WO2015125168A1 - 2-stroke engine having variable volume crankcase chamber functioning as supercharger - Google Patents
2-stroke engine having variable volume crankcase chamber functioning as supercharger Download PDFInfo
- Publication number
- WO2015125168A1 WO2015125168A1 PCT/IT2015/000041 IT2015000041W WO2015125168A1 WO 2015125168 A1 WO2015125168 A1 WO 2015125168A1 IT 2015000041 W IT2015000041 W IT 2015000041W WO 2015125168 A1 WO2015125168 A1 WO 2015125168A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- shoulders
- mobile
- reciprocating
- piston
- stroke engine
- Prior art date
Links
- 238000005086 pumping Methods 0.000 claims abstract description 37
- 125000004122 cyclic group Chemical group 0.000 claims abstract description 22
- 230000008878 coupling Effects 0.000 claims abstract description 13
- 238000010168 coupling process Methods 0.000 claims abstract description 13
- 238000005859 coupling reaction Methods 0.000 claims abstract description 13
- 238000002485 combustion reaction Methods 0.000 claims abstract description 10
- 230000000694 effects Effects 0.000 claims abstract description 5
- 230000003993 interaction Effects 0.000 claims description 6
- 238000013459 approach Methods 0.000 claims description 5
- 238000010586 diagram Methods 0.000 claims description 5
- 239000002283 diesel fuel Substances 0.000 claims description 3
- 230000009467 reduction Effects 0.000 claims description 3
- 230000006835 compression Effects 0.000 claims description 2
- 238000007906 compression Methods 0.000 claims description 2
- 238000003780 insertion Methods 0.000 claims description 2
- 230000037431 insertion Effects 0.000 claims description 2
- 239000012530 fluid Substances 0.000 claims 2
- 239000000446 fuel Substances 0.000 claims 1
- 239000000203 mixture Substances 0.000 description 9
- 239000007789 gas Substances 0.000 description 6
- 238000005406 washing Methods 0.000 description 4
- 230000008901 benefit Effects 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000007792 addition Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B33/00—Engines characterised by provision of pumps for charging or scavenging
- F02B33/02—Engines with reciprocating-piston pumps; Engines with crankcase pumps
- F02B33/24—Engines with reciprocating-piston pumps; Engines with crankcase pumps with crankcase pumps other than with reciprocating pistons only
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
- F02B75/00—Other engines
- F02B75/02—Engines characterised by their cycles, e.g. six-stroke
- F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
- F02B2075/025—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle two
Definitions
- This invention refers to a reciprocating internal combustion supercharged two-stroke engine, in which the overpressure of power is due to a particular conformation of the motor shaft which is able to cause a cyclic variation of the volume of the pumping chamber that is added to that caused by the reciprocating movement of the piston.
- the two-stroke engine has in its lightness, simplicity and economy of construction its most important qualities, but currently it is used only in small displacements due to the high consumption and excessive pollution caused mainly by the loss of unburned hydrocarbons from the exhaust.
- One of the main defects of existing engines with two-stroke cycle is to have a low pumping pressure (0.2 - 0.4 bar) which results in a low value of torque as a function of number of cycles.
- This invention aims to solve these problems also because there will be a considerable development of gasoline direct injection into the combustion chamber in the near future. This technique became mandatory in Formula 1 engines in 2014 and it will bring a remarkable development of related technology, which can be applied to two-stroke engines, making them still current and clean.
- the purpose of this invention is to greatly increase the washing pressure of the fresh gas in the pump housing and, not being able to use expensive turbo compressors due to the low exhaust pressure, and to allow to have a diagram of opening of the exhaust ports and less stringent racking. This fact allows to better exploit the stroke of the piston in the expansion phase of the gases, significantly increasing the torque and improving the washing and, with a higher pressure of the fresh gas inlet of the cylinder, while also improve the combustion.
- a field of application of an engine with these features may be that of an auxiliary motor for electric cars being very light and powerful, and since it works in a regime of fixed speed it would be easily controlled in exhaust pipe emissions.
- the purpose of the invention is achieved through a two-stroke reciprocating internal combustion engine, in accordance with claim 1 , in which the drive shaft includes a pair of fixed shoulders, rigidly connected by a pin coupling, which rotates on the corresponding housings in a crankcase.
- the rotation of the motor shaft and the resulting reciprocating movement of the piston cause the cyclic variation of the volume of a pumping chamber.
