US3802401A

US3802401A - Charge forming method and apparatus with overspeed governor

Info

Publication number: US3802401A
Application number: US00076981A
Authority: US
Inventors: W Nutten; B Phillips
Original assignee: Borg Warner Corp
Current assignee: TILLOTSON Ltd (TILLOSTSON") A CORP OF IRELAND
Priority date: 1970-09-30
Filing date: 1970-09-30
Publication date: 1974-04-09
Anticipated expiration: 1991-04-09

Abstract

The invention disclosed embraces a charge forming method of and apparatus embodying an instrumentality responsive to engine vibrations or disturbances brought into operation when the engine reaches a predetermined speed to automatically deliver excess fuel to the engine thereby momentarily providing a nonignitible mixture preventing overspeeding of the engine.

Description

United States Patent n 1 Nutten et a1.

CHARGE FORMING METHOD AND APPARATUS WITH OVERSPEED GOVERNOR Warren 1). Nutten, Grafton, Wis; Barnard C. Phillips, Toledo, Ohio Borg-Warner Corporation, Chicago, 111.

Inventors:

Assignee:

Filed: Sept. 30, 1970 App], No: 76,981

US. Cl 3/115, 123/100. 123/106. 123/109, 123/198 D, 123/198 DB, 137/539 Int. Cl. F02d 13/00, F 16k 17/00 Field of Search 123/77, 100, 106, 109, 123/198, 115; 137/539 References Cited UNITED STATES PATENTS Duer et a1 123/106 1 Apr. 9, 1974 2,739,581 3/1956 Garrett 123/103 3,320,937 5/1967 Meininger..... 3,601,102 8/1971 Schneider... 3,521,652 7/1970 Reeks 123/198 Primary ExaminerLaurence M. Goodridge Assistant Examiner-Ronald B. Cox Attorney, Agent, or Firm-Harry O. Ernsberger {57} ABSTRACT The invention disclosed embraces a charge forming method of and apparatus embodying an instrumentality responsive to engine vibrations or disturbances brought into operation when the engine reaches a predetermined speed to automatically deliver excess fuel to the engine thereby momentarily providing a nonignitib1e mixture preventing overspeeding of the engine.

11 Claims, 76 Drawing Figures PATENTEBAPR 9 1914 saw 01 ur 1e INVENTORS Mmm/fl Warm/v & awn/mo a? Pym/p5 PATENTEBAPR 919m 3302.401

SHEEI 03 HF 16 INVENTORS' WARM Q My??? &

BY Emma? 15. Pam/P5 MGM PATENTED 9 1974 3,802,401

saw 12 HF 16 BY EMA/M0 6. PM: UPS

CHARGE FORMING METHOD AND APPARATUS WITH OVERSPEED GOVERNOR The irgvention relates to a method of and apparatus for controlling delivery of fuel and air mixture to an internal combustion engine to normally supply a power mixture for engine operation under load conditions and to automatically modify the mixture at predetermined engine speed to govern the engine and prevent excessive high speed.

Internal combustion engines of the reciprocating piston type and particularly two cycle engines are used extensively for powering tools, such as chain saws, and for other uses where the engine is periodically subjected to high loads. When the load is suddenly reduced or removed, overspeeding of the engine results if the throttle remains in full open position. One of the most important uses of small two cycle engines where such overspeeding of the engine is encountered is that of op erating chain saws. In the felling of trees or cutting of logs and tree limbs by the use of an engine driven chain saw, the saw is subjected to intermittent loading. When cutting a log or limb, the load on the engine endures until the log or limb is severed. when the saw cut is completed, the saw breaks through and the engine, being momentarily unloaded, attains an excessively high speed within a fraction of a second after the load is removed. Overspeeding of a small engine, particularly an engine of the two cycle type, may result in severe damage to the engine for several reasons. As the lubricant for a two-cycle engine is contained in the liquid fuel there may be insufficient lubrication at excessive high speed. The components of the engine subjected to excessive high speed may be broken or fractured by centrifugal forces. As running friction is greatly increased at high engine speeds, piston or bearing seizure may ensue rendering the engine inoperable.

If the operator does not instantly reduce the speed of the engine by manipulation of the throttle when a no load condition occurs, engine damage is liable to ensue. Chain saw operators, in trimming limbs from a felled tree are prone to walk along the tree trunk cutting off the limbs successively while holding the throttle continuously in wide open position causing severe overspceding of the engine between the limb cutting operations, a practice which usually results in damage to the engine. Such conditions of operation greatly reduce engine life and subject the saw manufacturer to excessive warranty claims. The same difficulties are encountered in other uses of internal combustion engines where the engine is subjected to overspeeding under no load conditions.

