US3146769A

US3146769A - Fuel injection system

Info

Publication number: US3146769A
Application number: US183872A
Authority: US
Inventors: Leon H Hall
Original assignee: Simmonds Precision Products Inc
Current assignee: Simmonds Precision Products Inc
Priority date: 1962-03-30
Filing date: 1962-03-30
Publication date: 1964-09-01
Anticipated expiration: 1981-09-01

Description

Sept. 1, 1964 Filed March 30, 1962 L. H. HALL FUEL INJECTION SYSTEM 2 Sheets-Sheet 1 INVENTOR L EON H. HA LL.

ATTORNEY Sept. 1, 1964 L. H. HALL 3,146,769

FUEL INJECTION SYSTEM Filed March 30, 1962 2 Sheets-Sheet 2 76 75 l (D r:"--"*-"1 l NH l 74 4 c.

INVENTOR LEON H. HALL ATTORNEY United States Patent 3,146,769 FUEL INJECTION SYSTEM Leon H. Hall, South Burlington, Vt., assignor to Simmonds Precision Products, Inc., Tarrytown, N. a corporation of New York Filed Mar. 30, 1962, Ser. No. 183,872 3 Claims. (Cl. 123-440) This invention relates to improved fuel injection systems.

Fuel injection systems have been used in increasing numbers in recent years with internal combustion engines as a replacement for carburetors. In a great many instances a fuel injection system provides a much better means of delivering an accurate charge of fuel to the cylinders of an internal combustion engine than does a conventional carburetor because of the ability to control more accurately the charge of fuel which is mixed with the air to make up the charge being propelled into the cylinders.

As is known, fuel injection systems are generally designed to be controlled by three variables: speed of the engine, intake manifold pressure and intake manifold temperature. The hydraulic pumping device of a fuel injection system must automatically produce a metered quantity of fuel which is compensated for over a range of variations in speed, pressure and temperature which is to be expected with the type of internal combustion engine employed.

The present fuel injection system being of the speeddensity type is arranged to deliver fuel in accordance with manifold pressure and speed.

One of the objects of the invention is to sense speed and throttle position and to thereby operate a cut-off in the fuel injection pump during overrun conditions.

Still another objectof the invention is to provide an overspeed control to limit maximum engine speed by controlling operation of the fuel injection pump speed.

A further object is the improved method of valving to accomplish cut-off within the fuel injection pump.

Other objects and advantages of the invention will be hereinafter described or will become apparent to those skilled in the art, and the novel features of the invention will be defined in the appended claims.

In the drawings:

FIG. 1 is a horizontal cross-sectional view of the improved pump with the centrifugal switches indicated in block diagram;

FIG. 2 is a diagrammatic view of the pump as electrically connected with the throttle body; and

FIG. 3 is a view on line 33 of FIG. 1.

Referring to FIG. 1, there is illustrated an injector pump provided with a shaft 11 carried within a body 12 and arranged to be driven by the engine at crankshaft speed. The shaft 11 carries a skewed portion 13 which functions as a piston reciprocally supported thereon and keyed thereto by key 14. A well-known bearing ring 15 is carried on the skewed portion 11 and imports a rhythmic wobble motion to the wobble plate 16. A series of fuel plungers 17 reciprocally mounted in plunger block 18 are biased against the wobble plate 16 by means of springs 18'. The skewed portion 13 can be axially displaced to varying degrees along the center line of the shaft 11, while still retaining the phase relationship of each of these elements by key 14. As is known to those skilled in the art, the axial displacement of the skewed portion 13 governs the longitudinal displacement of the wobble plate 16, thus making it possible to vary the stroke of the plungers 17, all in accordance with the fuel charge quantity desired. A stop sleeve 13 which surrounds shaft 11 is interposed between the lower surface of the skewed shaft 13 and a retaining ring 13" on shaft 11 above slide valve 35. By

3,146,759 Patented Sept. 1, 1964 this arrangement of elements the skew shaft 13 will reciprocate Within a limited area on the shaft 11.

At the upper extremity of shaft 11 there is provided an eccentric portion 19 which is arranged to drive a distributor valve 20. The distributor valve 20 has a number of discharge ports 21 formed therethrough which, in a time sequence, are made to correspond with the position of the orifices 22 of the pump chambers 23 within which the plungers 17 are arranged to reciprocate. The sequence of the rotation of the distributor valve 20 is such as to provide an opening between the orifice 22 of a single pump chamber 23 and one of the outlet passages 24 formed in the distributor block 25. The distributor block 25 also is provided with the usual gasoline inlet and outlet ports and an oil inlet port 28. Communication is made between the plunger ports 22 and suitable outlet ports in the distributor block 25 through grooves 29 and communicating port 30 which have been cut in valve 20 as the valve 20 is driven by the eccentric 19. The plungers are filled through ports 29 when the valve 20 uncovers a cylinder port such as shown in FIG. 2.

