GB2211890A

GB2211890A - Engine throttle valve motor vehicle speed control

Info

Publication number: GB2211890A
Application number: GB8825196A
Authority: GB
Inventors: Yasuhiko Miyamoto
Original assignee: Fuji Jukogyo KK; Fuji Heavy Industries Ltd
Current assignee: Subaru Corp
Priority date: 1987-10-30
Filing date: 1988-10-27
Publication date: 1989-07-12
Anticipated expiration: 2008-10-27
Also published as: FR2622636A1; FR2622636B1; GB8825196D0; JPH0171145U; JPH0723557Y2; GB2211890B; DE3836482A1

Description

MOTOR VEHICLE SPEED CONTROL DEVICE 22 1189 The present invention relates

to a motor vehicle speed control device capable of controlling the speed of a motor vehicle without any negative sensation to the feeling of the driver of the vehicle.

As is well known in the art, there have been used various leisure or sport cars whose maximum speed is limited, and various types of vehicle speed control devices have been therefore devised and proposed.

For instance, Japanese Laid-Open Utility Model Publication (Kokai) No. 5973544 published May 18, 1984 discloses a motor vehicle speed control device of the is type in which an engine is equipped with a governor and an actuator adapted to be operated in response to load on the governor in such a manner that when a load higher than a predetermined value is imposed to the engine, an air intake is cut and consequently the rotational speed of the engine is decreased.

However, with he vehicle speed control device of the type described above, when a load higher than a predetermined value acts on the engine, the rotational speed thereof is decreased independently of the speed of the vehicle, so that, in some cases, as shown in FIG. 7, even when the engine has a sufficient output capacity, it becomes difficult to start the vehicle on an uphill slope 1 due to the decrease of the engine rotational speed. Furthermore, in the case of driving on a non-sloping road where the load is not so considerably increased, it sometimes becomes difficult to suppress the increase in vehicle speed. Thus, it is difficult to control the vehicle speed exactly.

Furthermore, Japanese Laid-Open Utility Model Publication (Kokai) No. 5921060 published February 8, 1984 discloses a motor vehicle control device of the type in which a governor which limits the maximum speed of an engine is incor porated with a flip-flop circuit and in which in response to a combination of transmission gears mounted on the vehicle, the degree of opening of a control lever of said governor is adjusted. With the vehicle speed control device of the type just described above, it is difficult to use it when a vehicle is not equipped with a power transmission system. As a result, the use of such vehicle speed control device is limited. 20 In order to solve the above and other problems, for instance, Japanese Laid-Open Utility Model Publication (Kokai) No. 60152056 published October 9, 1985 discloses a technique in which an air intake pipe and an exhaust pipe are intercommunicated by way of an intercommunicating pipe with a valve installed therein such that when the speed of the vehicle exceeds a predetermined value, the exhaust gas is conducted to the intake pipe through said valve thereby preventing increase in rotational speed of the engine.

With the vehicle speed control device of the type described immediately above, however, when the rotational speed of the engine increases quickly, a large amount of exhaust gas is sucked into the cylinders, frequently causing mis-firing. As a result, a negative sensation is given to the driver.

In view of the above, the primary object of the present invention is to provide a motor vehicle speed control device capable of correctly controlling the speed of the vehicle by making effective use of the output power from the engine regardless of whether the vehicle is equipped with a power transmission or not, without giving negative sensation to the driver of the vehicle.

To the above and other ends, the motor vehicle speed control device according to the present invention comprises: a throttle shaft provided on a throttle valve of a carburetor of an engine; a throttle lever rotatable 1 in response to operation of an accelerator pedal; governor means mounted on an output shaft of the engine representing the rotational speed of driving wheels; a control arm mounted to said throttle shaft so as to rotate or operate the same; means operatively connecting said governor means to the control arm to cause the control arm to operate the throttle shaft to prevent the speed of the vehicle from exceeding a predetermined speed in response to the operation of said governor means; and elastic means interposed between the throttle lever and the control arm so as to be able to transmit the rotation of the throttle lever to the control arm.

With the vehicle speed control device in accordance with the present invention, when the throttle lever is rotated by the accdlerator means, the control arm is rotated through the elastic means thereby opening the throttle valve while the control arm is rotated against the biasing force of the elastic means, thereby causing the throttle valve to rotate toward its closed position.

