GB1563143A

GB1563143A - Throttle control mechanism

Info

Publication number: GB1563143A
Application number: GB4360176A
Authority: GB
Original assignee: Horstmann Gear Co Ltd
Current assignee: Horstmann Gear Co Ltd
Priority date: 1977-10-19
Filing date: 1977-10-19
Publication date: 1980-03-19

Description

(54) THROTTLE CONTROL MECHANISM (71) We, THE HORSTMANN GEAR COMPANY LIMITED, a British Company, of Newbridge Works, Bath BA1 3EF, Avon, do hereby declare the invention, for which we pray that a patent be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: This invention relates to devices for improving the fuel economy of internal combustion engines, particularly in automotive vehicles.

It is well known that in internal combustion engined vehicles the fuel consumption in miles-per-gallon terms varies widely for a predetermined route according to the manner in which the vehicle is driven, so that within the minimum and maximum limits peculiar to the vehicle the m.p.g. is driver dependent.

The main drivercontrolled factors responsible for high consumption are frequent over-acceleration, such as occurs in congested traffic conditions; the opening of the throttle valve at a rate significantly faster than the vehicle can accelerate, irrespective of the gear in which it is being driven; and the opening of the throttle valve to its maximum when climbing a hill the gradient of which causes a progressive reduction in road speed.

All carburettor systems involve compromise between ideal fuel/air ratios under constant speed/constant load conditions and the independently and rapidly varying r.p.m.

and load conditions met in road vehicles.

Most of these systems are characterised by an inadequate fuel entrainment when a sudden increase in engine performance is required, especially at lower r.p.m., and it is for this reason that it is common practice to fit carburettors with an acceleration pump linked directly to the throttle valve so that when the latter is opened, especially suddenly, raw fuel is injected independently of the jet system to ensure an adequate fuel/air ratio to promote acceleration.

It follows from the foregoing that if, instead of being driver dependent, the rate of throttle valve opening is automatically related to the acceleration capability of the vehicle, irres pective of load and road conditions, then significant economies in fuel could be achieved and the present invention seeks to provide means, after an initial limited throttle valve opening, to automatically control the rate of opening to maintain adequate acceleration.

The invention may be provided with a semi automatic over-ride to limit the degree of opening and throttle valve closure to maintain near constant speeds, and/or a manually operated over-ride, more particularly but not exclusively for use with automatic gearboxes.

According to the invention there is provided a control mechanism for a vehicle mounted internal combustion engine, the mechanlsm comprising a lost motion device adapted for fitting in a mechanical linkage between a manually-operated accelerator device and a carburettor throttle valve or fuel injection control device of an engine, and rate control means operating in dependence upon forward longitudinal acceleration of the vehicle, for controlling the rate of take up of the lost motion device.

In order that the invention and its various other preferred features may be understood more easily, an embodiment thereof will now be described, by way of example only, with reference to the drawing which shows a schematic view of a carburettor throttle linkage incorporating a throttle.

A carburettor butterfly throttle valve 10 has a spindle with a shaft extension 11 at the end of which remote from the butterfly valve, one end of a lever 12 is fixedly attached. The other end of the lever, remote from the said shaft, is pivotally attached to the bottom of an hydraulic cylinder 13.

The hydraulic cylinder, preferably located with its axis in a vertical plane, encloses a piston 14 and actuating rod 1S. The piston has mounted therein a one-way valve 16 which permits oil or other suitable fluid to pass freely from above the piston to the bottom of the cylinder when the piston is withdrawn therefrom. The top end of the cylinder is enclosed by a suitably attached end cap 17 through which slidably passes the piston rod through a suitable seal which pre vents loss of fluid between piston rod and cap.

The end of the piston rod remote from the piston, is pivotally attached to a suitable bracket fixedly attached to the engine or to an appropriate part of the vehicle, so that the lever 12, which is pivotally connected to the bottom of the cylinder, can arcuately rise and fall and in so doing move the cylinder 13 up and down in relation to the piston 14 and at the same time open or close the throttle valve 10.

Located in the side of the cylinder are two ports 18 and 19. Port 18 is positioned above the piston when it is at its maximum stroke distance permitted by throttle valve opening movement and the port 19 is adjacent to the bottom of the cylinder. The ports are connected by flexible tubes to a rotary valve 21, having a control rotor or plug 22 which is coupled to a pendulum 23 by means of a shaft. The pendulum, rotary valve body and plug are totally enclosed in a suitable case having ported entries to the valve passageways for connection via the flexible tubes to the cylinder ports 18 and 19.