The invention embraces a method of preventing excessive high speed of an internal combustion engine by automatically modifying the fuel and air ratio of the fuel and air mixture when the engine exceeds a predetermined speed, the modification or change in fuel to air ratio being effected through a medium or means responsive to engine vibrations or disturbances independently of the aspiration or reduced pressure existent in the charge forming apparatus or carburetor providing the normal fuel and air mixture.

Another object of the invention resides in a method of governing the operation of an internal combustion engine, the method involving the automatic delivery of an excess amount of liquid fuel to the engine whenever the engine attains a predetennined speed, the delivery of excess fuel being controlled by a vibrafion responsive instrumentality.

Another object of the invention resides in a method of governing or limiting the speed of an internal cornbustion engine to prevent overspeeding of the engine involving a medium responsive to engine vibration occurring at a predetermined engine speed effective to superimpose excess liquid fuel on the normal fuel and air mixture supplied to an engine to effect an impaired or slow burning mixture resulting in an instantaneous decrease in the power of the engine and hence a substantial reduction in engine speed. 4

Another object of the invention resides in a method of governing the speed of an internal combustion engine involving the automatic delivery of an excess of liquid fuel into any region of the i nduction system through the use of an instrumentality responsive to a predetermined frequency of vibration of the engine.

Another object of the invention resides in an apparatus or device activated by or rendered out of phase with engine vibration of predetermined frequency to thereby deliver an excess of fuel into the induction system operative to reduce the engine speed.

Still another object of the invention is the provision in the induction system of an internal combustion engine of a vibration responsive valve rendered effective at a predetermined frequency to admit an excess of liquid fuel into the induction system or charge forming device to thereby reduce engine speed.

Another object of the invention is the provision of a vibration responsive valve associated with the induction system or charge forming apparatus for an internal combustion engine intercalated with fuel conveying passage means for delivering excess fuel to the engine at a predetermined frequency of vibration of the engine to prevent overspeeding thereof.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, operation and function of the related elements of the structure, to various details of construction and to combinations of parts, elements per se, and to economics of manufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

H0. 1 is a side elevational view of a portion of a chain saw of conventional construction illustrating the engine and a combined diaphragm carburetor and fuel pump construction embodying a form of the invention;

FlG. 2 is a top plan view of a combined diaphragm carburetor and diaphragm fuel pump construction shown in FIG. 1 embodying a form of the invention;

FIG. 3 is a side elevational view of the construction shown in FIG. 2;

FIG. 4 is an elevational view of the opposite side of the construction shown in FIG. 2;

FIG. 5 is a view of the air inlet end of the carburetor and fuel pump construction shown in FIG. 2;

FIG. 6 is a view of the mixture outlet end of the carburetor and fuel pump construction;

FIG. 7 is an enlarged longitudinal sectional view through the carburetor and fuel pump construction, the section line being taken substantially on the line 7-7 of FIG. 2;

FIG. 8 is an enlarged transverse sectional view taken substantially on the line 88 of FIG. 7;

FIG. 9 is an enlarged fragmentary sectional view taken substantially on the line 99 of FIG. 3;

FIG. 10 is an enlarged sectional view taken substantially on the line 10- 10 of FIG. illustrating one form of overspeed governor means embodied in the carburetor;

FIG. 11 is an enlarged fragmentary sectional view taken substantially on the line 11l1 of FIG. 4 illustrating the overspeed governor means shown in FIG.

FIG. 12 is a detail sectional view of a modified form of overspeed governor instrumentality;

FIG. 13 is a detail sectional view illustrating another form of overspeed governor instrumentality similar to that shown in FIG. 11;

FIG. 14 is an enlarged longitudinal sectional view of a charge forming apparatus or carburetor of the floatcontrolled type embodying a form of overspeed governor instrumentality of the invention;

FIG. 15 is an elevational view illustrating a reciprocating-piston internal combustion engine of the four cycle type illustrating a form of overspeed governor instrumentality of the invention associated therewith;

FIG. 16 is a top plan view of a portion of the carburetor or charge forming apparatus of FIG. 15 illustrating the position of the overspeed governor means of the invention;

FIG. 17 is an enlarged fragmentary detail sectional view of a form of overspeed governor means of FIG. 15, the view being taken substantially on the line l717 of FIG. 15;

FIG. 18 is an end view of the construction shown in FIG. 17;

FIG. 19 is an elevational view of a two cycle engine associated with a float type carburetor and embodying a form of overspeed governor instrumentality of the invention;

FIG. 20 is an elevational view of a two cycle engine associated with a diaphragm type carburetor and embodying a form of overspeed governor instrumentality of the invention;

