JPH0374533A - Output adjusting device for engine - Google Patents

Abstract

PURPOSE:To prevent an abrupt increase in load at the time of landing after a jump by detecting the amount of stroke of the suspension of a motorcycle, and temporarily suppressing the output of an engine when a length of the time for which the detected value exceeds a specified amount is longer than a specified value. CONSTITUTION:With a motorcycle for motocross, a rear wheel is journaled to the free end of a rear fork 8 pivoted 16 on a lower part in the rear of the body frame so that it can freely oscillate up and down, and the power of the engine 10 is transmitted to the rear wheel through a drive sprocket 13, and a chain 14. In this case, in relation to the rear fork 8 supported on the body through a rear cushion, a stroke sensor 23 is provided to input its output signals to a control unit 25 along with each output signal from a rotation sensor 26 and a throttle sensor 27. When a length of time for which the rear cushion exceeds a specified amount of stroke is longer than a specified value, the ignition timing of an ignition plug 22 is adjusted to be delayed through an ignition unit 28 to suppress the output of the engine.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an engine output adjustment device for a motorcycle or the like.

[Conventional technology]

For vehicles such as motocross and rally cars that make jumps where the front and rear wheels completely separate from the road surface, when landing, the impact force of the landing and the contact pressure of the tires against the ground momentarily increases, causing engine drive. The force is impulsively applied to the drive system components as a high load. In particular, when the landing surface is a sandy, sloping surface, the rear wheels dig into the sand as the vehicle moves forward, resulting in a high load acting on the drive system for a relatively long period of time. Therefore, drive system parts such as wheels (hubs, spokes, nipple rims, bearings, etc.), drives and driven sprockets, drive chains or drive shafts, output shafts, crankcases,
When designing the mission gear, the strength had to be determined by taking into account the long-term driving load as well as the impactful driving load at the time of landing. Furthermore, in order to suppress such uneven load on the crankcase, Japanese Patent Publication No. 60-21113 discloses a special structure in which a drive sprocket and an engine mount are provided on an extension of the rear fork. [Problems to be Solved by the Invention] By the way, considerations such as increasing the strength of drive system parts and special structures are determined based on the rare case of extreme conditions when landing after a jump. Because the strength and structure were greater than necessary for normal driving, the drivetrain parts had to be made heavier and made of expensive materials. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vehicle that can reduce the weight of the vehicle and also ensure freedom in design. [Means for Solving the Problems] In order to solve the above problems, an engine output adjustment device according to the present invention is provided with an engine output control control unit for controlling ignition timing, etc. The control unit includes a stroke sensor that detects a stroke amount, and the control unit temporarily suppresses engine output when the suspension exceeds a predetermined stroke amount for a longer time than a predetermined value based on an output signal of the stroke sensor. The feature is that it is controlled so as to [Operation of the invention] When the rear wheels leave the ground during a jump, the suspension of the vehicle extends, and when the stroke amount exceeds a predetermined amount (hereinafter referred to as the limit stroke) and the time is longer than the set value, this limit stroke is extended. Based on the detected output signal of the stroke sensor, the control unit temporarily suppresses the engine output. Therefore, even if the driver opens the accelerator and lands on the ground, the engine output is temporarily reduced, so the driving load applied to the drive system components is reduced. Furthermore, since an engine case with a special structure is not required, the degree of freedom in design is not restricted. [Example] An example is shown in FIGS. 1 to 6. Figure 1 shows the external appearance of a motorcycle for motocross, where 1 is the front wheel, 2 is the front fork, 3 is the handlebar, 4 is the fuel tank, 5 is the seat, 6 is the frame, 7 is the rear traction, and 8 is the rear fork. , 9 is the rear wheel. The rear suspension 7 and the rear fork 8 constitute a rear suspension. At the position of the rear wheel 9 shown by the imaginary line in the figure, S wax indicates when the rear suspension is fully extended, and S win indicates when the rear suspension is fully retracted. An engine 10 is mounted on the frame 6. The engine case 11 of the engine 10 also serves as a crankcase and a transmission case, and has engine mount parts 12a, 1
