WO1981002630A1

WO1981002630A1 - Throttle control device

Info

Publication number: WO1981002630A1
Application number: PCT/AU1981/000024
Authority: WO
Inventors: P Mcconnell
Original assignee: P Mcconnell
Priority date: 1980-03-13
Filing date: 1981-02-24
Publication date: 1981-09-17
Also published as: GB2079848A; JPS57500300A; BR8107435A; EP0047254A1; EP0047254A4; NZ196462A

Abstract

A throttle control device for automobiles using internal combustion engines is mounted adjacent the accelerator pedal (21) and is connected to the engine intake vacuum by a hose (19). The vacuum operates a diaphragm (8) in the device to release a retractable spool (3) for rotation when the vacuum pressure is sufficiently high and above a predetermined level. A wire (16) wound on the spoll (3) extends from the device and is connected to one end of a spring (17). The other end of the spring (17) is connected to the accelerator pedal (21). Thus when the vacuum is above said predetermined level the accelerator pedal (21) may be depressed without any noticeable extra effort. When the vacuum falls below said level the diaphragm (8) causes locking of the spool (3) against rotation and the force of the spring (17) must be overcome to depress the accelerator pedal (21) further.

Description

THROTTLE CONTROL DEVICE

This invention relates to a throttle control device for automotive vehicles using internal combustion engines and in particular to a device which operates from the engine intake vacuum pressure. A commonly accepted form of vehicle fuel conservation has been the fitting and use of a vacuum gauge which constantly monitors engine inlet manifold vacuum in order that the vehicle driver can visually appreciate the air fuel mixture which enters the engine enabling adjustment of driving habits to maintain economical fuel usage. It is recognised that as the carburettor throttle butterfly is opened, the air flow through the carburettor venturi is increased and, therefore, fuel flow through the system is increased a like amount. However, very often, the throttle butterfly opening is in excess of the actual amount needed for the immediate requirement and hence this fuel is wasted. The vacuum gauge when fitted and used correctly will minimize this .excessive fuel usage and will, therefore, return greater fuel economy to the driver. Generally speaking, the optimum manifold vacuum figure which will return good performance and economy is in the region of minus 27 to minus 40 k.p.a. Several problems become apparent, however, when endeavouring to maintain this goal. These are as follows:- (a) the need for constant observance of the instrument, possibly to the loss of some safety considerations, (b) the tendency to forget economy and apply greater than necessary throttle pressure and so return to the excessive fuel usage condition, and

(c) fatigue of the ankle, foot and leg by having to be constantly held in a "floating" position which, after only a short period of driving, may reach a point where body fatigue can become apparent.

It is the main object of this invention to provide an improved throttle control device which obviates or at least reduces the aforementioned problems.

Accordingly one broad form of the invention provides a throttle control device for internal combustion engines, characterized in that, it includes vacuum actuated control means for connection to the engine intake vacuum, said control means being adapted to respond to said vacuum pressure in a manner causing locking of extendible and retractable cable means associated with said control means when said vacuum pressure falls below a predetermined minimum pressure, said cable means being adapted for connection to the engine throttle linkage adjacent an accelerator pedal and having a resilient link therein for applying a retarding force to said pedal against throttle opening, when said locking occurs. In order that the invention may be more readily understood reference should now be made to the accompanying drawings which show a preferred embodiment and in which, Fig. 1 is a plan view, partly in section, of a device according to the embodiment; Fig. 2 is a sectional side elevation of the device according to Fig. 1, and Fig. 3 shows schematically the device in use on a motor vehicle. Before proceeding it should be mentioned that the device according to the invention may take various different orientations in use but for the purpose of this description the device will be considered in an orientation as shown in the drawings wherein the mounting bracket is connected to the top surface of the device.

