GB2242230A

GB2242230A - Delaying movement of an I.c. engine regulating element

Info

Publication number: GB2242230A
Application number: GB9106005A
Authority: GB
Inventors: Gerardus Antonius Keers
Original assignee: Individual
Current assignee: Individual
Priority date: 1990-03-21
Filing date: 1991-03-21
Publication date: 1991-09-25
Also published as: GB9106005D0; IT1245565B; ITMI910757A1; ITMI910757A0; FR2660015A1

Abstract

To delay movement of a throttle valve 3 in the in let manifold 1 of the engine or a control rod adjusting a fuel injection pump relative to the movement of an accelerator 8, in the power increasing direction, a pressure chamber 11 subject to inlet manifold pressure and also connected to ambient atmosphere by an adjustable throttle 15 is located in the connecting linkage. The pressure chamber (21, 37, 65, Figs. 2 to 4) may be defined between a pair of pistons or diaphragms and an electric motor (49, Fig. 4) may form part of the connecting linkage. <IMAGE>

Description

Title: DELAYING MOVEMENT OF A REGULATING ElEMENT OF AN INTERNAL COMBUSTION ENGINE Description of Invention This invention relates to a method of, and apparatus for, delaying the movement of a regulating element which changes the power output of an internal combustion engine. The regulating element may be, for example, a throttle valve in an inlet manifold of the engine, or a control rod adjusting a fuel injection pump of the engine. The invention interposes a pressure responsive element between a setting element (such as the accelerator control of a motor vehicle, which sets the required position of the regulating element) and the regulating element, the pressure element delaying the movement of the regulating element relative to operation of the setting element, and including a pressure chamber which is subject to the inlet manifold pressure of the engine.

With an internal combustion engine having atmospheric induction, the pressure to which the pressure chamber is subject is below atmospheric pressure, the so-called inlet manifold vacuum, while with supercharged engines the pressure is above atmospheric pressure, but with the assistance of suitable balancing means, a decreasing supercharging pressure has the same affect as increasing inlet manifold vacuum.

In the case of Otto engines, the said pressure may be taken from the inlet manifold downstream of the throttle valve. In the case of Diesel engines, the pressure may be collected by a venturi nozzle in a bypass pipe leading to the inlet manifold.

The following explanation, as is the case in the described embodiments, refer to Otto engines.

It is known from the prior art to provide throttle valve closing dampers, wherein opening movement of the throttle valve, against the effect of a closing spring, follows directly the movement of the setting element (the accelerator) but closing movement of the throttle valve does not directly follow the movement of the setting element. A delay is introduced by the effect of a vacuum element between the setting element and the throttle valve, the vacuum element being subject to inlet manifold vacuum downstream of the throttle valve.

Such devices are known, for example, from Dutch patent specification 167,009, the purpose of such devices being to ensure complete combustion of fuel even during deceleration. The problem under such conditions is that when the accelerator is released, the inlet manifold vacuum downstream of the throttle valve cause fuel lying on the walls of the inlet manifold to evaporate quickly, producing a fuel-rich mixture. As a result, during deceleration, the concentration of unburned hydrocarbons in the exhaust of the engine reaches very high values, because the supply of air to the engine through the closed throttle valve has been reduced. However, by delaying the closing movement of the throttle valve by means of such a damping device, the effects of a sudden increase in the manifold vacuum can be avoided.A further problem which cannot be solved by the devices of the above mentioned type is that rapid opening of the throttle valve leads to incomplete combustion, i.e. to the presence of unburned hydrocarbons in the exhaust gas and to an increase in fuel consumption. Actuation of a carburettor accelerator pump caused by opening the throttle valve, which is intended to counteract the production of a leaner mixture as a result of the suddenly reduced vacuum in the inlet manifold causes an additional amount of fuel to be added, which amount of fuel has to be sufficient even for the conditions of high speed with a cold engine. However, in most other operating conditions the amount of fuel added by the accelerator pump is too high, leading to incomplete evaporation of the fuel and incomplete combustion.

In the case of Diesel engines, a delayed movement of the fuel pump regulating rod is desirable in order to prevent so-called load impact, i.e. a sudoer increase and decrease in the engine's power. This is important for reasons of driving comfort and with supercharged engines it prevents the formation of soot during acceleration, and thus the increase in fuel consumption due to over-fuelling and lack of air.

