US2891701A

US2891701A - Regulating means for liquid fuel metering apparatus for internal combustion engines

Info

Publication number: US2891701A
Application number: US639264A
Authority: US
Inventors: Downing Eric William; Duddell Howard
Original assignee: Lucas Industries Ltd
Current assignee: ZF International UK Ltd
Priority date: 1956-02-14
Filing date: 1957-02-11
Publication date: 1959-06-23
Anticipated expiration: 1976-06-23

Description

June 23, 1959 E. w. DOWNING ETAL 2,891,701

REGULATING MEANs FOR LIQUID FUEL METERING APPARATUS FOR INTERNAL COMBUSTION ENGI Es Filed Feb. 11, 1957 2 Sheets-Shet 1 June 1959 E. w. DOWNING ET AL 2,891,701 REGULATING MEANS FOR LIQUID FUEL METERING APPARATUS FOR INTERNAL COMBUSTION ENGINES Filed Feb. 11, 1957 2 Sheets-Sheet 2 United States Patent ()filice 2,891,701 Patented June 23, 1959 REGULATING MEANS FOR LIQUID FUEL METER- IN G APPARATUS FOR INTERNAL COIVIBUSTION ENGINES Eric William Downing, Dorridge, and Howard Duddell, Kettlebrook, Tamworth, England, assignors to Joseph Lucas (Industries) Limited, Birmingham, England Application February 11, 1957, Serial'No. 639,264

Claims priority, application Great Britain February 14, 1956 2 Claims. (Cl. 222-250) This invention relates to regulating means for a liquid fuel metering apparatus of the shuttle type for internal combustion engines. Such an apparatus comprises a rotary cylindrical valve contained in a ported body part and adapted to be rotated by the engine, and at least one freely movable reciprocatory shuttle contained in a longitudinal bore in the valve, the shuttle being actuated by pressure of liquid fuel supplied by a pump to the opposite ends of the shuttle alternatively, and the range of movement of the shuttle beingdetermined by a pair of end stops, one of which is adjustable by an automatic regulating means responsive to the air-pressure in the air intake manifold of the engine.

The object of the present invention is to provide an improved regulating means for the adjustable shuttle stop, whereby a supply of fuel can be supplied in excess of the normal'maximum when starting a cold engine.

A regulating means in accordance with the invention includes an endwise slidable stop-actuating cam which is movable transversely to the adjustable stop of the metering apparatus by a spring-loaded piston or diaphragm responsive to air pressure in the'intake manifold of the engine and is supported at one side by an abutment which is movable by a temperature responsive means, the arrangement being such that when the engine is cold the cam occupies a position at which it allows the adjustable stop to move beyond its normal maximum supply position.

In the accompanying drawings:

Figure 1 is a sectional view of a mechanism embodying the invention.

Figure 2 is a part sectional view of the mechanism in a plane at right angles to that of Figure 1, the sectional part of Figure 2 being taken on the line 2--2 of Figure 1.

Figure 3 is a side elevation of a valve contained in a chamber in the body part of the mechanism for controlling the flow of heated air over the temperature responsive means associated with the stop-actuating cam of the mechanism.

Figure 4 is a fragmentary view illustrating an alternative means for heating the air which acts on the temperature-responsive means.

In the particular form of fuel metering mechanism shown at the left-hand side of Figure 1 there is contained in a cylindrical body part 5 a liner 6 which encloses a rotatable cylindrical valve 7, the latter being connected at one end to a spindle 8 or other rotary means driven by the engine. In the valve are formed (in this example) a pair of longitudinal bores each containing a shuttle 9. Linear movement of the shuttle in one direction is limited by a fixed stop 10, and in the other direction by an adjustable stop 11. The rotary valve and body are suitably ported so that the liquid fuel supplied by a feed pump to an inlet connection (not shown) can impart reciprocatory movement to the shuttles, and thereby cause the fuel to be discharged through outlet pipe connections as 12 to the engine cylinders in the shuttles. In another example the rotary valve has a single and axially located bore in which case a single shuttle and end stops are provided. The action of such a metering mechanism is Well known, and this mechanism forms no part of the present invention. The invention relates to the regulating means employed for effecting automatic adjustment of the stops (or stop) 11.

In the regulating means illustrated by the drawings, there is provided a hollow body part 13 adapted for attachment to one end of the body part 5 of the metering apparatus. In the body part 13 is contained an endwise slidable thrust piece 14 loaded by a spring 15 and located in contact with the adjustable stops 11 (or stop) of the metering apparatus.