- the reciprocating motion of the piston is obtained by a connecting rod whose head is mounted on the plug coupling, with a particular conformation of the drive shaft adapted to create an additional cyclic variation of the volume of the pumping chamber, the further cyclic variation when added to that caused by the reciprocating motion of the piston, it increases the difference between minimum and maximum volumes obtainable for the only effect of the piston stroke.
- the effect of cyclically varying the volume of the pumping chamber is obtained by a pair of mobile shoulders, adjacent to the mentioned pair of fixed shoulders and mounted so as to axially slide in the two directions of a few millimetres, the axial sliding causing further variation cyclic volume of the pumping chamber, means being provided to cause the axial sliding in a cyclic manner so that when the piston is at B.D.C. (bottom dead centre) the two mobile shoulders are at the minimum mutual distance, and the pumping chamber has minimum volume; while, when the piston is at T.D.C.(top dead centre), the two mobile shoulders are at the maximum mutual distance and the pumping chamber has the maximum volume.
- balandng shaft crank As previously illustrated, the manufacturers of two-stroke engines are forced to realize the shoulders of the motor shaft in a cylindrical shape to minimize the space within carter-pump, but the ideal configuration for the balance of the reciprocating masses of the motor shaft is the crankshaft as in the 4-stroke engines in order to counterbalance the weight of the connecting rod and the piston.
- the invention using two mobile shoulders covering the fixed left and right shoulders of the drive shaft allows to correctly size this component without increasing the space in the crankcase-pump also using a shape crankshaft and without resorting to expensive counter-balancing shafts that absorb power.
- Any vibrations that can be created by the axial movement of the mobile shoulders that cover the fixed shoulders of the motor shaft can cancel each other having an opposite motion.
- the engine - according to the invention - has the characteristics indicated in the independent claims 1- further advantageous features of such an engine are indicated in the dependent claims.
- the mentioned engine (100) is characterized by comprising a particular motor shaft able to create a cyclic variation of the volume of a pumping chamber (101) able to create a supercharger of the engine (100).
- the crankshaft of a two-stroke engine includes a pair of fixed shoulders (6), connected by a pin coupling (4), which rotate on the corresponding housings in a crankcase (3).
- the pin (4) rigidly connects the two shoulders (6) in such a way that the motor shaft can carry out the function.
- on the plug (4) is mounted a connecting rod (1), on which is mounted a piston (2) that linearly slides inside a cylinder (not shown).
- the two fixed shoulders (6) identify together with the crankcase (3) the pumping chamber (101), the volume of which cyclically varies as a result of the movement of the piston (2).
- the mobile shoulders (5) Adjacent to the fixed shoulders (6), there are the mobile shoulders (5) which are mounted so as to slide axially a few millimetres, since there are means provided to cause the axial sliding.
- the axial sliding which is cyclic and in the two directions, causes a cyclic variation of the volume of the pumping chamber (101).
- the volume of the pumping chamber (101) is reduced when the two mobile shoulders (5) approach each other, while increases when they move apart.
- the sliding of the mobile shoulders (5) is favoured by the interposition of bushes (7) between a seat specially formed on the mobile shoulders (5) and the plug coupling (4).
- the fixed shoulders (6) are provided with balancing masses (6a). This is possible because the mobile shoulders (5) enclose the fixed shoulders (6), so it is the set of the two shoulders, fixed and mobile, which externally appears as a traditional cylindrical fixed shoulder, therefore it does not create problems of increase of the volume of the pumping chamber (101).
- the invention using two mobile shoulders (5) covering the fixed shoulders (6), allows to realize the balancing masses (6a), thus avoiding the use of expensive counter- balancing shafts which absorb power.
- the balancing masses can be implemented on mobile shoulders (5) (not shown) or on both.
- these means able to cause axial sliding of the mobile shoulders (5) include: • a first sliding track (10), circular and coaxial with the pin coupling (4), realized on mobile shoulders (5);
- the shape of the sliding tracks, in relation to the position chosen for the projections (8) and the roller (9) is such that when the piston (2) is at B.D.C. the two mobile shoulders (5) are at the minimum mutual distance, while when the piston (2) is at T.D.C., the two mobile shoulders are at the maximum mutual distance. It follows that when the piston is at B.D.C. the pumping chamber (101) has the minimum volume, while when the piston (2) is at T.D.C., the pumping chamber (101) has the maximum volume.