The above and other objects, effects and advantages of the present invention will become more apparent from the following description of a preferred embodiment thereof taken in conjunction with the accompanying drawings.

FIG. 1 is an exploded perspective view illustrating major component parts of a motor vehicle speed control device in accordance 1 with the present invention; FIG. 2 is a fragmentary side view of the vehicle speed control device; FIG. 3 is a sectional view of a governor; FIG. 4 is a sectional view taken along the line IV IV of FIG. 3; FIG. 5 is a schematic view explanatory of the power transmission system of a vehicle; FIG. 6 shows an engine output - engine rotational speed characteristic curve with the engine output plotted along the ordinate and the rotational speed along the abscissa; and FIG. 7 shows an output-rotational speed characteristic curve in a conventional engine.

Referring first to FIG. 5, an intake pipe la of an engine 1 has a carburetor 3 operatively coupled to an accelerator such as an accelerator pedal 2. A transmission 4 is connected to the engine 1 in such a manner that an input shaft 4a of the transmission 4 may is be connected through a clutch lc to a crankshaft lb of the engine 1.

An output shaft 4b of the transmission 4 extends in parallel with the input shaft 4a in the transmission 4.

The output shaft 4b and the input shaft 4a are drivingly coupled to each other through a plurality of transmission gears 4c which can b'e meshed with each other in different combinations by a shift lever 6 disposed adjacent to a driver's seat. The output shaft 4b is drivingly coupled through output gears 5a and 5d to driving wheels 5b and 5c of a motor vehicle.

Referring next to FIG. 4, a governor chamber 7 def ined by a cover 7a is provided in one side of the transmission 4, and one end of the output shaft 4b is extended into the governor chamber 7 and slidably carries thereon a governor sleeve 8. Each of governor weights 8a for shifting the governor sleeve 8 is rotatably pivoted with a pivot pin 8d to a flange 8b of a bush 8c which is securely mounted on the output shaft 4b. It therefore follows that when the rotational speed of the driving wheels 5b and Sc reaches a speed corresponding to, for instance, a speed of 40 Km/hr, in unison with the rotation of the output shaft 4b, each weight 8a is caused to rotate about the pivot pin 8d radially outwardly so that an arm 8e of each weight 8a is pressed axially against the governor sleeve 8 which in turn is caused to slide in the rightward direction as viewed in FIG. 4 with respect to the output shaft 4b.

Referring also to FIG. 3, a governor shaft 9 extends rotatably through a boss 7b integrally extended inwardly from the cover 7a and carries securely at the inner end thereof the base end of a swinging member 9a, which is in contact with the governor sleeve 8. It therefore follows that when the gover'nor sleeve 8 is caused to slide to push the swinging member 9a in the rightward direction as viewed in FIG. 4, the governor shaf t 9 is rotated in a counterclockwise direction.

one end of a governor lever 11 is securely f ixed to the outer end of the governor shaft 9 extended beyond the governor chamber 7 while the other end of the governor lever 19 is securely attached to one end of a governor cable 12.

As best shown in FIG. 1, one end of a governor spring lla is engaged with the governor lever 11 at an intermediate point between the ends thereof while the other end of the governor spring lla is engaged with the casing of the transmission 4.

The governor cable 12 extends toward the caburetor 3 as shown in FIG. 5, and, as illustrated in FIG. 1, a control arm 14 is securely attached to one end of a throttle shaft 13 of the throttle valve 13a of the carburetor 3. The governor cable 12 with a stopper 12a securely attached to the end thereof remote from the governor lever 11 is slidably passed through a swivel stub shaft 14a of the control arm 14. When the governor lever 11 is rotated, the governor cable 12 is pulled so that the stopper 12a thereof is caused to contact with the swivel stub shaft 14a. Then, the control arm 14 is rotated so that the throttle valve 13a is rotated toward its closed position.

As shown in Fig. 2, a throttle lever 16 is loosely fitted on the throttle shaft 13 in a manner rotatable relative to the same, and one end of the throttle lever 16 is engaged with one end of an accelerator wire 17 so that when the accelerator pedal 2 is depressed, the throttle lever 16 is caused to rotate in the direction opposite to said direction of rotation of the control arm 14; that is, in the direction in which the throttle valve 13a is opened.