The height relationship between the cylinder and the case containing the pendulum/ valve assembly is such that the cylinder, flexible tubes, pendulum case and valve can be filled with liquid to a level sufficiently above the port 18 to allow the piston to displace liquid from below the piston, through the flexible tube and pendulum controlled valve, back to the cylinder through the return tube connected to the port above the piston upon closure of the throttle without the ingress of air.

There is an internal connection between the exit port of the valve body to the inside of the pendulum casing (not shown) to maintain the casing filled with liquid, the purpose of which is to damp out unwanted oscillauons of the pendulum the axis of which is mounted in the horizontal plane at right angles to the fore and aft line of the vehicles.

The lever 12 has pivotally connected to it, at a point adjacent to the bottom end of the cylinder, a pendent rod 24 having mounted thereon, at a suitable point remote from the lever 12, a fixed cup 25 formed to retain one end of a compression spring 26, the other end of the spring being located in similar cup 27 slidably mounted on the pendent rod 24.

Fixedly attached to the end of the pendent rod remote from the arm 12 is a collar 28 which maintains the spring 26 at a predetermined degree of compression when the throttle valve is closed. The throttle pedal 29 of the vehicle is connected to a slidable collar 31 which forms the input element of the lost motion device so that when the throttle pedal is depressed the slidable cup 27 moves on the pendant rod 24 to further compress the spring 26, which then transmits energy through the cup 25 to the rod 24 and lever 12 which can only move to open the throttle valve 10 at the rate at which the piston 14 can force liquid through the valve 21 controlled by the pendulum 23, which rate changes between predetermined minimum and maximum rates according to the acceleration forces experienced by the pendulum.

In vehicles, all throttle pedals are separately spring-urged to the throttle valve closed position, so that, in the arrangement described, on release of the throttle pedal the slidable cup 27 on the pendent rod 24 would follow the collar 31 and would move until it and the collar 31 came into abutment with the collar 28 fixedly attached to the end of the rod and thereafter cause the rod 24 and lever 12 to cause the bottom of the cylinder to move away from the piston, this movement being unconstrained as the liquid in the cylinder is freely able to pass to the opposite side of the piston through the one-way valve 16, thus permitting rapid closure of the carburettor butterfly throttle valve.

In practice, adjustable stops are incorporated to limit the movement of the pendulum so that in association with the design characteristics of its associated valves the system may be adjusted so that the rate of throttle valve opening is consistent with the maximum rate of acceleration of a vehicle in top gear on a level road and a maximum rate of acceleration in bottom gear on a level road; but in the interests of economy the maximum rate of acceleration in second gear on a level road may be preferred.

Since the pendulum is sensitive to gradients which the vehicle must traverse, the rate of opening of the throttle valve will be increased when climbing a hill and decreased when descending a hill. These inherent characteristics are not considered a disadvantage.

In vehicles in which the prime mover is a diesel engine, or in other engines operating by fuel injection, the system is applied to control the degree of fuel injection by suitably connecting the previously described carburettor butterfly control shaft 11 to the control spindle of the fuel injection pump.

It will be appreciated that other arrangements of lost motion device are possible. For example instead of a compression spring, an extension spring acting between the sliding cup and the collar could be employed. Instead of springs, other resilient members could be employed e.g. a resilient pad.

The lost motion can be provided at any position along the control linkage between the throttle actuating device 29 and the throttle valve 10. The lost motion could be effected by making a part of the arm 12 resiliently bendable before actuation of the throttle valve.

Instead of employing the lower end of the cylinder as a reservoir for hydraulic fluid a separate reservoir can be employed in which case a one way valve between the upper end of the cylinder and the reservoir would be provided instead of the valve 16 in the piston so as to permit return of fluid to the cylinder when the throttle pedal is released.

Instead of employing a liquid hydraulic fluid, air could be employed provided that the stroke length of the piston in the cylinder was sufficient to provide sufficient resistance to movement due to air compression. In such a case, the valve 21 could be arranged to control release of air from the upper end of the cylinder and the lower end of the cylinder could be open to permit passage of air through the one way valve 16 when the piston was returned along the cylinder upon release of the throttle pedal.

It will be appreciated that a similar operation is possible with the cylinder coupled to a fixed point on the vehicle and the piston coupled with the throttle operating linkage.

In addition although the embodiments described suggest the movement of piston and cylinder to reduce the volume of an enclosed portion of the cylinder to effect compression of the contents of the cylinder and provide resistance to relative motion between piston and cylinder the opposite configuration in which relative movement between piston and cylinder causes an increase in volume of an enclosed portion of the cylinder and a reduction of pressure of the contents of the cylinder can be employed to provide the resistance to relative motion.

Although the pendulum mechanism is par ticularly suitable for effecting operation of the control valve, in view of its extreme sensitivity to acceleration changes, it is envisaged that other acceleration sensitive control mechanisms could be employed e.g. a weight movable along a guide which weight is coupled to a valve control mechanism.

