JPH04321479A - Human power driven device equipped with engine - Google Patents

Abstract

PURPOSE:To enhance the feeling of driving a human power driven device equipped with engine such as a bicycle by sensing the load for human power drive and the rotational angle of a crank shaft, determining the mean load of the human power driving system, and controlling the engine output on the basis of a certain specified conversion characteristic for the obtained mean load. CONSTITUTION:A drive shaft is fitted with a load sensing means 30 to sense the drive torque due to human power, and the output from sensing is fed to a mean load sensing means 68, which is also fed with a crank angle given from a crank angle sensing means 50 mounted on the crank shaft. The means 68 calculates the mean load from the crank angle and the drive torque sensed by the load sensing means 30. On the basis of the result therefrom a controller 60 controls a throttle 46a with a specific relationship to the mean load while following the motion program stored in a memory. Thus the output of the engine drive system 40 is controlled.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine-equipped human power drive system in which a human power drive system and an engine drive system are provided in parallel.

0002

[Background of the Invention] In devices driven by human power, such as bicycles, a drive device uses an electric motor in combination to reduce the load on human power when the load increases, such as when climbing a hill, while still maintaining the bicycle-like driving feeling. The applicant of the present application previously proposed (Japanese Patent Application No. 2-214947). In this proposed system, a drive system using an electric motor is provided in parallel with a human-powered drive system, and the output of the electric motor is changed in response to changes in the load on the human-powered drive system.

[0003] Here, it has been considered to use a small gasoline engine in place of the electric motor. In a gasoline engine, the engine output is normally controlled by the throttle valve opening, but in this case, the delay in engine output change relative to the opening and closing of the throttle valve is much larger than in an electric motor.

On the other hand, when a crank pedal is used for manual driving, the driving torque changes periodically depending on the rotation angle (crank angle) of the crankshaft. For this reason, even if the throttle valve is changed periodically in synchronization with the rotation of the crankshaft, the change in engine output lags significantly behind the change in throttle valve opening, resulting in a problem of poor driving feel. arise. For example, if the conversion characteristics are determined so that the engine drive torque increases in response to an increase in the drive torque caused by human power, if the engine output does not increase when the crank pedal is strongly depressed, but the pedal force becomes lighter after that, This causes inconveniences such as an increase in engine output and a mismatch between the driver's sensation and the engine output.

[0005]

[Object of the Invention] The present invention was made in view of the above circumstances, and it is possible to improve the feeling of driving by human power and the driving force by the engine when using both human power and an engine whose output is controlled accordingly. An object of the present invention is to provide a human power drive device with an engine that can improve the driving feeling by reducing the sense of inconsistency with changes in the speed.

[0006]

According to the present invention, the object is to reduce the load on the human-powered drive system in an engine-equipped human-powered drive system in which a human-powered drive system using a crank pedal and an engine-based drive system are provided in parallel. load detection means for detecting; crank angle detection means for detecting the rotation angle of the crankshaft rotationally driven by the crank pedal; and average load detection for determining the average load of the human-powered drive system using the detected crank angle. This is achieved by a human-powered engine-equipped drive system characterized by comprising: a controller for controlling the output of the engine according to a predetermined conversion characteristic with respect to the detected average load;

[0007]

[Example] Fig. 1 is a block diagram showing the concept of the present invention, Fig. 2
is a diagram showing an example of application to a bicycle, FIG. 3 is an exploded view of its drive system, FIGS. 4 and 5 are diagrams showing an example of its load detection means, and FIG.
is the engine throttle valve opening Θ from the human-powered driving torque.
FIG. 7 is a diagram showing conversion characteristics for determining th.

In FIG. 2, reference numeral 10 indicates a rear wheel that is a driving wheel, 12 a front steering wheel, 14 a steering handle, 16 a seat, and 18 a crank pedal. Pedal 18 to rear wheel 1
The human power drive system 20 (FIG. 1) that reaches 0 is formed by a crankshaft 22 that holds the pedal 18, a bevel gear 24, a drive shaft 26, and a bevel gear 28. In the middle of the drive shaft 26, there is a driving force generated by this human power, that is, a driving torque Th.
A load detecting means 30 is interposed for detecting. For example, as shown in FIG. 4, this load detection means 30 includes a shaft half 26a on the crankshaft 22 side and a shaft half 26b on the rear wheel 10 side.
The torsion bar spring 32 connected to the shaft halves 26a, 26
A potentiometer (for example, a rotating sliding resistor) 34 determines the relative angle change between the two positions. Alternatively, as shown in FIG. 5, the drive shaft 26 may have a small diameter in the middle, and the torsion of the small diameter portion 26c may be detected by a strain gauge 36. The signal a of these potentiometers 34 and strain gauges 36
is removed, for example, via a slip ring (not shown).

