GB2033485A - Preventing unauthorised starting of fuel injection internal combustion engines - Google Patents

Abstract

A centrifugal governor, especially for diesel engines is provided with a stop lever (27, 27a), by means of which the fuel regulating member (21) of the injection pump (P) is held in a cut-off position for stopping the engine in order to prevent an unauthorized or undesired starting of the engine. The stop lever (27) is held in its operating position illustrated by a tension spring (28), Fig. 2 (not shown), so that the governor can operate normally via the governor sleeve (3) and via a guide lever (15) and a two-part intermediate lever (17) by compression of an idling spring (9) in the idling speed range and stretching of a maximum speed governing spring (11) in the maximum speed range as set by an accelerator pedal (22). The tension spring (28) acts as a toggle and is disposed so that the stop lever (27) is held both in the engine running position as shown and in the stop position in which the lever portion 27a engages a pin 25. For this purpose, the force of the toggle spring (28) is greater than the force of an auxiliary spring (24) between the parts (170 and 175) of the two- part lever (17), which parts separate to prevent damage to the governor linkage if the accelerator is operated with the lever in the stop position. <IMAGE>

Description

SPECIFICATION Centrifugal speed governor for injectiontype internal combustion engines The invention relates to centrifugal governors for injection-type internal combustion engines, Governors are known which are provided with a separate stop lever which acts directly or indirectly upon the regulating rod of the fuel injection pump, serving as a fuel-delivery adjusting member, to displace the control regulating rod mechanically in the fuel cut-off direction, whereby the engine is stopped.

Once the engine has stopped, the stop lever is brought back again, by means of a spring, into its operating position in which the regulating rod of the fuel injection pump can move freely.

If, however, a vehicle which is fitted with a diesel engine and the described governor has been parked on an incline or on sloping ground, the diesel engine may start automatically because of the vehicle moving if there is a defect in or fading of the braking force of the hand brake or if the brake is released without authorization and at the same time the gear is not in the neutral position, and the vehicle may set off unmanned. It is therefore necessary to provide a safety device which prevents automatic or unauthorized starting when the engine has stopped.

The present invention provides a centrifugal governor for an injection-type internal combustion engine comprising an adjusting member which is displaceable under the force of flyweights, a governor linkage which transmits the changed position of the adjusting member to a fuel-delivery quantity regulating member, a stop lever which is drawn selectively into its engine-operating position and its stop position by a toggle spring and which is used to displace the fuel-delivery regulating member into its cut-off position to stop the internal combustion engine, and an auxiliary spring which yields to prevent the governor linkage from becoming overloaded when the stop lever is in its stop position, the force developed by the toggle spring when the stop lever is held thereby in its stop position being greater than the force developed by the auxiliary spring.

Thereby undesirable or unauthorized starting of the engine is not possible. Because of the toggle spring, the stop lever remains in its stop position, which holds the fuel-delivery regulating member in the cut-off position, when, for example, the operating lever of the governor is pressed into the full-load position by operation of the accelerator pedal, for then the auxiliary spring, which is softer than the toggle spring, acts as a drag link and is tensioned or compressed depending upon the type of construction of the drag link. A further advantage can be seen in the design of the governor which is cheap and extremely easy to realise.

Preferably, the stop lever is pivotable about a centrifugal governor in which the stop lever is pivotable about a stop shaft and the toggle spring is a tension spring, one end of the toggle spring being attached at a point on the stop lever and the other being attached at a mounting point which is located on the governor housing in the swivel plane of the stop lever lying on the side of the stop shaft opposite the stop lever. A space-saving and simple arrangement, which requires no additional components, is thereby obtained.

The invention is further described by way of exampie, with reference to the drawings, in which: Figure 1 is a cross-section through one embodiment of a governor which is designed according to the invention, and Figure 2 is an external view of the governor to a smaller scale.

The drawings illustrate a governor of a diesel engine of a mechanically propelled vehicle.