It is the object of the present invention to provide a method for delaying movement of a regulating element of an internal combustion engine to change the power output thereof, relative to the movement of a setting element, by means of an interposed pressure element including a pressure chamber subject to inlet manifold pressure, whereby the above described problems can be overcome or alleviated.The invention has the further objective of providing a device of simple design for achieving the delay in change of engine power, which may be capable of reducing fuel consumption and the emission of pollutants in the case of vehicles operating with frequent changes in engine load, without causing significant power losses.

The objects are achieved in the method of the present invention by providing that a non-rigid connection is established between the regulating and setting element by way of the pressure chamber subject to inlet manifold pressure, wherein the pressure chamber is also subject to ambient atmospheric pressure by way of an adjustable throttle, the pressure thus established in the chamber effecting movement of the regulating element to follow movement of the setting element at least in the direction to increase the power output of the engine.

The follow-up movement of the regulating element may be achieved by pneumatic/mechanical or pneumatic/electric means.

According to another aspect of the invention, we provide a device for delaying movement of a regulating element which changes the power output of an internal combustion engine, relative to the movement of a setting element which sets the required position of the regulating element, the device comprising a pressure responsive element establishing a non-rigid connection between the setting element and regulating element, the pressure element comprising a pressure chamber connected so as to be subject to inlet manifold pressure of the engine and also connected to ambient atmosphere by way of an adjustable throttle, the pressure thus established in the pressure chamber effecting movement of the regulating element to follow movement of the setting element at least in the direction to increase the power output of the engine.

In a device according to the invention, a component forming one boundary of the pressure chamber of the pressure element has to be connected directly to the setting element whereas a further component forming a boundary of the pressure chamber is designed to act on the regulating element, e.g. the engine's throttle valve, by a tranmission means. The transmission means may comprise a mechanical lever arrangement, operating against the force of a throttle valve closing spring. However, it is alternatively possible to arrange an electromechanical position detecting unit at the further component forming a boundary of the pressure chamber, by which it is possible to control a servo motor for actuating the regulating element. Suitable control assemblies for ensuring an analogue transfer of the movement of the component to the movement of the throttle valve are known.

The device is suitable for acting as a delaying means both during acceleration and deceleration, thereby allowing improvements in fuel consumption under conditions where loads change frequently. The device is easily incorporated into the throttle actuating mechanism without requiring any interference with the carburettor or fuel injection system. The invention provides embodiments in which a housing of the pressure chamber is freely suspended in the throttle actuating mechanism, so as to be movable as a whole, or can be arranged as a component firmly attached to the vehicle. In the former case, a simple piston cylinder unit is provided, while in the latter case a housing having two pistons and cylinders, or diaphragms, is proposed.

The invention will now be described by way of example with reference to the accompanying drawings, wherein: Figure la shows diagrammatically a first emb(sdirtneria device according to the invention, in the condition wherein the engine is idling; Figure 1a shows part of the device of Figure 1 during an acceleration phase; Figure 2 shows a second embodiment of device according to the invention, in an acceleration phase; Figure 3 shows a third embodiment of device according to the invention, in an idling phase; Figure 4 shows a fourth embodiment of device according to the invention, including an electro-mechanical transmission assembly.

Referring firstly to Figure la of the drawings, there is shown in illustrated longitudinal section an inlet manifold 1 having a pivoted throttle valve 3 and a venturi section 2. The throttle valve 3 is arranged to be spring biased towards its closed position by a closing spring 6, operating on the throttle valve through an angle lever 5 and a link indicated as a broken line, connecting the angle lever to a throttle valve lever 4. The required position of the throttle valve 3 is determined by an accelerator pedal 8, a connection between the accelerator 8 and the angle lever 5 being established by way of a pressure element indicated at 71. The pressure element 7 which forms a delaying device, comprises a housing or body 9 defining a cylinder within which is axially movable a piston 10.