- these means able to cause axial sliding of the mobile shoulders (5) include a pair of pins (12), integral with the engine casing (3) which engage a third raceway (13), suitably shaped according to the distribution diagram, formed on the outer circumference of the mobile shoulders (5).
- these means able to cause axial sliding of the mobile shoulders (5) comprise a fourth raceway (15), in relief, and a pair of rollers (14), positioned in the lower part of the crankcase (3), ranging in contact with the sliding track (15). Even the fourth sliding track (15) is shaped as a function of the distribution diagram.
- these means able to cause axial sliding of the mobile shoulders (5) include:
- the example of application has been done with reference to a classic two-stroke engine, powered with gasoline mixed with oil, in which in the pumping chamber (101) passes a mixture gas - air.
- the power supply can only be made with air and through the use of an injector (not shown), designed to inject gasoline directly into the combustion chamber (not shown).
- the washing step is carried out with air only, with a consequent strong reduction of consumption, since dispersions of unburned hydrocarbons to the exhaust are avoided.
- the engine according to the invention can also operate according to the two-stroke cycle engines. This can be achieved by performing the power supply only with air and through the use of an injector (not shown), designed to inject diesel fuel directly into the combustion chamber (not shown).
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Cylinder Crankcases Of Internal Combustion Engines (AREA)
Abstract
This invention relates to a supercharged reciprocating internal combustion two-stroke engine, in which the supercharging effect is due to a particular configuration of the motor shaft which is able to cause a cyclic variation of the volume of the pumping chamber that is added to that caused by the reciprocating movement of the piston. In the engine (100) according to the invention, the drive shaft has a pair of fixed shoulders (6), rigidly connected by a pin couplings (4), which rotate in the corresponding housings in a crankcase (3). The rotation of the drive shaft and the resulting reciprocating movement of the piston (2) causing the cyclic variation of the volume of a pumping chamber (101), the reciprocating motion of the piston (2) being obtained through a connecting rod (1), whose connecting rod head (la) is mounted on the coupling pin (4) is characterized by a particular configuration of the drive shaft adapted to create an additional cyclic variation of the volume of the pumping chamber (101). The additional cyclic variation when added to that caused by the reciprocating motion of the piston (2), increases the difference between minimum and maximum volumes obtainable by the effect of the piston stroke (2) alone.
Description
2-STROKE ENGINE HAVING VARIABLE VOLUME CRANKCASE
CHAMBER FUNCTIONING AS SUPERCHARGER
This invention refers to a reciprocating internal combustion supercharged two-stroke engine, in which the overpressure of power is due to a particular conformation of the motor shaft which is able to cause a cyclic variation of the volume of the pumping chamber that is added to that caused by the reciprocating movement of the piston.
The two-stroke engine has in its lightness, simplicity and economy of construction its most important qualities, but currently it is used only in small displacements due to the high consumption and excessive pollution caused mainly by the loss of unburned hydrocarbons from the exhaust.
One of the main defects of existing engines with two-stroke cycle is to have a low pumping pressure (0.2 - 0.4 bar) which results in a low value of torque as a function of number of cycles.
This problem has forced manufacturers to reduce to a minimum the spaces inside the crankcase-pump with various solutions, but in certain points this reduction is not physically possible. This occurs in the inner part of the piston, in the area of movement of the connecting rod and in the space occupied by the transfer ducts.
In these areas the fresh gases are compressed in the descent phase of the piston but being compressible gas do not allow an appropriate increase of the washing pressure that is given only by the volume of air that compresses the piston in its downward stroke which is equivalent to the displacement.
This invention aims to solve these problems also because there will be a considerable development of gasoline direct injection into the combustion chamber in the near future. This technique became mandatory in Formula 1 engines in 2014 and it will bring a remarkable development of related technology, which can be applied to two-stroke engines, making them still current and clean.
The purpose of this invention is to greatly increase the washing pressure of the fresh gas in the pump housing and, not being able to use expensive turbo compressors due to the low exhaust pressure, and to allow to have a diagram of opening of the exhaust ports and less stringent racking. This fact allows to better exploit the stroke of the piston in the expansion phase of the gases, significantly increasing the torque and improving
the washing and, with a higher pressure of the fresh gas inlet of the cylinder, while also improve the combustion.
A field of application of an engine with these features may be that of an auxiliary motor for electric cars being very light and powerful, and since it works in a regime of fixed speed it would be easily controlled in exhaust pipe emissions.