An engine drive means 40 is provided on the drive shaft 26 between the load detection means 30 and the rear wheel 10. The engine drive means 40 includes, for example, a two-stroke air-cooled single-cylinder engine 42, a worm gear mechanism 44 that decelerates the rotation of the engine 42, and transmits the rotation to the drive shaft 26.
It has a clutch 46 interposed between the engine 42 and the worm gear mechanism 44. This clutch 46 is composed of, for example, a one-way clutch or an electromagnetic clutch.

A carburetor 48 is connected to the intake pipe of the engine 42, and this carburetor 48 is provided with a throttle valve 48a. The throttle valve 48a is opened and closed by an actuator 48b such as a stepping motor.

The rotation angle of the crankshaft 22, ie, the crank angle θ, is detected by a crank angle detection means 50. The crank angle detecting means 50 includes a gear 52 fixed to the crankshaft 22, and a light emitting element 54 and a light receiving element 56 arranged opposite to each other with the gear 52 in between. Note that two pairs of the light emitting/receiving elements 54 and 56 are provided with a phase difference of 90° with respect to the period of the teeth of the gear 52, but only one pair is shown in FIG. 3. Therefore, two light receiving elements 56
The rotational direction and rotation amount of the crankshaft 22 can be detected based on the output of the crankshaft 22 . Further, the reference angular position of the crankshaft 22 can also be detected by partially changing the spacing between the teeth of the gear 52 or by providing a notch that indicates another reference position. As a result, the absolute angle of the crank angle θ can always be detected.

Next, the controller 60 will be explained. The controller 60 is a microcomputer (hereinafter referred to as CPU).
) 62, a ROM 64 for storing operating programs and various data, and a driver 66. In this embodiment, the CPU 62 has the function of an average load detection means 68 for calculating the average value Thm of the human-powered drive torque Th detected by the load detection means 30.

The average load detecting means 68 detects the crankshaft 22
Torque T due to change in rotation angle, that is, crank angle θ
This eliminates the fluctuation of h. In other words, the crank angle θ(
deg), the torque Th changes periodically as shown by the solid line A in FIG. Generally, this solid line A is the torque Th
With respect to changes in , only the amplitude changes, but the period does not change much. Therefore, the average load, that is, the average torque Thm can be determined by any of the following three methods.

■ θ=45°(θ1), 135°(
θ2 ), 225° (θ3 ), 215° (θ4 )
Since the torque Th at these crank angles θ1...θ4 is an intermediate value between the maximum value and the minimum value, the torque Th at these crank angles θ1...θ4 is set as the average value Thm. ■ θ=0°, 1
At 80° (θm1 and θm2, respectively), the torque Th becomes the minimum value Th (min), and when θ=90°, 27
The maximum value Th (Max
), the arithmetic mean is taken as the average value Thm. That is, Thm = [Th (min) + Th (Max)]
/2. ■ Calculate the average value Thm by integrating sample values T(θ) of torque Th taken at every small fixed angle from θ=0 to 90°, and dividing this integrated value ΣT(θ) by the number of samples n. demand. Thm=ΣT(θ)/n

Note that under operating conditions where the torque Th is extremely large, not only does the amplitude of the solid line A in FIG. 7 actually increase, but the phase of the crank angle θ also lags, as shown by the virtual line B in the figure. . Therefore, taking this into consideration, the torque T
When h is large, θ1 in each method of ■ and ■ above...θ
4, θm1, θM1... may be provided with means for correcting the crank angles. Also, for method ■, the integral range (0-
90°) or may perform integration over an arbitrary range of 180°.

