US3926160A

US3926160A - Accelerator damper

Info

Publication number: US3926160A
Application number: US445277A
Authority: US
Inventors: Reed J Husband
Original assignee: Individual
Current assignee: Individual
Priority date: 1974-02-22
Filing date: 1974-02-22
Publication date: 1975-12-16
Anticipated expiration: 1992-12-16

Abstract

An accelerator damper for yieldingly resisting the movement of an accelerator in a direction which places its engine under load. The resistance of the accelerator damper can be overcome by sufficient force exerted on the accelerator, but the resistance serves as a reminder and retarder which in normal usage will limit the rate of opening of a carburetor throttle and thereby conserve fuel by limiting acceleration. The retarding force diminishes as the engine conditions approach equilibrium operation.

Description

United States Patent Husband Dec. 16, 1975 ACCELERATOR DAMPER 3,365,016 [/1968 BrcckJr 123/103 R x 76 1 t: Rd.Hb d,65OC 11W, I 1 nven or zs g 2;; 91107 arm Pru'nary E.\'ammerCharles J. Myhre Assistant Examiner-W. C. Anderson [22] Filed: Feb. 22, 1974 Attorney, Agent, or Firm-Donald D. Mon

[21] Appl. No.: 445,277

[57] ABSTRACT U S Cl l23/103 E An accelerator damper for yieldingly resisting the [51] In.t .Cl WFOzD 11/08 movement of an accelerator in a direction which [58] Fieid R 103 E places its engine under load. The resistance of the accelerator damper can be overcome by sufficient force [56] References Cited exerted on the accelerator, but the resistance serves as a reminder and retarder which in normal usage will UNITED STATES PATENTS limit the rate of opening of a carburetor throttle and 2, 50,0 9/19 8 Dulong l23/10 R X thereby conserve fuel by limiting acceleration. The re 3 12/1957 123/103 E tarding force diminishes as the engine conditions ap- 2,325,418 3/1958 Kershman 1. 123/103 E X proach equilibrium Operation 3,099,329 7/1963 VonBerg et a1 123/103 R X 3,215,222 11/1965 Parker 123/103 E 23 Claims, 9 Drawing Figures [/V6/Nf //V7AKE MAN/F020 US. Patent Dec. 16, 1975 m m i ACCELERATOR DAMPER This invention relates to an accelerator damper which yieldingly resists the movement of an accelerator in a direction which places its engine under load, while still maintaining available to the operator the full potential power of his engine. The resistance decreases as the engine approaches equilibrim operation.

It is well known that the efficiency of an engine in terms of miles per gallon is greatly improved by limiting the acceleration to which the vehicle is subjected. A light touch on the accelerator pedal will considerably improve the efficiency of an automobile engine. Means have heretofore been suggested to limit acceleration, but such means have heretofore involved governors and other limiting devices which deny to the driver the full power of the engine if he should suddenly need it. It is an object of this invention to provide an accelera tor damper which, at any position of accelerator pedal travel, can exert a retarding effect on the opening of the throttle, and which can readily be overridden so that the engine can provide full power.

It is another object of this invention to provide a damper whose retarding effect diminishes as the engine approaches equilibrium operation.

An accelerator damper according to this invention is intended to retard the movement of an accelerator. The accelerator controls the supply of fuel to an engine which includes an intake manifold or some other source of fluid whose pressure rises when the engine is placed under an accelerative load. The accelerator has a path of movement in a first direction to open a carburetor throttle upstream of the intake manifold, and in a second direction to permit the throttle to close. The accelerator damper itself comprises a body that encloses a cavity. An internal wall at least partially bounds the cavity, and a barrier in the cavity makes a peripheral fluid-sealing fit with the internal wall. The barrier thereby divides the cavity into a first and a second chamber. At least'a portion of the barrier is bi-directionally movable along an axis, whereby inversely to enlarge the volume of one chamber and reduce the volume of the other chamber.

First conduit means communicates the fluid pressure source (for convenience herein, an intake manifold will be used as an exemplary pressure source) with the first chamber. The first chamber is that one which, when it contains a greater pressure than the second chamber, will cause the portion to move in the said first direction. Second conduit means fluidly interconnects the first conduit means and the second chamber. A bleed conduit means fluidly interconnects the first conduit means and the second chamber. Flow check means permits fluid flow through the second conduit means from the second chamber to the first conduit means and resists or prevents fluid flow in the reverse direction. A re strictor in the bleed conduit means limits the rate of fluid flow therethrough. The movable portion of the barrier is adapted to be connected to the accelerator. It resists movement of the accelerator in the first direction when the consequence of said movement is an increase of pressure in the engine intake manifold (or other pressure source).