FIG. 21 is a longitudinal sectional view of the diaphragm type carburetor illustrated in FIG. 21);

FIG. 22 is an elevational view of a reciprocating piston four cycle engine equipped with a float-controlled type carburetor in combination with an engine-driven fuel pump and an overspeed governor means of the invention associated with the mixture intake manifold;

FIG. 23 is a top plan view of the carburetor shown in FIG. 22 embodying an overspeed engine governor instrumentality;

FIG. 24 is a view similar to FIG. 23 illustrating a fitting between the carburetor and the intake manifold equipped with an overspeed governor means of the invention;

FIG. 25 is a sectional view of a diaphragm type carburetor and fuel pump construction similar to the form shown in FIG. 8 and embodying a form of overspeed engine governor means of the invention:

FIG. 26 is a top plan view ofa diaphragm type carburetor and fuel pump disposed within an air filter enclosure, the arrangement embodying a form of overspeed governor of the invention;

FIG. 27 is an enlarged detail sectional view ofa form of overspeed governor device embodied in the arrangement shown in FIG. 26;

FIG. 28 is a top plan view of a diaphragm type of charge forming apparatus or carburetor equipped with an overspeed governor means of the invention;

FIG. 29 is a longitudinal sectional view through the carburetor, the view being taken substantially on the line 29-29 of FIG. 28;

FIG. 30 is a transverse sectional view taken substantially on the line 3030 of FIG. 28;

FIG. 31 is an enlarged fragmentary transverse sec tional view taken substantially on the line 31-31 of FIG. 28;

FIG. 32 is a view similar to FIG. 31 illustrating a form of capillary seal arrangement for a main fuel delivery orifice associated with the overspeed governor device of the invention;

FIG. 33 is a top plan view of a carburetor similar to FIG. 28 embodying a modified form of overspeed governor device;

FIG. 34 is an enlarged detail sectional view taken substantially on the line 3434 of FIG. 33;

FIG. 35 is a top plan view of a charge forming apparatus similar to FIG. 33 embodying a form of overspeed governor means of the invention;

FIG. 36 is an enlarged detail sectional view taken substantially on the line 3636 of FIG. 35;

FIG. 37 is a longitudinal sectional view through a carburetor similar to FIG. 10 illustrating a modified fuel channel arrangement for the overspeed governor device;

FIG. 38 is an enlarged detail sectional view taken substantially on the line 3838 of FIG. 37;

FIG. 39 is a top plan view of a diaphragm type carburetor embodying a form of overspeed governor of the invention;

FIG. 40 is a side elevational view of the construction shown in FIG. 39;

FIG. 41 is a horizontal sectional view taken substantially on the line 41-41 of FIG. 40;

FIG. 42 is an enlarged detail sectional view taken substantially on the line 42-42 of FIG. 41;

FIG. 43 is an enlarged detail sectional view taken substantially on the line 43-43 of FIG. 40',

FIG. 44 is an enlarged fragmentary sectional view similar to FIG. 42 illustrating a capillary seal anti-back bleed means in the main fuel delivery orifice;

FIG. 45 is an enlarged sectional view illustrating a modified form of overspeed governor instrumentality;

FIG. 46 is an enlarged sectional view illustrating another modification of overspeed governor means;

FIG. 47 is an end view of the construction of FIG. 46;

FIG. 48 is an enlarged sectional view illustrating another modified form of overspeed governor means;

FIG. 49 is a bottom plan view ofa carburetor with the diaphragm removed showing the fuel chamber. the carburetor being of the general character shown in FIGS. 39 and 40 and embodying a further modification of overspeed governor means of the invention;

FIG. 50 is a sectional view taken substantially on the line 5050 of FIG. 49 illustrating the overspeed governor means;

FIG. 51 is an enlarged detailed sectional view illustrating another modified form of overspeed governor means;

FIG. 52 is an end view of the construction of FIG. 51;

FIG. 53 is an enlarged sectional view of a further modification of overspeed governor means;

H6. 54 is a sectional view taken substantially on the line 54-54 of FIG. 53;

FIG. 55 is a view similar to FIG. illustrating a modified form of overspeed governor construction of the invention;

F i0. 56 is a sectional view taken substantially on the line 56-56 of FIG. 55;

FIG. 57 is an enlarged detail sectional view of the overspecd governor construction shown in FIGS. 55 and 56;

FIG. 58 is an end view of the construction shown in FIG. 57;

FIG. 59 is a sectional view of a closure member for the construction shown in FIG. 57;

FIG. 60 is a view of the construction shown in FIG.

