US2063087A

US2063087A - Automatic primer for internal combustion engines

Info

Publication number: US2063087A
Application number: US715133A
Authority: US
Inventors: Gerald John W Fitz
Original assignee: Briggs and Stratton Corp
Current assignee: Briggs and Stratton Corp
Priority date: 1934-03-12
Filing date: 1934-03-12
Publication date: 1936-12-08
Anticipated expiration: 1953-12-08

Description

1 J. w. FlTZ GERALD 2,063,037

AUTOMATIC PRIMER FOR INTERNAL COMBUSTION ENGINES Filed March 12, 1934 2 Sheets-Sheet 1 mmM z JZ/fin MEXIZEFFE/H Dec. 8, 1936. J. w. FlTZ GERALD 2,063,087

\ AUTOMATIC PRIMER FOR INTERNAL COMBUSTION ENGINES Filed'March 12, 1954 2 Sheets-Sheet 2 2 IMWM Patented Dec. 8, 1936 UNITED STATES PATENT OFFICE AUTOMATIC PRIMER FOR INTERNAL COMBUSTION ENGINES Application March 12, 1934, Serial No. 715,133

9 Claims.

This invention relates to new and useful improvements in primers for internal combustion engines and has as an object to provide an automaticthermally controlled priming device par- 5' ticularly adaptable for automotive vehicle engines. Another object of this invention is to provide an automatic priming device wherein a valve biasedto open position and closed by engine suc- 10 tion, has its opening and closing movements directly controlled by temperature actuated means.

And a further object of this invention is to provide an automatic priming device of the character described, which is extremely simple in conll;v struction and positive in operation.

With the above and other objects in view which will appear as the description proceeds, my invention resides in the novel construction, combinatio n and arrangement of parts substantially go as hereinafter described and more particularly defined by the appended claims, it being understood that such changes in the precise embodiment of the hereindisclosed invention may be made as come within the scope of the claims. 5 In the accompanying drawings, I have illustrated one complete example of the physical embodiment of my invention constructed according to the best mode I have so far devised for the practical application of the principles thereof, and 30 in which:

Figure 1 illustrates part of the carburetor and manifolds of an internal combustion engine showing the application of this invention thereto;

Figure 2 is an enlarged side view of the primer 35 showing the position of the thermal control members at cold temperatures;

Figure 3 is a longitudinal section view taken through Figure 2 on the plane of the line 3-3;

Figure 4 is a cross section view taken through 40 Figure 3 on the plane of the line |-4; and

Figure 5 is a side view similar to ,Figure 2, showing the thermal control membersin their opposite positions towards which they move in response to higher temperatures;

45 Referring now more particularly to the ac.- companying drawings in which like numerals indicate like parts throughout the several views,

the numeral 5 designates the carburetor of an internal combustion engine supplied with fuel erally by the numeral 1, which, as is customary, has a portion thereof juxtapose the exhaust manifold 8..

In accordance with this invention, an auby a supply line 6. The outlet of the carburetor connects with an intake manifold indicated gentoinatic priming device, indicated generally by the numeral 9, and mounted in the region of the exhaust manifold, provides a controlled communication between the supply line 6, through ducts l and H directly to' the intake manifold, as clearly shown in Figure l.

When the engine is cold, as during the starting cycle, the priming device permits a direct communication between the supply line 6 and the intake manifold so that fuel may be drawn di- 10 rectly into the manifold. Upon increase in suction in the intake manifold produced by the engine in operation, the communication between the supply line 6 and the manifold is closed a degree dependent upon the temperature of the 16 engine.

To this end, the priming device comprises a body l2 having an inlet l4 and an outlet I6 with which the ducts l0 and II respectively, connect. Leading from the inlet I4 is a small diameter 20 bore l3. At a medial point in the length of the body I2, the bore I3 is abruptly increased in diameter to afford a larger diameter bore IS with which the outlet l6 communicates through a lateral bore IS. The outer end of the bore I5 is further'abruptly enlarged to provide a comparatively large diameter bore H, which opens to the adjacentpnd of the body to be closed by a head l8.

The'bor'es l3, l5 and I6 provide a fuel passage through the body and the bore I1 affords a cylinder within which a piston I9 is slidably disposed.

The piston I9 is fixed to the stem 20 of a needle valve 2|, arranged with its point projecting into the bore l3 to completely close the fuel passage.

The valve stem 20 is slidably passed through the head I8 to project therebeyond for a purpose to be hereinafter described.