As best shown in FIG. 1, the throttle lever 16 and the control arm 14 are interconnected to each other through an elastic means 18 such as a torsion spring in the form of a coil spring. The coil spring 18 is disposed around the throttle shaft 13 and has one end engaged with the throttle lever 16 and the other end engaged with the control arm 14. When the accelerator pedal 2 is depressed to cause the throttle lever 16 to rotate relative to the throttle shaft 13, the rotating force is transmitted through the elastic means 18 to the control arm 14 whereby the arm 14 is rotated accordingly and the throttle valve 13a is rotated toward its open position. When the covernor lever 11 is rotated as above, the control arm 14 is caused to rotate against the elastic force of the elastic means 18 so that the throttle valve 13a is rotated toward its closed position regardless of the angle of rotation of the throttle valve 13a.

One end of a return spring 19 is engaged with one end of the throttle lever 16 such that the lever 16 is normally urged to rotate in the direction opposite to the direction of rotation due to the pulling of the acceleration wire 17, under the biasing force of the return spring 19.

That is, in the case of an emergency when the driver releases the accelerator pedal 2, the return spring 19 acts on the throttle lever 16 to cause it to return in a counterclockwise direction in FIG. 1, and concurrently therewith the control arm 14 is also caused to rotate in the same direction via the elastic means 18 whereby the throttle valve 13a is rotated toward its closed position. Thus, safe operation of the vehicle speed control device is ensured.

Next, the mode of operation of the preferred embodiment with the above-described construction will be described. When the engine 1 is started and the throttle lever 16 is rotated through the acceleration wire 17 with respect to the throttle shaft 13, the rotation of the throttle lever 16 is transmitted through the elastic means 18 to the control arm 14 whereby the control arm 14 is rotated in unison with the throttle lever 16.

1 Since the control arm 14 is securely attached to the throttle shaft 13, when the control arm 14 is rotated, the throttle shaft 13 is also rotated in the same direction whereby tAe throttle valve 13a is opened and therefore the rotational speed of the engine 1 is gradually increased.

Then, the transmission gears 4c are coupled to each other by the operation of the shift lever 6 with a first gear ratio, and when the accelerator pedal 2 is operated and the clutch lc is connected, the rotation of the output shaf t 4b of the engine 1 is transmitted through the output gears 5a and 5d to the driving wheels 5b and 5c whereby the vehicle is started. In this case, the transmission gears 4c are so intermeshed with each other as to select, for instance, the first gear ratio.

Therefore, even when the rotational speed of the engine 1 is increased, the rotational speed of the output shaft 4b does not reach a pre'determined rotational speed, and even when a load is applied to the engine 1, the transmission of the power produced by the engine 1 is not adversely affected and the output power from the engine 1 is transmitted to the driving wheels 5b and 5c.

Thereafter, as a second gear ratio and then a third gear ratio areselected in the order named, the vehicle 15 speed is increased. In this case, as shown in FIG. 6, the rotational speed of the engine and hence the input shaft 4a of the transmission 4 vary in response to the selected gear ratio. According to the present invention, the governor starts its operation at a predetermined speed so that the output power produced by the engine can 1 be effectively utilized.

Upon rotation of the output shaft 4b, the governor weights or flyweights 8a attached through the flange 8b to the output shaft 4b are expanded to cause the governor sleeve 8 to slide in the rightward direction in FIG. 4.

Thereupon, the governor sleeve 8 causes the swinging member 9a to swing counterclockwise as viewed in FIG. 4 so that the governor shaft 9 is rotated in the same direction and therefore the rotating torque is produced by the governor lever 11. Since the governor lever 11 is engaged with the governor spring lla, when the rotational speed of the output shaft 4b exceeds a predetermined rotational speed so that the flyweights 8a press against the governor sleeve 8, the rotating torque of the governor lever 11 increases and overcomes the force of the governor spring lla whereby the governor lever 11 is rotated. The stopper 12a of the governor cable 12 connected securely to the governor lever 11 is therefore brought into contact with the control arm 14, and consequently the throttle valve 13a is rotated through the control arm 14 toward its closed position.

is Therefore, the quantity of the intake air and fuel charged into the engine 1 is limited so that the rotational speed thereof is decreased and therefore the vehicle speed slows down. The throttle lever 16 operatively coupled to the accelerator pedal 2 is loosely mounted on the throttle shaft 13 and is further connected through the elastic means 18 to the control arm 14, so that as long as the rotating torque is acting on the governor lever 11, even when the accelerator pedal 2 is depressed, only the elastic means 18 is deformed and the.25 rotation of the throttle shaft 13 is not influenced.