As shown in the drawings the device consists essentially of an upper body portion 1 and a lower body portion 10 which are connected together to define a sealed cavity therebetween which is accessible via vacuum connecting tube 15. The body parts.1 and 10 may be formed in various ways and according to this embodiment are moulded from a plastics type material. The two body parts are connected together by suitable screws or bolts and nuts (not shown) which pass through the respective holes 20 arranged around the perimeter of the body parts. A diaphragm 8 is arranged between the two body portions and is held at its outer perimeter by the clamping action which occurs when the two parts are fixed together by the aforementioned screws or bolts. The diaphragm 8 has a.diaphragm plate 9 in the central portion thereof for a purpose which will become apparent hereinbelow. The diaphragm is spring biased in an upward direction as shown in Fig. 2 by means of diaphragm spring 14. The diaphragm spring 14 is arranged on a diaphragm shaft 13 which extends centrally through the body and is fixed against rotation. A cable spool 3 is also mounted on the diaphragm shaft 13 above the diaphragm 8 in the orientation shown in Fig. 2. The spool 3 accommodates an operating cable 16 which is wound around the spool and extends outwardly through a suitable aperture to a position outside the enclosed body. The operating cable 16 is spring. biased to re-wind onto the spool 3 by means of a recoil spring 4. The recoil spring 4 is a spiral spring which connects at one end to the spool and at the other end is accommodated in a slot in the diaphragm shaft 13.

Friction washers 2 are arranged on either side of the spool 3. The lower friction washer bears against the aforementioned diaphragm plate 9 and the upper friction washer 2 bears against a planar surface on the inside of the upper body portion 1. The respective surfaces of the spool 3 are made flat so as to properly engage the respective friction washers. With the device in the non-connected situation the spring 14 causes the diaphragm plate 9 to be forced against the lower friction washer 2 and in turn force the spool 3 against the upper friction washer 2. Thus in the non-connected position the spool 3 is prevented from rotation and the cable 16 is therefore not capable of being withdrawn or retracted in relation to the body. When a suitable vacuum pressure is applied to the vacuum connecting tube 15 the diaphragm 8 is caused to move downwardly and the spool 3 is free to rotate whereby the cable 16 may be withdrawn against the spring 4 and when released will be re-wound on the spool 3.

For the purpose of providing adjustment of the vacuum pressure required to move the diaphragm sufficient to release the cable spool 3, an adjusting screw 12 is provided in the underside of the lower body portion 10. The adjusting screw 12 provides a stop for the spring 14 and rotation of the screw 12 either reduces or increases the tension in the spring 14. A lock nut 11 ensures that the screw 12 is retained in its set position. On the top of the device a mounting bracket 5 is attached by means of mounting screws 6 which screw into threaded holes in the upper body portion. The mounting bracket 5 is adapted to attach the device to a suitable solid mounting point of a motor vehicle. A mounting bolt 7 is adapted to attach the bracket to the vehicle.

As shown in Fig. 1 a vacuum hose 19 is adapted to be connected to the vacuum connecting tube 15 and the tube 19 is for the purpose of connecting the device to the engine manifold vacuum. Furthermore, a throttle pedal loading spring 17 is adapted to connect to a loop in the outer or free end of the operating cable 16 and the other end of the spring is connected to the accelerator pedal arm 21 as is shown schematically in Fig. 3.