The purpose of the invention is achieved through a two-stroke reciprocating internal combustion engine, in accordance with claim 1 , in which the drive shaft includes a pair of fixed shoulders, rigidly connected by a pin coupling, which rotates on the corresponding housings in a crankcase. The rotation of the motor shaft and the resulting reciprocating movement of the piston cause the cyclic variation of the volume of a pumping chamber. The reciprocating motion of the piston is obtained by a connecting rod whose head is mounted on the plug coupling, with a particular conformation of the drive shaft adapted to create an additional cyclic variation of the volume of the pumping chamber, the further cyclic variation when added to that caused by the reciprocating motion of the piston, it increases the difference between minimum and maximum volumes obtainable for the only effect of the piston stroke.
The effect of cyclically varying the volume of the pumping chamber is obtained by a pair of mobile shoulders, adjacent to the mentioned pair of fixed shoulders and mounted so as to axially slide in the two directions of a few millimetres, the axial sliding causing further variation cyclic volume of the pumping chamber, means being provided to cause the axial sliding in a cyclic manner so that when the piston is at B.D.C. (bottom dead centre) the two mobile shoulders are at the minimum mutual distance, and the pumping chamber has minimum volume; while, when the piston is at T.D.C.(top dead centre), the two mobile shoulders are at the maximum mutual distance and the pumping chamber has the maximum volume.
Another advantage of this solution concerns the balandng shaft crank. As previously illustrated, the manufacturers of two-stroke engines are forced to realize the shoulders of the motor shaft in a cylindrical shape to minimize the space within carter-pump, but the ideal configuration for the balance of the reciprocating masses of the motor shaft is the crankshaft as in the 4-stroke engines in order to counterbalance the weight of the connecting rod and the piston.
The invention using two mobile shoulders covering the fixed left and right shoulders of the drive shaft allows to correctly size this component without increasing the space in
the crankcase-pump also using a shape crankshaft and without resorting to expensive counter-balancing shafts that absorb power.
Any vibrations that can be created by the axial movement of the mobile shoulders that cover the fixed shoulders of the motor shaft can cancel each other having an opposite motion.
The engine - according to the invention - has the characteristics indicated in the independent claims 1- further advantageous features of such an engine are indicated in the dependent claims.
The invention will now be described, with illustrative and not limitative purpose, according to a preferred embodiment and with reference to the attached pictures, in which:
• Pictures 1 (a, b, c) show assembled and unexploded two-stroke engine according to the invention;
• Pictures 2 (a, b, c), 3 (a, b, c) and 4 (a, b, c) show the variations of the control system of the axial movement of the mobile shoulders;
• Picture 5 shows a detail of the coupling of the fixed shoulders with the mobile shoulders;
• Picture 6 shows a directional valve positioned on the mobile shoulders.
The application example will be made with reference to a classic two-stroke engine, powered with gasoline mixed with oil.
Later it will be shown how the power can be made by direct injection of gasoline or diesel fuel.
With reference to pictures 1 (a, b, c), with (100) it is indicated a two-stroke reciprocating internal combustion engine, according to the invention. The mentioned engine (100) is characterized by comprising a particular motor shaft able to create a cyclic variation of the volume of a pumping chamber (101) able to create a supercharger of the engine (100).
According to the prior art, the crankshaft of a two-stroke engine includes a pair of fixed shoulders (6), connected by a pin coupling (4), which rotate on the corresponding housings in a crankcase (3). The pin (4) rigidly connects the two shoulders (6) in such a way that the motor shaft can carry out the function. Again according to the known technique, on the plug (4) is mounted a connecting rod (1), on which is mounted a piston (2) that linearly slides inside a cylinder (not shown).
The two fixed shoulders (6), of cylindrical shape, identify together with the crankcase (3) the pumping chamber (101), the volume of which cyclically varies as a result of the movement of the piston (2). It happens that the volume of the pumping chamber (101) increases when the piston (2) performs its stroke toward the T.D.C. and decreases when the piston (2) carries out its movement to the B.D.C. Through a coordinated movement of special valves (lamellar or rotating), when the volume of the pumping chamber (101 ) increases, the carburettor passes a mixture petrol - air, while when the volume of the pumping chamber (101 ) decreases, this mixture petrol - air is poured into the cylinder. What has been just described is already known in details, both functional and constructive, so it will not be further described.