[0016] Since the human-powered drive torque Th constantly changes during driving, the average value Thm within a certain cycle determined as in the above embodiment is different from the average value Thm in the next cycle. result in different values. Therefore, the average value Thm changes stepwise over time. Therefore, in order to prevent sudden changes in this average value Thm, the average value Thm
It is desirable to smooth the

Furthermore, when the rotation of the crankshaft 22 stops or becomes extremely slow, the average value Th
There is a problem that m cannot be determined or becomes inaccurate. Therefore, in such a case, that is, when the period (cycle) for calculating the average value becomes longer than the predetermined setting time,
It is desirable to change the way the average value is calculated. For example, the torque Th over a sufficiently short period of time may be integrated regardless of the crank angle to obtain an average value over that time, or the detected torque Th may be used as is without using the average value.

In this embodiment, the average load detecting means 6
8 is assumed to be held by the CPU 62 of the controller 60,
That is, although the explanation has been made as having the CPU 62 as an operating program, it is of course possible to configure it as a circuit independent from the CPU 62.

The average value Thm of the human-powered drive torque Th obtained as described above is used by the CPU 62 to determine the throttle valve opening Θth of the engine 42. That is, the CPU 62 determines the throttle valve opening Θth of the engine 42 in accordance with the operating program stored in the ROM 64 in a predetermined relationship with respect to the average value Thm. For example, as shown by A in FIG. 6, it is possible to have a linear relationship, or as shown in B and C, the rate of increase can have a gradual decreasing or increasing characteristic.

In order to obtain these characteristics A, B, and C, store the characteristics A, B, and C in the ROM 64, for example, and determine the opening that the throttle valve 48a should take when the average torque of human power drive is Thm. The driver 66 reads the degree Θth from the ROM 64 and drives the actuator 48b so that the throttle valve 48a reaches the opening degree Θth. 70 is a battery for driving this actuator 48b.

In FIG. 2, 72 is a fuel tank for the engine 42, which is mounted above the crank pedal 18 as shown in FIG. Further, a control box 74 that houses the controller 60 is attached below the seat 16.

In the above embodiment, the driving torque T
The opening Θth of the throttle valve 48a is controlled in accordance with the conversion characteristic shown in FIG. 6 in response to the average value Thm of h. However, in the present invention, the throttle valve opening Θth may be determined based on, for example, the human-powered driving torque Th and the rotational speed of the crankshaft 22, that is, the vehicle speed V. Further, the throttle valve opening Θ is determined using the intake pipe negative pressure between the throttle valve 48a and the engine 42.
th may be determined.

The present invention is applicable not only to bicycles, but also to and includes human-driven three- and four-wheeled vehicles, vehicles for the handicapped, rehabilitation equipment, play equipment, fitness equipment, robots, and the like.

[0024]

[Effects of the Invention] As described above, the present invention calculates the average value (Thm) of the drive torque (Th) of the human-powered drive system,
Since the driving force of the engine is controlled using a predetermined conversion characteristic with respect to this average value (Thm), even if the human power driving torque (Th) changes periodically as the crankshaft rotates, the engine output does not change periodically. Moreover, even if the control response of the engine output is poor, the driving feeling will not deteriorate. Therefore, the driving feeling can be improved.

[Brief explanation of drawings]

[Figure 1] Block diagram showing the concept of the present invention

[Figure 2] Diagram showing an example of application to bicycles

[Figure 3] Developed diagram of the drive system

[Figure 4] Diagram showing an example of the load detection means

[Fig. 5] A diagram showing another example of the load detection means.

[Figure 6] Conversion characteristic diagram between human-powered driving torque and throttle valve opening

[Figure 7] Diagram showing periodic changes in drive torque due to human power

[Explanation of symbols]

10 Drive wheel 20 Human power drive system 30 Load detection means 40 Engine drive system 42 Engine 48a Throttle valve 50 Crank angle detection means 60 Controller 68 Average load detection means

Claims (1)

[Claims] 1. An engine-equipped human-powered drive system in which a human-powered drive system using a crank pedal and an engine-based drive system are provided in parallel, comprising: load detection means for detecting a load on the human-powered drive system; a crank angle detection means for detecting the rotation angle of a crankshaft rotationally driven by a pedal; an average load detection means for calculating an average load of the human-powered drive system using the detected crank angle; A human power drive device with an engine, comprising: a controller that controls the output of the engine with predetermined conversion characteristics.