EP0246370A1 - Moteur à combustion interne à deux temps avec un dispositif de balayage - Google Patents

Moteur à combustion interne à deux temps avec un dispositif de balayage Download PDF

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Publication number
EP0246370A1
EP0246370A1 EP86303877A EP86303877A EP0246370A1 EP 0246370 A1 EP0246370 A1 EP 0246370A1 EP 86303877 A EP86303877 A EP 86303877A EP 86303877 A EP86303877 A EP 86303877A EP 0246370 A1 EP0246370 A1 EP 0246370A1
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EP
European Patent Office
Prior art keywords
cylinder
piston
auxiliary
engine
crank
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.)
Withdrawn
Application number
EP86303877A
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German (de)
English (en)
Inventor
Sen Hsiung Lin
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
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Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to EP86303877A priority Critical patent/EP0246370A1/fr
Publication of EP0246370A1 publication Critical patent/EP0246370A1/fr
Withdrawn legal-status Critical Current

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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
    • F02B33/06—Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps
    • F02B33/22—Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with pumping cylinder situated at side of working cylinder, e.g. the cylinders being parallel
    • 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
    • F02B33/06—Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps
    • F02B33/08—Engines with reciprocating-piston pumps; Engines with crankcase pumps with reciprocating-piston pumps other than simple crankcase pumps with the working-cylinder head arranged between working and pumping cylinders