Adjacent to the fixed shoulders (6), there are the mobile shoulders (5) which are mounted so as to slide axially a few millimetres, since there are means provided to cause the axial sliding. The axial sliding, which is cyclic and in the two directions, causes a cyclic variation of the volume of the pumping chamber (101). In particular, the volume of the pumping chamber (101) is reduced when the two mobile shoulders (5) approach each other, while increases when they move apart. The sliding of the mobile shoulders (5) is favoured by the interposition of bushes (7) between a seat specially formed on the mobile shoulders (5) and the plug coupling (4).
To avoid loss of pressure in the compression phase, due to leakage of gasoline mixture - air between the pumping chamber (101) and a gap (18) existing between the mobile shoulder (5) and the fixed shoulder (6), it is preferable to use at least one seal segment (20), as shown in picture 5.
As it can be observed from picture 1c, the fixed shoulders (6) are provided with balancing masses (6a). This is possible because the mobile shoulders (5) enclose the fixed shoulders (6), so it is the set of the two shoulders, fixed and mobile, which externally appears as a traditional cylindrical fixed shoulder, therefore it does not create problems of increase of the volume of the pumping chamber (101).
The invention, using two mobile shoulders (5) covering the fixed shoulders (6), allows to realize the balancing masses (6a), thus avoiding the use of expensive counter- balancing shafts which absorb power.
Alternatively, the balancing masses can be implemented on mobile shoulders (5) (not shown) or on both.
According to a first preferred realization, shown in pictures 1 (a, b, c), these means able to cause axial sliding of the mobile shoulders (5) include:
• a first sliding track (10), circular and coaxial with the pin coupling (4), realized on mobile shoulders (5);
• a second sliding track (1 1), which is also circular and realized on mobile shoulders (5), but coaxial with the axis of rotation of the motor shaft;
· a pair of projections (8) made on the two sides of the connecting rod head (1a), the projections (8) being in contact with said first sliding track (10);
• a pair of rollers (9), positioned in the lower part of the crankcase (3) that get in contact with the second sliding track (11).
The interaction between these projections (8), formed on the connecting rod head (1 a), and the first sliding track (10) cause the mutual spacing of the mobile shoulders (5). The interaction between the rollers (9) and the second sliding track (11) causes the mutual approach of the mobile shoulders (5). The shape of the sliding tracks, in relation to the position chosen for the projections (8) and the roller (9) is such that when the piston (2) is at B.D.C. the two mobile shoulders (5) are at the minimum mutual distance, while when the piston (2) is at T.D.C., the two mobile shoulders are at the maximum mutual distance. It follows that when the piston is at B.D.C. the pumping chamber (101) has the minimum volume, while when the piston (2) is at T.D.C., the pumping chamber (101) has the maximum volume.
On the basis of what is described, it is evident that:
· when the piston (2) rises to T.D.C. the volume of the pumping chamber (101) increases more than it would grow in the absence of the mobile shoulders (5), so it is able to suck a greater amount of gasoline mixture - air;
• when the piston (2) descends towards the B.D.C. the volume of the pumping chamber (101) is reduced more than it would be reduced in the absence of the mobile shoulders (5), and then it is able to decant in the cylinder the greater amount of gasoline mixture - sucked air.
According to a second preferred realization, shown in pictures 2 (a, b, c), these means able to cause axial sliding of the mobile shoulders (5) include a pair of pins (12), integral with the engine casing (3) which engage a third raceway (13), suitably shaped according to the distribution diagram, formed on the outer circumference of the mobile shoulders (5).
According to a third preferred realization, shown in pictures 3 (a, b, c), these means able to cause axial sliding of the mobile shoulders (5) comprise a fourth raceway (15), in relief, and a pair of rollers (14), positioned in the lower part of the crankcase (3), ranging
in contact with the sliding track (15). Even the fourth sliding track (15) is shaped as a function of the distribution diagram.
According to a fourth preferred realization, shown in pictures 4 (a, b, c), these means able to cause axial sliding of the mobile shoulders (5) include:
· the above-mentioned first sliding track (10), circular and coaxial with the pin coupling (4), realized on mobile shoulders (5);
• the above-mentioned pair of projections (8) made on the two sides of the connecting rod head (1a), these projections (8) being in contact with the first sliding track (10);
• one or more elastic elements, for example of the helical springs (17), interposed between the fixed shoulders (6) and the mobile shoulders (5), so as to cause the removal of the mobile shoulders (5) from the fixed shoulders (6).
The interaction between the projections (8), formed on the connecting rod head (1a), and the first sliding track (10) causes the mutual spacing of the mobile shoulders (5). The thrust of the springs (17) instead causes the mutual approach of the mobile shoulders (5).
Alternatively or in addition to the use of these springs (17) in order to cause the removal of the mobile shoulders (5) from the fixed shoulders (6), it can be used the same mixture petrol - pressurized air. The insertion of this mixture petrol - air interspace (18) between the two shoulders facing, takes place through an unidirectional valve (21) (picture 6) positioned on one of the two shoulders. It happens that, during the step of reducing the volume of the pumping chamber (101) the mixture of gasoline - air passes from the pumping chamber (101) to the interspace (18), but not vice versa in the phase of increase in the volume of the chamber pumping (101), this passage stopping when the pressure in the cavity equals the maximum value reached in the pumping chamber (101).
The example of application has been done with reference to a classic two-stroke engine, powered with gasoline mixed with oil, in which in the pumping chamber (101) passes a mixture gas - air. Alternatively the power supply can only be made with air and through the use of an injector (not shown), designed to inject gasoline directly into the combustion chamber (not shown). In this case it has the considerable advantage that the washing step is carried out with air only, with a consequent strong reduction of consumption, since dispersions of unburned hydrocarbons to the exhaust are avoided. The engine according to the invention can also operate according to the two-stroke cycle engines. This can be achieved by performing the power supply only with air and
through the use of an injector (not shown), designed to inject diesel fuel directly into the combustion chamber (not shown).
The invention has been shown and described only with reference to a particular realization and to a very limited number of variants. However it will be clear to experts that various changes, substitutions and additions of parts with others having equivalent functions may be made without departing from the purpose defined by the following claims.
Claims
1. endothermic reciprocating two-stroke engine (100), whose motor shaft includes a pair of fixed shoulders (6), rigidly connected by a pin coupling (4), which rotate on the corresponding housings in a crankcase motor (3), the rotation of the drive shaft and the resulting reciprocating movement of the piston (2) cause the cyclic variation of the volume of a pumping chamber (101), the reciprocating motion of the piston (2) being obtained through a connecting rod (1), whose connecting rod head (1a) is mounted on the above-mentioned coupling pin (4), characterized in that it includes a particular conformation of the drive shaft adapted to create an additional cyclic variation of the volume of the pumping chamber (101), the additional cyclic variation when added to that caused by the reciprocating motion of the piston (2), so as to increase the difference between minimum and maximum volumes obtainable for the only effect of the piston stroke (2).
2. endothermic reciprocating two-stroke engine (100), according to claim 1 , characterized in that it includes a pair of mobile shoulders (5), adjacent to the pair of fixed shoulders (6) and mounted so as to slide axially in two lines of some millimetres, the axial sliding causing additional cyclic variation of the volume of the pumping chamber (101), means being provided to cause the axial sliding in a cyclic manner so that when the piston (2) is at B.D.C. the two mobile shoulders (5) are at the minimum mutual distance, and the pumping chamber (101) has the minimum volume, while when the piston (2) is at T.D.C., the two mobile shoulders (5) are at the maximum mutual distance and pumping chamber (101) has the maximum volume.
3. endothermic reciprocating two-stroke engine (100), according to claim 2, characterized in the mentioned means, able to cause axial sliding in a cyclic manner, include:
• a first sliding track (10), circular and coaxial with the pin coupling (4), realized on the mentioned mobile shoulders (5);
• a second sliding track (11), which is also circular and carried on the mobile shoulders (5), but coaxial with the axis of rotation of the motor shaft;
• a pair of projections (8) made on the two sides of the connecting rod head (1a), the projections (8) being in contact with the first sliding track (10);
• a pair of rollers (9), set on the engine crankcase (3) that get in contact with the second sliding track (11); in which:
• the interaction between the projections (8), formed on the connecting rod head (1a), and the first sliding track (10) causes the mutual spacing of the mobile shoulders (5);
• the interaction between the rollers (9) and the second sliding track (11) causes the mutual approach of the mobile shoulders (5).
4. endothermic reciprocating two-stroke engine (100), according to claim 2, characterized in those means, able to cause axial sliding in a cyclic manner, include a pair of pins (12), integral with the crankcase (3) which engage a third raceway (13), suitably shaped according to the distribution diagram, formed on the outer circumference of the mobile shoulders (5),
5. endothermic reciprocating two-stroke engine (100), according to claim 2, characterized in those means, able to cause axial sliding in a cyclic manner, include a pair of rollers (14), positioned on the engine crankcase (3), ranging contact a fourth raceway (15), in relief and suitably shaped according to the distribution diagram, formed on the outer circumference of the mobile shoulders (5).
6. endothermic reciprocating two-stroke engine (100), according to claim 2, characterized in those means, able to cause axial sliding in a cyclic manner, include:
• the first sliding track (10), circular and coaxial with the pin coupling (4), realized on mobile shoulders (5);
• the pair of projections (8) made on the two sides of the connecting rod head (1a), the projections (8) being in contact with the first sliding track (10);
• elastic means, interposed between the fixed shoulders (6) and the mobile shoulders (5), so as to cause the removal of the mobile shoulders (5) from the fixed shoulders (6); the interaction between the projections (8), formed on the connecting rod head (1a), and the first sliding track (10) causing the moving apart of the mobile shoulders (5) and the thrust of the elastic means causing instead mutual approach of the mobile shoulders (5).
7 endothermic reciprocating two-stroke engine (100), according to claim 6, characterized in that elastic means include helical springs.
8. endothermic reciprocating two-stroke engine (100), according to claim 6, characterized in the elastic means include a pressurized gaseous fluid inserted in a gap (18) between the fixed shoulder (6) and the adjacent mobile shoulder (5), there being provided a one-way valve (21) positioned on one of the two shoulders, the insertion taking place during the phase of reduction of the volume of the pumping chamber (101)
and stopping when the pressure in the cavity (18) equals the maximum value reached in the pumping chamber (101).
9. endothermic reciprocating two-stroke engine (100), according to any of claims 1 to 8, characterized in that it provides the use of an injector for injecting fuel directly into the combustion chamber.
10. endothermic reciprocating two-stroke engine (100), according to any of claims 1 to 8, characterized in that it provides the use of an injector adapted to inject diesel fuel directly into the combustion chamber.
11. endothermic reciprocating two-stroke engine (100), according to any one of claims 1 to 10, characterized in that it includes balancing masses (6a) formed on the fixed shoulders (6) or mobile (5) or both, the set of two shoulders, fixed (6) and mobile (5), externally presenting smooth surfaces.
12. endothermic reciprocating two-stroke engine (100), according to any one of claims 1 to 11 , characterized in that it includes at least one seal segment (20), between the mobile shoulder (5) and the fixed shoulder (6) suitable to avoid loss of pressure in the compression phase, due to leakage of gaseous fluid between the pumping chamber (101) and the interspace (18) and vice versa.
Applications Claiming Priority (2)
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ITSO2014A000002 | 2014-02-21 | ||
ITSO20140002 | 2014-02-21 |
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PCT/IT2015/000041 WO2015125168A1 (en) | 2014-02-21 | 2015-02-16 | 2-stroke engine having variable volume crankcase chamber functioning as supercharger |
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Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4712520A (en) * | 1986-07-25 | 1987-12-15 | John Pasquin | Crank case compressor unit for a two cycle engine |
DE19541127A1 (en) * | 1995-10-27 | 1997-04-30 | Gunar Unger | Crankshaft for two-stroke engine |
WO2004011786A1 (en) * | 2002-07-30 | 2004-02-05 | Julian George Daniel Branston | Improvements in or relating to reciprocating piston engines |
US7000581B1 (en) * | 2002-09-10 | 2006-02-21 | Nagesh S. Mavinahally | Mono-shaft four-stroke engine |
-
2015
- 2015-02-16 WO PCT/IT2015/000041 patent/WO2015125168A1/en active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4712520A (en) * | 1986-07-25 | 1987-12-15 | John Pasquin | Crank case compressor unit for a two cycle engine |
DE19541127A1 (en) * | 1995-10-27 | 1997-04-30 | Gunar Unger | Crankshaft for two-stroke engine |
WO2004011786A1 (en) * | 2002-07-30 | 2004-02-05 | Julian George Daniel Branston | Improvements in or relating to reciprocating piston engines |
US7000581B1 (en) * | 2002-09-10 | 2006-02-21 | Nagesh S. Mavinahally | Mono-shaft four-stroke engine |
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