When the rotational speed of the engine 1 is decreased so that the rotation of the output shaft 4b slows down, the rotating torque of the governor lever 11 is decreased whereupon the governor lever 11 is returned under the force of the governor spring lla and the governor cable 12 is also returned. Meanwhile the cable 12 slides with respect to the swivel stub shaft 14a so that the control arm 14 is not directly returned in response to the return of the cable 12, but is forced to rotate in the return direction under the force of the elastic means 18. Therefore, the throttle shaft 13 is rotated in the return direction; that is, in the opening direction so that the throttle valve 13a is caused to rotate again toward the valve opening position. The above-described control steps are repeated so that the vehicle speed can be maintained at a predetermined value.

When the force of the elastic means 18, the force of the governor spring lla and the rotating torque of the governor lever 11 produced by the rotation of the output shaft 4b are balanced, the adjusting operation of the throttle valve 13 is stopped so that the vehicle speed can be correctly maintained, for instance, at 40 km/hr 1 without adversely affecting the driving sensation of the driver.

So far the vehicle speed control device in accordance with the present invention has been described when the vehicle is equipped with the transmission 4, but it will be apparent to those skilled in the art that the motor vehicle speed control device can be equally mounted on a vehicle without a transmission of the type described above.

It will also be apparent to those skilled in the art that the motor vehicle speed control device in accordance with the present invention can be mounted not only on sport or leisure vehicles but also other vehicles such as. on-road vehicles.

As described above, according to the motor vehicle speed control device in accordance with the present invention, since the rotational speed of the output shaft on the side of the driving wheels which represents a vehicle speed is detected and controlled, it becomes possible to effeQtively utilize the output from the engine even at the first or low gear regardless of the selection of any desired gear ratios. Furthermore, the present invention has the feature that the vehicle speed can be correctly controlled without giving any negative sensation to the driver.

le -is-

Claims

CLAIMS:

1 A motor vehicle speed control device comprising a throttle valve of a carburetor mounted on an engine, an accelerator pedal for the engine, and governor means for controlling said throttle valve to govern the speed of the vehicle: characterized in that a throttle shaft is provided on the throttle valve, and a throttle lever is provided so as to rotate in response to operation of the accelerator means that the governor means is mounted on an output shaft of the engine representing the rotational speed of the driving wheels and a control arm is mounted to the throttle shaf t so as to rotate the same, and that the governor means is operatively connected to the control arm by way of connecting means which causes the control arm to operate the throttle shaft in a manner to prevent the speed of the vehicle from exceeding a predetermined speed, in response to the operation of the governor means, and elastic means is interposed between the throttle lever and the control arm so as to be able to transmit the rotation of the throttle lever to the control arm

2. The motor vehicle speed control device according to claim 1, characterized in that said throttle lever is loosely mounted on the throttle shaft so as to be rotatable independently of the throttle shaft

3. The motor vehicle speed control device according to claim 1 or 2, characterized in that said throttle lever is connected to the accelerator means by way of an accelerator wire

4. The motor vehicle speed control device according to claim 1 or 2, characterized in that said control arm is fixedly connected to the throttle shaft, and said governor means has a governor lever which rotates when the governor means operates, the governor lever being connected to the control arm via a governor cable

5. The motor vehicle speed control device according to claim 4, characterized in that said control arm has thereon a swivel stub shaft through which the governor cable is passed slidably relative to the stub shaft said governor cable having at the tip end thereof a stopper adapted to abut agaLsnt the stub shaft when the governor cable is pulled by the governor means.

6. The motor vehicle speed control device according to claim 1 or 2, characterized in that said elastic means is a torsion coil spring one end of which is engaged with the throttle lever and the other end of which is engaged with the control arm said coil spring being disposed around the throttle shaft

7. The motor vehicle speed control device according to claim 1 or 2, characterized in that said output shaft of the engine is an output shaft of a transmission connected between the engine and the driving wheels A motor vehicle speed control device substantially as hereinbefore described with reference to the accompanying drawings.

1 Published 1989 atTbe Patent Office. State House,6671 Mgh Holborn, LondonWC1R4TP.Furtlier copies maybe obtainedfrom The Patent OfEice. Sales Branch. St Mary Cray, Orpington, Kent BR5 3RD Printed by Multiplex techniques ltd, St Mary Cray, Kent, Con. 1187