According to a preferred but optional feature of the invention, the barrier is coupled to the accelerator by means of a spring means and a tension link member which does not transmit compressive force. The ten- 2 sion link member permits accelerator movement in the second direction without impediment by the barrier.

The above and other features of this invention will be fully understood from the following detailed description and the accompanying drawings in which:

FIG. 1 is a side view, principally in axial cutaway cross-section and partly in schematic notation, showing the presently preferred embodiment of the invention;

FIG. 2 is a cross-section taken at line 22 of FIG. 1;

FIG. 3 is a fragmentary cross-section taken at line 33 of FIG. 1;

FIGS. 4 and 5 are fragmentary axial cross-sections showing other parts which can be used in the invention;

FIG. 6 is a side elevation, principally in axial cutaway cross-section and partly in schematic notation, showing another embodiment of the invention;

FIG. 7 is a fragmentary cross-section showing another part which can be used in the invention; and

FIGS. 8 and 9 are an axial crosssection and a side elevation, partly in cross-section, of other suitable embodiments of tension link members for use in the invention.

In FIG. 1 there is shown an accelerator damper 10 according to the invention. This damper is intended to be responsive to the fluid pressure in an engine intake manifold 11, or some other suitable source of fluid under pressure. The manifold receives a fuelair charge (fluid) from the throat 12 of a carburetor 13 (the carburetor not being completely shown). The carburetor includes a throttle 14 in the form of a conventional pivoted butterfly pivoted at pivot pin 15.

Fuel-air mixture from the carburetor is discharged. as schematically shown, along path 16 to the engine intake manifold which is fluidly connected to the accelerator damper. The manifold also supplies the mixture to the cylinders through the inlet valves for operation of the engine.

The operating conditions of the engine are controlled by an accelerator 20. The conventional form of accelerator is a pedal 21 mounted by a pivot 22 to a floorboard 23. A compression spring 24 yieldingly resists clockwise movement and acts as a return spring. The accelerator includes a bellcrank 25 and a connecting link 26 hinged thereto. Another linkage 27, a conventional carburetor linkage, connects the accelerator pedal to the throttle. The accelerator is bi-directionally movable. It has a path of movement. In a first direction shown by arrow 28 the accelerator moves in its path to open the throttle. In an opposite second direction 29 in its path, it closes the same. It is an object of this invention to damp the movement of the accelerator pedal in the first direction when the consequence of that movement would be an increase of fluid pressure in the engine intake manifold (or of any other fluid source which is used instead) and to permit the ready return of the pedal when it is released by the operator.

The accelerator damper itself includes a body having an internal cavity 36. An internal wall, which preferably is a circular cylinder, bounds at least a portion of the cavity. A barrier in the cavity makes a peripheral fluid-sealing fit with the internal wall and divides the cavity into a first chamber 41 and a second chamber 42. At least a portion 43 of the barrier is axially movable along axis 44, whereby inversely to enlarge the volume of one chamber and reduce the volume of the other chamber when it moves.

Conveniently, portion 43 can comprise a flat plate connected to a rod 45. Rod 45 passes through an open 3 ing 46 in the body through a seal, such as an O-ring 47, for connection to the accelerator.

In the preferred embodiment of the invention as shown in FIG. 1, body is formed of two

parts

48, 49 which are joined together by fastener means not shown to clamp the rim 50 of the barrier between them. The rim is a flexible diaphragm of the type known as a roll sock." The roll sock permits portion 43 to move back and forth along the axis as a consequence of a differential pressure across it, rolling at bight 51 to accommodate for this movement. This barrier may be made of any convenient material, such as neoprene rubber and the like, suitable for the use to which it is put. A conventional diaphragm can be used instead of a roll sock, but a roll sock permits a longer stroke of movement of portion 43 than a conventional diaphragm can accommodate. It has the further advantage of providing for reciprocation of the portion without rubbing contact with the internal wall. This enables the body and portion to be made of inexpensive and non-critical material, such as masonite, which will not take a smooth enough finish to allow a fluid-sealing, sliding fit between portion 43 and the internal wall.

A first conduit means 55 enters the first chamber. The first chamber is defined as that chamber which, when it contains a higher pressure than the second chamber, will cause a resistance to the opening of the throttle, i.e., resistance to movement of the accelerator in its first direction.