Referring now to Fig. 3 the device is shown schematically in use on a motor vehicle. The device is connected to any suitable part of the motor vehicle frame generally below and behind the vehicle dashboard by means of the screw or mounting bolt 7 which is adapted to pass through the bracket 5 and through a. suitable hole arranged in the vehicle body. The device is. arranged such that the cable extends outwardly from the upper body portion 1 in a direction towards the accelerator pedal operating arm in a manner whereby, when the cable 16 is connected to the arm via spring 17, depression or opening of the accelerator will cause unwinding of the cable 16 from the spool 3. The spring 17 has its free end connected to the accelerator pedal linkage by means of a suitable clamp 22. The vacuum hose 19 is arranged to extend through the vehicle fire wall and is connected to the vehicle inlet manifold vacuum either by a direct connection to the engine manifold or by intercepting some other hose which is connected to the same vacuum using a suitable tee piece (not shown). In some instances it may be possible to connect the hose 19 to a source of manifold vacuum without passing the hose through the fire wall to the engine compartment. As should be evident to persons skilled in the art, when the vacuum pressure is low there will be insufficient force applied to the underside of the diaphragm 8 to move the diaphragm downwardly thus releasing the spool 3 for rotation. When the vacuum pressure reaches a sufficiently high value the diaphragm 8 will move down and the spool 3 will become free for rotation. For the purpose of clarification it should be pointed out that a high vacuum pressure is not to be confused with a high pressure but instead means a high negative pressure. Conversely a low vacuum pressure is a more positive pressure in the sense that it is not as high in the negative direction. In use, by adjusting the tension of spring 14 such that a pressure in the negative direction above approximately minus 27 k.p.a. pressure is required to release the cable spool 3 for rotation, the device provides a suitable driving aid to improve fuel efficiency. Essentially, at any time the vacuum pressure falls to a negative pressure below about minus 27 k.p.a. the diaphragm moves upwardly and thus, by means of the friction washers, prevents the spool 3 from rotation. The cable 16 is therefore locked into position and any depression of the accelerator pedal requires an additional force to overcome the force applied by tension spring 17. The driver is therefore able to appreciate, because of the additional pedal pressure required, that he is driving uneconomically and should not depress the accelerator pedal further. In emergency situations such as overtaking, the throttle may be depressed by overriding the force of spring 17 merely by applying a greater, force to the accelerator pedal. The spring 17 is then extended. It has been found that by driving according to the device improvements in fuel efficiency averaging about 12% are readily attained and in many instances improvements up to 35% can be achieved.

A further advantage of the invention involve the simplicity of the device and the ease with which it may be installed in an automobile. By virtue of the recoiling cable 16, the position of the device relative to the accelerator pedal or linkage arm is not critical. Thus it is only necessary to be able to mount the device in proximity to the accelerator pedal with some reasonable alignment between the cable 16 and the direction of depression of the accelerator in order to properly install the device. In other words there is no need to have a fixed distance between the device and the accelerator pedal or linkage as would be the case if a rigid connection was necessary. The simplicity of installation means that the average home handyman can install a device on his automobile without the need to engage qualified technical personnel. It should be appreciated that the device of the invention is an add-on device which does not require any modification at all of the existing accelerator linkage mechanism to the vehicle throttle valve. Furthermore, the location of the device directly at the accelerator pedal means that the additional load or retarding force applied on the accelerator pedal is not transmitted through the throttle linkages to the vehicle throttle valve.

Claims

1. A throttle control device for internal combustion engines, characterized in that, it includes vacuum actuated control means for connection to the engine intake vacuum, said control means being adapted to respond to said vacuum pressure in a manner causing locking of extendible and retractable cable means associated with said control means when said vacuum pressure falls below a predetermined minimum pressure, said cable means being adapted for connection to the engine throttle linkage adjacent an accelerator pedal and having a resilient link therein for applying a retarding force to said pedal against throttle opening, when said locking occurs.

2. A device according to claim 1, characterized in that, said control means includes a housing defining a pneumatically sealed chamber therein having an outlet for connection to said engine intake vacuum and accommodating a diaphragm, said diaphragm being spring biased to a position causing, in the absence of a vacuum pressure above said predetermined minimum, frictional locking against rotation of a spool for said cable and in the presence of a vacuum pressure above said predetermined minimum said diaphragm releasing said cable spool and said spool being spring biased to recoil said cable as allowed by the position of said pedal.

3. A device according to claim 2, characterized in that, said diaphragm has central diaphragm plate for bearing on a friction washer between said plate and said spool to cause said locking, and said resilient link is a spring.

4. A device according to claim 3, characterized in that, a further friction washer is arranged on the opposite side of said spool to said first mentioned washer to further enhance said locking by bearing against said spool and said housing.

5. A device according to claim 2, 3 or 4, characterized in that it includes adjusting means associated with said diaphragm spring to enable adjustment of the tention therein so as to vary said predetermined minimum pressure at which locking occurs.