High pressure oil is arranged to be fed from a pump 30 through passage X to the area around plunger block 18 (chamber A) and then through a three-way solenoid operated valve 31 to the inlet port 28 of the distributor valve block 25. The solenoid operated valve is merely illustrative of one type of valve that is suitable for the purpose intended. Those skilled in the art will recognize that other types of valves can be substituted for this valve and will achieve a similar function. The shaft 11 has an axially extending drilled passage 32 which is in communication with the inlet port 28. That portion of shaft 11 which is provided with the drilled axial passageway 32 is also provided with radial drillings 34, the high pressure oil being prevented from intermingling with the servo pressure oil by the valve 35. It is also to be noted that the slidable sleeve valve 35 is of adequate length to cover the radial drillings 36 which are arranged to communicate with the axially extending passageway for drain purposes provided at 37 in shaft 11. A spring 38 is interposed between a ball bearing race 39 supported by the slidable sleeve valve 35. The chamber C is provided with a sealed capsule 41 which contains suitable dry inert material at sub-atmospheric pressure. The interior of upper capsule 40 is vented to atmosphere through an axial boring 43 in a stud 44 and above the stud 44 is positioned a cap 45 which is threadedly positioned within the body 10 and thereby arranged to preload the capsules 40 and 41. Chamber C is connected to an engine intake manifold by a suitable conduit (not shown) thereby subjecting chamber C, and hence the exterior of capsules 40 and 41, to engine intake manifold pressure. As the engine intake manifold pressure increases the engine fuel requirements also increase thereby requiring a longer pumping stroke. As the pressure in chamber C increases, capsules 40 and 41 thus contract. The resulting movement is transferred to sleeve valve 35 via rocker arm 47 and pin 46. This resulting downward movement of sleeve valve '35 provides an increased exposed area from radial holes 34 to chamber B and a decreased exposed area from radial holes 36 to chamber B. Since high pressure oil is supplied thru passageway 32 and radial holes 34 while passageway 37 and radial holes are subjected to oil drain Thus, it will be seen that spring 38 is used to balance the force on skewed shaft 13 caused by the differential pressure.

In the present system, when cut-off operation is contemplated, a means of reducing the stroke of the plungers 17 to zero in the pump is suitably provided for. With zero plunger stroke, no fuel will be delivered to the engine. Accordingly, high pressure oil is supplied to the injector pump through the passage X indicated in base 12. When it is desired to put the pump 10 into its cut-off stage, the three-way solenoid operated valve 31 is actuated. Upon actuation of the solenoid operated valve 31, the high pressure oil is prevented from being transmitted through the center passageway 32 of the mainshaft 11 to the slide valve 35. In addition, at this time the center passage 32 of the mainshaft 11 is connected to a drain passageway 33 in the three-way valve. This puts the area under the skewed shaft 13 in chamber B under drain pressure. With high pressure oil in chamber A above the skewed shaft 13 and drain pressure of chamber B beneath the lower skirt portion the resulting high differential pressure thus forces skewed shaft 13 downwardly against the stop collar 13 as shown in FIG. 1. This stop collar is arranged to locate the skewed shaft 13 in a position so that the plunger stroke is zero which is necessary to prevent the nozzles (not shown) from being evacuated thereby causing a slow recovery from cut-off.

Further, with regard to the operation of the injection system, see the diagrammatic view of FIG. 2. The throttle body located at 70 is provided with a butterfly valve operated by shaft 71 and a depending lever 72, which cooperates with a microswitch 73. The microswitch 73 is utilized to sense the throttle position by closing when the throttle is closed. It is to be understood from this that the microswitch 73 will open with only a very slight amount of throttle opening.

Centrifugal switches

74 and 75 are electrically connected to microswitch 73, three-way solenoid operated valve 31, and the vehicles electrical system as shown in FIG. 2. Two centrifugal switches, 74 and 75 are provided at the top of distributor block 25 and are suitably attached to shaft 76. Shaft 76 is driven by shaft 11 through a tang and slot type connection. Therefore,

centrifugal switches

74 and 75 are rotated by the engine. This type of centrifugal switch is covered by US. Patent No. 2,616,682, issued November 4, 1952, to Joseph Greenhut and entitled Centrifugal Speed Responsive Device with Spring Support.

