CA1095834A - Engine with secondary piston - Google Patents
Engine with secondary pistonInfo
- Publication number
- CA1095834A CA1095834A CA346,747A CA346747A CA1095834A CA 1095834 A CA1095834 A CA 1095834A CA 346747 A CA346747 A CA 346747A CA 1095834 A CA1095834 A CA 1095834A
- Authority
- CA
- Canada
- Prior art keywords
- piston
- engine
- cylinder
- main
- main cylinder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Combustion Methods Of Internal-Combustion Engines (AREA)
Abstract
ENGINE WITH SECONDARY PISTON
Abstract An engine producing combustion of a fuel by com-pression rather than by spark ignition comprises a main engine cylinder having at least one secondary cylinder arranged at the upper portion of the cylinder chamber and in communication therewith. The piston of the secondary cylinder is driven by a cam arrangement in a direction transverse to the axis of the main cylinder and in synchronization therewith. The secondary piston operates in conjunction with the main piston, entering into the maximum compression phase when the main piston is at 0 degrees top dead center in the compression stroke to produce combustion by compression thereby eliminating the need for electric spark ignition.
Abstract An engine producing combustion of a fuel by com-pression rather than by spark ignition comprises a main engine cylinder having at least one secondary cylinder arranged at the upper portion of the cylinder chamber and in communication therewith. The piston of the secondary cylinder is driven by a cam arrangement in a direction transverse to the axis of the main cylinder and in synchronization therewith. The secondary piston operates in conjunction with the main piston, entering into the maximum compression phase when the main piston is at 0 degrees top dead center in the compression stroke to produce combustion by compression thereby eliminating the need for electric spark ignition.
Description
109~
ENGIN~ WITH ~ECONDARY PISTON
This invention relates to piston engines and partic-ularly to an improved internal combustion engine operat-ing upon the compression-ignition principle.
Because of the growing shortages of petroleum fuel needed for internal combustion engines, it is particular-ly important to provide engines having higher efficien-cies. Increasing ths compression ratio is one important approach to providing higher efficiency. However, as compression ratios are increased, so-called "compression-ignition" occurs because the compressed gases become sohot that the air-fuel mixture is ignited simply because of the high compression. Thus, it is difficult to raise the compression ratio much beyond the ratio used in present engine practice for electrical spark ignition engines because the compression ignition occurs too early in the compression cycle, resulting in poor engine performance.
Compression ignition is usefully employed in diesel engines, In those engines, the timing of the fuel burning is controlled by injecting the fuel only at the end of the compression stroke when combustion is desired.
~ J
e il~
~9S834 However, the fuel injection system of a diesel engine is subject to a high rate of wear, and the supply of diesel fuel in the total mix of distillates available from the petroleum industry is quite limited so that it is not physically possible to convert all internal combustion engines to the use of diesel fuel.
The present invention provides a solution to these problems in permitting the use of combustion ignition with fuels other than diesel fuels, especially fuels which are more volatile, such as gasoline, and in eliminat-ing the need for fuel injection, permitting the use of the less expensive low pressure fuel carburetors which are commonly used with electrical spark ignition engines.
At the same time, the need for spark plugs and electrical timing systems for the ignition is completely eliminated, and the need for periodic engine tune-ups is virtually eliminated. As a consequence, the engine of the present invention provides greater efficiency, more complete combustion of the fuel, and less pollution than conven-tional engines.
In carrying out the invention, there is provided anengine haviny at least one main engine cylinder with a piston mounted for travel within the chamber formed by the cylinder walls, at least one secondary cylinder ar-ranged at the upper boundary of said main cylinderchamber and defining a secondary cylinder chamber communi-1~9S834 cating with said main cylinder chamber, a secondary piston reciprocable within said secondary cylinAer, a piston rod coupled to said secondary piston at one end and coupled to a fixed pivot at the other end, said piston rod comprising two portions pivotably intercon-nected to provide an articulated knee, eccentric means driving said secondary piston rod to impart a rapid advancing compression motion to said secondary piston by straightening said articulated knee, spring means mounted opposite said eccentric means for driving said piston rod for retracting said second~ry piston, said eccentric means being operable to advance said secondary piston in conjunction with the substantial completion of the com-pression stroke by said main piston such that said secon-dary piston suddenly increases the fuel-air mixture pres-sure to produce combustion of the fuel in said main cylinder by compression ignition at the required time at the beginning of the power stroke.