Definitions

  • This invention relates to a two-stroke internal combustion engine, and particularly to an improved scavenging device for a two-stroke engine which includes an auxiliary cylinder and an auxiliary piston operating in relation with the piston of the engine to deliver fresh air and fuel-and-air mixture together through a passage at the cylinder head of the engine so as to scavenge the exhaust gas efficiently.
  • a two-stroke engine with a scavenging fan has been known in the art, in which the scavenging fan delivers fresh fuel-and-air mixture into the combustion chamber, through a port in the wall of the cylinder, to remove and replace the burned spent gases.
  • the scavenging fan delivers fresh fuel-and-air mixture into the combustion chamber, through a port in the wall of the cylinder, to remove and replace the burned spent gases.
  • Another two-stroke engine which is scavenged by using the crank-case of the engine as a pump to deliver fuel-and-air mixture into the combustion chamber to replace the burned gases, wherein the scavenging fuel-and-air mixture is drawn into the crank case and is forced to flow into the combustion chamber by the action of the piston of the engine.
  • some of the fuel-and-air mixture may escape from the cylinder together with the exhaust gases during the scavenging operation.
  • Such engines are not suitable for use in high power vehicles, since the power is produced is low, generally about 5 to 200 horsepower.
  • the known crank-case scavenged engine has another disadvantage in that the fuel-and-air mixture is delivered into the combustion chamber through an inlet port which is at the lower side of the cylinder and near the exhaust port, and lubricating oil must be mixed with the fuel-and-air mixture. Since the fuel-and-air mixture contains lubricating oil, the efficiency of combustion is low and fuel consumption thus increases.
  • the general object of the invention is to provide a two-stroke engine of enhanced efficiency.
  • the invention seeks to provide a two-stroke engine with an improved scavenging device which can efficiently remove exhaust gases from the combustion chamber, and can also minimise loss of fuel together with the exhaust gases, thereby reducing fuel consumption.
  • the invention may also provide a two-stroke engine with an improved scavenging device which can compress the fuel-and-air mixture prior to it's delivery to the combustion chamber so that the efficiency of combustion can be enhanced.
  • the invention may provide a two-stroke engine in which the fuel-and-air mixture need not be mixed with a lubricating oil.
  • the invention is characterised by a device for scavenging exhaust gases from a two-stroke engine which comprises an auxiliary cylinder and piston movably disposed therein, provided adjacent the engine.
  • the auxiliary cylinder has a first variable-volume closed chamber at one side of the auxiliary piston for receiving a fuel-and-air mixture and a second variable-volume closed chamber at the other side of the piston for receiving fresh air.
  • the auxiliary cylinder also has a fuel inlet port and a fuel outlet port communicating with the first closed chamber, and an air inlet port and an air outlet port communicating with the second closed chamber.
  • the scavenging device further includes a passage communicating with the fuel outlet port, the air outlet port and the combustion chamber of the engine cylinder.
  • the passage extends to the cylinder head of the engine cylinder and communicates with the combustion chamber.
  • the auxiliary piston operates in conjunction with the engine piston to deliver fresh air into the combustion chamber to remove the exhaust gas at a first stage and then to deliver the fuel-and-air mixture into the combustion chamber to remove and replace the exhaust gases at a second stage. Since fresh air is delivered into the combustion chamber before the fuel-and-air mixture, escape of fuel together with the exhaust gases can be eliminated. Moreover, the fresh air or the fuel-and-air mixture are admitted in the combustion chamber through a port at the cylinder head to remove and replace the burned spent gases efficiently.
  • the passage includes a first passage to intercommunicate the first closed chamber and the combustion chamber, and a second passage to intercommunicate the second closed chamber and the combustion chamber.
  • the scavenging device further includes a compressed fresh air receiving chamber communicating with the second closed chamber and the passage.
  • the auxiliary cylinder and the engine cylinder are arranged side by side with their axes parallel.
  • the crank mechanism of the engine includes a means for transmitting the movement of the engine piston to the auxiliary piston.
  • the transmission means may include a change speed gear assembly.
  • the transmission ratio may be 2:1 so that the auxiliary piston operates at a faster rate than the engine piston.
  • the auxiliary cylinder is disposed at the top side of the engine cylinder, and the auxiliary piston and the engine piston are aligned co-axially and interconnected by an axial connecting rod.
  • a first embodiment of a two-stroke engine including an engine cylinder 11, a scavenging unit 30, and a crank case 9.
  • the engine cylinder 11 has a cylinder head 12 with two inlet passages 21 and 22, and a piston 15 movable in the cylinder 11.
  • the cylinder head 12, the wall of the cylinder 11 and the top side of the piston 15 co-operatively confine a variable volume combustion chamber 14 at the top side of the cylinder 11.
  • a spark plug 19 is fitted in the cylinder head 12 to ignite the gases in the combustion chamber 14, and two inlet valves 23 and 24 are disposed in the inlet passages 21 and 22.
  • the inlet valves 23 and 24 are controlled by two cams 25 and 26 of a valve operating system (not shown) which is known in the art.
  • a valve operating system not shown
  • At a certain location in the wall of the cylinder 11 there is an exhaust port 16.
  • the scavenging unit 30 is disposed adjacent the cylinder 11. It includes an auxiliary cylinder 31 with a cylinder head 32, and a piston 33 movable in the cylinder 31.
  • the piston 33 divides the cylinder 31 into a chamber 38 a for receiving a fuel-and-air mixture flowing from a carburettor (not shown) and a chamber 38 b for receiving fresh air.
  • Outside the cylinder 31 is a compressed-air storage chamber 36.
  • To the piston 33 is connected a piston rod 331 which passes through a first sealing cover 34 and a second sealing cover 35.
  • In the sealing cover 34 is disposed an opening 341 to interconnect the chambers 38 b and 36.
  • a valve 345 is mounted on the sealing cover 35 to control the opening and closing of the opening 341.
  • the compressed-air storage chamber 36 communicates with the inlet passage 21 of the engine cylinder 11. When the valve 23 is opened, the chamber 36 communicates with the combustion chamber 14 of the engine cylinder 11 through the inlet passage 21.
  • an air inlet port 37 which is open to the atmosphere.
  • a valve 371 In the inlet port 37 there is a valve 371. When the piston 33 ascends, a vacuum develops in the chamber 38 b below the piston 33 and the valve 371 will open.
  • the upper chamber 38 a of the cylinder 31 communicates with a fuel inlet port 39 in the cylinder head 32 which is regulated by a valve 391, and with a fuel outlet port 321 which is regulated by a valve 322.
