Classifications

• • 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
  • F02B13/00—Engines characterised by the introduction of liquid fuel into cylinders by use of auxiliary fluid
  • F02B13/10—Use of specific auxiliary fluids, e.g. steam, combustion gas
• • 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
  • F02B17/00—Engines characterised by means for effecting stratification of charge in cylinders
• • 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
  • F02B25/14—Engines characterised by using fresh charge for scavenging cylinders using reverse-flow scavenging, e.g. with both outlet and inlet ports arranged near bottom of piston stroke
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M67/00—Apparatus in which fuel-injection is effected by means of high-pressure gas, the gas carrying the fuel into working cylinders of the engine, e.g. air-injection type
  • F02M67/06—Apparatus in which fuel-injection is effected by means of high-pressure gas, the gas carrying the fuel into working cylinders of the engine, e.g. air-injection type the gas being other than air, e.g. steam, combustion gas
• • 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
  • F02B1/00—Engines characterised by fuel-air mixture compression
  • F02B1/02—Engines characterised by fuel-air mixture compression with positive ignition
  • F02B1/04—Engines characterised by fuel-air mixture compression with positive ignition with fuel-air mixture admission into cylinder
• • 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

• the subject matter of this invention is the two-stroke engine with spark ignition, in which the energy of exhaust gases produced during the engine operation is used to pre ⁇ pare the combustible charge.
• One of the design trends which improve operation of the two stroke engine consists in eliminating the outlet losses by supplying fuel to the cylinder space after the exhaust port has been closed, and controlling combustion by spacial qualitative differentia ⁇ tion of the fuel charge, which consists, among other things, in producing an enriched mixture in the spark plug zone.
• a method of producing such a laminar structure of the mixture is known, in which a gaseous charge containing fuel is introduced from a separate feed chamber to the air, or to a lean combustible mixture compressed by the piston in the cylinder space.
• the charge containing fuel consists of vaporized liquid fuel mixed with air or with exhaust gases; it is very rich m fuel, beyond the flammability limit.
• the fuel charge jet is introduced during the compression stroke through the feed canal leading from the feed chamber where the fuel charge is compressed to a pressure higher than that in the cylinder space at the moment of delivering the fuel charge.
• the feed canal is oriented towards the spark plug. Mutual mixing of the two charges results in the desired differentiation of the mixture, as regards its com ⁇ bustibility properties, in the engine cylinder space.
• the operation of the nozzle and the cut-off valve are controlled by a processor performing a program based on a general principle: the valve is opened at the end of the compression stroke and is closed after the moment of igni ⁇ tion; fuel is injected during the power stroke. With the- cut-off valve open, the direction of gas flow depends on the pressure difference between the two connected spaces. In the first period after the valve is opened, a rich fu ⁇ el-exhaust gas mixture, prepared m the previous phase, le- aves the feed chamber. The increase in pressure in the cy ⁇ linder space, caused by the piston movement, results in the reversed flow direction even before the moment of ignition.
• the computer-controlled valve is closed after the mixture is ignited, and the pressure in the feed chamber is suffi ⁇ cient to prepare the mixture in the next cycle, the exact moment depending on the engine load.
• a computer-controlled amount of fuel is injected to the gases accumulated in the feed chamber under high pres ⁇ sure. The fuel vaporizes quickly in hot exhaust gases, thus producing a rich, chemically active fuel-exhaust gas mixtu ⁇ re used in the next engine operation cycle.
• each cylinder has its own feed chamber equ ⁇ ipped with a cut-off valve and a spray nozzle.
• Exhaust gases are also used in the operation of the engine described in the specification of the Polish patent No. 140 368.
• the feed chamber is connected with the working space by means of a feed canal leading to the cylinder wall, its outlet being located between the upper edge of the exhaust port and the top dead centre.