The inner end of the thrust piece 14 is held in contact with one edge of an end-wise slidable cam 16 by pressure of the fuel in the metering apparatus. One end of the cam 16 is pivotally attached to one end of a link 17 pivoted on and extending from a piston 18 (or diaphragm) contained in a cylinder 19 formed on, or secured to the body part and loaded by a spring 20, one end of the cylinder being adapted for pipe connection to the air intake manifold of the engine, so that with depression of pressure in the manifold the piston (or diaphragm) is moved in opposition to the spring for moving the cam 16 transversely to the thrust piece 14 in the direction for reducing the range. of movement of the shuttle or shuttles in the metering device. The end of the link 17 to which the cam 16 is attached is provided with a roller 21 which is supported on a fixed guide 22. The other end of the cam is provided with a roller 23 which is supported by an abutment 24, along which the roller 23 can move under the action of the piston 18. The abutment 24 consists of a radial arm attached at one end to a pivot 25 and retractable by the action of a heatresponsive means to a position (as shown by dotted lines) which allows the cam 16 to move to a position beyond its normal maximum fuel supply position, and so enable a larger fuel supply to be obtained when starting a cold engine, the abutment being returned to its normal position by the action of heat on the heat responsive means.

In the example illustrated the heat-responsive means consists of a spirally coiled bi-metal spring strip 26 contained in a chamber 27 on the body part 13, and attached at one end to the pivot 25, the other end of the strip being attached to an adjustable fixed pin 28. The chamber 27 is supplied with heated air through a pipe attached to the inlet 29 and connected to a heat exchanger associated with the exhaust gas pipe of the engine, the air being subsequently discharged into the air intake manifold of the engine through a pipe connected to the outlet 30 of the said chamber. The inner end of the bi-metal strip 26 is also attached to a pin 31 extending from an angularly adjustable air control valve to be hereinafter described.

The free end of the arm 24 is provided with a lateral projection 32 which during normal Working conditions abuts against an oblique face 33 on a plunger 34 extending from and actuated by a barometric device. The latter, in the example shown by the drawings, consists of an elastic bellows 35 loaded by a spring 36 and contained in a chamber 37 to which filtered air is admitted at atmospheric pressure.

The arrangement is such that when the engine is cold, the arm 24 occupies a position as shown by dotted lines in Figure 1. The thrust piece 14 is then free to move to the right and allow the associated adjustable stop or stops 11 of the fuel metering apparatus to move likewise to an extent sufiicient to enable the fuel to be supplied to the engine at a rate in excess of the normal maximum rate. After the engine has been started, the hot air acting on the bi-metal strip 26 causes the latter to move the arm 24 to the position shown by full lines in Figure 1 which determines the normal maximum fuel supply rate. Movement of the piston 18 in response to reduction of pressure in the air intake manifold of the engine moves the cam 16 upwardly for altering the position of the aforesaid adjustable stops or stop and thereby reduce the rate of fuel supply in a manner dependent on the pressure in the air intake manifold. With reduction of am bient atmospheric air-pressure, the bellows 35 extends and allows the arm 24 to move to the left under the spring action of the bimetal strip, so causing a reduction in the rate of supply of fuel to the engine.

The hot air control valve above mentioned consists of a fixed seating plate 38 in which are formed a plurality of equi-spaced ports 39. In contact with the inner side of the seating plate is placed an angularly movable closure member consisting of a plurality of radial arms 40 adapted to vary the effective areas of the ports 39. Also one or each arm has formed it in a notch 41 which allows a limited flow of hot air through the chamber 27 when the closure member is in its fully closed position. The valve is such that when starting the engine the ports 39 are fully open. With gradual warming up of the bi-metal strip the valve is progressively closed. The continued restricted flow of hot air through the chamber 27 after the valve has been moved to its closed position maintains the bi-metal strip in a sufficiently heated condition to hold the arm 24 in its normal position.

Instead of heating the air by heat derived from the exhaust gases of the engine an electric heating element 42 may be provided in the chamber 27 as shown in Figure 4.

Having thus described our invention what we claim as new and desire to secure by Letters Patent is:

1. A liquid fuel metering apparatus of the shuttle type, comprising the combination with an adjustable stop for limiting the range of the shuttle movements, of an elongated and end-wise movable cam arranged transversely to and supporting the stop, spring-loaded camactuating means responsive to air pressure and con nected to one end of the cam, a pivoted arm forming an abutment against which the other end of the cam bears, and a temperature-responsive device in the form of a bimetal strip by which the pivoted arm is adjustably movable about its pivot axis, and which when cold causes the pivoted arm to assume a position whereby the cam allows abnormal movement of the stop for permitting increase of the normal range of the shuttle movements, the pivoted arm being arranged so that the distance between its pivot axis and the adjacent end of the cam varies with movement of the spring-loaded cam-actuating means.

2. A liquid fuel metering apparatus according to claim 1. and having in combination a chamber which contains the bi-metal strip, and through which heated air can flow, and a valve responsive to the action of the bi-metal strip for controlling the rate of fiow of the heated air through the chamber.

References Cited in the file of this patent UNITED STATES PATENTS 2,126,709 Alden Aug. 16, 1938 2,245,562 Becker June 17, 1941 2,435,902 Reggie Feb. 10, 1948 2,516,147 Robinson July 25, 1950 2,525,635 Bedale et al. Oct. 10, 1950 2,655,907 Downing Oct. 20, 1953 2,731,175 Downing Jan. 17, 1956 2,807,252 Downing Sept. 24, 1957