The first conduit means communicates the intake manifold with the first chamber and tends to maintain the intake manifold pressure in the first chamber. Second conduit means 56comprises a port 57 extending through portion 43 and through an aligned port 58 extending through the barrier. The second conduit means fluidly interconnects the first conduit means and the second chamber (the connection to the first conduit means being through the first chamber in this embodiinent).

Bleed conduit means 60 fluidly interconnects the first conduit (and thereby the engine intake manifold) to the second chamber. In the preferred embodiment shown, the bleed conduit means includes an adjustable restrictor 61. It constitutes a conventional needle 62 and seat 63 combination to restrict the rate of fluid flow through the bleed conduit means.

A flow check means 65 permits fluid to flow through the second conduit means from the second chamber to the first conduit means (through the first chamber in this embodiment) and resists fluid flow in the reverse direction. In fact, in the embodiment shown, it prevents fluid flow in the reverse direction. Means 65 constitutes a flapper 66 pivotally mounted to the portion 43. When in the solid line condition shown in FIG. 1, the flapper seats to prevent the flow of fluid from the first to the second chamber. When the differential pressure is appropriate, namely when the pressure is sufficiently higher in the second chamber than in the first chamber, the flapper will pivot to the illustrated dashed line position,.ope ning the second conduit means and permitting fluid to flow from the second chamber to the first ,Chamber so as to tend to equalize their pressures.

The rod 45 is connected to the accelerator pedal by means of a resilient tension spring'70, which tends initially to be stretched when the accelerator pedal is moved in its first direction to attempt to open the throttle. The spring in turn pulls on the barrier. Accordingly,

4 the barrier acts as a movable anchor for spring 70 and tends to retard the opening-'ofthe.throttle.

In order to be certain that the throttle can reopen even if the barrier becomes stuck, it is good practice further to connect the accelerator and the barrier by means of a tension link member 72. Member 72 is serially connected with the spring 70 between the portion 43 and the accelerator pedal. The term tension link member means a link which can pull but not push. The member, which is preferably a chain comprised of a plurality of links 73, can transmit a pull in tension, but goes limp in compression. A flexible cable is another example. Also, the devices of FIGS. 8 and 9 are tension link members.

FIG. 4 shows that a piston 75 having an O-ring seal 76 can be directly substituted for the barrier 40 of FIG. 1, and will constitute a barrier to perform the same functions as barrier 40. Identical numbers indicate similar parts as already disclosed in FIG. 1. When a piston is used, the internal wall must be smooth and suited for completing a sliding fluid seal with the piston.

FIG. 5 shows a form of combined flow check means 80 and restrictor 81. It is shown installed in portion 43. With such an arrangement, conduit means 60 and re strictor 61 would be eliminated. A seat is formed in the second conduit means 56. A ball 86 is adapted to bear against seat 85 and to move away from it against the resistance of a bias spring 87. This forms the flow check means. It will fully open when the pressure is suitably higher in the second chamber than in the first (i.e., higher on the left side in FIG."5), and will tend to close under other conditions. In this embodiment, bleed conduit means 90 comprises a channel 91 across seat 85, the restrictor 81 comprising a portion of the channel, for example the portion immediately adjacent to the smaller diameter part of the seat. The restrictor is always open, even when the ball is seated, and this is the same function as the combination of the two elements in FIG. 1.

FIG; 6 shows another embodiment of accelerator damper 95 wherein a body 96 has an internal wall 97 and a barrier 98 in the form of a piston making a fluidsealing fit therewith. Rods 99, 100 pass through respective first and

second chamber

101, 102. The double rod construction eliminates any differential force as a consequence of unbalanced areas on opposite sides of the barrier. First conduit means enters the first chamber, and second conduit means 106 includes a unidirectional flow check means 107, permitting fluid flow away from the second chamber, but retarding it or preventing it entirely in the reverse direction. The second conduit interconnects the second chamber and the first conduit means. Bleed conduit means 110 is connected in parallel with the flow check means and includes a restrictor 111 (which may be fixed or adjustable).

FIG. 7 illustrates a barrier l 15 suitable for use in any of the embodiments of the invention wherein the flow check means of FIG. 1 is modified by the provision of a bleed conduit -means 116 therethrough, the bleed conduit means constituting or including a restrictor 117 which is effective to restrict the rate of flow to the left in FIG. 7, but which will be ineffective when the flapper is moved away from the illustrated position when the pressure is greater in the second chamber than in the first. This construction is the full equivalent of the construction shown in FIG. 5.