• the con ⁇ nection of the fuel chamber with the working space is con ⁇ trolled by the piston edge.
• the feed chamber is connected by means of a non-return valve with a vacuum device which sprays fuel into the air jet that is sucked into the fuel chamber, or the exhaust gas taken from the exhaust canal. Gases are sucked into the fuel chamber when it is periodi ⁇ cally connected with the crankcase space.
• the two spaces are connected via an additional suction canal which ends on the cylinder wall below the upper edge of the piston in its top dead centre.
• Exhaust gases from the engine cylinder space are introduced, during the power stroke, to the fuel chamber containing a rich fuel charge.
• the chamber space is then tightly closed for, at least, the charge exchange pha- se; the chamber is opened again m the compression phase.
• the control of the connection between the fuel chamber and the working space is done at the two control edges appro ⁇ priately spaced on the piston.
• the control edges are made in a special projection of the piston head; they are formed by the upper edge and an additional transfer canal made in ⁇ side the piston.
• the engine developed by this invention prepares the com ⁇ bustible charge using a method similar to that described above, however with a different design, using different technical means.
• the essence of this design consists m that the engine feed chamber is formed by the inner space of a rotary distributor, which is closed by a rotary con ⁇ trol element driven by a transmission from the engine cran ⁇ kshaft.
• the control element has two openings, an inlet and outlet one, spaced at such a central angle, and coupled with the transmission in such a position that, when the element is rotating, the inlet opening meets the feed canal outlet in the rotary distributor during the power stroke, and the outlet opening is met in the compression stroke.
• the two spaces become connected when the piston is below the feed canal opening in the cylinder wall.
• the feed chamber is cut off by two pairs of sliding surfaces connected m series, between the piston and the cylinder wall, and m the rotary distributor. Owing to such a design, there is no pressure loss during forma ⁇ tion and storage of the fuel-exhaust gas mixture in the fe- ed chamber, which is of fundamental importance to appro ⁇ priate stratification of the charge and the engine effi ⁇ ciency.
• the fuel spraying device can operate either in a continuous mode - with the amount of fuel controlled by its pressure, or in a cyclic mode - with the amount of fuel controlled by the valve opening time.
• This design is especially advantageous in a multi-cylin ⁇ der engine.
• the cylinder spaces are connected with one com ⁇ mon feed chamber by means of feed canals, the openings of which are spaced at symmetrical pitch of the rotary distri ⁇ butor central angle, corresponding to the number of cylin ⁇ ders and the sequence of ignition.
• there are particularly advantageous conditions for gas flow which minimize the effect of inertia.
• the rotary distributor can actually be of any design.
• the design that is particularly advantageous has the feed cham ⁇ ber formed by the inner space of the control element - de ⁇ signed as a rotary chamber supported by bearings in the distributor body.
• One end of the chamber is connected with a non-slip transmission by means of a coupling and a pres ⁇ sure spring.
• the other end of the chamber which has an in ⁇ let and outlet openings, is pressed against the cover of the body in which the opening of the feed canal is placed to mate with the two openings mentioned above.
• the co ⁇ ver positioned in the distributor rotation axis, there is a fuel spraying device directed towards the axially posi ⁇ tioned opening made in the bottom of the control element.
• the combustion chamber is connected with the feed chamber by means of one feed canal with two directions of flow, to transfer exhaust gas or the fuel-exhaust gas mixture. During each power stroke the flow of gases is reversed in the feed canal zone of the feed chamber.
• a further development of the invention aims at en ⁇ suring an orderly flow in the feed chamber, increasing ho ⁇ mogeneity of the mixture at high frequencies caused by high rotation speeds of the engine and/or the high number of cy ⁇ linders controlled by one distributor.
• the control element of the rotary distributor is made as a shaft with a machined concentric chamber at the front end, closed by the distributor body cover in which a fuel spraying device is installed.
• the cylinder space is connec ⁇ ted with the feed chamber by means of the exhaust gas ca ⁇ nal, in addition to the feed canal.