As Fig. 1 shows, flyweights 2 are secured in an articulated manner on a cam shaft 1 of a fuel injection pump P, which is only shown indicatively, and they act upon one end of a governor sleeve 3, which serves as an adjusting member, their speed dependent pivotal movement being converted into a longitudinal movement of the governor sleeve 3. The upper end of a tensioning lever 6 is rotatably mounted on a bearing pin 5 secured in the governor housing 4, whilst a pressure spindle 8 is displaceably disposed in a spring retainer 7 which is secured at the lower end of the tensioning lever, the end 8a of the pressure spindle being directed towards the flyweights 2 and abutting against an end face 3a of the governor sleeve 3.The pressure spindle 8, which is displaceable within the spring retainer 7, is held in the illustrated position by an idling spring 9 which is supported by one end, at the head 8a of the pressure spindle and by the other end in the spring retainer 7.

Disposed between the tensioning lever 6 and the housing 4 is a maximum speed governor 11 which is to govern the highest speed to be limited and whose initial tension acts upon the governor sleeve 3 by way of the tensioning lever 6.

When the engine is running, the flyweights 2 press against the governor sleeve 3 with a force which corresponds to the engine speed and, depending upon the actual speed, displace this sleeve counter to the force of the idling spring 9 in the event of low-idle-speed governing or respectively counter to the force of the maximum speed governor spring 11 in the event of the set maximum speed being reached.

The upper end of a guide lever 1 5 is pivotably mounted also on the bearing pin 5, and the lower end of this lever is connected to the governor sleeve 3 in a pivotal manner by a pin 16. A pin 18 is secured in the central portion of this guide lever 15, and a two-part intermediate lever 17, also referred to herein as a floating lever, is pivotably mounted on the pin 1 8 and comprises two lever parts 1 70 and 1 75 which are each pivotable about the pin 1 8. An adjusting lever 19 engages a point of articulation 1 71 located at the end of the first lever part 170, and keeps this point in the illustrated position during the idling operation of the engine The extreme end 1 73 of the second lever part 175, is connected by a connecting link to a regulating rod 21, which serves as the fuel-delivery adjusting member of the injection pump P. A portion 1 9a of the adjusting lever 1 9 is located outside the governor housing 4 (see also in this connection Fig. 2) and is optionally operated by an accelerator pedal 22 in that it is pivoted in order to change the fuel delivery to be set. The point of articulation 1 71 of the intermediate lever 1 7 is thereby displaced, the intermediate lever 1 7 is pivoted about the pivot pin 18, serving as the actual fulcrum and the regulating rod 21 is adjusted accordingly. In addition, a starting spring 23, which is secured to the governor housing 4, also engages the second lever part 175.

In the event of a change of speed and a resultant displacement of the position of the governor sleeve 3, the guide lever 15 is pivoted about the bearing pin 5, and the intermediate lever 1 7 is thereby pivoted about the point of articulation 171, which now serves as the actual fulcrum, by means of the pin 1 8 and the position of the regulating rod 21 is displaced accordingly. lf the regulating rod 21 is displaced to the right to the position shown in Fig. 1, then the quantity of fuel injected decreases, but, if it is displaced to the left, then the quantity of fuel injected increases. An internal portion 27a of a stop lever 27, which is pivotable about a stop shaft 26, lies opposite a transverse pin 25 by which the connecting link 20 is attached to the regulating rod 21.As can be seen from Fig. 2, one end of a toggle spring 28, in the form of a tension spring, is hooked on the external portion of the stop lever 27 at a point 27b, whilst its other end is hooked on the governor housing 4 at a mounting point 29.