In the accompanying drawings;
FIG. 1 is a schematic perspective view, partially in cross section, showing a preferred embodiment of the invention.
FIG. 2 is a side cross-sectional view of the embodi-ment of FIG. 1 showing the construction and operation of one of the secondary cylinders and pistons in more detail.
109S83~
FIG. 3 is a top view of the embodiment of FIG. 1 showing schematically the operation and arrangement of the secondary cylinders, and, FIGS. 4A, B, C and D are diagrammatical illustra-tions of the operation of the engine just before, andduring, the beginning of the power stroke.
~ eferring more particularly to FIG. 1, the engine 50 is shown to include a main cylinder 12 having a piston 10 with a plurality of rings 11. The piston 10 is connected to a main shaft (not shown) by piston rod 13.
A pair of secondary pistons 14 and 15 are arranged for reciprocation within secondary cylinders at the upper boundary 45 of the main cylinder in an opp~sed relation-ship. The secondary cylinders are ported into the top of the main cylindex so that the chamber formed by each secondaxy cylinder is in communication with the chamber formed by the main cylinder. The secondary pistons 14 and 15 are respectively connected to piston rods 16 and 17. Piston rods 16 and 17 each include two portions pivotally interconnected respectively at 18 and 21 to provide an articulated knee. The other ends of the respective piston rods 16 and 17 are respective]y con-nected to fixed pivots 23 and 24. Piston rods 16 and 17 are respectively driven by eccentric cams 19 and 20 against the action of return springs 25 and 26. The piston rods 16 and 17 are resiliently urged by the return ~09S~34 springs 25 and 26, respectively, to return to their initial positions against the urging of the cams 19 and 20.
As shown particularly in FIGS. 2 and 3, the secondary pistons 14 and 15 slide within piston guide bars 29a and 29b and 30a and 30b within the secondary cylinders and into the compression chambers 31 and 32 formed therein.
The engine cylinder 12 includes an exhaust valve ~3 and an intake valve 34. The intake valve 34 and the exhaust valve 33 are activated by respective rocker arms 35 and 36.
The operation of the engine is depicted schematically in FIGS. 4A, 4B, 4C, and 4D. FIG. 4A shows the piston 10 at a point 10 degrees before top dead center near the end of the compression stroke with the secondary pistons in a withdrawn position. The fuel-air mixture has been pre-viously introduced into the cylinder during an intake stroke from a carburetor through the intake valve. The engine is preferably a four cycle engine. In FIG. 4B the main cylinder is at 0 degrees top dead center at the com-pletion of the compression stroke and the secondary pistons have been substantially, but not completely ad-vanced. As shown in FIG. 4C, at approximately 5 degrees after top dead center, at the beginning of the power stroke the secondary pistons have been rapidly advanced, substantially raising the compression, and causing the 1~95834 compression ignition of the fuel-air mixture in the main cylinder chamber. The final FIG. 4D shows piston 10 at approximately 10 degrees beyond top dead center into the power stroke of the engine cylinder wherein the secondary pistons 14 and 15 are completely advanced into a forward position. "0" degrees represents the top most point of a circle in the aforementioned motion which is described by the rotating crank shaft.
It is an important feature and advantage of the present invention that the rapid advancing movements of the secondary pistons 14 and 15 at the end of the com-pression stroke of the main piston inherent from the articulated knee construction of the secondary piston rods provides for a rapid and sudden increase in the pressure of the fuel-air mixture at the precise time when compression ignition is required. Thus, precise control of the timing of the commencement of combustion is avail-able without the need for electrical spark ignition, and without the need for fuel injection.
While not illustrated, it will be understood that it is possible to provide that the connecting rod drive cams 19 and 20 may be adjustably positionable upon the asso-ciated cam shafts to provide for adjustment of the ignition point of the fuel. Such adjustments may be permanent, or means may be provided for adjusting the cams on an instan-taneous basis to permit a retardation of the ignition point during starting, with a subsequent advance of the ignition point after starting.
Also, while not shown, glow plugs may be provided in the engine for the purpose of enhancing the starting operation. Such glow plugs may be of the type which are common in diesel compression ignition engines.
The secondary piston drive cams 19 and 20 are pref-erably driven at the same rotational speed as the crank shaft of the engine so that the secondary pistons are advanced not only during the compression stroke of the main piston but also during the exhaust stroke of the main piston so as to enhance the complete exhaustion of com-bustion products from the engine.