FIGS. 1, 4 and 6 illustrate embodiments wherein the bleed conduit means is connected in parallel and separate fluid circuitry with the second conduit means, while FIGS. 5 and 7 illustrate situations wherein these elements are combined and function alternatively. However, the effect on the circuitry of the fluid circuit is the same, namely that fluid can readily flow out of the second chamber through the second conduit means, but its rate of entrance thereto is retarded by the restrictor. In FIGS. 5 and 7, the flow check and re strictor functios are combined, and the flow check means, in effect, are leaky.

In FIG. 8, a tension link member 120 is shown which comprises a tubular sleeve 121 with an internal collar 122. The sleeve is to be connected to connecting link 26, or forms part of it. A rod 123 is to be connected to spring 70. It has a shoulder 124 which engages the collar when the link member is pulled in tension, but simply slips in the tubular passage 125 in the sleeve when a compressive force is exerted on the link member.

In FIG. 9, another tension link member 126 is shown. It comprises a hook member 127 having a channel 128 formed by a bight 129. A second hook member 130 also has a bight 131. Member 127 is to be connected to spring 70, and member 130 is to be connected to link 26. The bights can engage one another to exert a pull ing action, but merely move apart in compression.

The tension link members of FIGS. 8 and 9 can be substituted directly for member 72 in FIG. 1. A flexible cable can also be substituted for it.

The operation of this accelerator damper is as follows. When a vehicle is coasting, it will have a relatively low intake fluid manifold pressure. When it is cruising, it will have a somewhat higher manifold pressure. At idle it will be higher still. When crusing under heavy load, the pressure will approach atmospheric still more closely. When accelerating swiftly, or climbing a hill, the manifold will be still closer to atmospheric pressure. In all cases, these will be sub-atmospheric pressures, but the situations described illustrate that, when the engine is placed under a load, the tendency will be to raise the fluid pressure in the intake manifold. It is the rate of increase of the intake manifold pressure which is utilized to generate a force that resists the operating of the throttle. This force will be felt by the foot of the user. It can readily be overcome by stepping hard enough on the accelerator pedal to overcome spring 70, thereby making full power available to the engine when desired. When the engine is operating at an equilibrium condition with no change in intake manifold pressure, the pressure in the first and the second chambers will equalize, and there will be no tendency for the barrier to assume any particular position or to exert a retarding effect. Therefore, this device exerts its retarding effect only during acceleration, which is the only time it is desired. The driver is therefore not tired by having to overcome a larger force on the pedal to maintain a higher speed than a lower speed on account of this device. The return spring exerts its customary force, of course.

When a single rod is used, as in Flg. 1, there is some small unbalanced area exposed to atmosphere giving rise to a force that tends to move the barrier to the left (because in operation, both chambers are at less than atmospheric pressure). This force will ordinarily be small, and should it be undesirable, it can be overcome by using the double rod arrangement of FIG. 6. The unbalanced force can be reduced by reducing the crosssection of the rod relative to that of the internal wall. An internal wall diameter between about 1% inches and 2% inches, and a rod with a diameter of about 1 /16 inch, results in a relatively small force to the left. Therefore, even with a single rod construction, the situation is substantially one of equilibrium in steady op eration. Now, should the accelerator be moved in its first direction, it will open the throttle, which will cuase a rise in engine intake manifold pressure. It will also stretch tension spring 70. At this time, the higher intake manifold pressure will readily be transmitted to the first chamber, through the first conduit means, which is large enough to provide for such ready flow. However, the flow check means will close so as to close the second conduit means, and flow of the higher pressure fluid into the second chamber is retarded by the restrictor means. Therefore, there is a tendency for the pressure to remain lower in the second chamber than in the first, and there is a force to the left on the barrier tending to retard the opening of the throttle by exerting a retarding force on the accelerator pedal. As heretofore stated, this can be overcome by stepping hard enough on the pedal to stretch spring 70, but the skillful driver will tend to avoid this in response to the retarding force. As the engine speeds up, and time passes, the higher pressure fluid from the engine intake manifold will pass through the bleed conduit means, tending to equalize the pressure in the chambers. At equilibrium conditions, i.e., no change in the manifold pressure, and sufficient time having elapsed for the pressure to equalize in the chambers, the retarding force will dis appear, except for the negligible amount which may be generated as a consequence of the unbalanced rod area.

