US2253613A - Ignition assembly - Google Patents

Description

Aug. 26, 1941. ELLIOTT 2,253,613

IGNITION ASSEMBLY Filed July 13, 1939 2 Sheets-Sheet 1 INVENTOR TORNEY A ug. 26, 1941. N, EL OTT 2,253,613

IGNITION ASSEMBLY Filed July 13, 1939 2 Shee'l'Qs-Shet 2 W Y U v- Ne/s o //I Off TORNEY Patented Aug. 26, 1941 UNITED STATES PATENT OFFICE Nelson Elliott, New Westminster, British Columbia, Canada Application July 13', 1939', serial No. 284,370

. 8 Claims.

This invention relates to an ignition assembly for internal combustion engines;

An object of the present inventionis the provision of an ignition assembly particularly for internal combustion engines using oil or other low grade fuels.

Another object is the provision of an ignition assembly adapted to eliminate the necessity of extremely high compressions in the power cylinders of" internal combustion engines.

Another object is the provision of a sman auxiliary cylinder in which a charge of fuel' is" fired by the heat of compression and the burriing gases are injected into the power cylinder to ignite compress'edfuel' therein.

A further object is the provision of an ignition assembly for internal combustion engines using oil or the like as fuel, adapted to ensure smooth and even operation of the" engine.

A further object is the provision of adevic'e" of this character for ensuring complete combustion of the fuelin'the engine with which it is used.

Many attempts have b'eenma'de to eli i'iin'ate the necessity of extremely high compressions by utilizing an auxiliary piston for'injectirig burnirig fuel into a power cylinder to ignite cempres'sed fuel therein. These" attempts have been unsuccessful. It is believed that the main' reasons for failure areas follows:

1. The charge in the auxiliary cylinder had to be fired while the auxiliary piston still traveling upwardly, resulting in a knock in the" engine and a great strain on the various parts. 2. The charge in the auxiliary cylinder was not completely ignited when it wasinjefcted into" the power cylinder, resulting in incomplete combustion in the latter.

3; The auxiliary piston was unable completely to clear its cylinder of ,exhaust'g'ases'.

The present invention overcomesthese diffi culties by providing an assembly in which an auxiliary piston, preferably connected directly to the crank-shaft, is operated in an auxiliary cylinder, said piston being adapted to'com'press and ignite a charge of fuel therein, and then the pistonmoves downwardly and; upwardly practically through two strokes before a valve opensto allow the ignited 'fuelto be-injectedinto This delayed injection afthe main cylinder. fords a time interval in which complete? combustion takes place in the auxiliary cylinder be fore the gases are injected into thepower cylinder. By connecting the auxiliary pistonto the crankshaft, it is reciprocated steadily and smoothly. In the known devices of this character, the auxiliary pistons are reci-procated by means of rods riding on cams of Variousdesigns, causing the pistons to move suddenly at certain times and to remain stationary at other times.

A feature of this invention is that the auxiliary piston is compressible. In all auxiliary cylinders, ignition must take place before the upper dead centre is reached by the piston. As the valve for admitting the gases into the power cylinder cannot be opened until after ignition has taken place, the pressure in the auxiliary cylinder is still increased after ignition. This means the piston receives a terrific shock and has to Work against extremely great pressure. The compressible piston absorbs a good deal of the shock and it is designed to prevent the pressure in the cylinder from rising above a predetermined maximum. The piston is compressed by the gases in the cylinder and when the latter are injected into the power cylinder, the piston assum'es its normai position and moves right up to the head of the cylinder completely to expel the ases. g

An eng'ine employing the improved ignition assembly is' described by Way of example, in the following specification and illustrated in the accom anying drawings, in which Figure 1 is a longitudinal sectional view taken through the internal combustion engine and substantially along the line ll of Figure 3;

Figure 2 is a fragmentary transverse sectional View through the auxinary cylinder, taken substantially along the line 2 2 of Figure 3;

Figure 3' is a reduced fragmentary plan view of the engine, and

Figures 4 to 7 diagrammatically illustrate one stroke of the auxiliary and power pistons of" the engines;

