optimum gear ratio is calculated based on the actual engine speed Ne, the target engine speed given by the throttle opening θ, and the vehicle speed V. Next, the process proceeds to step S8, where the current gear ratio C sent from the gear ratio detection sensor Se is compared with the gear ratio calculated in step S7, and if the rain noise is the same, it is determined to stop shifting, and if they are not equal, the gear shift is stopped. It is determined that it will not stop.

If it is determined in step S8 that the shift is to be stopped, the shift operation of the actuator 28 is stopped, and the process returns to step S2+. If it is determined in step S8 that the gears will not be stopped, the process proceeds to step S9, and the actuator 28 is adjusted by the necessary value.
is activated, and the process returns to step S2. The flow from step 7 to step 9 is a normal shift control flow and is the same as the conventional one.

Further, when it is determined in step S4 that Q<o is not satisfied, and when it is determined in step S5 that 9≦9t is not satisfied, the normal control is immediately advanced to step S7.

Further, when it is determined in step S6 that V≧Vl, the process advances to step SIO. In step SlO, it is determined whether or not the wheels have been locked, that is, the wheel rotational speed has dropped more rapidly than the actual vehicle speed, for a predetermined time period T1 or longer.

The set time T1 in this case is determined based on the following guideline. That is, when the heavy wheel lock time is short, there is almost no change in the actual vehicle speed, but when the wheel lock time is long, there is a deceleration effect due to friction during the wheel lock. therefore,
The actual vehicle speed after the wheels are locked is smaller than the actual vehicle speed before the wheels are locked.

How much it will decrease can be estimated to some extent from the friction coefficient and wheel lock time. Therefore, whether or not it is necessary to take the deceleration effect due to friction into consideration for control purposes is determined based on the length of the wheel lock time. Therefore, the criterion for determining the set time TI is whether or not to take into account the deceleration effect due to friction.

In step SIO, when the wheel lock time T<TI, it is determined that the deceleration effect due to friction can be ignored, and the process proceeds to step S11, where the gear ratio is maintained at the value immediately before the wheels are locked, that is, immediately before rapid deceleration.

Then, the process returns to step S2.

When wheel lock time T≧T I, it is determined that the deceleration effect due to friction significantly affects the actual vehicle speed,
Proceeding to step SI2, the actual vehicle speed is estimated and calculated according to the wheel lock time. Then, in step SI3, that H(=
A gear ratio suitable for the constant vehicle speed is calculated and set to 1 in step S14.
．． The gear ratio calculated in step 13 is controlled by shifting to the OW side. After that, the process returns to step S2.

Next, the operation of this embodiment will be explained by taking as an example the case where the motorcycle is run on a road with muddy spots.

Assume that while driving on a muddy road, the brakes are suddenly applied and the rear wheels Wr decelerate to a level greater than the actual speed of the vehicle, causing the wheels to lock.

Then, it is determined that the wheel lock has started according to the sudden drop in the rotational speed (2) of the rear wheel Wr. When it is determined that wheel lock has started, the gear ratio of the continuously variable transmission TM is either held at the value immediately before the wheel lock, depending on the wheel lock time, or shifted to the LOW side by an amount corresponding to the estimated vehicle speed. The gear will be changed.

Therefore, when the rear wheels Wr bite against the road surface, a gear ratio suitable for the actual vehicle speed is ensured, and the engine is prevented from overspeeding.

In addition, in the above embodiment, when the wheel rotational acceleration is below a certain set value, it is determined that the rear wheel rotational speed has suddenly decreased to more than the actual vehicle speed. Not limited.

For example, the rate of change in wheel rotational speed, or acceleration, when the wheels are stopped from a no-load idling state by applying braking can be stored in advance as data, so this acceleration curve can be approximated within the error range. It can be determined that the wheels are decelerating more than the actual vehicle speed.

It is also possible to detect the wheel rotational speeds of the front wheels and the rear wheels separately, and to make the same determination if the rotational speed of the rear wheels suddenly decreases compared to the rotational speed of the front wheels.

Further, in the above embodiment, the case where the present invention is applied to a motorcycle for traveling on rough terrain has been explained, but the present invention can be applied to various types and types of vehicles as long as they are equipped with a continuously variable transmission. Can be applied.

Further, the type of continuously variable transmission is not limited to the llft pressure type, but may be a belt drive type or other type.

[Effects of the Invention] As described above, according to the present invention, when the driving wheels suddenly decelerate compared to the actual vehicle speed, whether the gear ratio is maintained at the speed ratio immediately before the sudden deceleration or when the sudden deceleration is released, Since the gear ratio is controlled according to the actual vehicle speed, when the speed of the driving wheels and the actual vehicle speed match, a gear ratio suitable for the actual vehicle speed is ensured, and overspeeding of the engine is prevented.

[Brief explanation of the drawing]

The drawings are for explaining one embodiment of the present invention.
1 is a plan view of the motorcycle, FIG. 2 is a side view of the same, FIG. 3 is a hydraulic circuit diagram of a power transmission system, and FIG. 4 is a control flowchart. E...Engine, TM...Continuously variable transmission, sb...Engine speed sensor, Sc...
・Vehicle speed sensor, 9...Wheel rotational acceleration, 91.
...Motoboku acceleration. Applicant: Honda Motor Co., Ltd. Flute 4

Claims (1)

[Claims] In a speed change control method for a vehicle with a continuously variable transmission that sets the gear ratio based on the engine rotation speed and the drive wheel rotation speed that represents the vehicle speed, when the drive wheels suddenly decelerate from the actual vehicle speed, the gear ratio immediately before the sudden deceleration is 1. A method for controlling a gear change in a vehicle with a continuously variable transmission, characterized in that the actual vehicle speed at the time of sudden deceleration is maintained or the sudden deceleration is released is estimated, and the gear ratio is controlled in accordance with the estimated actual vehicle speed.