The housing 9 is directly connected to the accelerator 8, and the piston 10 is directly connected to the angle lever 5. The housing 9 and piston 10 define a pressure chamber 11 which is connected by a first connecting sleeve 12 and a flexible tube, indicated by a broken line, to a connecting sleeve 13 in the inlet manifold downstream of the throttle valve 3, the direction of air flow in the inlet manifold being as indicated by the arrow in the drawing. A second connecting sleeve 14 provided on the housing 8 has a needle throttle valve 15 establishing an adjustable communication with the external atmosphere. A compression spring 17 acts on the piston 10 within the housing 9, to overcome frictional forces.

By virtue of the connection by way of connection sleeve 12, 13 to the inlet manifold downstream of the throttle valve, and by virtue of the adjustable throttle valve 15 providing a connection to ambient atmosphere, the pressure chamber 11 is subject to a pressure which is a dynamic balance between the inlet manifold pressure and the ambient atmospheric pressure. The tension spring 16 acting on angle lever 5 urges the piston 10 to its outermost (left-hand in the drawing) position, and the housing 9 is also returned to an extreme position in the idling condition, by virtue of the pressure which is a partial vacuum existing in the chamber 11. The spring 17 overcomes frictional forces of the piston 10.

During acceleration, Figure shows how the accelerator 8 is operated drawing the housing 9 to its outermost (right-hand) position, whereas the piston 10, held bacic by the spring 6, is still virtually in its original position. Air is able to flow into the pressure chamber 11 from the inlet manifold by way of the connecting sleeve 12, and the vacuum in the pressure chamber 11 is now reduced and balanced as a result of flow of air through the inlet manifold and the throttle valve 14. The piston 10 now follows the movement of the housing 9, so that the throttle valve 3 opens fully. During deceleration, i.e. when returning the accelerator 8 to the position shown in Figure i the movement of the throttle valve takes place virtually as if it were rigidly connected to the accelerator 8.

In the embodiment shown in Figure 2 the same reference numerals as used in Figure 1 are used for parts whose function corresponds to the parts in the Figure 1 embodiment. Figure 2 shows an inlet manifold 1, throttle valve 3, venturi section 2, and throttle lever 4 connected to an angle lever 5 and spring 6.

Again, a connecting sleeve 13 is provided downstream of the throttle valve 3 in the inlet manifold 1. The accelerator 8 is shown in the same position as in Figure 1b. Interposed between the accelerator 8 and angle lever 5 is a pressure element 7 which comprises an axially fixed cylinder housing 19 having two pistons 18, 20 therein. The first piston 20 is directly connected to the angle lever 5 and thus to the throttle valve 3. A second piston 18 is directly connected to the accelerator 8. The twc pistons are connected to each other by a tension spring 27 and a spacing sleeve 28 which ensures a minimum distance between the two pistons 18, 20.

Between the two pistons 18, 20 is defined a pressure chamber 21 which, by way of a connecting sleeve 22, is connected to the sleeve 13 in the inlet manifold 1. The connecting sleeve 22 is connected to a further sleeve 44 in which an adjustable needle throttle valve 45 is provided, for controlled admission of ambient atmospheric air into the pressure chamber 21.

On the opposite side of piston 20 from the pressure chamber 21, there is defined a further pressure chamber 29. The rod by which piston 20 is connected to angle lever 5 passes out of the housing 19 through a seal 30. An adjustable needle throttle valve 25 is provided on a fitting 24, for controlled admission of ambient atmospheric air into the pressure chamber 29.

During a rapid movement of the accelerator 8 towards the right, the pistons 18 and 20 become separated from one another because of the force of closing spring 16 acting on piston 20, and the fact that attempted movement of piston 20 to the right causes a reduction in pressure in the pressure chamber 29.

However, because the tension spring 27 is stronger than the spring 6, and because of the partial vacuum existing in chamber 21, the piston 20 follows the movement of piston 18 to the extent that this is permitted by the flow of air through the throttle 25. When the accelerator is released, the tension spring 6 again pulls the piston units 20 and 18 to the left, with such return movement being damped by the throttle 25 or, if an excess pressure valve is provided for the chamber 29 a substantially undamped return movement is permitted.

Referring now to Figure 3 of the drawings, once again the same reference numerals are used for parts of corresponding function to those above described. Figure 3, as for Figure 1 and Figure 2, shows an inlet manifold 1, venturi section 2, throttle valve 3, and throttle lever 4 connected to an angle lever 5 and throttle-closing spring 6. A connecting sleeve 13 is provided downstream of the throttle valve 3 in the inlet manifold 1. A setting element in the form of an accelerator pedal 8 is provided, and in Figure 3 it is in the idling position.