An over-ride facility may be provided to cancel the delayed response effect on demand.

Such an over-ride facility may be provided by a bypass line for the control valve which line may be opened to bypass the valve by means of a manual control on the vehicle.

The bypass line may be operated advantageously by so called kick down action whereby the bypass line is opened upon full depression of the throttle pedal.

WHAT WE CLAIM IS:- 1. A control mechanism for a vehicle mounted internal combustion engine, the mechanism comprising a lost motion device adapted for fitting in a mechanical linkage between a manually-operated accelerator device and a carburettor throttle valve or fuel injection control device of an engine, and rate control means operating in dependence upon forward longitudinal acceleration of the vehicle, for controlling the rate of take up of the lost motion device.

2. A control mechanism as claimed in Claim 1, wherein the lost motion device comprises a spring coupled between the throttle actuating device and the throttle valve and effective to transmit motion therebetween.

3. A control mechanism, as claimed in Claim 2, wherein the spring is a compression spring.

4. A control mechanism as claimed in Claim 3, including a rod adapted at one end for connection with the linkage to the throttle valve and provided with a cup slidably mounted thereon and adapted for coupling with and slidable movement by the throttle actuating device and a second cup fixedly mounted on the rod between the sliding cup and said one end the spring being mounted on the rod and acting between the cups.

5. A control mechanism as claimed in any preceding claim wherein the control means comprises a piston and cylinder assembly for connection between the throttle actuating linkage and a fixed point to permit relative movement of the piston and cylinder when the throttle actuating device is operated one end of the cylinder being closed but having an opening controlled by a control valve responsive to acceleration.

6. A control mechanism as claimed in Claim 5, wherein both ends of the cylinder are closed and are linked together via said valve.

7. A control mechanism as claimed in Claim 5 or 6, wherein the piston has a one way valve communicating between ends of the cylinder which permits release of pressure in a direction from said one end of the cylinder to the other end of the cylinder.

8. A control mechanism as claimed in Claim 5, 6, or 7, wherein said control valve is actuated by a pendulum in response to acceleration.

9. A control mechanism as claimed in Claim 8, wherein the pendulum is contained within a casing for containing a liquid for damping pendulum movement.

10. A control mechanism as claimed in any preceding claim including means for over riding the control means to allow substantially immediate take up of the lost motion in the linkage.

11. A control mechanism substantially as described herein with reference to the drawings.

12. A vehicle powered by an internal combustion engine having an operating linkage incorporating a control mechanism as claimed in any preceding claim.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. case a one way valve between the upper end of the cylinder and the reservoir would be provided instead of the valve 16 in the piston so as to permit return of fluid to the cylinder when the throttle pedal is released. Instead of employing a liquid hydraulic fluid, air could be employed provided that the stroke length of the piston in the cylinder was sufficient to provide sufficient resistance to movement due to air compression. In such a case, the valve 21 could be arranged to control release of air from the upper end of the cylinder and the lower end of the cylinder could be open to permit passage of air through the one way valve 16 when the piston was returned along the cylinder upon release of the throttle pedal. It will be appreciated that a similar operation is possible with the cylinder coupled to a fixed point on the vehicle and the piston coupled with the throttle operating linkage. In addition although the embodiments described suggest the movement of piston and cylinder to reduce the volume of an enclosed portion of the cylinder to effect compression of the contents of the cylinder and provide resistance to relative motion between piston and cylinder the opposite configuration in which relative movement between piston and cylinder causes an increase in volume of an enclosed portion of the cylinder and a reduction of pressure of the contents of the cylinder can be employed to provide the resistance to relative motion. Although the pendulum mechanism is par ticularly suitable for effecting operation of the control valve, in view of its extreme sensitivity to acceleration changes, it is envisaged that other acceleration sensitive control mechanisms could be employed e.g. a weight movable along a guide which weight is coupled to a valve control mechanism. An over-ride facility may be provided to cancel the delayed response effect on demand. Such an over-ride facility may be provided by a bypass line for the control valve which line may be opened to bypass the valve by means of a manual control on the vehicle. The bypass line may be operated advantageously by so called kick down action whereby the bypass line is opened upon full depression of the throttle pedal. WHAT WE CLAIM IS:-

1. A control mechanism for a vehicle mounted internal combustion engine, the mechanism comprising a lost motion device adapted for fitting in a mechanical linkage between a manually-operated accelerator device and a carburettor throttle valve or fuel injection control device of an engine, and rate control means operating in dependence upon forward longitudinal acceleration of the vehicle, for controlling the rate of take up of the lost motion device.