• the exhaust gas canal ends at the cylinder wall with an opening positioned above the upper edge of the exhaust port.
• the feed and exhaust gas canals are connected separately with two control sec ⁇ tions of the rotary distributor; the sections are spaced along the axis of the annular wall of the shaft.
• the ex ⁇ haust gas canal section has an inlet opening, and the feed canal section has an outlet opening.
• the inlet and outlet openings are spaced at such a central angle and the non-slip transmission is coupled at such a ratio that, whi ⁇ le rotating, the inlet opening meets the opening of the ex ⁇ haust canal during the power stroke, and the outlet opening meets the feed canal opening during the compression stroke.
• the connections are open when the piston is below the ope- nings of the feed and the exhaust gas canals positioned on the cylinder wall.
• a further development of the invention consists in placing the outlet. opening and feed canal section closer to the ro ⁇ tary distributor cover.
• this design has, in the case of a multi-cylinder engine, one common fe ⁇ ed chamber and the exhaust gas canals and the feed canals are spaced on the circumference of the rotary distributor sections at a symmetrical pitch of the rotary distributor central angle, corresponding to the number of cylinders and the sequence of ignition.
• Fig. 1 Cross section of the engine
• Fig. 2 longitudinal section of a three-cylinder engine equipped with a rotary distributor having control openings positioned on the circumference of the control element which has the form of a hollow shaft
• the cross sections are taken through the feed canal planes of individual cylinders.
• Fig. 6 an axial cross section thro ⁇ ugh another distributor with control openings located on the front surface.
• Fig. 7 view of the front surface of the distributor of Fig.
• Fig. 6 designed to co-operate with a three cylinder engine, and driven by 1:1 transmission
• Fig. 8 - a longitudinal section of a three-cylinder engine controlled by a two-sectional distributor
• Figs. 9 and 10 - sections through the exhaust gas section and the feed canal section, respectively.
• the working space 8 is enclosed by the walls of the cylinder 1, the he ⁇ ad 6, and the bottom of the piston 5.
• the piston 5 is con ⁇ nected with the crankshaft 10 by means of a connecting rod 9.
• the crankshaft 10 is supported on bearings in the crank- case 11.
• the piston 5 uncovers the inlet 3 and exhaust 4 ports located in the wall of the cy ⁇ linder 1. Air is sucked into the crank case 11 through a suction canal and a self-closing, one-way plate valve 12.
• the basic design of the two-stroke engine with precompres- sion of charge in the crankcase, as described above, is supplemented with a device for preparing the combustible load.
• the rotary distributor unit A is equipped with a sle ⁇ eve-type control element 16 driven by 1:1 non-slip trans ⁇ mission 17 from the crankshaft 10.
• the inner space of the control element 16 constitutes the feed chamber 13 which is periodically connected with the cylinder space 8 through the inlet 18 and outlet 19 openings, and the feed canal 14.
• the nozzle of the fuel spraying unit 15, in this case - an injector with electromagnetic control, is built into the feed chamber 13.
• the feed canal 14 ends at the wall of the cylinder 1, with the opening situated slightly above the upper edge of the outlet port 4 and directed towards the hole in the head 6 where the spark plug 7 is installed.
• the operation of the feed chamber 13 is controlled on a geome ⁇ tric basis: the value of the central angle ⁇ between the inlet 18 and outlet 19 openings on the circumference of the control element 16 is slightly greater than the angle of rotation of the crankshaft 10 for the travel of the piston 5 between covering and uncovering of the feed canal 14.
• the angle a. equ ⁇ als 220°.
• the opening of the feed canal 14 is closed by the piston head edge before the ins ⁇ tance of ignition.
• the feed chamber 13 connected with the cylinder space 8 for the second time in the same cycle - this time through the inlet opening 18.
• Some portion of the exhaust gases flows into the feed cham ⁇ ber 13 which acts as a pressure accumulator and a generator of the fuel-exhaust gas mixture.
• the period including the final part of the power stroke, the charge exchange phase and the beginning of the compression stroke is long enough to ensure a complete vaporization of the fuel injected and chemical activation of thus produced gaseous mixture.