The secondary pistons 14 and 15 are illustrated in the drawings as having a rectanqular cross section. This configuration is preferred because it permits a high compression ratio, especially when one of the long sides of the rectangular cross section of the piston is arranged adjacent to the upper margin of the main cylinder. ~30w-ever, it is within the scope of the invention to employcircular secondary pistons.
It is evident from the above description that the secondary piston cylinder chambers are in communication with the main cylinder. Preferably, a separate intercom-munication port or opening is provided from each secondarypiston chamher into the main piston chamber. Also, the ~095834 intake and exhaust valves communicate separately with the main piston chamber.
While the entire description above relates to the use of two secondary pistons for each main piston, it is quite obvious that the principles of the invention may be applied in a similar embodiment which simply omits one of the secondary pistons, since a single secondary piston will accomplish a substantial final increase in compres-sion.
Also, the invention has been described in terms of a single main cylinder. However, it will be understood that the same principles are applicable to an engine having a plurality of main cylinders, such as, for instance, four, six, or eight main cylinders for automotive use.
Because of the high compression in the engine of this invention, more power is developed per cylinder. Further-more, there is more efficient combustion and less pollution from the operation of the engine. The engine may be used with various fuels including gasoline, diesel fuel, etc.
and is simple and inexpensive to manufacture as well as having the aforementioned operating advantages.
ENGIN~ WITH ~ECONDARY PISTON
This invention relates to piston engines and partic-ularly to an improved internal combustion engine operat-ing upon the compression-ignition principle.
Because of the growing shortages of petroleum fuel needed for internal combustion engines, it is particular-ly important to provide engines having higher efficien-cies. Increasing ths compression ratio is one important approach to providing higher efficiency. However, as compression ratios are increased, so-called "compression-ignition" occurs because the compressed gases become sohot that the air-fuel mixture is ignited simply because of the high compression. Thus, it is difficult to raise the compression ratio much beyond the ratio used in present engine practice for electrical spark ignition engines because the compression ignition occurs too early in the compression cycle, resulting in poor engine performance.
Compression ignition is usefully employed in diesel engines, In those engines, the timing of the fuel burning is controlled by injecting the fuel only at the end of the compression stroke when combustion is desired.
~ J
e il~
~9S834 However, the fuel injection system of a diesel engine is subject to a high rate of wear, and the supply of diesel fuel in the total mix of distillates available from the petroleum industry is quite limited so that it is not physically possible to convert all internal combustion engines to the use of diesel fuel.
The present invention provides a solution to these problems in permitting the use of combustion ignition with fuels other than diesel fuels, especially fuels which are more volatile, such as gasoline, and in eliminat-ing the need for fuel injection, permitting the use of the less expensive low pressure fuel carburetors which are commonly used with electrical spark ignition engines.
At the same time, the need for spark plugs and electrical timing systems for the ignition is completely eliminated, and the need for periodic engine tune-ups is virtually eliminated. As a consequence, the engine of the present invention provides greater efficiency, more complete combustion of the fuel, and less pollution than conven-tional engines.
In carrying out the invention, there is provided anengine haviny at least one main engine cylinder with a piston mounted for travel within the chamber formed by the cylinder walls, at least one secondary cylinder ar-ranged at the upper boundary of said main cylinderchamber and defining a secondary cylinder chamber communi-1~9S834 cating with said main cylinder chamber, a secondary piston reciprocable within said secondary cylinAer, a piston rod coupled to said secondary piston at one end and coupled to a fixed pivot at the other end, said piston rod comprising two portions pivotably intercon-nected to provide an articulated knee, eccentric means driving said secondary piston rod to impart a rapid advancing compression motion to said secondary piston by straightening said articulated knee, spring means mounted opposite said eccentric means for driving said piston rod for retracting said second~ry piston, said eccentric means being operable to advance said secondary piston in conjunction with the substantial completion of the com-pression stroke by said main piston such that said secon-dary piston suddenly increases the fuel-air mixture pres-sure to produce combustion of the fuel in said main cylinder by compression ignition at the required time at the beginning of the power stroke.
In the accompanying drawings;
FIG. 1 is a schematic perspective view, partially in cross section, showing a preferred embodiment of the invention.
