US2190348A

US2190348A - Starting system for compression ignition engines

Info

Publication number: US2190348A
Application number: US211622A
Authority: US
Inventors: Abel W Bach
Original assignee: International Harverster Corp
Current assignee: Navistar Inc
Priority date: 1938-06-03
Filing date: 1938-06-03
Publication date: 1940-02-13
Anticipated expiration: 1957-02-13

Description

Feb. 13, 1940. A. w. BACH 2,190,348

STARTING SYSTEM FOR COMPRESSIONIGNITION ENGINES Filed June 3, 195a 2 Sheets-Sheet 1 Feb. 13, 1940. A. w. BACH 2,1905348 STARTING SYSTEM FOR COMPRESSION IGNITION ENGINES Fil ed June 3, 1938 2 Sheets-Sheet 2 I II- 7200150? Patented Feb. 13 1944) PATENT OFFICE STARTING SYSTEM FOR COMPRESSION IGNITION ENGINES and w. Bach, Chicago, 111., assignor to Intcrnational Harvester Company, a corporation of New Jersey Application June 3, 1938, Serial'No. 211,622

3 Claims.

' This invention relates to a Starting system for compression ignition engines. More specifically, it relates to a construction in which a fuel, pump is utilized to supply a heavy fuel for operation 6 on the Diesel cycle or a volatile fuel for operaw of auxiliary combustion chambers whereby the engines may be operated on a volatile fuel with spark ignition. It is to a starting system of this type that the present invention relates. I

The principal object of the present invention $0 is to use a fuel injection pump normally operative to supply a heavy fuel for operation on the Diesel cycle with compression ignition for supplying a volatile fuel during a starting period of operation on low compression with spark ignition. 25 A secondary object is to interconnect the controls for shifting from low to high compression for cutting out the supply of volatile fuel and for changing the supply point of the fuel from the regular injection nozzle to the auxiliary combus 0 tion chamber.

Other more specific objects, such as the arrangement and actuation of the various valves and control mechanisms will be apparent from the detailed description to follow.

35 In the drawings,

Figure 1 is an end view of an engine incorporating the-invention with the cylinder head and the upper portion of the cylinder shown in section;

Figure 2 is an enlarged sectional view taken on a transverse vertical plane through the top of the fuel pump shown in elevation in Figure 1; and,

Figure 3 is a section taken on the line 33 of Figure 2.

In the drawings, an engine block III isshown broken away at the top by a vertical transverse section to show a cylinder liner II and a piston l2. A cylinder head I3 of a conventional construction is mounted on the top of the block I0. A space between the top of the piston l2 and the cylinder head forms a combustion chamber 14 for operation on the Diesel cycle. -A precombustion cup assembly I5 is mounted in the cylinder head. A precombustion chamber it, formed in said assembly, is provided with an outlet passage [1 (01. 123-182) V 1 which communicates with the combustion chamber l4.

.A fuel supply line I! communicates with a conduit l9 extending through the precombustion cup assembly to the precombustion chamber It.

A discharge valve 28 controls the discharge of fuel into the precombustion chamber I6. Said valve is held in seated position by a spring 2l until the pressure in the line has reached the de- 4 sired pressure. In any nomle, this pressure must m be sufficient to discharge against the pressure existing in the precombustion chamber It. 'The nozzle and precombustion chamber construction have been shown somewhat diagrammatically and have been only briefly described. This construction is conventional and may .be of any known type. V

A fuel pump casing 22 is mounted on a bracket 23 at the side of the engine block ID. A head member 24, mounted on the pump casing 22, supports the cylinders of the pump and contains all 'of the valve mechanism'which regulates actuation of the pump. a

Referring to Figure 2, a pump cylinder 25 isformed with a flanged top portion 26, which fits 25 in the bottom of a vertical bore 21 formed in the member 24. An-injecting piston 28 is mounted for reciprocation in the cylinder 25, being op erated in timed relation withthe engine crank shaft by any suitable mechanism. A valve cage 29 is mounted in the bore 21. Said cage is formed with a passage 30 communicating with a conduit 3|, which supplies fuel to the injection pump. The member 29 is formed with a discharge opening 32, which is controlled by a spring pressed 3:;

discharge valve 33. Said valve controls delivery of fuel to a discharge passage 34, which communicates through a fitting with the discharge conduit l8, previously described.