57 with a sealing means for sealing the adjustment in' fixed position;

FIG. 61 is a view similar to HS. 57 illustrating a mod ified form of seat configuration for the vibration responsive ball valve;

FIG. 62 is an eniarged sectional view similar to H6. 57 illustrating a closure means for the anjustsuie ber;

FIG. 6; is an end view of the construction shown in FIG. 62;

FIG. 64 is an enlarged sectional view illustrating a modified form of adjustable overspeed governor construction',

FIG. 65 is an end view of the construction shown in FIG. 64;

FIG. 66 is a fragmentary sectional view of a portion of the construction shown in FIG. 64 illustrating a sealing means for the adjustment;

FlG. 67 is an enlarged sectionat view iilustrating another form of overspeed governor construction of the invention;

FIG. 68 is an end view of the construction shown in FIG. 67;

FIG. 69 is an enlarged sectional view illustrating another form of overspeed governor construction;

FIG. 70 is an end view of the construction shown in H0. 69;

FIG. 71 is an enlarged sectional view similar to FIG. 69 illustrating a closure for the housing of the overspeed governor construction;

FIG. 72 is an end view of the construction shown in FIG. 7];

FIG. '73 is an enlarged longitudinal sectional view illustrating another form of overspeed governor means;

FIG. 74 is an end view of the construction illustrated in FIG. 73;

FIG. 75 is a schematic sectional view of a reciprocating piston engine illustrating the relationship of the overspeed gcn ernor means shown in FlG. 73 with moving components of an engine for attaining overspeed governor operation, and

FIG. 76 is an enlarged sectional view of another modification of the overspeed governor means of the invention.

The method and the apparatus of the invention involve feeding an excess of liquid fuel to a reciprocating piston internal combustion engine of either the two cycle or four cycle type through the use of a vibration responsive body actuated by or rendered out of phase with engine vibrations or disturbance occurring at a particular speed of the engine to cause oscillation or relative displacement of the body and thereby admit fuel into the engine induction system in an amount effective to reduce the engine speed and prevent overspeed of the engine.

The apparatus for accomplishing this method is referred to herein generally as a vibration responsive instrumentality, means or unit providing an overspeed governor, the governing medium being responsive to and actuated or displaced by engine vibrations when the engine attains a predetermined speed. The overspeed governor method and arrangement of the inven tion have particular utility'with low horsepower two and four cycle engines and especially engines employed for powering chain saws lawn mowers, portable drills and the like.

it is found that the vibration responsive means or valve may be arranged to deliver liquid fuel into various regions of the induction system of an engine and the drawings illustrate various arrangements for positioning or mounting a vibration responsive body or valve whereby it is subjected to engine vibrations and is effeetive to a particuiar frequency of vibration to be moved or oscillated by such vibration to admit excess fuel to the engine for engine governing purposes.

Referring initially to FIG. I, there is illustrated a side elevational view, partly in section, of a portion of the power driven chain saw showing a form of charge forming apparatus or carburetor embodying the invention associated with the engine. The arrangement shown in FIG. 1 is inclusive of a chain saw frame construction 10 which forms an integral part of an engine crankcase ll of a two cycle engine I2 on which is mounted a cylinder i having cooling fins l5. Slidahle in the cylinder 14 is a conventional piston 16 having a piston pin 17 connected by a connecting rod I8 with a crank pin 19 on a crank arm of a crankshaft 20 journally supported in the crankcase 11.

The engine illustrated is of the two cycle type, viz. wherein the fuel and air mixture is admitted into the chamber provided by the crankcase l l and compressed I above the piston in the conventional manner. The mixture is ignited by a spark plug 22 at each revolution of the crankshaft.

The fuel and air combustible mixture is provided through a combined fuel pump and carburetor or charge forming apparatus 24 mounted by the engine crankcase, the carburetor iiiustrated being shown in detail in FIGS. 2 through it and hereinafter described.

The frame 10 is fashioned with a forwardly extending portion 34 to which is secured an elongated plate-like member 35 providing a support and guide means for an endless chain type saw construction 36. The saw support plate 35 is secured to the frame by means of bolts 37. The forward end of the support member 35 is provided with a housing 38 which journally supports a roller guide 39 which is engaged by the chain saw 36 in the conventional manner.