There are three front and rear needles 2b and 12c provided. Furthermore, a drive sprocket 13 is supported at the rear. A chain 14 is wound around the drive sprocket 13 and a driven sprocket 15. Further, a pivot portion 16 of a beam fork 8 is provided at the rear lower part of the frame 6, and a link bracket 18 for a link member 17 connecting the rear traction 7 and the rear fork 8 is provided. In the figure, reference numeral 19 is a cylinder, 20 is a carburetor, 21 is a throttle wire, and 22 is a spark plug. Furthermore, E is the ground, and B is the sandy slope where the vehicle lands. In addition, the engine 10, engine case 11, drive sprocket 13, chain 14,
The driven sprocket 15, rear wheel 9, etc. are part of the drive system components, and the strength of each of these components is set on the basis of sufficient strength for normal driving. FIG. 2 is an enlarged view of the engine 10 to schematically show its output control system, and a stroke sensor 23 is provided on the reaction 7 side. Various structures are possible for the stroke sensor 23, and as shown in an example in FIG.
4 may be used, or simply a piston position sensor provided on either side of the inner and outer cylinders constituting the damper portion of the reaction 7 (for example, a plurality of magnetic sensors may be installed on the inner wall surface of the inner cylinder, etc. along the movement axis of the piston). The damper may be arranged in a straight line) to detect the amount of expansion of the damper. Furthermore, it may have a structure such as a potentiometer that is attached to, for example, the link bracket 18 in FIG. 1 and detects the amount of rotation of the link member 17 or the like. A detection signal from this stroke sensor 23 is input to a control unit 25 including a CPU. On the other hand, this control unit 25 includes a rotation sensor 26 consisting of a known magnetic pickup device or the like for detecting the rotation speed Ne of the crankshaft (engine), and a rotation sensor 26 provided on the carburetor 20 side for detecting the throttle opening θTH. Each output signal from the throttle sensor 27 is also input. The throttle sensor 27 can also be provided on the grip side of the handle 3 to which one end of the throttle wire 21 is connected. The control unit 25 is activated under a predetermined condition, for example, when the stroke amount when the rear suspension is fully extended (Smax in FIG. 1) is the limit stroke, and this state continues for a predetermined period of time, the ignition unit 28, which constitutes a part of the control unit 25, is activated. The ignition timing is adjusted by changing the timing of applying voltage to the spark plug 22 via the spark plug 22. The limit value of the limit stroke and its duration is determined in advance based on the relationship between the design strength of the drive system components and the expected magnitude of the drive load, with a certain safety factor in mind. Note that engine output suppression is mainly achieved through ignition timing control by the ignition unit 28, but by controlling the exhaust timing and fuel supply amount in conjunction with this, it is possible to perform more accurate output control. . FIG. 2 shows such a combination type, in which the control unit 25 is further comprised of an exhaust valve control unit 29 and a fuel control unit 3.
0 is provided, and these enable the control operation of a known variable exhaust valve device 31 that changes the opening timing of the exhaust port and the carburetor 20 (injector in the case of electronic fuel injection control system). An example of the variable exhaust valve device 31 is shown in FIG. 4, in which a drive pulley 33 is attached to a servo motor 32 that is driven and controlled by an exhaust valve control unit 29, which rotates a driven pulley 34, and the drive pulley 33 rotates a driven pulley 34. The arm 35 of the device is designed to swing up and down. Arm 3
5 is provided on the earthen wall of the exhaust passage 37 facing the exhaust boat 36, and a valve 38 connected to the tip thereof moves up and down on the inner wall surface of the cylinder 39 to change the exhaust timing. Note that the driven pulley 34 is provided with a rotation sensor 40, whereby the vertical amount of the valve 38 is constantly fed back to the exhaust valve control unit 29. Next, the operation of this embodiment will be explained along the flowchart of FIG. Step fl: When the car body jumps, the rear wheels 9 leave the ground E (Fig. 11), and the rear suspension (reaction 7) reaches a fully extended state (limit stroke, Fig. 1 5) due to rebound.
nax). In the steps: When the stroke sensor 23 senses the fully extended state of the rear suspension, it inputs a limit stroke signal S0 to the control unit 25. The stroke sensor 23 in this case is of the type shown in Fig. 3, and measures all changes in the stroke amount continuously in an analog manner. The control unit 2 sequentially controls the stroke signal S that fluctuates.
5, the control unit 25 compares and judges the stroke signal S with the limit stroke signal S0. However, in this embodiment, the former example will be explained below. In the steps: The control unit 25 measures the full extension state duration T. The full extension state duration T is determined by the stroke sensor 23.
This is the time during which the limit stroke signal S0 is continuously inputted, and it is determined whether or not this exceeds a predetermined value To.