FIG. 2 is a side cross-sectional view of the embodi-ment of FIG. 1 showing the construction and operation of one of the secondary cylinders and pistons in more detail.
109S83~
FIG. 3 is a top view of the embodiment of FIG. 1 showing schematically the operation and arrangement of the secondary cylinders, and, FIGS. 4A, B, C and D are diagrammatical illustra-tions of the operation of the engine just before, andduring, the beginning of the power stroke.
~ eferring more particularly to FIG. 1, the engine 50 is shown to include a main cylinder 12 having a piston 10 with a plurality of rings 11. The piston 10 is connected to a main shaft (not shown) by piston rod 13.
A pair of secondary pistons 14 and 15 are arranged for reciprocation within secondary cylinders at the upper boundary 45 of the main cylinder in an opp~sed relation-ship. The secondary cylinders are ported into the top of the main cylindex so that the chamber formed by each secondaxy cylinder is in communication with the chamber formed by the main cylinder. The secondary pistons 14 and 15 are respectively connected to piston rods 16 and 17. Piston rods 16 and 17 each include two portions pivotally interconnected respectively at 18 and 21 to provide an articulated knee. The other ends of the respective piston rods 16 and 17 are respective]y con-nected to fixed pivots 23 and 24. Piston rods 16 and 17 are respectively driven by eccentric cams 19 and 20 against the action of return springs 25 and 26. The piston rods 16 and 17 are resiliently urged by the return ~09S~34 springs 25 and 26, respectively, to return to their initial positions against the urging of the cams 19 and 20.
As shown particularly in FIGS. 2 and 3, the secondary pistons 14 and 15 slide within piston guide bars 29a and 29b and 30a and 30b within the secondary cylinders and into the compression chambers 31 and 32 formed therein.
The engine cylinder 12 includes an exhaust valve ~3 and an intake valve 34. The intake valve 34 and the exhaust valve 33 are activated by respective rocker arms 35 and 36.
The operation of the engine is depicted schematically in FIGS. 4A, 4B, 4C, and 4D. FIG. 4A shows the piston 10 at a point 10 degrees before top dead center near the end of the compression stroke with the secondary pistons in a withdrawn position. The fuel-air mixture has been pre-viously introduced into the cylinder during an intake stroke from a carburetor through the intake valve. The engine is preferably a four cycle engine. In FIG. 4B the main cylinder is at 0 degrees top dead center at the com-pletion of the compression stroke and the secondary pistons have been substantially, but not completely ad-vanced. As shown in FIG. 4C, at approximately 5 degrees after top dead center, at the beginning of the power stroke the secondary pistons have been rapidly advanced, substantially raising the compression, and causing the 1~95834 compression ignition of the fuel-air mixture in the main cylinder chamber. The final FIG. 4D shows piston 10 at approximately 10 degrees beyond top dead center into the power stroke of the engine cylinder wherein the secondary pistons 14 and 15 are completely advanced into a forward position. "0" degrees represents the top most point of a circle in the aforementioned motion which is described by the rotating crank shaft.
It is an important feature and advantage of the present invention that the rapid advancing movements of the secondary pistons 14 and 15 at the end of the com-pression stroke of the main piston inherent from the articulated knee construction of the secondary piston rods provides for a rapid and sudden increase in the pressure of the fuel-air mixture at the precise time when compression ignition is required. Thus, precise control of the timing of the commencement of combustion is avail-able without the need for electrical spark ignition, and without the need for fuel injection.
While not illustrated, it will be understood that it is possible to provide that the connecting rod drive cams 19 and 20 may be adjustably positionable upon the asso-ciated cam shafts to provide for adjustment of the ignition point of the fuel. Such adjustments may be permanent, or means may be provided for adjusting the cams on an instan-taneous basis to permit a retardation of the ignition point during starting, with a subsequent advance of the ignition point after starting.
Also, while not shown, glow plugs may be provided in the engine for the purpose of enhancing the starting operation. Such glow plugs may be of the type which are common in diesel compression ignition engines.
The secondary piston drive cams 19 and 20 are pref-erably driven at the same rotational speed as the crank shaft of the engine so that the secondary pistons are advanced not only during the compression stroke of the main piston but also during the exhaust stroke of the main piston so as to enhance the complete exhaustion of com-bustion products from the engine.