Referring more" particularly to the drawings, I0 isthe water-cooled block of an internal com-- bustion engine, said block having a ren 'iovable, Water-jacketed head H, at least one power cyl'-. inder l2, and a relatively srriall auxiliary cylinder l't for'each power cylinder. A power piston l4 adaptedto-operate in the cylinder IZQls connected to the crank-shaft (not shown) of the engine by a connecting rod [5. A combustionchamber [5' is formed in the head [I above and communicating with the power cylinder. This chamber overlaps the auxiliary cylinder l3 and a partition l1 separates the chamber from the. cylinder, said partition having aninjection port [8 therein normally closed by a valve 2 0 Fuel issupplied to the combustion chamber is and ex- An auxiliary piston 21 having piston rings is slidably mounted in the auxiliary cylinder i3.

This piston is formed with an upper section 35 spaced from a lower section BI and joined together by a bolt 32. The bolt 32 is threaded into the lower end of the upper section at 33, and it slidably extends through the top of the lower section 3| at 34. The lower section is secured upon the bolt 32 by a nut 35 threaded on to the lower end of the bolt while a lock nut 36 retains the upper section in its proper position on the bolt. A compression spring 3'! surrounding the bolt 32, holds the upper and lower sections of the auxiliary piston apart. The tension on this spring may be regulated by loosening the nut 36 and turning the bolt 32 to move the upper and lower sections towards or away from each other. A connecting rod 38 connects the auxiliary piston to the crank shaft of the engine, the crank of the auxiliary piston being so arranged in relation to the crank of the power piston that the former piston is always behind the latter piston, i. e., the power piston reaches its upper and lower dead centres before the auxiliary piston reaches its upper and lower dead centres, respectively.

A fuel inlet port 40 is formed in the side wall of the auxiliary cylinder l3 near the lower end thereof. This port is so situated that it is just cleared by the auxiliary piston when the latter reaches its lower dead centre. A valve 4| having a stem 42 is normally held seated in the port 40 by a spring 43 and the valve is operated in any suitable manner, such as, by a cam 44 (see Figure 3) mounted on a cam rod 45 and operating in a yoke 45 connected to the stem 42 of the valve. The cam rod is rotatably connected to a rotating part of the motor, such as the drive shaft thereof. The valve 4| operates in a chamber 41 and a fuel pipe 48 connected at one end to the carburetor (not shown) of the engine, is

adapted to supply vaporized fuel through a passage 50 formed in the block of the engine, to the chamber 41, whence said fuel passes through the port 40 into the auxiliary cylinder when the former is open.

The valve 20 is slidably mounted in a relatively long bearing sleeve 5| which is mounted on the head The valve is provided with one or more expansion rings 52 similar to piston ring, and it is formed with a reduced portion 53 at its lower end which is adapted to fit into the injection port I8. The upper end of sleeve 5| is formed with. a packing gland 54 in which packing 55 is held around the valve 2|) by a packing nut 56. A comparatively long casing 51 having a cover 58 is mounted on the head H over the bearing sleeve 5| and a cage 60 slidably mounted in said casing, is connected to the upper end of the valve 20. A compression spring 5| is fitted between the top of the cage 60 and the cover 58 and normally holds the valve 20 with the reduced portion 53 closing the port IS. A cam 62, rotated in any suitable manner, operates within the cage 60 to raise the valve 20 sufficiently to open the port l8 at predetermined times, said cam being adapted to make one revolution during two revolutions of the crank-shaft of the engine.

The engine illustrated in the drawings operates on the four cycle principle. Assuming the auxiliary cylinder I3 is charged with vaporized fuel, the auxiliary piston 21 compresses the charge until it is ignited by the heat of compression. The fuel continues to burn while the auxiliary piston moves through a downward and another upward stroke. As the piston approaches the end of its second upward stroke, the valve 20 opens the port l8 and the burning fuel or gases are injected into the combustion chamber I6 where they ignite a charge of fuel that has been compressed by the power piston M. Then the valve 20 closes the port l8 and the auxiliary piston moves downwardly again creating a vacuum in the auxiliary cylinder. When the piston clears the inlet port, the valve 4| opens said port and a charge of vaporized fuel rushes into the cylinder to fill the vacuum therein. For the sake of convenience, the first, second, third and fourth strokes of the auxiliary piston will be called the compression, burning, injecting and intake strokes, respectively, the first and third strokes being in an upward direction while the second and fourth strokes are in a downward direction.