A removable housing on the opposite side of housing 42 encloses a conventional centrifugally-actuated clutch for establishing a drive connection between the engine crankshaft 20 and a saw driving sprocket (not shown) when the engine is operated above idling speed. The housing also encloses a fuel tank (not shown) pro-

Claims

1. An arrangement for preventing excessive speed of a reciprocating-piston internal combustion engine having a crankcase and cylinder providing a frame, in combination, means providing a fuel and air induction system for the engine including charge forming apparatus having a mixing passage for normally conveying a combustible fuel and air mixture to the engine for operating the engine, means providing a fuel passage connected with a fuel supply and the induction system, said fuel passage means including a valve seat, a movable valve body associated with the fuel passage and having a spherically curved valve portion cooperating with the valve seat normally impeding fuel flow through the fuel passage means, said valve body being movable laterally relative to the valve seat, said body being disposed to be influenced solely by a frequency of engine structural vibration transmitted through the engine frame occurring at a speed at which the engine is to be governed whereby at such speed the valve body is vibrated laterally of the valve seat from fuel flow impeding position to admit excess fuel through the fuel passage means into the induction system providing an overrich mixture for reducing the speed of the engine.

2. Apparatus for controlling delivery of fuel to the induction system of an internal combustion engine having a crankcase and cylinder providing a frame to limit the speed of the engine including means providing a chamber having a valve seat surface defining a fuel port, said port being arranged for communication with a fuel supply and the induction system, a movable valve body in said chamber having a spherically curved valve surface, said valve body being movable laterally relative to said port, means normally biasing the valve body to engage the curved valve surface with the valve seat surface to obstruct fuel flow through the port, said valve body being responsive solely to engine structural vibration transmitted through the engine frame at a predetermined engine speed whereby at said speed the valve body is vibrated laterally away from the port to admit fuel flow into the induction system in amount sufficient to impair normal engine operation.

3. The combination according to claim 2 wherein the biasing means for the valve body comprises a resilient member.

4. The combination according to claim 3 wherein the resilient member provides a biasing pressure on the valve body in a range between 5 grams and 50 grams.

5. Apparatus for limiting the speed of an internal combustion engine having a crankcase and cylinder providing a frame and an induction system providing a passage conveying a normal fuel and air mixture to the engine, a fueL flow control means for delivering excess fuel to the passage including a housing associated with the passage, said housing having a chamber therein and a valve seat surface defining a fuel delivery port, said port being arranged to deliver fuel from a supply to said passage, a movable valve body in said chamber having a spherically-shaped surface, said valve body being movable laterally relative to said port, resilient means normally biasing the valve body to a position engaging the spherically-shaped surface of the body with the valve seat surface closing said port, said valve body being arranged to be influenced solely by engine structural vibration transmitted through the engine frame, and means for regulating the biasing pressure of the resilient means to permit vibration of the valve body laterally away from port-closing position by engine vibration occurring at a predetermined speed and thereby admit excess fuel to said passage to prevent overspeeding of the engine.

6. In combination with an engine having a crankcase and cylinder providing a frame, a carburetor having a body provided with a mixing passage and a fuel chamber, a diaphragm forming a wall of the fuel chamber, inlet valve means actuated by the diaphragm for controlling delivery of fuel from a supply into the fuel chamber, fuel passage means opening into the mixing passage for delivering fuel from the fuel chamber into the mixing passage for normal engine operation, a bore in the carburetor body means for delivering excess fuel into the mixing passage for impairing engine operation to govern the speed of the engine including a housing disposed in the bore, said housing being formed with a chamber, a movable valve member in the chamber, a valve seat in the housing providing a fuel port, said valve member having a spherically curved region for cooperation with the valve seat, said valve member being movable laterally relative to the valve seat, said fuel port being in communication with the mixing passage, passage means for conveying fuel from the fuel chamber in the carburetor body into the chamber in the housing, resilient means in said housing normally biasing the valve member to port-closing position, and an abutment in the housing for said resilient means, said relatively movable valve member being disposed to be influenced solely by a frequency of engine structural vibration transmitted through the engine frame occurring at a speed at which the engine is to be governed whereby at such speed the relatively movable valve member is vibrated laterally from its seat to admit excess fuel through said port into the mixing passage providing an overrich mixture for reducing the speed of the engine.

7. The combination according to claim 6 wherein the abutment is adjustable for controlling the biasing pressure of the resilient means.

8. The combination according to claim 6 wherein the valve member is spherically shaped, the bore in the housing arranged to snugly receive the abutment, said abutment being adapted to be slidably moved to control the biasing pressure of the resilient means.

9. The combination according to claim 6 wherein the valve member is spherically shaped, the bore in the housing having a threaded portion, said abutment being threaded into the threaded portion of the bore for adjusting the biasing pressure of the resilient means.

10. The combination according to claim 7 including indentations in the housing adjacent the abutment for locking the abutment in adjusted position.

11. The combination according to claim 6 including a closure for the bore in the housing adjacent the abutment.