US2040253A - Automatic primer for internal combustion engines - Google Patents

Description

May 12, 1936. J. w. FITZ GERALD 2,040,253

AUTOMATIC PRIMER FOR INTERNAL COMBUSTION ENQINES Filed Marh 12, 1934 2 Sheets-Sheet 1 L/Zvhn IKE/2575b May 12, 1936. 1.1. w. FITZ GERALD 2,040,253

AUTOMATIC PRIMER FOR INTERNAL COMBUSTION ENGINES Filed March 12, 1934 2 Sheets-Sheet 2 32 Z8- Z9 r V I7 1 I a 1 3O 4/ 38 5 I5 7/0 3 MIC 37 i 35 36 Z0 22 I8 Ij i 4 o 4 w //G 1/ 5'0 28 3? I9 25 2/ m o Z0 F r L Z7/727 W E/gEPi/d 1%: 5* ea 35 6263922 X Q Patented May 12, 1936 UNITED STATES AUTOMATIC PRIMER FOR INTERNAL COMBUSTION ENGINES John w. Fitz Gerald, Milwaukee, will, assignor to Briggs & Stratton Corporation, Milwaukee, Wis., a corporation of Delaware Application March 12, 1934, Serial No. 715,136

6 Claims. (01. 123-1875) This invention relates to new and useful improvements in automatic primers for internal combustion engines, and has as an object to provide an automatic priming device which is controlled jointly by engine suction, and the thermal condition of the engine.

Another object of this invention is to provide a priming device of the character described in which the admission of priming fuel to the englue is controlled by two independent-valves, one controlled jointly by engine suction and temperature variations, and the other controlled solely by temperature changes.

A further object of this invention is to provide a priming device of the character described,

defined by the appended claims, it being-understood that such changes in the precise embodiment oi the hereindisclosed invention may be made as come within the scope of the claims.

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 in which: v

Figure 1 is an elevation view showing part of a carburetor and the manifolds of an internal combustion engine, and illustrating the application of this invention thereto;

Figure 2 is a side elevation view of the priming device per se;

Figure 3 is a'longitudinal section view through Figure 2 on the plane of the line 3-8;

Figure 4 is a section view taken through Figure 3 on the plane of the line 5-4; and- Figure 5 is a section view similar to Figure 3, but illustrating the valves in difierent positions.

Referring now more particularly to theaccompanying 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 by asupply line 5 and conducting a combustible mixture to an intake manifold! through a riser 8. As is customary, an exhaust manifold 9 is located in juxtaposition to the intake manifold.

The primer, indicated generally by the numeral ID, has an inlet ll connected to the supply line 8 by a pipe l2 and an outlet l3 connected by a pipe I to the intake manifold to afford a direct communication between the supply line and the manifold under certain conditions.

As best shown in Figures-3 and 4, the inlet ll leads to a transverse bore K5 in the body l6 of the device with which two lateral bores I1 and t8 communicate. Intermediate the length of the body IS, the bores l1 and 18 are counter- 10 bored as at l9 and, respectively, to define abrupt shoulders forming valve seats 2| and 22, respectively.

Adjacent the valve seats, both bores I l and I8 communicate with a cross bore 23, the opposite ends of which are closed by plugs. At a medial point, the bore is connected with the outlet 13 through 'a bore 24.

The several bores formed in the body provide two separate fuel passages from the inlet II to the outlet l3. These passages are independently closed by needle valve members and 26 operating in the bores l9 and 20 for cooperation with 'the valve seats 2! and 22, respectively.

The valve member 25 is controlled entirely 25 thermostatically. Its outer end projects through a pocket 21 formed as a counterbore to the bore 7 l9, and has a stop flange 28 fixed thereto, be-

and its other end bifurcated to engage in an annular groove 32 in a head 33 fixed to the extreme outer end of the stem of the valve member 25.

The disposition of the metals of the thermostatic member 30 is such that when the ambient temperature is cold, the valve member is permittedto be moved to open position by its spring 29, as shown in Figure 3, but as the temperature rises, the thermostat 3B flexes and brings its free end in toward the body it to gradually close the valve member 25 against the action of the spring 29.

The stem 31 of the other valve member 26' extends outwardly through a bore 35, which forms a cylinder for a piston 36 secured to the stem. The outer end of the stem 31 is slidable in a hole through a plug 38, which closes the end of the cylinder bore 35. Air bleeds 38' through the plug, permit the piston 36 to respondto suction created within the cylinder bore through its communication with the intake manifold I.