An inlet chamber 36 is formed in the member 4 24, with which the passage 3| communicates.

: Said chamber is in communication with a Diesel fuel supply reservoir 31 formed at the top of the member 24 by a cover 38. The communication is formed by a threaded fitting, a sleeve 41:, 5

and a valve cage 4| A valve 42 is fitted at the lower end of the cage 4|, permitting the intake of fuel under suction on the intake stroke of the piston 28. The valve 42 is maintained in closed position during the discharge stroke of the piston 4 by a spring 43.

Fuel is supplied to the reservoir 31 by a conduit 44. A valve 45, operable to cut off the supply of fuel through the conduit 44 is operable by a lever 48 connected thereto.

Means are also provided for supplying a more readily volatile fuel to the supply chamber 36. Said means consists of a fitting 41 having a central opening therethrough. Flow of fuel through said opening is controlled by a valve 48, the stem of which extends outwardly and carries at the outer end an abutment disk 49. A spring 58, fitted at one end against the fitting 41 and at the other end against the disk 49, acts to normally maintaimthe valve 48 in closed position.

A cup-like member 5| is fitted against the side wall of the member 24 to "form a fuel supply chamber around the fitting 41. A fuel supply conduit 52 is connected with the member 5| to supply a readily ignitible fuel thereto.

A pivot pin 53 connected to an operating lever 54 extends into the member 5| and carries within said member a lever arm in the form of a spring 55. Said spring has a' curved end portion fitted between the outer end of the spring 58 and the inner end of the disk 49. By operating the lever 54, tension may be relieved on the spring 58 whereby fuel will be drawn from the conduit 52 rather than from the heavy oil supply reservoir 31.

The lever arm 54 is connected by a link 56 with the lever arm 46,- previously described. Said arm is in turn connected by a link 51 with a lever arm 58 mounted on a rock-shaft 59. Said rock-shaft extends transversely across the engine, being rotatably mounted in suitable bearings. As will be noted, the, shaft is mounted in an extension member 68 mounted at the top of the cylinder head l3. The shaft 59 also carries at its outer end an operating lever 6|, by means of which the operator may manually shift from operation on the Otto cycle to operation on the Diesel cycle. The -mechanism for this shaft has not been shown in detail as it is old in the art, as shown in the Johnston Patent No. 2,032,755 of March 3, 1936.

In order to lower the compression, the shaft 59 carries a spiral worm 62, which engages the teeth of a worm gear 63 mounted on a longitudinally arranged shaft 64. Said shaft carries a cam 65 operable to engage the top end of a valve stem 66. Said valve stem is slidably mounted in a guide 61 extending into an auxiliary compression chamber 68 formed in the cylinder head. Said chamber communicates with the combustion chamber l4 by means of an opening 69. The valve stem 66 carries a valve 18 operable to open and'close the passage 69, whereby the compression'ratio of the engine may be altered.

A spark-plug 1| is mounted in the auxiliary compression chamber 68. Means have not been shown for supplying current to the spark-plug 1|, as any conventional timing mechanism may be employed.

An auxiliary injection nozzle assembly 12 is mounted in the wall of the auxiliary chamber 68 for supplying, a fuel thereto, which is readily ignitib'le by spark ignition means. A conduit 13 is connected with the nozzle assembly and with a conduit 14, communicating by means of a second conduit 15, both formed in the precombustion chamber assembly, with the Diesel fuel supply conduit. IS. A valve 16 is positioned to control the flow of fuel through the conduit 15. The stem of said valve extends-outwardly through a fitting 11, being normally maintained in closed position by a spring 18.