In the meantime, it may be that the engine will be slowed down by releasing the pedal. Then a lesser manifold pressure will be transmitted to both chambers. Under these circumstances, outflow from both chambers is substantially equally 'swift for the reason that the flow check valve will open, as shown in FIG. 1 in dashed line, and therefore, at the time of a decrease in engine manifold pressure, there will be no net tendency to move the barrier one direction or the other, except for the force caused by the unbalanced rod area. When the engine is shut off, or accelerated, then the pressure will rise toward atmospheric, but the pressure rise will be faster in the first chamber than in the second chamber, so there will be a net force tending to return the barrier to the left in FIG. 1. It will therefore be seen that in all practical operations, there will periodically be conditions at which time the barrier will tend to be moved to the left and in effect be reset. Therefore, its position tends, over the long period of time, to stabilize itself, and the barrier will remain in a position such that, relative to the tension spring 70, it can exert its retarding effect at the time of acceleration at any speed or throttle setting. The unit resets itself each time that the engine is shut down, idles, or slows down.

The tension link member is provided so that the accelerator can pull against the barrier, but cannot push against it. This assures that, should for some reason the barrier stick in the body, the throttle will not be held open.

FIG. 4 illustrates that a piston is the full equivalent of the roll sock arrangement of FIG. 1.

FIGS. 5 and 7 illustrate that the second conduit means and bleed conduit means can be combined or used alternatively instead of in a completely separate parallel construction. In these devices, the bleed conduit means interconnects the second chamber to the first conduit means when it functions, even though it may be opened or removed from one of its positions when the flow check means is open.

FIG. 6 illustrates that the flow check means and the bleed conduit means can be placed in parallel connection between the first conduit means and the second chamber directly, rather than connecting the second chamber to the first conduit means through the first chamber.

The terms pressure source or source of fluid under pressure means any source wherein the pressure rises when the engine is accelerated or placed under a heavier load. Engine oil pressure is one such source, as is the engine intake manifold. A pump driven by the engine solely to provide such pressures is another example. Any fluid can be used-either gas, liquid, or fuel-air mixtures.

This invention thereby provides a rugged and simple device which tends to inhibit the opening of an engine throttle, but which can readily be overcome by extra force on the accelerator pedal. It is simple in concept and reliable in operation.

This invention is not to be limited by the embodiments shown in the drawings and described in the description, which are given by way of example and not of limitation, but only in accordance with the scope of the appended claims.

I claim:

1. An accelerator damper for an accelerator that controls the supply of fuel to an engine which includes a source of fluid under pressure whose pressure increases when the engine is accelerated, the accelerator having a path of movement in a first direction to open a carburetor throttle, and in a second direction to permit the throttle to close, the accelerator damper comprising: a body enclosing a cavity; an internal wall at least partially bounding said cavity; a barrier in said cavity making a peripheral fluidsealing fit with said intemal wall so as to divide the cavity into a first and a second chamber, at least a portion of said barrier being bidirectionally movable along an axis whereby inversely to enlarge the volume of one chamber and reduce the volume of the other chamber; first conduit means for communicating the pressure source with said first chamber, said first chamber being that chamber which, when it holds a greater pressure than the second chamber, will cause the said portion to move and tend to close the throttle; second conduit means fluidly interconnecting the first conduit means and the second chamber; a bleed conduit means fluidly interconnecting the first conduit means and the second chamber; flow check means permitting fluid flow through the second conduit means from the second chamber to the first conduit means and resisting fluid flow in the reverse direction; and a restrictor in the bleed conduit means to limit the rate of fluid flow therethrough, the said movable portion of the barrier being adapted to be connected to the accelerator to resist movement of the accelerator in the first direction when the consequence of said movement is an increase of pressure in the pres sure source.

2. An accelerator damper according to claim 1 in which resilient spring means couples the accelerator to the said portion of the barrier so ,the spring means yieldingly resists movement of the accelerator in its first direction.

3. An accelerator damper according to claim 1 in which a tension link member couples the accelerator to the barrier so as to permit accelerator movement in the second direction'without impediment by the barrier.

4. An accelerator damper according to claim 1 in which the accelerator and the barrier are connected to each other by means of a resilient spring member and a tension link member, which members are serially connected to each other.

5. An accelerator damper according to claim 1 in which the internal wall is cylindrical, and in which the barrier is a piston that makes a sliding, fluid-sealing fit therein.

6. An accelerator damper according to claim 1 in which the barrier comprises a flexible diaphragm which extends across and makes a fluid seal with the internal wall.

7. An accelerator damper according to claim 1 in which the second conduit means is formed in the barrier, and in which the flow check means is mounted to the barrier.