As seen in the swivel plane of the stop lever 27, the mounting point 29 is located on the governor housing 4 on the side of the stop shaft 26 opposite the stop lever 27 with a space relative to this stop shaft. The position shown in Fig. 2 for the mounting point 29 is such that, as shown by fully solid lines in the drawing, the stop lever 27 is held in this position by the tension of the toggle spring 26 when the stop lever 27 is in the stop position, but that, as shown by dash-dot lines, the toggle spring 28 also holds the stop lever 27 in the position denoted by 27' when the stop lever is in its operating position. The stop lever 27 thereby operates with a toggle action.The force arising from the tension in the holding spring 28, in the two end positions of the stop lever shown as 27 and 27' in Fig. 2 is always greater than the force arising from an auxiliary spring 24 (see Fig. 1) between the two lever parts 1 70 and 1 75. The auxiliary spring 24 draws the second lever part 1 75 in the illustrated starting position against a lever portion 1 72 which is firmly connected to the first lever part 170, and the entire arrangement thereby acts as a drag link which could also be replaced by a resilient link which is inserted instead of the connecting link 20.The object of this drag link is to prevent the governor linkage from becoming overstressed, and the force whilch can arise at the connecting pin 25 as a result of its initial tension is weaker than the holding force of the toggle spring 28, so that, when the stop lever 27 is in the illustrated stop position 27', the regulating rod 21 cannot move, even upon actuation of the accelerator pedal 22 and consequential pivoting of the intermediate lever 17, because the weaker auxiliary spring 24 yields and only the first lever part 1 70 actually pivots, whilst the second lever part 1 75 and therewith also the regulating rod 21 are held in the cut-off position by the inner stop lever 27a.

The auxiliary spring 24 also operates when the engine is running in the following manner: When the engine is running, the stop lever 27 is in the position shown in Fig. 1 and by a solid line in Fig. 2. The internal portion 27a does not come into contact with the pin 25 on the regulating rod 21. If, however, the stop lever 27 is pivoted in an anticlockwise direction to stop the engine and is brought into its second end position which is denoted by 27' in Fig. 2 and is shown therein by dash-dot lines, then the internal portion 27a of the stop lever 27 presses the transverse pin 25 and displaces the regulating rod 21 into its cut-off position in which no more fuel is delivered by the fuel injection pump P to the engine and the engine stops. Without changing the positions of the other parts of the governor linkage whose positions are determined by the adjusting lever 1 9 and which are controlled by the governor sleeve 3, the second lever part 1 75 is thereby pivoted about the pin 1 8 by means of the connecting link 20 counter to the force of the auxiliary spring 24. It thereby moves away from the lever portion 1 72 of the first lever part 1 70.

The auxiliary spring 24, which is weaker and also softer than the toggle spring 28, thereby transmits such low forces tothe governor linkage that there is no danger whatsoever of any overloading of the governor linkage.

Because of the position of application of and the magnitude of the initial tensioning force of the toggle spring 28, and also because of the arrangement of the auxiliary spring 24, it is ensured for all desirable and undesirable operating cases which may arise that, when the stop lever 27 is pivoted to its stop position 27', the regulating rod 21 of the fuel injection pump P is always held in the cut-off position. Thus the required safety function of the toggle spring 28 is achieved simply, and the self-igniting diesel engine cannot automatically start even with unauthorized pushing of the vehicle or with undesired motion upon release of the vehicle brake.

Claims (2)

1. A centrifugal governor for an injection type internal combustion engine comprising an adjusting member which is displaceable under the force of flyweights, a governor linkage which transmits the changed position of the adjusting member to a fuel-delivery quantity regulating member, a stop lever which is drawn selectively into its engineoperating position and its stop position by a toggle spring and which is used to displace the fuel-delivery regulating member into its cut-off position to stop the internal combustion engine, and an auxiliary spring which yields to prevent the governor linkage from becoming overloaded when the stop lever is in its stop position, the force developed by the toggle spring when the stop lever is held thereby in its stop position being greater than the force developed by the auxiliary spring.

2. A centrifugal governor as claimed in claim 1, in which the stop lever is pivotable about a stop shaft and the toggle spring is a tension spring, one end of the toggle spring being attached at a point on the stop lever and the other end being attached at a mounting point which is located on the governor housing in the swivel plane of the stop lever lying on the side of the stop shaft opposite the stop lever.