Between the accelerator pedal 8 and angle lever 5 there is provided a pressure element 73 which comprises a fixed housing 31 on opposite ends of which are two diaphragm housings 32, 33 provided with respective flexible diaphragms 34, 35.

The two diaphragm housings are connected to one another by a passage 36 to define a single pressure chamber 37. In respective branches from the passage 36 there are provided a fitting 44 with an adjustable needle throttle valve 45 for controlled admission of air from the external atmosphere to the chamber 37. A connecting sleeve 42 is connected to the connecting sleeve 13 on the inlet manifold 1.

The diaphragm 34 is connected to an actuating element 38 which in turn is connected to the accelerator pedal 8. The other diaphragm 35 is connected by a transmission element in the form of rod 39 to the angle lever 5.

The rod 39 has two spaced abutments 40, 41 thereon, and is slidable between limits determined by these abutments within an extension fitted to the element 38. A spring biases the element 38 and the extension to the left, with reference to the drawing, to provide a return spring for the diaphragm 34.

In the illustrated idling position, the diaphragm 35 is pulled to its extreme left-hand position by the throttle-closing spring 6. The diaphragm 34 is pulled into its extreme left-hand position by the partial vacuum existing in the chamber 37, which is set by the dynamic balance between the inlet manifold vacuum and the admission of ambient air into the chamber 37 through the adjustable throttle 45.

When the accelerator pedal 8 is moved to the right to increase the power output of the engine, the element 38 and the diaphragm 34 are moved towards the right. The diaphragm 35 and the member 39 follow, at a speed determined by the dynamic balance set between the inlet manifold vacuum and the admission of ambient air through the throttle 45. If the accelerator is then released to return to its illustrated position, the throttle-return spring 6, by way of the element 38 and stop 41, returns the rod element 39 in a substantially undamped manner to the illustrated position.

In e the described embodiments, a throttle may be provided in the conslection between the connecting sleeve 13 of the inlet manifold and the respective connecting sleeves of the pressure element.

Referring finally now to Figure 4 of the drawings, once again the same reference numerals are used for parts corresponding to those above described.

There is an inlet manifold 1 having a throttle valve 3 and a venturi section 2, the throttle valve 3 being connected to an operating lever 4 and thus to an angle lever 5. In this embodiment, however, the angle lever 5 is adjustable by a toothed rack 46 constrained by a linear guide 47 and movable by a gear wheel 48 provided on the shaft of an electric servo-motor 49 whose control will be described later.

There is an accelerator pedal 8, and a connecting sleeve 13 provided in the inlet manifold 1 downstream of the throttle valve 3.

A pressure element 74 comprises a housing in the form of a cylinder 50 provided with end covers 51, 52. Two piston rods 53, 54 are axially slidable through the covers 51, 52, and are connected to respective pistons 57, 58 sliding in the cylinder 50. The piston rods 53, 54 extend beyond the pistons so that they can contact each other so as to define a minimum volume of a pressure chamber 65 defined between the pistons 57, 58 which have sealing engagement with the wall of the cylinder 50. The covers 51,52 have respective pressure balancing vent apertures 55, 56 therein. A connecting sleeve 42 leads into the pressure chamber 65 defined within the housing 50, and a fitting 44 on the sleeve 42 is provided with an adjustable needle throttle valve 45 for controlled admission of air from the surrounding atmosphere into the sleeve 42 and pressure chamber 65.The sleeve 42 connects to the connecting sleeve 13 on the inlet manifold, so that the pressure prevalent in the chamber 65 is a dynamic balance between the inlet manifold pressure and the throttled admission of ambient air. The first piston rod 53 is connected to the accelerator pedal 8, and a compression spring 59 urges the piston 57 to the left, away from the cover 51. The second piston rod 54 is provided with a rack portion 60 which engages a gear wheel 61 provided on an electrical position detecting and control unit 62 which is supplied with electric power through wires 63 and is connected by wires 64 to the servo-motor 49 which controls the position of the throttle valve 3.