  • a fuel inlet port 39 in the cylinder head 32 which is regulated by a valve 391
  • a fuel outlet port 321 which is regulated by a valve 322.
  • crank case 9 is a crank mechanism 90 including a crank shaft 91 on which is mounted a driving toothed crank disc 911, and a crank shaft 92 on which is mounted a driven toothed crank disc 921.
  • the two toothed crank discs 911 and 921 are interconnected by a chain 93.
  • a piston rod 94 is connected to the crank disc 911 and the piston 15, and a crank arm 922 is connected to the crank disc 921 and to the piston rod 331.
  • the ratio of the number of teeth on the discs 911 and 921 is 2:1 so that the speed of the piston 33 is faster than that of the piston 15.
  • crank mechanism may include a change speed gear assembly instead of the toothed crank disc 911 and 921 to maintain the piston 33 at a rate which allows the movement of the piston 33 to best match the operation of the engine piston and the opening and closing operation of the inlet valves 23 and 24 of the engine cylinder so as to achieve an efficient scavenging effect.
  • the piston 15 is reciprocated up and down through the crank mechanism 90 by power produced by the combustion of the gases.
  • the subsequent downward movement of the piston 33 continuously pushes fresh air into the chamber 36 from the chamber 38 b , and draws the fuel-and-air mixture into the chamber 38 a .
  • the piston 33 again moves upward.
  • the exhaust port 16 is still opened.
  • the valve 23 is closed and the valve 24 is opened.
  • the ascending piston 33 forces the fuel mixture into the combustion chamber 14 to remove and replace the exhaust gas subsequent to the initial fresh-air scavenging stage.
  • the piston 15 As the piston 15 continues to ascend, it covers the port 16, the valves 23 and 24 are closed and the fuel-and-air mixture is compressed. In the cylinder 31, the piston 33 descends, compressing fresh air into the chamber 36 and drawing the fuel mixture into the chamber 38 a . In this way, the pistons 15 and 33 move reciprocally in the cylinders respectively to perform the engine operation.
  • the lubricating system for the auxiliary cylinder 31 is incorporated in the piston 33 as shown in Fig. 3.
  • the piston 33 has an interior chamber 333 for receiving lubricating oil and oil passages (not shown) which communicate with the chamber 333 and open at the periphery of the piston 33.
  • the piston rod 331 is of hollow construction and has an oil passage 331 a .
  • At the top side of the piston 33 is an oil inlet port 335 in which is disposed a ball valve 336 and a spring 337 biasing the valve 336 to close the port 335.
  • In the cylinder head 32 is an oil injecting port 338 and a spring-loaded ball valve 339 to close the port 388.
  • the oil injecting port 338 communicates with an oil conduit 340.
  • the ball valves 336 and 339 push against one another so that they retract into and open the respective ports 335 and 338.
  • the ports 335 and 338 approach and communicate with one another, and the lubricating oil from the conduit 340 flows into the chamber 333 of the piston 33.
  • the excess lubricating oil will flow into the hollow piston rod 331.
  • a second embodiment of the present invention includes an engine cylinder 41 with a piston 45 movable therein and defining the wall of the cylinder 41 a combustion chamber 44.
  • the wall of the cylinder 41 has an exhaust port 46 and the cylinder head 42 has an inlet passage 48 controlled by a valve 49.
  • auxiliary cylinder 51 having an auxiliary piston 53.
  • the piston 53 divides the cylinder 51 into two variable-volume closed chambers 58 a and 58 b for receiving the fuel-and-air chamber and fresh air respectively.
  • a fuel inlet port 59 controlled by a valve 591 and a fuel outlet port 52 contrlled by a valve 522 are provided in the cylinder 51 and communicate with the chamber 58 a .
  • An air inlet port 57 controlled by a valve 571 and an air outlet port 572 controlled by a valve 573 are communicated with the chamber 58 b .
  • the auxiliary piston 53 and the engine piston 45 are interconnected by an axial connecting rod 47 which passes slidably through and is kept in a gas-tight relationship with sealing covers 54 and 55 and the cylinder head 42.
  • the piston 45 is further connected to a piston rod 451 which in turn is connected to a crank mechanism (not shown) provided in a crank disposed at the lower side of the cylinder 41.
  • pistons 53 and 45 ascend and descend at the same speed.
  • the valve 49 is closed.
  • the spark plug ignites the compressed fuel-and-air mixture admitted in the combustion chamber, and the burning gases thrust the piston 45 downward.
  • the piston 53 descends, drawing fresh air into the chamber 58 b and compressing the fuel-and-air in the chamber 58 a .
  • the exhaust port 46 is uncovered by the piston 45, the exhaust gases escape.
  • the valve 49 of the cylinder 41 opens.
  • the piston 53 forces the fuel mixture to flow out of the chamber 58 a .
  • the fuel mixture is delivered into the combustion chamber together with the compressed fresh air which fills the lower part of the chamber 56, and the compressed fresh air and the fuel-and-air mixture together remove and replace the exhaust gases.
  • the piston When the piston ascends, it covers the exhaust port 46. The valve 49 then closes, and the piston 45 compresses the fresh fuel-and-air mixture until it reaches it's highest position. As the piston 45 ascends, the piston 53 ascends, drawing in the fuel-and-air mixture from the carburettor 60 to the chamber 58 a and compressing the fresh air in the chamber 58 b .
  • the lubricating system in the auxiliary cylinder 51 is the same as that provided in the auxiliary cylinder of the first embodiment.
  • FIG. 5 A third embodiment of the present invention is schematically shown in Fig. 5 in which the members which are the same as those illustrated in Fig. 1 are represented by the same reference numerals.
  • the auxiliary cylinder 31 and the auxiliary piston 33 define a single closed chamber 38 a at the upper side of the cylinder 31 for receiving the fuel-and-air mixture.
  • the engine piston 15 and the auxiliary piston 33 are connected respectively to two piston rods 94 and 331 which in turn are connected to crank means 95 and 96 mounted on a crank shaft 97.
  • crank means 95 and 96 mounted on a crank shaft 97.
  • the pistons 15 and 33 ascend and descend simultaneously at the same rate.
  • the fresh fuel-and-air mixture from the chamber 38 a is forced to flow into the combustion chamber 14 when the engine piston 15 ascends from it's lowest position. This is because the valve 322 is opened when the piston 33 ascends simultaneously with the piston 15.
  • no fresh air is delivered into the combustion chamber to constitute an initial scavenging stage, such an arrangement can reduce the escape of the fuel together with the exhaust gases since the exhaust gases are first flushed out by the pressure itself, and the fuel mixture is delivered to replace the remaining exhaust gases only when the exhaust port is about to be covered by the piston.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Combustion Methods Of Internal-Combustion Engines (AREA)
EP86303877A 1986-05-21 1986-05-21 Moteur à combustion interne à deux temps avec un dispositif de balayage Withdrawn EP0246370A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP86303877A EP0246370A1 (fr) 1986-05-21 1986-05-21 Moteur à combustion interne à deux temps avec un dispositif de balayage