Overrun Operation During overrun, since the engine is not delivering power, it is desirable to stop all fuel flow to the engine to improve operating economy and reduce unburned hydrocarbons in the exhaust gases. Centrifugal switch 74 is designed to close contacts 74' above approximately 1200 rpm. and open again below about 1000 rpm. To those skilled in the art, it can be seen that this switch will be closed during overrun. As previously stated, the microswitch 73 will be closed during closed throttle operation. From this it will be noted that during everrun, microswitch 73 as well as the contacts 74 of centrifugal switch 74 will both be closed. Referring to FIG. 2, it can be seen that current will flow from the vehicles battery D through three-way solenoid operated valve 31, microswitch 73, contacts 74' to the vehicles ground connection, thereby actuating the three-way sole- 1 The definition of overrun as applied to this application is When vehicle momentum is sufiicient to propel the vehicle at the desired rate of speed, or greater, with the throttle closed. At such a condition, the engine speed will be greater than the idle speed, and as stated, the throttle will be closed. This condition can exist when the vehicle is descending a grade or is decelerating for a stop.

noid operated valve 31. When the three-Way solenoid operated valve 31 is actuated, the fuel flow will be stopped as previously explained. If either the engine speed drops below about 1000 rpm. or the throttle is opened, the electrical circuit is broken; thereby allowing the fuel injection pump 10 to deliver fuel according to the normal parameters.

Over-speed Operation It is possible to limit the maximum speed that the engine may attain by stopping the fuel fiow to the engine. Again, referring to FIG. 2, this can be accomplished as follows: Centrifugal switch is designed to close contacts 75' at the maximum permissible engine speed. It is also designed to reopen again when the speed drops slightly below the speed at which it is set to close. When the engine speed reaches the contact closing speed of centrifugal switch 75, current from the vehicles battery will flow through three-way solenoid operated valve 31 and the contacts of switch 75' to the vehicles ground connection, thereby actuating three-way solenoid operated valve 31. As explained earlier, when the three-way solenoid operated valve 31 is actuated, the fuel flow to the engine will be interrupted. When fuel flow to the engine is terminated, the engine is thus prevented from increasing in speed. When the engine speed drops slightly below the closing point of centrifugal switch 75, the contacts of switch 75' will reopen, thereby allowing the fuel injection pump 10 to deliver fuel according to the normal parameters.

Although but one embodiment of the invention has been depicted and described, it will be apparent that this embodiment is illustrative in nature and that a number of modifications in the apparatus and variations in its end use may be effected without departing from the spirit or scope of the invention as defined in the appended claims.

I claim:

1. In a fuel injection system for internal combustion engines including an engine, an intake manifold positioned thereon, a throttle body having air throttle means secured to said manifold, first switch means carried by said throttle body and arranged to be actuated by said air throttle means, a hydraulic fuel pump including fuel supply means provided with a housing associated with said engine and said throttle body, solenoid operated valve means for controlling said fuel supply means mounted on said housing, said valve means being arranged to cut off the fuel supply when the solenoid is energized, and two speed responsive switch means on said housing, said solenoid'valve being arranged to be energized by one of said switches at a predetermined speed and by the other of said switch means at a different prcdeterr'nine'd speed, when the throttle means is closed.

2. In a fuel injection system for internal combustion engines as claimed in claim 1, wherein the output of said hydraulic fuel pump means is controlled by capsule-like sensing means subjected to the influence of varying pressure in the intake manifold.

3. In a fuel injection system for internal combustion engines as claimed in claim 1, wherein the first switch means is manually actuated.

References Cited in the file of this patent UNITED STATES PATENTS 2,588,522 Harris Mar. 11, 1952 2,856,910 Goodridge Oct. 11, 1958 2,950,706 Senckel Aug. 30, 1960 FOREIGN PATENTS 311,643 Great Britain May 16, 1929

Claims

1. IN A FUEL INJECTION SYSTEM FOR INTERNAL COMBUSTION ENGINES INCLUDING AN ENGINE, AN INTAKE MANIFOLD POSITIONED THEREON, A THROTTLE BODY HAVING AIR THROTTLE MEANS SECURED TO SAID MANIFOLD, FIRST SWITCH MEANS CARRIED BY SAID THROTTLE BODY AND ARRANGED TO BE ACTUATED BY SAID AIR THROTTLE MEANS, A HYDRAULIC FUEL PUMP INCLUDING FUEL SUPPLY MEANS PROVIDED WITH A HOUSING ASSOCIATED WITH SAID ENGINE AND SAID THROTTLE BODY, SOLENOID OPERATED VALVE MEANS FOR CONTROLLING SAID FUEL SUPPLY MEANS MOUNTED ON SAID HOUSING, SAID VALVE MEANS BEING ARRANGED TO CUT OFF THE FUEL SUPPLY WHEN THE SOLENOID IS ENERGIZED, AND TWO SPEED RESPONSIVE SWITCH MEANS ON SAID HOUSING, SAID SOLENOID VALVE BEING ARRANGED TO BE ENERGIZED BY ONE OF SAID SWITCHES AT A PREDETERMINED SPEED AND BY THE OTHER OF SAID SWITCH MEANS AT A DIFFERENT PREDETERMINED SPEED, WHEN THE THROTTLE MEANS IS CLOSED.