US2804861A - Fuel activating means - Google Patents

Description

p 1957 R. c. HEIDNER 2,804,861

FUEL. ACTIVATING MEANS Filed Feb. 15, 1956 INVENTOR. Rmrmao C. HEIONER ATTORNEY United States Patent FUEL ACTIVATING MEANS Richard C. Heidner, Hartford, Wis., assignor to West Bend Aluminum Co., West Bend, Wis., a corporation of Wisconsin Application February 13, 1956, Serial No. 564,918 7 Claims. (Cl. 123-59) This invention relates to improvements in multiple cylinder, alternate firing two cycle internal combustion engines, and particularly to means for preventing the heavier portions of the fuel charge from accumulating as puddles of liquid fuel in pockets in the engine.

In this type of engine the fuel is introduced into a separate crankcase chamber for each cylinder as a mist or mechanical suspension of small particles of gasoline and oil in air. Hereinafter this suspension will be called mist and the crankcase chamber is defined as all space within a cylinder in which mist is compressed by the down stroke of the piston. Whenever there is slowing of the motion of this mist, the heavier drops or particles will fall out from the mist and accumulate in puddles of liquid fuel hereinafter called (puddles) in any pocket or de pression in the crankcase. This fall-out may occur because of: slower engine speed; entrapment of the mist in deep pockets such as are found necessary with vertically arranged crankcases and horizontal manifolds; creation of eddy currents at sharp corners; and other causes. These puddles have a high B. t. u. value per cubic unit as com pared to the B. t. u. value of the same cubic unit of mist. Hence such puddles will: (a) unbalance the energy available to one cylinder with a crankcase chamber having such fall-out as compared to a cylinder with a cranckcase where there was no such fall-out: (b) lower overall engine efficiency; (c) increase fuel consumption and increase operating costs; and (d) cause uneven operation, sputtering, misfire, stalling, hard starting and the like.

It is the object of this invention, therefore, to provide a means for agitating any such puddles and cause the liquid fuel to again enter into the mist for use in the same crankcase chamber to which it was originally distributed.

This object is obtained by utilizing the pressure pulse in the crankcase chamber of one cylinder to agitate and break up the puddle in the crankcase chamber of another cylinder and force it back into the mist. A restricted passage leading from the crankcase chamber of one cylinder to the pocket in the crankcase chamber of another cylinder is provided with a check valve to prevent reverse flow. During each compression pulse a small volume of mist is forced through this passage into such pocket. The B. t. u. value of this mist is insufiicient to cause an appreciable unbalance in fuel distribution. However, due to its velocity, there is suflicient impact to break up the puddle in such pocket and force the particles back into the mist in the same crankcase chamber where the puddle is located. Thus the fuel supply in all crankcase chambers can be maintained at substantially even value. Furthermore, loss of fuel is thus reduced and engine efliciency increased.

This invention is embodied for illustration in a two cylinder two cycle internal combustion engine as shown in the accompanying drawing in which:

Fig. 1 is a view in side elevation of such engine embodying the present invention, the parts, shown partly in plan view and partly in section within the broken away area, illustrate the application of the invention to puddles which 2,804,861 Patented Sept. 3, 1957 may collect in any pocket formed by machining, because of other necessities; I

. Fig. 2 is an enlarged sectional view taken on the line .22 of Fig. 1 showing the application of the invention to puddles which may form in a pocket at the bottom of a vertically extending portion of a reed valve cavity;

Fig. 3 is a sectional view taken on the line 3-3 of Fig. 2;

Fig. 4 is an enlarged view section of the parts within the and Fig. 5 is a sectional view taken on the line 5-5 of Fig. 4.

The engine 10 shown in the drawing is a two cylinder, alternately firing, the type commonly used in outboard motors. 'It has a vertical crankshaft to the upper end of which is fixed a fly-wheel 12. A crankcase cover 14 provides an upper crankcase chamber 16 separated by middle crankshaft. bearing and partition 18 from a lower crankcase chamber 20 coring or partly in plan and partly in broken away area of Fig. l;

The crankcase cover has horizontally arranged and unconnected reed valve cavities 22 and 24. The bottom of cavity 24 leads flatly into the crankcase chamber 20 with out forming a pocket. Since the crankcase chambers are vertically arranged and the manifold and reed valve cavities horizontally arranged, the entrance from cavity 22 into crankcase chamber 16 is raised above the floor of such cavity, a pocket 26 is thus formed by a sloping wall 25 of the cavity 22 and a reed plate 28 where a puddle accumulates or may accumulate.

The reed plate 28 has two reed valve assemblies 30 (only one shown) positioned within the related reed valve cavity. A manifold 32 with a horizontal distributing channel leading from a single carburetor 34 to each reed assembly is mounted on the reed plate and both secured to the crankcase cover.