Figure '7 illustrates the auxiliary piston at its lower dead centre with the valve 4| open to permit the vaporized fuel to enter the cylinder. The auxiliary piston is just about to commence its compression stroke while the power piston l4 has started its exhaust stroke with the exhaust valve 24 open. In Figure 4, the valve 20 is closed and the auxiliary piston nears the point where the fuel is ignited by the heat of compression While the power piston has reached the end of its exhaust stroke. In Figure 5, the auxiliary piston has just started its burning stroke while the power piston is well advanced on its intake stroke with the inlet valve 23 open. Figure 6 shows the auxiliary piston approaching the end of its burning stroke and the power piston at the end of its intake stroke.

Figures 4 to 7 may be used to describe the balance of operation of the pistons, the only difference being the positions of the various valves. With the valves 4| and 24 closed, Figure 7 illustrates the auxiliary piston about to commence its injection stroke and the power piston advanced on its compression stroke. With the valve 20 open, Figure 4 shows the piston 21 at the point where it starts to inject the burning fuel into the combustion chamber I6 to fire the fuel therein to start the power piston on its power stroke, said piston having reached the end of its compression stroke. In Figure 5, with the valve 23 closed, the auxiliary piston has started its intake stroke while the piston I4 is well advanced on its power stroke. In Figure 6, the power piston has reached the end of its power stroke and the auxiliary piston is nearing the end of its intake stroke. Figure 7 illustrates the beginning of the next cycle. 7

As the auxiliary piston nears the end of its compression stroke, the fuel is ignited by the heat of compression. This results in an explosion and an impact on the piston but the spring 31 absorbs the shock and, therefore, there is no appreciable knock in the engine. This spring is designed to give only at a certain pressure, which pressure is just above that necessary to ignite the fuel. As the piston continues to travel upwardly after ignition has taken place,

he sp in 31 absorbs most of themovenient so that the pressure in the cylinder does not. beome too reat which mi ht result in an unevenness o eration of he en ine and a waste i owe Th s sprin makes it possible to comp e the compression stro e of the auxiliary pis on i h u openin the valve 2.0. As the piston travels through the entire burning stroke and hro gh h gr ater part of the. next injection stroke, the fuel or gases burn in the cylinder. This allows sufficient time for complete, combustion to take place. The valve 20 is opened a the iston nears the end of its injection stroke o a l w the urninggases o be inje t d in o the combustion chamber. This also reduces the p es ur he auxiliary chamber. The auxiliary piston continues upwardly until it contacts the upper end of; its cylinder, at which t me the ases are. comp etely ejected from the yl n and the valve 2.0 starts to close. The spring 31 ake it. pos ible to have the. piston contact the en o he cy inder sli htl f re ts rank reaches its uppermost. position so. that the piston remains contact with the top of the cylinder for a short period; of. time. Then the piston starts on its intake stroke during which it creates a vacuum in the auxiliary cylinder and when the valve 40 is opened, vaporized fuel flows into the cylinder from the carburetor.

As stated above, the auxiliary piston is arranged to travel behind the. power piston. The distance may be as desired: but it preferably is about one quarter oi a stroke. In other words, when the power piston is at; the end of its compression stroke, the auxiliary piston is only three q a er w y th ou h. i nje tion stroke! The injection valve 20; opens as soon as the power pigton reaches the ,end of its compression stroke so hat th bu ni g a s a inje ted into the; power cylinder during the last quarter of the injection stroke of the auxiliary piston and during the first quarter of the power stroke of thepower piston.