Encircling the stem between the piston and the bottom of the bore I1 is a' compression spring 4 22, which yieldably tends to hold the needle valve open. The action of the spring is opposed by the suction of the engine created within the intake manifold and acting upon, the piston l9. To insure communication between the outlet port I6 and the bore or cylinder H, the inner end of the valve stem is polygonal-in cross section, as clearly shown in Figure 4, and to allow free response on the part of the piston to the effects of suction, the head l8 has a plurality of air bleeds 23.

Hence, it will be seen that when the engine is stationary or when it isoperating under such conditions that the suction created thereby is insuflicient to overcome the force of the spring 22,

the need e valve 2| will be held open, permitting fuel to be drawn directly from the supply line 8 into the intake manifold, ,but when the eifect of suction is increased, its-action upon the piston l9 overcomes the spring 22 and closes the needle valve 2| to close the fuel passage and shut off the admission of fuel to the intake manifold.

The admission of the priming fuel to the engine isffurther controlled by means responsive to variations in the ambient temperature. This means comprises two

thermal elements

24 and 25, both preferably formed-of strips of bi-metal anchored at one end to the body I 2 as at 26 and 21 respectively, to overlie opposite sides thereof with their free ends projecting'beyond the adjacent end of the body.

Each of the thermal elements .at its free end carries an adjustable stop, the stop 28, which is carried by the member 24 having a rounded nose 29 and the stop 30, which is carried by the member having a square inner end 3|. These .stops are directed inwardly toward each other to engage a disc 32, adjustably'flxed on the extended end of the valve stem. The inner face of this disc is-stepped as at 33, and the outer face thereof is inclined to provide a substantially conical surface 34.

When the engine'is 061d, as during an mamaw starting cycle, the

thermal elements

24 and 25 are flexed to their positions illustrated in Figure 2. At such prevailing temperatures, the member 24 holds the stop 23 entirely away from the disc 32, but the member 25 holds its stop toward the axis of the valve stem engaging its inner end 3| with the stepped inner face 33 of the disc, it being understood that the valve stem'is held outwardly under such conditions by the spring 22. Consequently, the valve-will be held against closing in response to the efl'ect of suction on the piston l9 until the. ambient temperature has raised willciently to move the thermal-control element 25 outwardly to disengage the end 3| of its stop 3.

from the steps of the disc 32 with which it is engaged.

close the needle valve thus progresses step by step as determined by the response of the thermal .elemeat 25 to the rising ambient temperature. Concomitantly with the movement of the member 25 to carry its stop away from the disc 32, the thermal element 24 moves its stop 23 inwardly to dle valve is precluded even though thesuction of the engine may drop to an extent which normally 'would permit the spring 22 to function. Obviously, as the ambient temperature. drops, the. reverse procedure on the part of the

thermal control elements

24 and 25 takes place. 1

As the free end of the control element 24 moves outwardly,'can'y ing its stop 23 toward the outer periphery of the conical surface 34 of the disc 32, the spring 22 forces the valve 'stem 20 outwardly to maintain the conical surface 34 in engagement with the rounded nose 23 of the stop 28. During this time, the thermal control element The inward movement of the valve stem to The engagement'of the stop with the stepped portion of the member 32, however, does not affect the outward projection of the valve stem by its spring 22 as the frictional engagement between the end of the stop and the stepped portion of the disc is insuiiicient to oppose the action of the spring 22. Consequently, the valve stem moves outwardly at a rate determined by the outward flexure of the control element 24', until the element 24 is moved a distance suilicient to disengage its stop 23 from the disc, whereupon the spring 22 is free to move the valve stem to its outermost position at which the needle valve 2| is entirely open.

It is to be understood that while in Figure 1 the exhaust manifold, it may be located adjacent any other part of the engine which is subject to variation in temperature as is required for proper operation of the device.

valve to openposition, a valve stem for the valve having. a part projecting to the exterior of the body, engine suction operated means within the body and connected with said valve stem to claw the valve, and temperature responsive means mounted on the exterior of the body and operably associated with the valve stem to regulate the opening vof the valve by its yieldable urging means in accordance with temperature changes in the region inwhich said body a m'olmted and to prevent closing of the valve'by engine suction until a predetermined ambient temperature has been reachedat said region. Y

2. In an automatic priming device of the character described comprising a body having a fuel passage therethrough, a valve operable within the body to close said passage and to control the admission of fuel into the engine, a valve stem movable with the valve, a spring yieldingly urging the valve open," a piston connected to the stem and operating in' a. .cylinder formed in the body, said cylinder being communicated with a. source of engine suction so that the piston is ve to engine suction; to close the valve against the action of the spring, and temperature actuated means operable on the stem in accordance with priming device is shown in the region of the temperature variations of the engine parts adjacent the device for controlling the opening of the valve-by its-yieldable urging means and for preventing the closing of the valve by the response ofsaid piston to engine suction until a predetermined ambient temperature has been reached. r

3. An automatic priming device of the character. described including a valve for controlling the admission'of fuel to the engine, a spring to yieldably urge the valve open, engine suction responsive means to close the valve against the changes thereat, and a member connected with 7 aoeaoar the valve and engageable by parts carried by said thermal elements.