8. An accelerator damper according to claim 7 in which the flow check means comprises a pivoted flapper.

9. An accelerator damper according to claim 8 in which the bleed conduit means is formed in the flapper and is in fluid circuit with the second conduit when the flow check means resists flow, the restrictor comprising a portion of said bleed conduit means.

10. An accelerator damper according to claim 1 in which the flow check means comprises a seat in said second conduit means, a ball adapted to bear against said seat and to move away from it, and spring bias means pressing the ball toward the seat.

1 1. An accelerator damper according to claim 10 in which the bleed conduit means comprises a channel across said seat, the restrictor comprising a portion of said channel.

12. An accelerator damper according to claim 1 in which the bleed passage means enters the second chamber through the body, the restrictor comprising an adjustable orifice therein.

13. An accelerator damper according to claim 1 in which the second conduit means and the bleed conduit means are connected in parallel between the first conduit means and the second chamber.

14. In combination: an accelerator comprising a pivotally mounted accelerator pedal having a path of movement in a first direction to open a carburetor throttle, and in a second direction to permit the throttle to close; an accelerator damper according to claim 1; and resilient spring means coupling the accelerator to said portion of the barrier so that spring means yieldingly resists movement of the accelerator pedal in its first direction.

15. A combination according to claim 14 in which a pressure source is provided, said pressure source comprising an intake manifold on the engine controlled by the accelerator.

16. In combination: an accelerator comprising a pivotally mounted accelerator pedal having a path of movement in a first direction to open a carburetor throttle, and in a second direction to permit the throttle to close; an accelerator damper according to claim 1; and a tension link member coupling the accelerator to the barrier so as to permit accelerator movement in the second direction without impediment by the barrier.

17. A combination according to claim 16 in which a pressure source is provided, said pressure source comprising an intake manifold on the engine controlled by 21. A combination according to claim 20 in which the diaphragm is a roll sock.

22. A combination according to claim 18 in which the second conduit means is formed in the barrier, and in which the flow check means is mounted to the barrier.

23. A combination according to claim 18 in which the bleed passage means enters the second chamber through the body, the restrictor comprising an adjustable orifice therein.

Claims

1. An accelerator damper for an accelerator that controls the supply of fuel to an engine which includes a source of fluid under pressure whose pressure increases when the engine is accelerated, the accelerator having a path of movement in a first direction to open a carburetor throttle, and in a second direction to permit the throttle to close, the accelerator damper comprising: a body enclosing a cavity; an internal wall at least partially bounding said cavity; a barrier in said cavity making a peripheral fluid-sealing fit with said internal wall so as to divide the cavity into a first and a second chamber, at least a portion of said barrier being bidirectionally movable along an axis whereby inversely to enlarge the volume of one chamber and reduce the volume of the other chamber; first conduit means for communicating the pressure source with said first chamber, said first chamber being that chamber which, when it holds a greater pressure than the second chamber, will cause the said portion to move and tend to close the throttle; second conduit means fluidly interconnecting the first conduit means and the second chamber; a bleed conduit means fluidly interconnecting the first conduit means and the second chamber; flow check means permitting fluid flow through the second conduit means from the second chamber to the first conduit means and resisting fluid flow in the reverse direction; and a restrictor in the bleed conduit means to limit the rate of fluid flow therethrough, the said movable portion of the barrier being adapted to be connected to the accelerator to resist movement of the accelerator in the first direction when the consequence of said movement is an increase of pressure in the pressure source.

2. An accelerator damper according to claim 1 in which resilient spring means couples the accelerator to the said portion of the barrier so the spring means yieldingly resists movement of the accelerator in its first direction.

3. An accelerator damper according to claim 1 in which a tension link member couples the accelerator to the barrier so as to permit accelerator movement in the second direction without impediment by the barrier.

11. An accelerator damper according to claim 10 in which the bleed conduit means comprises a channel across said seat, the restrictor comprising a portion of said channel.

17. A combination according to claim 16 in which a pressure source is provided, said pressure source comprising an intake manifold on the engine controlled by the accelerator.

18. A combination according to claim 17 in which a resilient spring means is serially connected to the flexible member between the accelerator and the barrier.

19. A combination according to claim 18 in which the internal wall is cylindrical, and in which the barrier is a piston that makes a sliding, fluid-sealing fit therein.

20. A combination according to claim 18 in which the barrier comprises a flexible diaphragm which extends across and makes a fluid seal with the internal wall.

21. A combination according to claim 20 in which the diaphragm is a roll sock.