The valve 44 is operated to open the inlet port each alternate time the auxiliary piston is at substantially its, lower dead centre and the valve 2,0, is operated each alternate time this piston approaches its upper dead centre. the valve 29 is. operated alternately to the valve 4,1. In other words, thevalve M is opened whenthe piston is at substantially its lower dead centre, then the valves remain closed as the piston moves through its upper and lower dead centres until. it approaches th upper dead centre a sec- 0nd time, when the valve 20. opens, and then the. valves remain. closed as the; piston moves through its lowe and upper dead. centres again until it reachesits lower dead centre a fourth time when the valve-4| opens again,

When the charge of fuel is fired in the. auxiliary cylinder, the burning gases remain in said cylinder through substantially two strokes of the piston before they are injected into the power cylinder. This delayed injection after ignition, affords an interval to allow for complete combustion of the gases before they are expelled from the cylinder. The delayed injection also allows sufficient time for the opening and closing of the injection valve. With the piston traveling at high speeds, the delay makes it possible to inject all the burning gases into the power cylinder.

By inserting a compression spring between the auxiliary piston and its reciprocating means,

Furthermore the shock of the explosion as the piston moves upwardly isabsorbed to.a certain extent by the spring. The spring also controls the pressure to which the fuel or gases may be compressed and it permits the piston to contact the top of the cylinder to expel .all the gases. Furthermore, the spring protects the various parts from damage or breakage should carbon build u on the top of the piston or the cylinder.

The .fuel inlet port is positively controlled by a valve so that it is possible to operate the auxiliary piston through two strokes with the burning gases remaining in the cylinder. This also makes it possible to create a vacuum in the cylinder so. that the vaporized fuel quickly and completely fills the cylinder as soon as the valve is opened.

While the fuel in the auxiliary cylinder has been. described as being ignited by the heat of compression, it will be understood that, if desired, suitable igniting means, such as a spark plug, may be employed. This ignition assembly has been primarily designed for use with engines using low grade fuels but it is to be understood that it may be used with any type of fuel capable of being used in an internal combustion engine.

Various modifications may be made in this invention without departing from the spirit thereof or the scope of the claims, and therefore the exact forms shown are to be taken as illustrative only and not in a limiting sense, and it is desired that only such limitations shall be placed thereon as are disclosed in the prior art or are set forth in the accompanying claims.

What I claim as my invention is:

1. In combination with a power cylinder of an internal combustion engine having a power piston operating therein, an auxiliary cylinder situated adjacent the power cylinder and adapted to be brought into communication therewith, an auxiliary piston operating in the auxiliary cylinder, means for reciprocating the auxiliary piston, an inlet port formed in the auxiliary cylinder adjacent the lower end thereof, a valve adapted to control the inlet port, means for opening the port atv predetermined intervals to admit vaporized' fuel into the auxiliary cylinder when the auxiliary piston is at substantially its lower dead centre, said fuel being compressed by the auxiliary piston and ignited in its cylinder, valve means at the top of the auxiliary cylinder and cam. means for positively operating the valve means. whenthe fuel in the power cylinder is under compression to permit burning gases to be injected into,- the power cylinder to ignite the compressed charge of fuel therein.

2. In combination with. a power cylinder of an internal. combustion engine having a power piston. operating, therein,, an. auxiliary cylinder situated adjacent the power cylinder and adapted to be, brought into communicationtherewith, an auxiliary piston operating in the auxiliary cylinder, means for reciprocating the auxiliary piston, an inlet port formed in the auxiliary cylinder adjacent the lower end thereof, a valve adapted to control the inlet port, means for operating the inlet valve to open the port to admit vaporized fuel into the auxiliary cylinder each alternate time the auxiliary piston is at substantially its lower dead centre, said fuel being compressed by the auxiliary piston and ignited in its cylinder, valve means at the top of the auxiliary cylinder, and cam means for positively 0perating the valve means each alternate time the auxiliary piston approaches its upper dead centre to permit burning gases to be injected into the power cylinder to ignite a compressed charge of fuel therein, said valve means being operated alternately to the inlet valve.