To insure such communication between the cylinder bore and the manifold, the inner end 39 of the valve stem is polygonal in cross section to at all times afford communication between the cylinder bore 35 and the cross bore 23, which, as hereinbefore noted, is in constant communication with the intake manifold.

The extreme outer end of the valve stem 31 has an annular groove 40 with which the bifurcated end of a second bi-metallic U-shaped strip 4| engages. The opposite end of the strip 6| is anchored to the body "5 by securing means 42.

The spring tension of the thermostatic strip 4| is sufiioiently light to permit engine suction acting upon the piston 36 to move the valve member 26 to closed position just as soon as the engine becomes operative, but in the absence of main open to admit the maximum volume of auxiliary or priming fuel to the intake manifold.-

Just as soon as the enginebecomes operative under its own power, the suction builds up to a point suflicient to move the valve member to closed position against the spring tension of the thermostat 4|, by itsaction upon the piston 36. The volume of priming fuel flowing to the intake manifold is thus materially reduced.

'I'hevalve member 25, however, does not close at this time, but remains in open position until the temperature of the engine rises sufficiently to flex the thermostatic strip 30 by reason of its proximity to the exhaust manifold, toward the body of the priming device sufiiciently' to overcome the spring 29 and move the valve member 25 to closed position.

While the valve member 25 is being moved to closed position by its thermostatic strip 30, the thermostatic strip 4| is also being flexed by the temperature rise to force its free end in toward the, body I6 01 the device so that if after the engine is operating properly and normal operating temperature has been reached, and the effective suction of the engine is momentarily decreased as by suddenly opening the throttle, the valve member 26 will not be moved, being held in closed position by its thermostat 40.

. Obviously, when the engine cools off, after'being stopped, both valve members will again resume their open positions. I

From the foregoing description taken in connection with the accompanying drawings, it will be readily apparent to those skilled in :the art to .which this invention appertains, that this invention aii'ords a novel and extremely simple, fully automaticpriming device for internal combustion engines and that an exceptionally fine and even control of the supply of primingfuel to the engine, is had at all times. A

What I claim as my invention is:

1. In combination with an internal combustion engine, an automatic priming device comprising means providing a plurality of fuel passages connected in parallel forconducting fuel to the engine, valves in said passages for controlling the admission of fuel to the engine, engine suction responsive means for closing one of said valves, thermostatic means for opposing said engine suction responsive means and operable to hold said valve open when the ambient temperature is low and in the absence of engine suction and to hold the valve closed when the ambient temperature is high even though engine suction ceases, a spring for yieldably opening the other valve, and thermostatic means opposing said spring and tending to close said second designated valve as the ambient temperature rises.

2. In combination with an internal combustion engine, an automatic priming device comprising means providing a plurality of passages connested in parallel and adapted to'jointly supply fuel to the engine, valves in said passages for jointly controlling the admission of fuel to the engine, engine suction responsive means for closing one of the valves, temperature actuated means for opposing the suction responsive means and for holding said valve open until a predetermined degree of engine suction has been reached, said temperature actuated means also holding said valve closed when a temperature of apredetermined high degree has been reached regardless of variations in engine suction, and a second temperature actuated means for controlling the other valve. 1

3. In combination with an internal combustion engine, an automatic primin'g device comprising a body having two fuel passages connected in parallel through which fuel may pass simultane-' ously for admission to the engine, a valve for closing each passage, a piston connected with one valve and responsive to engine suction for closing the same, a spring for holding the other valve open, and temperature actuated means for controlling the actuation of said valves by the piston and spring in accordance with the ambient temperature. 3

- 4. In combination with an internal combustion engine, an automatic priming device comprising, a body having two fuel passages connected in parallel through which fuel may pass simultaneously'for admission to the engine, a valve to close each passage, 8. piston connected with one valve and responsive .to engine suction for closing said valve, a spring tending to hold the other valve open, and independent bi-metallic members anchored to said body and connected at their outer free ends with the valves for controlling the actuation of the valves by said piston and spring.

5. In combination with an internal combustion engine, an automatic-priming device, comprising a body having two fuel passages connected-in parallel, a valve for closing each passage, a piston responsive to engine suction for closing one of said valves, spring means for yieldably holding the other valve open, and bi-metallic U- shaped strips anchored to the body at one end 6. In combination with an internal combustion 75 for opposing said engine suction operated means whereby said valve is regulated Jointly by engine suction and changes in the ambient temperature, means for nulliiying any affect engine section might have on the other valve, and thermostatic means responsive to changes in the ambient temperature acting in conjunction with said last named means for regulating said other valve.

Joan w. FITZ GERALD.

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