• the position of the opening of the feed canal 14 on the wall of the cylinder 1 controls the timing of connecting the feed chamber 13 with the cylinder space 8.
• the connecting operation In the process of preparing the combustible mixture, the connecting operation must meet two opposing conditions, the introduction of the mixture must sufficiently precede the moment of ignition and the pressure in the feed chamber 13 must reach a suffi ⁇ cient value.
• the engine shown in Fig. 2 has a rotary distributor A with one common feed chamber 13 for three cylinders.
• the control element 16 has the form of a shaft with a machined concen ⁇ tric chamber at one end, closed by the cover 20 of the dis ⁇ tributor body 21. In the cover 20, the fuel spraying device 15 is mounted.
• the cen ⁇ tral angle ⁇ at which the inlet 18 and outlet 19 openings are spaced equals 240°.
• the central angle ⁇ representing the relative difference in the posi ⁇ tion of openings between the sections, must be 120°, in the direction opposite to the rotation of the crankshaft 10 and in accordance with the ignition sequence.
• the feed chamber 13 is always simulta ⁇ neously connected with cylinders on the power and compres ⁇ sion strokes.
• Fig. 2 shows the first and the second cylin ⁇ ders in this situation, connected by means of the canals 14.1 and 14.2.
• Fig. 6 shows an advantageous design of the rotary distri ⁇ butor A.
• the control element 16 takes in this design the form of a chamber supported by bearings in the distributor body 21; one end of the control element 16 is connected with the shaft of a non-slip transmission 17 by means of a dog clutch 23 movable along its axis.
• the inlet opening 18 and the outlet opening 19 are situated in a flat bottom of the control element 16, which is pressed against the cover 20 by means of a helical spring 24 incorporated in the clutch unit 23.
• the feed canals 14.1, 14.2, and 14.3 of the three cylinders are connected to the cover 20 in which a spray nozzle 15 is installed in the centre, along the axis of rotation.
• the control surface also seals the feed chamber 13.
• Fig. 7 shows the position of the control openings in the distributor of Fig. 6 in a three-cylinder engine with a non-slip 1:1 transmission 17. It is an obvious solution to use a reduction transmission to drive the distributor with the transmission ratio expressed by a natural number, with a resulting division of the central angle ⁇ .
• a three-cylinder engine as shown in Fig. 8 embodies so ⁇ mewhat modified, relative to those described above, prin ⁇ ciple of preparing the mixture.
• each cylinder is equipped with a exhaust gas canal 22.1, 22.2, and 22.3, respectively, en ⁇ ding with an opening in the cylinder wall, positioned above the upper edge of the exhaust port 4.
• These canals run to the rotary distributor A separately to two control sections allocated to the functions of exhaust gas transfer and mix ⁇ ture feed, rather than to individual cylinders.
• the exhaust gas flows through the feed chamber in one direction.
• the section with the outlet opening 19 corresponding to the fe ⁇ ed canals 14.2, 14.2, and 14.3, is situated closer to the distributor cover 20, which ensures the counter-current flow which intensifies evaporation and mixing of the spray ⁇ ed fuel with the gas stream.
• a processor-based control unit 26 which, based on signals coming from numerous sensors which scrutinize the engine operation, external conditions, the throttle position, determines the required setting of the fuel feed, controllable clutch and other controllable engi ⁇ ne units.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Combustion Methods Of Internal-Combustion Engines (AREA)
• Exhaust Gas After Treatment (AREA)
• Valve-Gear Or Valve Arrangements (AREA)
• Valve Device For Special Equipments (AREA)
• Ignition Installations For Internal Combustion Engines (AREA)

Applications Claiming Priority (3)

Publications (2)

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Family Applications (1)

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• 1994
  • 1994-08-16 PL PL94304731A patent/PL174629B1/pl unknown
• 1995
  • 1995-08-16 EP EP95928040A patent/EP0776423B1/de not_active Expired - Lifetime
  • 1995-08-16 DE DE69505831T patent/DE69505831D1/de not_active Expired - Lifetime
  • 1995-08-16 CZ CZ97431A patent/CZ43197A3/cs unknown
  • 1995-08-16 AT AT95928040T patent/ATE173055T1/de not_active IP Right Cessation
  • 1995-08-16 HU HU9701943A patent/HUT76953A/hu unknown
  • 1995-08-16 WO PCT/PL1995/000015 patent/WO1996005426A1/en not_active Application Discontinuation

Non-Patent Citations (1)

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