3. In combination with a power cylinder of an internal combustion engine having a power piston operating therein, an auxiliary cylinder situated adjacent the power cylinder and adapted to be brought into communication therewith, an auxiliary piston operating in the auxiliary cylinder, means for reciprocating the auxiliary piston, means for admitting vaporized fuel into the auxiliary cylinder, said fuel being compressed by the auxiliary piston and ignited in its cylinder, means connected with the auxiliary piston for controlling the pressure of the compressed gases in the auxiliary cylinder, valve means at the top of the auxiliary cylinder, and cam means for positively operating the valve means when the fuel in the power cylinder is under compression to permit burning gases to be injected into the power cylintherein,

4. In combination with a power cylinder of an internal combustion engine having a power piston operating therein, an auxiliary cylinder situated adjacent the power cylinder and adapted to be brought into communication therewith, an auxiliary piston operating in the auxiliary cylinder, means for reciprocating the auxiliary piston, means for admitting vaporized fuel into the auxiliary cylinder, said fuel being compressed by the auxiliary piston and ignited in its cylinder, spring means between the auxiliary piston and its reciprocating means, said spring being adapted to yield when a predetermined pressure is reached in the auxiliary cylinder, valve means at the top of the auxiliary cylinder, and means for operating the valve means at predetermined intervals to permit burning gases to be injected into the power cylinder to ignite a compressed charge of fuel therein.

5. In combination with a power cylinder of an internal combustion engine having a power piston operating therein, an auxiliary cylinder situated adjacent the power cylinder and adapted to be brought into communication therewith, an auxiliary piston operating in the auxiliary cylinder, said auxiliary piston being formed in two sections slidably held together, means connected to the lower section for reciprocating the auxiliary piston, means for admitting vaporized fuel into the auxiliary cylinder, said fuel being compressed by the auxiliary piston and ignited in its cylinder, a compression spring between the two sections of the auxiliary piston, said spring being adapted to yield when a predetermined pressure is reached in the auxiliary cylinder, a valve means at the top of the auxiliary cylinder, and means for operating the valve means at predetermined intervals to permit burning gases to be injected into the power cylinder to ignite a compressed charge of fuel therein. 7

6. In combination with a power cylinder of an internal combustion engine having a power piston operating therein, an auxiliary cylinder situated adjacent the power cylinder and adapted to be brought into communication therewith, an auxiliary piston operating in the auxiliary cylinder, said auxiliary piston being connected to a crank formed on the crank-shaft cf the engine, an inlet port formed in the auxiliary cylinder, a valve adapted to control the inlet port, means for opening the port at predetermined intervals to admit vaporized fuel into the auxiliary cylinder, said fuel being compressed by the auxiliary piston and ignited in it cylinder, spring means between the auxiliary piston and its reciprocating means, said spring being adapted to yield when a predetermined pressure is reached in the auxiliary cylinder, valve means at the top of the auxiliary cylinder, and means for operating the valve means at predetermined intervals to permit burning gases to be injected into the power cylinder to ignite a compressed charge of fuel therein.

'7. In combination with a power cylinder of an 'nternal combustion engine having a power piston operating therein, an auxiliary cylinder independent of and situated adjacent the power cylinder and adapted to be brought into communication therewith, an auxiliary piston operating in the auxiliary cylinder, means for reciprocating the auxiliary piston, means for admitting the vaporized fuel into the auxiliary cylinder, said fuel being compressed by the auxiliary piston and ignited in its cylinder, means for retaining the burning gases in the auxiliary cylinder throughout substantially two strokes of the auxiliary piston, said latter piston being adapted to eject the burning gases into the power cylinder towards the end of said second stroke, spring means on the auxiliary piston permitting the latter to eject all the gases from the cylinder, and means for forming a substantial vacuum in the auxiliary cylinder into which the fresh charge of vaporized fuel is admitted.

8. In combination with a power cylinder of an internal combustion engine having a power piston operating therein, an auxiliary cylinder situated adjacent the power cylinder and adapted to be brought into communication therewith, an auxiliary piston operating in the auxiliary cylinder, means connecting the auxiliary piston to a crank formed on the crank-shaft of the engine, said auxiliary piston being positively reciprocated, means for admitting vaporized fuel into the auxiliary cylinder, said fuel being compressed by the auxiliary piston and ignited in its cylinder, and means for absorbing substantially any shock imparted to the auxiliary piston by the ignition of the fuel,

NELSON ELLIOTT.

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