A lever arm 19, pivotally mounted on a bracket 88, is engageable with the stem of the valve 16 to open said valve for the fiow of fuel to the conduit 14 during the starting period. The lever arm 19 is connected to the change-over linkage by means of a lever arm 8| and a link 82, whereby the valve 16 will be opened when the shift in fuel supply and compression ratio is made.

The drawings show the engine in condition for operation on the Diesel cycle with the injection of heavy fuel by the fuel pump and firing of the fuel charge by compression ignition. The shift will now be described for putting the engine in condition for starting on low compression with spark ignition.

The operating lever 6| is moved to rotate the shaft 59. By rotationof the shaft in the direction indicated by the arrow in Figure 1, the cam 65 moves downwardly, opening the valve 18 and putting the auxiliary compression chamber 68 in communication with the combustion chamber l4, thereby lowering the compression ratio of the engine to a point where it can be manually cranked. When the shaft 59 is rotated, the lever arm 58 moves downwardly simultaneously, moving the

lever arms

46 and 54 downwardly. By these actuating means, the valve 45 is closed, cutting ofi' the supply of heavy oil to the reservoir. Simultaneously, tension on the spring 58 is reduced, permitting opening of the valve 48 upon suction created by the intake stroke of the piston 28. It will be understood that, with the valves in this position, the more readily volatized and ignitible fuel supplied through the conduit 52 will be delivered by the injection pump through the discharge conduit |8. In connection with the description of this invention, only a single cylinder has been considered. It will be understood that the injection pump 22 would function the same for a multiple cylinder engine, there being an independent injection piston for each cylinder of the engine.

When the lever 46 is moved downwardly in the shift for starting, the link 82 operates to move the lever 19 inwardly, thereby opening the valve 16. As the injection valve 28 of the Diesel fuel supply system is held by the spring 2| to open only upon a high pressure in the fuel supply I line, and as the injection nozzle 12 is constructed to open upon a relatively low pressure in the injection line, opening of the valve 16 by-passes the fuel from the injection nozzle leading into the precombustion chamber l6 to the nozzle assembly 12, delivering into the auxiliary compression chamber. The fuel delivered to said chamber is ignited by the spark-plug 1| fired in timed relation with respect to the stroke of the engine piston l2.

By the means above described, the engine is I converted to the Otto cycle and the Diesel supply pump is utilizedto supply the fuel for operation on lower compression with spark ignition. The shift to Diesel operation is made when the engine has been warmed up sufficiently and has attained the speed of rotation sufiicient to ro-- all modifications falling within the scope of the appended claims.

What is claimed is:

1. In combination, an engine having a main combustion chamber and a first valve for admitting heavy fiuid for normal compression ignition, and an auxiliary combustion chamber adapted to be connected'with the main'combustion chamher on starting and a second valve for admitting a. volatile starting fluid for lower compression and spark ignition, a pump connected with both valves and having a single plunger functioning to supply the proper fluid to the two valves, and means for connecting the auxiliary combustion chamber with the main combustion chamber and for causing the pump to supply volatile starting fluid to the second valve.

, 2. In combination, an engine adapted to operate normally on heavy fuel andhaving a first valve for admitting heavy fuel and a second valve for admitting a slight fuel, a pump having a single plunger for feeding light and heavy fuels, a first conduit connecting the pump and the first valve, a second conduit connecting the first 0on duit and the second valve, valve means for closing off the second conduit, sources of heavy and combustion chamber with a valve for admittingheavy fuel and an auxiliary combustion chamber adapted to be connected with the main combustion chamber for starting and having a valve therein for admitting light starting fuel, a pump having a single plunger for feeding light and heavy fuels, a first conduit connecting the pump and the first valve, a second conduit connecting the first conduit and the second valve, valve means for closing off the second conduit from the first conduit, sources of heavy and light fuels connectable with the pump, and means for simultaneously connecting the auxiliary and main combustion chambers, for opening the valve means connecting'the first and second conduits, and for connecting the pump with the source of light fuel.

ABEL W. BACK.