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP86303877A EP0246370A1 (fr) 1986-05-21 1986-05-21 Moteur à combustion interne à deux temps avec un dispositif de balayage

Publications (1)

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EP0246370A1 true EP0246370A1 (fr) 1987-11-25

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EP86303877A Withdrawn EP0246370A1 (fr) 1986-05-21 1986-05-21 Moteur à combustion interne à deux temps avec un dispositif de balayage

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0514982A1 (fr) * 1991-05-20 1992-11-25 PIAGGIO VEICOLI EUROPEI S.p.A. Moteur à combustion interne avec une chambre separée pour l'injection du carburant
EP0779420A1 (fr) * 1995-12-12 1997-06-18 PIAGGIO VEICOLI EUROPEI S.p.A. Agencement de dosage de combustible dans des dispositifs d'injection directe de combustible assistée pneumatiquement
CN108625980A (zh) * 2018-07-19 2018-10-09 高文峰 一种可变燃烧室二冲程汽油发动机

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE205378C (fr) *
DE391396C (de) * 1924-03-04 Karl Fierke Ladepumpe fuer Explosionsmotoren
US2384422A (en) * 1944-03-22 1945-09-04 Kinder Cloyd Lee Internal-combustion engine
DE809264C (de) * 1948-10-16 1951-07-26 Erich Wuttig Zweitakt-Brennkraftmaschine mit einem oder mehreren Arbeitszylindern und einem Hilfszylinder
DE847087C (de) * 1950-04-16 1952-08-21 Rudolf Dr-Ing Wille Zweitakt-Brennkraftmaschine mit Frischgasfoerdereinrichtung
DE874225C (de) * 1948-10-02 1953-04-20 Gertrud Schnuerle Zweitakt-Brennkraftmaschine mit Spuelung und Nachladung durch Luft
DE941827C (de) * 1951-03-15 1956-04-19 Hans Georg Zimmermann Zweitakt-Brennkraftmaschine mit einem Nachladezylinder je Arbeitszylinder

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE205378C (fr) *
DE391396C (de) * 1924-03-04 Karl Fierke Ladepumpe fuer Explosionsmotoren
US2384422A (en) * 1944-03-22 1945-09-04 Kinder Cloyd Lee Internal-combustion engine
DE874225C (de) * 1948-10-02 1953-04-20 Gertrud Schnuerle Zweitakt-Brennkraftmaschine mit Spuelung und Nachladung durch Luft
DE809264C (de) * 1948-10-16 1951-07-26 Erich Wuttig Zweitakt-Brennkraftmaschine mit einem oder mehreren Arbeitszylindern und einem Hilfszylinder
DE847087C (de) * 1950-04-16 1952-08-21 Rudolf Dr-Ing Wille Zweitakt-Brennkraftmaschine mit Frischgasfoerdereinrichtung
DE941827C (de) * 1951-03-15 1956-04-19 Hans Georg Zimmermann Zweitakt-Brennkraftmaschine mit einem Nachladezylinder je Arbeitszylinder

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0514982A1 (fr) * 1991-05-20 1992-11-25 PIAGGIO VEICOLI EUROPEI S.p.A. Moteur à combustion interne avec une chambre separée pour l'injection du carburant
US5271372A (en) * 1991-05-20 1993-12-21 Piaggio Veicoli Europei S.P.A. Cylinder head for internal combustion engines, with a device for pneumatically assisted direct fuel injection
EP0779420A1 (fr) * 1995-12-12 1997-06-18 PIAGGIO VEICOLI EUROPEI S.p.A. Agencement de dosage de combustible dans des dispositifs d'injection directe de combustible assistée pneumatiquement
US5694905A (en) * 1995-12-12 1997-12-09 Piaggio Veicoli Europei S.P.A. Fuel metering arrangement in pneumatically assisted direct fuel injection devices
CN108625980A (zh) * 2018-07-19 2018-10-09 高文峰 一种可变燃烧室二冲程汽油发动机
CN108625980B (zh) * 2018-07-19 2023-08-18 高文峰 一种可变燃烧室二冲程汽油发动机

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