The mode of operation of this embodiment of the invention with the two pistons 57, 58 is substantially the same as the embodiment of Figure 3 wherein two diaphragms are utilised. Thus when the accelerator pedal 8 is actuated to increase engine power, the piston 58 follows the movement of piston 57 with a delay dependent on the inlet manifold pressure and air admission through adjustable throttle 45. When the accelerator pedal is released, return of the piston 58 is substantially undamped because of the contact between the piston rods 53, 54. The motion of piston 58 is directly transmitted to the throttle valve 3 by way of the arrangement of the position detecting device 62 and servo-motor 49. Further influencing factors on the movement of the throttle valve 3 relative to the accelerator 8 may be introduced via the position detecting and control unit 62.

IrSe features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A method of delaying movement of a regulating element which changes the power output of a internal combustion engine, relative to a setting element which sets the required position of the regulating element, by providing between the setting element and the regulating element a pressure responsive element including a pressure chamber subjected to inlet manifold pressure of the engine, wherein the pressure in the pressure chamber causes the movement of the regulating element to follow that of the setting element at least in the sense of increasing the power output of the engine, and wherein the pressure chamber is also subject to ambient atmospheric pressure by way of an adjustable throttle.

2. A method according to Claim 1 wherein the movement of the regulating element relative to the setting element is effected pneumatically/mechanically.

3. A method according to Claim 1 wherein the following movement of the regulating element relative to the setting element is effected pneumatically/by an electric motor.

4. A device for delaying movement of a regulating element which changes the power output of an internal combustion engine, relative to the movement of a setting element which sets the required position of the regulating element, the device comprising a pressure responsive element establishing a non-rigid connection between the setting element and regulating element, the pressure element comprising a pressure chamber connected so as to be subject to inlet manifold pressure of the engine and also connected to ambient atmosphere by way of an adjustable throttle, the pressure thus established in the pressure chamber effecting movement of the regulating element to follow movement of the setting element at least in the direction to increase the power output of the engine.

5. A device according to Claim 4 wherein said pressure chamber is defined by an axially movable cylinder and a piston movable therein, one of said piston and cylinder components being directly connected to the setting element and the other component being connected to the regulating element by a transmission assembly.

6. A device according to Claim 5 wherein the cylinder is connected to the setting element and the piston is connected to the regulating element, the piston and cylinder being supported relative to each other by a spring outside the pressure chamber.

7. A device according to Claim 4 wherein the pressure chamber is enclosed between two pistons axially movable within a fixed cylinder, one piston being directly connected to the setting element and the other piston being connected to the regulating element by a transmission assembly, said pistons being connected to each other by a tension spring within the pressure chamber enclosed by them.

8. A device according to Claim 7 wherein the pressure chamber is connected to the ambient atmosphere by way of a throttle.

9. A device according to Claim 7 wherein a sealed operating chamber is defined behind the piston connected to the regulating element, said operating chamber having connection to ambient atmosphere by way of a throttle.

10. A device according to Claim 4 wherein the pressure element comprises a fixed housing having connected chambers bounded by respective flexible diaphragms, one of the diaphragms being directly connected to the setting element and the other being connected to the regulating element by a transmission assembly, the connected diaphragm chambers constituting the pressure chamber.

11. A device according to Claim 10 wherein the pressure chamber is connected to ambient atmosphere by a throttle.

12. A device according to Claim 10 wherein a first transmission member connected to the diaphragm associated with the setting element is guided on a second transmission member connected to the diaphragm associated with the regulating element, between two abutments.

13. A device according to Claim 4 wherein the pressure element comprises an axially fixed cylinder and two pistons movable therein defining limits of the pressure chamber, one of said pistons being directly connected to the setting element and the other one being connected to the regulating element by a transmission assembly.

14. A device according to any one of Claims 4 to 13 wherein the transmission assembly comprises a mechanical linkage.

15. A device according to any one of Claims 4 to 13 wherein the transmission assembly comprises an electro-mechanical transmission, comprising a position detecting element and a servo-motor for controlling the regulating element.

16. A method of delaying movement of a regulating element of an internal combustion engine, relative to a setting element, substantially as hereinbefore described.

17. A device substantially as hereinbefore described with reference to Figure 1, Figure 2, Figure 3 or Figure 4 of the accompanying drawings.

18. Any novel feature or novel combination of features described herein and/or in the accompanying drawings,