4. An automatic priming device of the char acter described comprising, a valve to control the admission of fuel to an engine, a spring to yieldably urge the valve open, engine suction actuated means to close the valve against the action of said means,'and temperature actuated means to control the closing and opening of the valve comprising a member movable with the valve and having surfaces at varying distances from the valve, and thermal elements having, stops engageable with said surfaces and movable in' opposite directions across said surfaces in response to temperature changes thereat.

5. An automatic priming device of the character described comprising a valve to control the admission of fuel to an engine, means to yieldably urge the valve open, means responsive to a condition of the engine to close the valve, and temperature actuated means to control the opening.

and closing of the valve comprising a member connected with -the valve to be movable therewith and opposite surfaces each of which has portions at different distances from the valve, and thermal elements having stops to engagesaid surfaces, engagement between the stop of one thermal element and its respective surface of said member limiting the movement of said member in one direction and engagement between the stop of the other thermal element and its respective surface of said member limiting the movement of said member in the opposite direction so that the opening and closing movements of the valve are limited to distances determined by the degree the spring, and temperature actuated means to. control the closing and opening of the .valve comprising, a member movable with the valve andhaving opposite surfaces with portions at pro-"' gressively different distances from the valve, bi-

metallic strips anchored at one end with their free ends disposed adjacent said "last designated member and at opposite sides thereof, stops carried by thefree ends of said bi-metallic strips to engage the opposite surfaces of said'member to limit the mdv'ement of said-member and consequently the valve to distances determined by the amount of engagement of said stops with the sur-' faces, and said bi-metallic strips moving in opposite directions in response to temperature changes thereatr 77,. An automatic priming device of the charac-' ter described comprising a body having a fuel passage connectable with a source of fuel and a source of engine suction and having a cylinder bore in communication with said passage, a valve said strip to close said passage andcontrol the admission of fuel to the engine, a stem on the valve extending through the cylinder bore to the exterior of the body, a spring to yieldably urge the valve open, a piston on said'stem operating in said cylinder bore and responsive to engine suction to close the valve, a member mounted on said stem exteriorly of the body and having opposite faces with portions 'at different distances from the valve, and temperature actuated means having 10 stops to engage said surface portions of said member to control the opening and closing of the valve in accordance with changes in temperature at said temperature responsive means.

8. An automatic priming device of the charac- 15 terdescribed comprising a body having a fuel passage connectable witha source of fuel and a source of engine suction and having a cylinder bore in communication with said passage, a valve to close said passage and control the admission 20 of fuel to the engine, a stem on the valve extending through the cylinder bore to the exterior of the body, a spring to yieldably urge the valve open, a piston on said stem' operating in said, cylinder bore-and responsive to engine suction to 25 close the'valve, a member mounted on said stem exte'riorly of the body and having opposite faces with portions at different distances from the valve, a pair of bi-metallic strips anchored at one end to said body with their free, end portions dis- 30 posed at opposite sides of said member, and stops valve in accordance with temperature conditions 35 at said bi-metallic strips.

9. An automatic priming device of the character described comprising a body having a fuel passage therethrough connectable with a fuel supply and a part of an engine subject to engine 40 suction and having a cylinder bore in communi- V cation with said passage, a valve in the body to close said passage and control the admission of fuel to said engine part, a spring yieldably urging the valve open, a stem on the valve projecting to 45 the exterior of said body and passing through said cylinder bore, a piston on said stem operat-l ing in said cylinder and responsive to engine suction to close the valve, a member on said stem exteriorly of the body and having one face'thereof stepped and its other face inclined, a'pair-of bi metallic strips anchored to said'body with theirfree ends arranged at opposite sides 'of id disc, and stops carried by the free end no tions of said strips, one of said stops being engageable 55 with the stepped surface of the disc to limit the closing movement of the valve in accordance with flexure of'said strip in response to temperature risesand' the stop of the other bi-metallic strip being engageable with the inclinedsurface of the disc to, limit the opening movement of the valve. to distances determined by the temperature at JOHN w. m GERALD.