The secondary pistons 14 and 15 are illustrated in the drawings as having a rectanqular cross section. This configuration is preferred because it permits a high compression ratio, especially when one of the long sides of the rectangular cross section of the piston is arranged adjacent to the upper margin of the main cylinder. ~30w-ever, it is within the scope of the invention to employcircular secondary pistons.
It is evident from the above description that the secondary piston cylinder chambers are in communication with the main cylinder. Preferably, a separate intercom-munication port or opening is provided from each secondarypiston chamher into the main piston chamber. Also, the ~095834 intake and exhaust valves communicate separately with the main piston chamber.
While the entire description above relates to the use of two secondary pistons for each main piston, it is quite obvious that the principles of the invention may be applied in a similar embodiment which simply omits one of the secondary pistons, since a single secondary piston will accomplish a substantial final increase in compres-sion.
Also, the invention has been described in terms of a single main cylinder. However, it will be understood that the same principles are applicable to an engine having a plurality of main cylinders, such as, for instance, four, six, or eight main cylinders for automotive use.
Because of the high compression in the engine of this invention, more power is developed per cylinder. Further-more, there is more efficient combustion and less pollution from the operation of the engine. The engine may be used with various fuels including gasoline, diesel fuel, etc.
and is simple and inexpensive to manufacture as well as having the aforementioned operating advantages.
Claims (7)
1. An engine having at least one main engine cylinder with a piston mounted for travel within the chamber formed by the cylinder walls, at least one secondary cylinder arranged at the upper boundary of said main cylinder chamber and defining a secondary cylinder chamber communicating with said main cylinder chamber, a secondary piston reciprocable within said secondary cylinder, a piston rod coupled to said secondary piston at one end and coupled to a fixed pivot at the other end, said piston rod comprising two portions pivotably interconnected to provide an articulated knee, eccentric means driving said secondary piston rod to impart a rapid advancing compression motion to said secondary piston by straightening said articulated knee, spring means mounted opposite said eccentric means for driving said piston rod for retracting said secondary piston, said eccentric means being operable to advance said secondary piston in conjunction with the substan-tial completion of the compression stroke by said main piston such that said secondary piston suddenly increases the fuel-air mixture pressure to produce combustion of the fuel in said main cylinder by compression ignition at the required time at the beginning of the power stroke.
2. An engine as claimed in claim 1 wherein said engine is a four-cycle engine and wherein said secondary piston is driven in substantial synchronism with said main cylinder including advancement of said secondary piston during the exhaust stroke in order to provide complete expulsion of the products of combustion from said main cylinder.
3. An engine as claimed in claim 1 wherein said secondary cylinder is arranged transverse to said main cylinder.
4. An engine as claimed in claim 3 wherein said secondary cylinder is rectangular in cross section and said secondary piston is substantially rectangular in cross section in order to provide for a high compression ratio, one of the longer sides of the rectangular cross section of the piston being arranged and positioned adjacent to and parallel to the upper surface of the main piston when in the advanced position, and a communication port interconnecting the top of the main cylinder and the adjacent long side of said secondary cylinder.
_10-
_10-
5. An engine as claimed in claim 3 wherein two secondary cylinders are provided at the upper boundary of said main cylinder chamber with two secondary pistons reciprocable within said respective secondary cylinders, said secondary cylinders being arranged side by side at the upper boundary of said main cylinder chamber and both of said cylinders being separately in communication with said main cylinder chamber through intercommunication ports.
6. An engine as claimed in claim 5 wherein the intake and exhaust valves for said main cylinder are positioned in the head of said main cylinder with one of said valves being positioned adjacent to the end of each of said respective secondary cylinders so that the upper end of said main engine cylinder is separately in com-munication with each of said valves and with each of said secondary cylinders.
7. An engine as claimed in claim 6 wherein there are provided a plurality of piston guide bars positioned within each of said secondary cylinders and arranged for guiding the reciprocable movement of said secondary pistons.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA346,747A CA1095834A (en) | 1980-02-29 | 1980-02-29 | Engine with secondary piston |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA346,747A CA1095834A (en) | 1980-02-29 | 1980-02-29 | Engine with secondary piston |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1095834A true CA1095834A (en) | 1981-02-17 |
Family
ID=4116371
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA346,747A Expired CA1095834A (en) | 1980-02-29 | 1980-02-29 | Engine with secondary piston |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1095834A (en) |
-
1980
- 1980-02-29 CA CA346,747A patent/CA1095834A/en not_active Expired
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |