WO2014183912A1 - Two-stroke engine with a port-type timing and crankcase scavenging - Google Patents

Two-stroke engine with a port-type timing and crankcase scavenging Download PDF

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Publication number
WO2014183912A1
WO2014183912A1 PCT/EP2014/055915 EP2014055915W WO2014183912A1 WO 2014183912 A1 WO2014183912 A1 WO 2014183912A1 EP 2014055915 W EP2014055915 W EP 2014055915W WO 2014183912 A1 WO2014183912 A1 WO 2014183912A1
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WO
WIPO (PCT)
Prior art keywords
crankcase
scavenging
cylinder
piston
sleeve valve
Prior art date
Application number
PCT/EP2014/055915
Other languages
French (fr)
Inventor
Georgi VASSILJEV
Original Assignee
Vassiljev Georgi
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Filing date
Publication date
Application filed by Vassiljev Georgi filed Critical Vassiljev Georgi
Publication of WO2014183912A1 publication Critical patent/WO2014183912A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D13/00—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing
    • F02D13/02—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation
    • F02D13/028—Controlling the engine output power by varying inlet or exhaust valve operating characteristics, e.g. timing during engine operation for two-stroke engines
    • F02D13/0284—Variable control of exhaust valves only
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L1/00—Valve-gear or valve arrangements, e.g. lift-valve gear
    • F01L1/36—Valve-gear or valve arrangements, e.g. lift-valve gear peculiar to machines or engines of specific type other than four-stroke cycle
    • F01L1/40—Valve-gear or valve arrangements, e.g. lift-valve gear peculiar to machines or engines of specific type other than four-stroke cycle for engines with scavenging charge near top dead centre position, e.g. by overlapping inlet and exhaust time
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L21/00—Use of working pistons or pistons-rods as fluid-distributing valves or as valve-supporting elements, e.g. in free-piston machines
    • F01L21/02—Piston or piston-rod used as valve members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L7/00—Rotary or oscillatory slide valve-gear or valve arrangements
    • F01L7/12—Rotary or oscillatory slide valve-gear or valve arrangements specially for two-stroke engines
    • 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
    • F02B25/00—Engines characterised by using fresh charge for scavenging cylinders
    • F02B25/02—Engines characterised by using fresh charge for scavenging cylinders using unidirectional scavenging
    • F02B25/04—Engines having ports both in cylinder head and in cylinder wall near bottom of piston stroke
    • F02B25/06—Engines having ports both in cylinder head and in cylinder wall near bottom of piston stroke the cylinder-head ports being controlled by working pistons, e.g. by sleeve-shaped extensions thereof
    • 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
    • F02B33/04—Engines with reciprocating-piston pumps; Engines with crankcase pumps with simple crankcase pumps, i.e. with the rear face of a non-stepped working piston acting as sole pumping member in co-operation with the crankcase
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L7/00—Rotary or oscillatory slide valve-gear or valve arrangements
    • F01L7/02—Rotary or oscillatory slide valve-gear or valve arrangements with cylindrical, sleeve, or part-annularly shaped valves
    • F01L7/021—Rotary or oscillatory slide valve-gear or valve arrangements with cylindrical, sleeve, or part-annularly shaped valves with one rotary valve
    • F01L7/025—Cylindrical valves comprising radial inlet and side outlet or side inlet and radial outlet
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L7/00—Rotary or oscillatory slide valve-gear or valve arrangements
    • F01L7/16—Sealing or packing arrangements specially therefor
    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—Pistons 
    • F02F3/24—Pistons  having means for guiding gases in cylinders, e.g. for guiding scavenging charge in two-stroke engines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—Pistons 
    • F02F3/28—Other pistons with specially-shaped head
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

Definitions

  • Present invention relates to a two-stroke piston engine intended for use in means of transport and other machinery as a source of mechanical energy. More specifically present invention relates to a two-stroke engine with port-type timing and crankcase scavenging.
  • the existing two-stroke engines with port-type timing (in other words port type gas distribution) and crankcase scavenging (for example, as described in the handbook ⁇ .
  • the objective of this invention is to propose a two-stroke engine with port-type timing and crankcase scavenging where the volume of air pressed out of the crankcase has been increased to the extent that enables complete cleaning of the cylinder from exhaust gases also without the inlet and exhaust systems tuning, as well as raising the air pressure in the cylinder higher than the atmospheric pressure through the scavenging ports either with the help of external compressor(s) or with the help of air pressed out of the crankcase with the piston.
  • the objective of the invention has been achieved by using a piston block that consists of a piston and a cylindrical sleeve valve with scavenging ports where the cylindrical sleeve valve starts from the piston head, goes through the cylinder head and connects the engine crankcase and a receiver or atmosphere to the scavenging ports that enables the filling of the crankcase with fresh air.
  • the structure of the piston block enables to press out of the crankcase through scavenging ports into the cylinder an air volume that exceeds the total cylinder capacity.
  • Raising the air pressure in the cylinder either by means of external compressor(s) or by means of air pressed out of the crankcase is enabled by a rotating sleeve valve that is placed between the exhaust ports and the exhaust pipe where the mentioned sleeve valve, after the end of scavenging until the closure of exhaust ports, separates the exhaust ports and the exhaust pipe from one another.
  • the subject of this invention is a two-stroke engine with port-type timing and crankcase scavenging that includes at least one piston block where the piston block contains a piston and a cylindrical sleeve valve connected to the piston where the cylindrical sleeve valve starts from the piston head and goes through the cylinder head.
  • the cylindrical sleeve valve comprises at least one scavenging port.
  • a sleeve valve mechanism is placed that is cinematically connected to the engine shaft and that during the time interval after the end of the cylinder scavenging until the closure of exhaust ports separates the exhaust ports and the exhaust pipe from one another that enables the compressed air, present during the given time period in the crankcase to move into the cylinder and thereby increase through scavenging ports the air pressure in the cylinder.
  • the sleeve valve of the valve mechanism between the exhaust ports and the exhaust pipe is made as a rotating sleeve valve or a rotary valve.
  • the air is directed into the engine crankcase either at the atmospheric pressure or at the pressure above the atmospheric pressure by means of an external compressor.
  • the subject of the present invention is a two-stroke engine with port-type timing and crankcase scavenging that includes at least one piston block where the piston block contains a piston and a cylindrical sleeve valve connected to the piston where the cylindrical sleeve valve starts from the piston head, goes through the cylinder head and comprises at least one scavenging port for connecting the crankcase to a receiver or atmosphere, and where by means of the reciprocating piston the air is compressed in the crankcase when the piston reaches the bottom dead centre and directed to the cylinder through scavenging ports.
  • a sleeve valve mechanism comprising at least one sleeve valve is installed between the exhaust ports and the exhaust pipe.
  • the exhaust ports are opened by means of the piston, and the free exhaust of exhaust gases from the cylinder is started until the pressure of exhaust gases in the cylinder has dropped below the pressure in the crankcase, after which the opening of scavenging ports will be performed and the cylinder scavenging will be started, until the cylinder scavenging is finished with the piston block moving back, and the exhaust ports and the exhaust pipe will be separated from one another by means of the sleeve valve of the sleeve valve mechanism.
  • crankcase is filled with air either via a, inlet ports, scavenging ports and cylindrical sleeve valve running through the cylinder head, or via the inlet ports and cylindrical sleeve valve running through the cylinder head.
  • the volume of air pressed out from the crankcase by means of the piston is greater than the cylinder capacity.
  • the exhaust ports and the exhaust pipe are separated from one another by means of the rotating sleeve valve of the sleeve valve mechanism.
  • the movement of compressed air from the crankcase to the cylinder is enabled in order to increase the air pressure in the cylinder.
  • the air is directed into the engine crankcase either at the atmospheric pressure or at the pressure higher than the atmospheric pressure by means of an external compressor.
  • the departure of fresh air with which the crankcase has been filled when the piston moves to the top dead centre is prevented from the piston block and its mixture with the air present in the crankcase is blocked.
  • the inlet and exhaust systems resonant tuning has been used to increase the volume of air entering the cylinder through the exhaust ports.
  • Figure 1 depicts schematically in longitudinal section a two-stroke engine with port-type timing and crankcase scavenging according to the invention at the moment, when in the cylinder the scavenging of the exhaust gases begins;
  • Figure 2 depicts schematically in longitudinal section a two-stroke engine with port-type timing and crankcase scavenging according to the invention with an external compressor and a rotating sleeve valve at the moment where in the cylinder the scavenging of the exhaust gases begins;
  • Figure 3 depicts schematically in longitudinal section a two-stroke engine with port-type timing and crankcase scavenging according to the invention, where two pistons are placed onto one cylindrical sleeve valve;
  • Figure 4 depicts schematically in longitudinal section a two-stroke engine with port-type timing and crankcase scavenging according to the invention having an external compressor and a rotating sleeve valve at the moment where in the cylinder the scavenging of the exhaust gases takes place; and
  • FIG 1 the engine is shown during the movement of the piston block into the bottom dead centre where the exhaust ports 4 are open and the pressure of exhaust gases in the cylinder 6 at the free exhaust has dropped below the pressure in the crankcase.
  • the cylindrical sleeve valve 2 opens scavenging ports 5 and starts the cylinder 6 scavenging with the compressed air present in the crankcase, until the cylindrical sleeve valve 2 on its backward movement closes the scavenging ports 5 and then yet at the forward motion, the piston 1 closes also the exhaust ports 4.
  • a sleeve valve of the exhaust pipe marked with reference number 11 in the figures is related to the fuel feed and it regulates the resistance of the exhaust pipe until the cylinder is partly cleaned (i.e. ventilated) at low rpm.
  • An ignition plug and/or a spray jet is marked with reference number 12, an oil ring with reference number 8, an air filter with reference number 13 and an inlet port with reference number 9.
  • the piston block while moving into the bottom dead centre increases the air pressure in the crankcase in order to perform scavenging, and while moving into the top dead centre, increases the crankcase capacity that will be filled with air at the atmospheric pressure through the scavenging ports 5 and the inlet ports 9.
  • the volume of air pressed out of the crankcase with a piston is smaller than the inner capacity of the piston block, the fresh air will not exit from the piston block and will not mix with the air present in the crankcase.
  • a resonant tuning of the inlet and exhaust systems can be used in order to increase the mass (quantity) of air entering the cylinder 6 through the exhaust ports.
  • the rotating sleeve valve 3 closes the exhaust ports, and until the closure of scavenging ports 5, the compressed air moves from the crankcase 7, from the receiver 13, as well as from the piston block into the engine cylinder 6 and increases the air pressure in the cylinder; during the forward motion until the closure of the exhaust ports the piston 1 compresses the air in the cylinder.
  • an oil ring is indicated with reference number 8, an inlet port with reference number 9, a plate valve with reference number 10 and an ignition plug and/or injector with reference number 12.
  • the scavenging ports are made spiral.
  • the piston block consists of two pistons 1 that are fastened to a cylindrical sleeve valve 2.
  • the valve control is identical to the valve control in the engine shown in Figure 1, and their mutual valve control phases are shifted by 180 degrees.
  • the pressure rings in the cylinder heads are lubricated with lubricant that is fed between the oil rings 8 (in direction of arrows).
  • the piston block is connected to the crankshaft by means of one connecting rod (these parts are not shown in the figures).
  • the piston lubrication bush 14 will be centred in the cylinder 1 with the help of three or more ears (see also Figure 5) that ensure a necessary axial slot for the oil rings 8.
  • an inlet port is indicated with reference number 9
  • a plate valve is indicated with reference number 10
  • an ignition plug and/or injector is indicated with reference number 12.
  • Comprex TM compressor a type of pressure wave supercharger
  • the maximum engine power in the case of the inlet and exhaust systems resonant tuning can also be achieved at lower shaft revolutions, e.g. at 3,500 rpm that increases the dynamics of the engine.
  • the sleeve valve 3 does not require lubrication since it is rotating in the housing with a gap (clearance) and closes the exhaust ports 4 of the cylinder 6 by raising their flow resistance.
  • Using a timing belt between engine shaft and sleeve valve 3 shaft makes it possible to use a mechanism controlling the timing of the closing moment of exhaust ports 4.
  • a mixture of oil and fuel can be used for lubrication.

Abstract

Present invention relates to a two-stroke engine with a port-type timing and crankcase scavenging, where the scavenging of the engine cylinder is implemented with the cylindrical sleeve valve connecting engine cylinder and crankcase. The structure of the cylinder block enables air volume exceeding the cylinder volume to be pushed from the crankcase to engine cylinder and the rotary sleeve valve allows the pressure in the engine cylinder to be increased with the help of the external compressor or with air pushed out of the crankcase with the help of the piston.

Description

TWO-STROKE ENGINE WITH A PORT-TYPE TIMING AND CRANKCASE SCAVENGING Technical Field
Present invention relates to a two-stroke piston engine intended for use in means of transport and other machinery as a source of mechanical energy. More specifically present invention relates to a two-stroke engine with port-type timing and crankcase scavenging.
Background Art
The existing two-stroke engines with port-type timing (in other words port type gas distribution) and crankcase scavenging (for example, as described in the handbook Б. А. Шароглазов, М. Ф. Фарафонтов, В. В. Клементьев, ДВИГАТЕЛИ ВНУТРЕННЕГО СГОРАНИЯ: ТЕОРИЯ, МОДЕЛИРОВАНИЕ И РАСЧЁТ ПРОЦЕССОВ, Челябинск, Издательство ЮУрГУ 2004) perform the engine cylinder scavenging with air that the piston presses out from the crankcase via transfer passages and scavenging ports into the cylinder. As the volume of air pressed out from the crankcase is smaller than the capacity of the whole cylinder, the performance of the cylinder complete cleaning is possible only with the inlet and exhaust systems resonant tuning, where the said tuning takes place in a narrow engine speed range, but at other speeds the cylinder scavenging remains insufficient and the losses of working mixture will increase when the carburettor is used. As regards this solution, also the air pressure increase in the cylinder by means of external compressor(s) through scavenging ports is excluded.
Disclosure of Invention
The objective of this invention is to propose a two-stroke engine with port-type timing and crankcase scavenging where the volume of air pressed out of the crankcase has been increased to the extent that enables complete cleaning of the cylinder from exhaust gases also without the inlet and exhaust systems tuning, as well as raising the air pressure in the cylinder higher than the atmospheric pressure through the scavenging ports either with the help of external compressor(s) or with the help of air pressed out of the crankcase with the piston.
The objective of the invention has been achieved by using a piston block that consists of a piston and a cylindrical sleeve valve with scavenging ports where the cylindrical sleeve valve starts from the piston head, goes through the cylinder head and connects the engine crankcase and a receiver or atmosphere to the scavenging ports that enables the filling of the crankcase with fresh air. The structure of the piston block enables to press out of the crankcase through scavenging ports into the cylinder an air volume that exceeds the total cylinder capacity.
Raising the air pressure in the cylinder either by means of external compressor(s) or by means of air pressed out of the crankcase is enabled by a rotating sleeve valve that is placed between the exhaust ports and the exhaust pipe where the mentioned sleeve valve, after the end of scavenging until the closure of exhaust ports, separates the exhaust ports and the exhaust pipe from one another.
The subject of this invention is a two-stroke engine with port-type timing and crankcase scavenging that includes at least one piston block where the piston block contains a piston and a cylindrical sleeve valve connected to the piston where the cylindrical sleeve valve starts from the piston head and goes through the cylinder head. The cylindrical sleeve valve comprises at least one scavenging port.
In the preferred embodiment of the invention between the exhaust ports and the exhaust pipe for exhaust gases a sleeve valve mechanism is placed that is cinematically connected to the engine shaft and that during the time interval after the end of the cylinder scavenging until the closure of exhaust ports separates the exhaust ports and the exhaust pipe from one another that enables the compressed air, present during the given time period in the crankcase to move into the cylinder and thereby increase through scavenging ports the air pressure in the cylinder.
Preferably, the sleeve valve of the valve mechanism between the exhaust ports and the exhaust pipe is made as a rotating sleeve valve or a rotary valve.
From the inlet port, the air is directed into the engine crankcase either at the atmospheric pressure or at the pressure above the atmospheric pressure by means of an external compressor.
Preferably, the subject of the present invention is a two-stroke engine with port-type timing and crankcase scavenging that includes at least one piston block where the piston block contains a piston and a cylindrical sleeve valve connected to the piston where the cylindrical sleeve valve starts from the piston head, goes through the cylinder head and comprises at least one scavenging port for connecting the crankcase to a receiver or atmosphere, and where by means of the reciprocating piston the air is compressed in the crankcase when the piston reaches the bottom dead centre and directed to the cylinder through scavenging ports.
For adjusting the flow resistance of exhaust ports and closing them, a sleeve valve mechanism comprising at least one sleeve valve is installed between the exhaust ports and the exhaust pipe.
After the piston block has moved to the bottom dead centre, the exhaust ports are opened by means of the piston, and the free exhaust of exhaust gases from the cylinder is started until the pressure of exhaust gases in the cylinder has dropped below the pressure in the crankcase, after which the opening of scavenging ports will be performed and the cylinder scavenging will be started, until the cylinder scavenging is finished with the piston block moving back, and the exhaust ports and the exhaust pipe will be separated from one another by means of the sleeve valve of the sleeve valve mechanism.
During a movement of the piston towards the top dead centre as the air pressure in the crankcase decreases, the crankcase is filled with air either via a, inlet ports, scavenging ports and cylindrical sleeve valve running through the cylinder head, or via the inlet ports and cylindrical sleeve valve running through the cylinder head.
Preferably, the volume of air pressed out from the crankcase by means of the piston is greater than the cylinder capacity.
According to another preferred embodiment, in the time interval from the end of the cylinder scavenging to the closure of exhaust ports, the exhaust ports and the exhaust pipe are separated from one another by means of the rotating sleeve valve of the sleeve valve mechanism.
According to yet another preferred embodiment, in the time interval from the end of the cylinder scavenging to the closure of scavenging ports, the movement of compressed air from the crankcase to the cylinder is enabled in order to increase the air pressure in the cylinder.
Preferably, the air is directed into the engine crankcase either at the atmospheric pressure or at the pressure higher than the atmospheric pressure by means of an external compressor.
Preferably, the departure of fresh air with which the crankcase has been filled when the piston moves to the top dead centre, is prevented from the piston block and its mixture with the air present in the crankcase is blocked.
Yet in another preferable embodiment of the invention, the inlet and exhaust systems resonant tuning has been used to increase the volume of air entering the cylinder through the exhaust ports.
Brief Description of Drawings
The technical nature of the invention is explained in detail below with references to the attached illustrations where:
Figure 1 depicts schematically in longitudinal section a two-stroke engine with port-type timing and crankcase scavenging according to the invention at the moment, when in the cylinder the scavenging of the exhaust gases begins;
Figure 2 depicts schematically in longitudinal section a two-stroke engine with port-type timing and crankcase scavenging according to the invention with an external compressor and a rotating sleeve valve at the moment where in the cylinder the scavenging of the exhaust gases begins;
Figure 3 depicts schematically in longitudinal section a two-stroke engine with port-type timing and crankcase scavenging according to the invention, where two pistons are placed onto one cylindrical sleeve valve;
Figure 4 depicts schematically in longitudinal section a two-stroke engine with port-type timing and crankcase scavenging according to the invention having an external compressor and a rotating sleeve valve at the moment where in the cylinder the scavenging of the exhaust gases takes place; and
Figure 5 depicts in longitudinal section a piston lubrication unit.
Best Mode for Carrying Out the Invention
On attached illustrations, the embodiment options of the engine are shown schematically and in simplified form without lubrication, cooling and ignition systems, without the driving gear of the sleeve valve mechanism and without some other parts.
In Figure 1, the engine is shown during the movement of the piston block into the bottom dead centre where the exhaust ports 4 are open and the pressure of exhaust gases in the cylinder 6 at the free exhaust has dropped below the pressure in the crankcase. As the piston block advances, the cylindrical sleeve valve 2 opens scavenging ports 5 and starts the cylinder 6 scavenging with the compressed air present in the crankcase, until the cylindrical sleeve valve 2 on its backward movement closes the scavenging ports 5 and then yet at the forward motion, the piston 1 closes also the exhaust ports 4.
A sleeve valve of the exhaust pipe marked with reference number 11 in the figures is related to the fuel feed and it regulates the resistance of the exhaust pipe until the cylinder is partly cleaned (i.e. ventilated) at low rpm.
An ignition plug and/or a spray jet is marked with reference number 12, an oil ring with reference number 8, an air filter with reference number 13 and an inlet port with reference number 9.
The piston block, while moving into the bottom dead centre increases the air pressure in the crankcase in order to perform scavenging, and while moving into the top dead centre, increases the crankcase capacity that will be filled with air at the atmospheric pressure through the scavenging ports 5 and the inlet ports 9. As the volume of air pressed out of the crankcase with a piston is smaller than the inner capacity of the piston block, the fresh air will not exit from the piston block and will not mix with the air present in the crankcase.
A resonant tuning of the inlet and exhaust systems can be used in order to increase the mass (quantity) of air entering the cylinder 6 through the exhaust ports.
In Figure 2, the engine is shown during the movement of the piston 1 into the bottom dead centre where the exhaust ports 4 are open and the pressure of exhaust gases in the cylinder 6 at the free exhaust has dropped below the pressure in the crankcase, in the receiver 13 and in the piston block. As the piston advances, the cylindrical sleeve valve 2 opens the scavenging ports 5 and the cylinder 6 scavenging starts until the scavenging ends when the piston 1 has moved back. Thereafter, the rotating sleeve valve 3 closes the exhaust ports, and until the closure of scavenging ports 5, the compressed air moves from the crankcase 7, from the receiver 13, as well as from the piston block into the engine cylinder 6 and increases the air pressure in the cylinder; during the forward motion until the closure of the exhaust ports the piston 1 compresses the air in the cylinder.
In the figure, an oil ring is indicated with reference number 8, an inlet port with reference number 9, a plate valve with reference number 10 and an ignition plug and/or injector with reference number 12.
In order to lubricate the pressure rings in the cylinder head, the scavenging ports are made spiral.
In Figure 3, an engine is shown that the piston block consists of two pistons 1 that are fastened to a cylindrical sleeve valve 2. In both cylinders 6, the valve control is identical to the valve control in the engine shown in Figure 1, and their mutual valve control phases are shifted by 180 degrees. The pressure rings in the cylinder heads are lubricated with lubricant that is fed between the oil rings 8 (in direction of arrows).
The piston block is connected to the crankshaft by means of one connecting rod (these parts are not shown in the figures).
In Figure 4, the engine is shown at the moment when the piston 1 is located in the bottom dead centre, the exhaust ports 4 are opened, and the cylinder 6 scavenging takes place until the scavenging ends when the piston 1 has moved back. Thereafter, the rotating sleeve valve 3 closes the exhaust ports 4, and until the closure of the scavenging ports 5, the compressed air moves from the crankcase 7 and the cylindrical sleeve valve 2 into the cylinder 6, and raises the pressure in the cylinder; at moving forward the piston 1 closes the exhaust ports 4 and compresses the air in the cylinder.
The piston lubrication bush 14 will be centred in the cylinder 1 with the help of three or more ears (see also Figure 5) that ensure a necessary axial slot for the oil rings 8. There is one or there are several lubricant inlet ports 15 in the bush, and it is used for covering the surface of the piston 1 between the oil rings 8 through the ports 16. The movement of lubricant is shown with arrows.
In Figure 4, an inlet port is indicated with reference number 9, a plate valve is indicated with reference number 10 and an ignition plug and/or injector is indicated with reference number 12.
For example, with the use of a Comprex™ compressor (a type of pressure wave supercharger) it is possible to integrate its housing with the cylinder housing similarly to the integration of the housing of the rotating sleeve valve.
In using a cylindrical sleeve valve, a higher degree of cylinder cleaning is achieved compared to the known versions of loop scavenging.
The maximum engine power in the case of the inlet and exhaust systems resonant tuning can also be achieved at lower shaft revolutions, e.g. at 3,500 rpm that increases the dynamics of the engine.
The sleeve valve 3 does not require lubrication since it is rotating in the housing with a gap (clearance) and closes the exhaust ports 4 of the cylinder 6 by raising their flow resistance.
Using a timing belt between engine shaft and sleeve valve 3 shaft makes it possible to use a mechanism controlling the timing of the closing moment of exhaust ports 4.
Also a mixture of oil and fuel can be used for lubrication.

Claims (7)

  1. A two-stroke engine with port-type timing and crankcase scavenging comprising at least one piston block, where the piston block consists of a piston (1) and a cylindrical sleeve valve (2) for connecting the crankcase to a receiver or with atmosphere, where the cylindrical sleeve valve (2) is connected to the piston and starts from the piston head, passes through the cylinder head and includes at least one scavenging port (5),
    where the reciprocating piston (1) during a movement of the piston towards the bottom dead centre compresses the air in the crankcase (7) and feds it into the cylinder through the scavenging ports (5),
    where a sleeve valve mechanism comprising at least one sleeve valve (3, 11) is installed between the exhaust ports (4) and the exhaust pipe for adjusting the flow resistance of exhaust ports and for closing them,
    where during a movement of the piston (1) towards the bottom dead centre the exhaust ports (4) are opened by means of the piston (1), and the free exhaust of exhaust gases from the cylinder (6) is started until the pressure of exhaust gases in the cylinder (6) has dropped below the pressure in the crankcase, after which scavenging ports (5) are opened and the scavenging of the cylinder (6) started, until the scavenging of the cylinder (6) is finished with the piston block moving back, and the exhaust ports (4) and the exhaust pipe will be separated from one another by means of the sleeve valve (3, 11) of the sleeve valve mechanism , characterized in that , where during a movement of the piston (1) towards the top dead centre as the air pressure in the crankcase decreases, the crankcase is filled with air either via a, inlet ports (9), scavenging ports (5) and cylindrical sleeve valve (2) running through the cylinder head, or via the inlet ports (9) and cylindrical sleeve valve (2) running through the cylinder head.
  2. A two-stroke engine with port-type timing and crankcase scavenging according to the claim 1, characterized in that the volume of the air pressed out of the crankcase (7) by means of the piston (1) is greater than the cylinder volume (6).
  3. A two-stroke engine with port-type timing and crankcase scavenging according to any one or several preceding claims, characterized in that in the time interval from the end of the cylinder (6) scavenging to the closure of the exhaust ports (4), the exhaust ports (4) and the exhaust pipe are separated from one another by means of the rotating sleeve valve (3) of the sleeve valve mechanism.
  4. A two-stroke engine with port-type timing and crankcase scavenging according to any one or several preceding claims, characterized in that in the time interval from the end of the cylinder (6) scavenging to the closure of scavenging ports (5), the movement of compressed air from the crankcase (7) to the cylinder (6) is enabled in order to increase the air pressure in the cylinder (6).
  5. A two-stroke engine with port-type timing and crankcase scavenging according to any one or several preceding claims, characterized in that the air is directed from the inlet port (9) into the engine crankcase either at the atmospheric pressure or at the pressure above the atmospheric pressure by means of an external compressor.
  6. A two-stroke engine with port-type timing and crankcase scavenging according to any one or several preceding claims, characterized in that the fresh air, that has filled the crankcase during the movement of the piston into the top dead centre, is prevented exiting from the piston block and mixing with the air present in the crankcase.
  7. A two-stroke engine with port-type timing and crankcase scavenging according to claims 1, 2 and 5, characterized in that the inlet and exhaust systems resonant tuning has been used to increase the volume of air entering the cylinder (6) through the exhaust ports.
PCT/EP2014/055915 2013-05-17 2014-03-25 Two-stroke engine with a port-type timing and crankcase scavenging WO2014183912A1 (en)

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EEU201300057 2013-05-17
EEU201300057U EE01274U1 (en) 2013-05-17 2013-05-17 Two-stroke engine with a port-type gas distribution and crankcase scavenging

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020238820A1 (en) * 2019-05-24 2020-12-03 梁刚 Uniflow stratified scavenging two-stroke engine

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GB249405A (en) * 1925-09-07 1926-03-25 Heinrich Schluepmann Improvements in two stroke cycle internal combustion engines
US2918045A (en) * 1957-02-06 1959-12-22 Arthur E Brown Double acting two stroke cycle internal combustion engine
US3181518A (en) * 1963-01-04 1965-05-04 Outboard Marine Corp Engine
WO1994007012A1 (en) * 1992-09-16 1994-03-31 Kostadin Asenov Goleminov An internal combustion engine
FR2714113A1 (en) * 1993-12-18 1995-06-23 Honda Motor Co Ltd Two-stroke engine, spark ignition type.

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB249405A (en) * 1925-09-07 1926-03-25 Heinrich Schluepmann Improvements in two stroke cycle internal combustion engines
US2918045A (en) * 1957-02-06 1959-12-22 Arthur E Brown Double acting two stroke cycle internal combustion engine
US3181518A (en) * 1963-01-04 1965-05-04 Outboard Marine Corp Engine
WO1994007012A1 (en) * 1992-09-16 1994-03-31 Kostadin Asenov Goleminov An internal combustion engine
FR2714113A1 (en) * 1993-12-18 1995-06-23 Honda Motor Co Ltd Two-stroke engine, spark ignition type.

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2020238820A1 (en) * 2019-05-24 2020-12-03 梁刚 Uniflow stratified scavenging two-stroke engine

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