Detects jumping state. When the full extension state duration T is a predetermined value T0<T., the control unit 25 does not adjust the engine output (
Step f4). Step f: Full extension state duration T is greater than or equal to a predetermined value T0 (T≧T(1)
At this time, the control unit 25 issues a command to suppress the engine output. Specifically, the ignition timing is delayed by a predetermined period of time via the ignition unit 28 to suppress the engine output over time. At this time, if necessary, it is also possible to issue commands to each of the exhaust valve control unit 29 to the fuel control unit 30 to simultaneously operate the variable exhaust valve device 31 and the carburetor 20 to suppress the output. Step 6: Through the adjustment in step f, the engine output is temporarily suppressed so as not to exceed a predetermined output value before landing. Step: When you land in the condition shown in Figure 1, the rear suspension strokes in the direction of compression. At this time, the impact upon landing and the instantaneous increase in tire ground pressure cause an impactful drive load to be applied to drive system components, but the extent of this load is determined in advance by a temporary reduction in engine output. By this,
It stops to the extent that each drive system component can withstand sufficiently. In particular, if the landing point is a sandy area on a downhill slope, the drive load on the drive system components will not be instantaneous but will be applied for as long as possible, as the rear wheels will move forward while crawling into the sand. . Step f: After landing, the stroke amount of the rear suspension increases, so the stroke sensor 23 receives the limit stroke signal S.
Stop outputting 0. In the step: When the stroke signal S0 is not input, the control unit 25 (fuel control unit 30 if necessary, variable exhaust valve device 3
Issue a command to 1). Step f+o: After a delay time, the engine output increases and returns to the original state. FIG. 6 is a time-lapse table for each output of the stroke sensor 23 and the engine before and after a jump. When the output of the stroke sensor 23 turns on at the start of a jump, the engine output decreases after a time T, and when the stroke sensor 23 hits the ground, This shows that when the output of the engine is turned off, the engine output is restored after a delay time. As described above, according to this embodiment, the drive load upon landing after a jump can be reduced, and the required strength of each drive system component can be reduced. Moreover, in this embodiment, as a condition for reducing the engine output, a correlation is taken between the limit stroke signal So and a predetermined duration value To, and as a means for reducing the output, in addition to adjusting the ignition timing, the exhaust timing and fuel supply are also adjusted. Since it is used in conjunction with control, more accurate and precise control is possible. Furthermore, since the engine output is restored after a predetermined delay time after landing, the impact driving load can be sufficiently reduced during this time. As a result, it is possible to reduce the weight and cost of drive system components, which in turn makes it possible to reduce unsprung weight and improve gap running performance. Furthermore, when the accelerator opening degree θTH is larger than a predetermined value (when high output is required), a step of determining the signal of the throttle sensor 27 before the output needs to be suppressed can be added. Furthermore, since it is not necessary to adopt a special structure, restrictions on the degree of freedom of design can be reduced. [Effects of the Invention] According to the present invention, a jump state is detected before landing and the engine output at the time of landing is temporarily suppressed. The drive load applied to the drive system components does not exceed the set value. Therefore, when designing the strength of each drive system component, there is no need to consider the strength conditions in the extreme state of such rare cases, and unnecessary increases in strength can be eliminated and weight reduction can be achieved. Moreover, restrictions on the degree of freedom of design can be reduced.

[Brief explanation of drawings]

1 to 6 are engine case 11, FIG. 1 is a side view of the motorcycle, FIG. 2 is a conceptual diagram of the output control system, and FIGS. 3 and 4 are conceptual diagrams of the main parts, respectively. FIG. 5 is a flowchart of output control, and FIG. 6 is a time table regarding each output of the stroke sensor and the engine. (Explanation of symbols) 7... Reaction, 8... Rear fork, 9...
... Fi wheel, 10... Engine, 20... Carburetor, 23... Stroke sensor, 25... Control unit, 28... Ignition unit.

Claims (1)

[Claims] In a vehicle equipped with a control unit for controlling engine output such as ignition timing control, the control unit includes a stroke sensor that detects the stroke amount of a suspension installed in a vehicle, and the control unit controls whether the suspension is adjusted to a predetermined level based on the output signal of the stroke sensor. If the time taken to exceed the stroke amount is longer than the predetermined value,
An engine output adjustment device characterized by controlling the engine output so as to temporarily suppress it.