In order to force the puddle which accumulates in the pocket 26 back into the mist within the crankcase chamber 16, a passage 36 is provided which leads from the crankcase chamber 20 to the sloping wall 25 in the pocket 26. In the outlet end of such passage there is a metering cup 38 which for the purposes of this illustration has a number 60 hole therethrough. This restricts the volume of mist which flows from the crankcase chamber 20 to the crankcase chamber 16 with each pressure pulse to an amount which does not materially disturb the equalization of mixture in each crankcase chamber. It also increases the velocity of such mist. Reverse flow from the crankcase chamber 16 to the crankcase chamber 20 is prevented by a reed valve 46 of usual construction mounted by a screw 42 so as to close the outlet of the passage 36 when a pressure pulse occurs in the crankcase chamber 16. The inlet end of passage 36 is located in a portion of the crankcase chamber 20 where there can be no puddle and only mist will be forced through the passage 36. The B. t. u. of the mist so transferred is inconsequential when compared to the B. t. u. of the puddle which is forced back into mist by such transfer. Hence any slight increase caused by such transfer is offset by preventing the great B. t. u. loss which results from the puddle.

Apparently the velocity and impact of the incoming mist creates the energy necessary to break up the puddle and return it to mist. Maybe the vibration of the reed valve 40 also imparts additional mechanical disturbance to the puddle to aid in breaking up the puddle into mist.

A reed valve such as reed valve 40 or some other type of valve means is necessary to prevent reverse flow through the passage 36 to prevent the transfer of the liquid fuel in the puddle in pocket 26 into the crankcase chamber 20 even though it might be in mist when it enters such chamber. If this occurred, the balance of distribution between two cycle internal combustion engineof- The arrangement shown in the broken away 'area' of Fig;

1 and in Figs. 4 and 5 illustrates another 'application'of .this invention. In the upper crankcase chamber 16 atthe inner end of the cylinder sleeve 44 there is a collection sump 46 into which oil and fuel in liquid state are wiped 'by the piston and the cheek of the upper crank. There is a path 48 in the sloping bottom 50 of the upper crankcase chamber 16 and oil wiped into it by the crank cheek will flow -to the middle crankshaft bearing. However, it is essential to break up the puddle ofliquid fuel which forms in the sump 46 and get itback into the mist. To do this a passage 52" inthe'partition between the two cylinders leads from the top. of the lower crankcase chamber 20 to the .bottom of the sump 46;. The upper end of this passage has a metering cup 5'4 with a number 60 restricting opening. A reed valve '56 is'held in the sump 46 by a screw 58 and closes the upper end of the passage 52 against flow from the upper crankcase chamber 16 to the lower crankcase chamber 20. The action of this arrangement in breaking up the puddle and returning it to mist within the same crankcase chamber is the same as that heretofore explained in connection withthe pocket 26.

I claim:

"1. In a multicylinder alternate firing two cycle engine having a first crankcase with a pocket therein and a second crankcase, means for converting a puddle of liquid fuel in said pocket into mist in said first chamber comprising a passage leading from said second crankcase chamber to said pocket whereby each compression pulse in said second crankcase chamber will cause a flow of mist from said second crankcase chamber into said pocket to break up said puddle and convert it into mist in said first chamber, and valve means for said passage preventing flow from said first crankcase chamber to said second crankcase chamber.

2. The combination as set forth in claim 1 in which there is a restricted opening in said passage to limit the volume of mist forced from said second crankcase chamber into said first crankcase chamber.

3. The combination as set forth in claim 1 in which said valve means consists'of a reed valve'in said pocket closing said passage to fiow from said pocket to said second crankcase chamber upon each compression pulse in said first crankcase chamber whereby the vibrations of said reed valve may aid the converting of said puddle into mist.

4. The combination as: setforth in claim 1 in which there is a restricted opening in. said passage to limit the volume of mist forced from saidsecondcrankcase chamberinto said firstcrankcasechamber, and'said valve means consists of a reed valve in said pocket closing said passage to flow from said pocket to said second crankcase chamber.

5."In a multicylinder alternate firing two cycle engine having vertically aligned crankcase chambers and horizontally aligned fuel inlet valves for each chamber, a pocket in the lower part of the upper of said chambers, a passage leading from the lower of said chambers to said pocket, and valve means for said passage preventing, flow from said pocket to said lower chamber.

6. In a multicy-linder alternate firing two cycle engine having each cylinder 'and rcommunicating crankcase chamber vertically arranged, and a vertical crankshaft with an intermediate'bearing between adjacent crankcase chambers, a sump in an upper of'saidchambers adjacent said bearing, a passage leading from the lower of said chambers to said sump, and valve mean in said sump for said passage preventing flow from said sump to said lower chamber.

7. Ida multicylinder alternate firing two cycle engine having crankcase chambers with pulsating pressure changes, a pocket in one of said chambers having a puddle of liquid fuel therein, and means in said pocket energized by the pressure changes in the other of said chambers to break said puddle into mist.

- References Cited in the file ofthis patent UNITED STATES PATENTS

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