Classifications

• • 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
• • 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
  • F01L1/38—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 other than four-stroke cycle, e.g. with two-stroke cycle
• • 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
  • F02B33/28—Component parts, details or accessories of crankcase pumps, not provided for in, or of interest apart from, subgroups F02B33/02 - F02B33/26
  • F02B33/30—Control of inlet or outlet ports
• • 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 present invention relates to a two-stroke engine comprising at least one cylinder having a combustion chamber supplied with fresh air by a positive displacement compressor and provided at its upper part with at least one intake orifice cooperating with an intake valve.
• a two-stroke engine comprising at least one cylinder having a combustion chamber supplied with fresh air by a positive displacement compressor and provided at its upper part with at least one intake orifice cooperating with an intake valve.
• the pistons constitute the main organs ensuring distribution.
• the two-time engines whether they operate as a diesel engine or as an internal combustion engine, have an engine cycle corresponding to one revolution of the crankshaft, so that the different instants of the cycle and the different phases of the distribution correspond to well defined crank angles.
• each particular point of the engine cycle corresponds to a strictly defined piston position in the cylinder, and this is notably the case for: the opening of the exhaust, the opening of the fresh gas insufflation duct or opening intake, closing the intake, and finally closing the exhaust of the burnt gases. Therefore, in many cases, the piston sliding in! E cy ⁇ n- dre is often the only distribution member used: it is a dis ⁇ distribution without valves.
• the cylinder has intake and exhaust ports made in its jacket, and suitably arranged in order to obtain a determined sequencing of opening and closing of the intake. and of the exhaust when the piston masks or unmasks said orifices during its movement.
• the distribution member used is only constituted by the piston, the angular offsets relative to the bottom dead center (PMB), of the exhaust opening and of the exhaust closure d on the one hand, of the intake opening and of the intake closure on the other hand, are necessarily symmetrical two by two, that is to say equivalent to the nearest sign.
• a camshaft associated with rocker arms and other connecting parts actuates valves located at one end of the cylinder. These perform the opening and closing of the intake ports at instants determined by the cam profile of the intake ports, the exhaust ports in this case being open and closed by the moving piston. is lying.
• the instants for opening and closing the intake of the engine cy ⁇ key can be calibrated asymmetrically with respect to the bottom dead center, whereas the instants for opening and closing the exhaust remain symmetrical in this case. with respect to said bottom dead center.
• One of the aims of the present invention is, therefore, to provide a two-stroke engine which eliminates or considerably reduces the drawbacks associated with the embodiments known in the current state of the art, that is to say a two-engine time having a distribution capable of ensuring good filling of the cylinder with fresh gas, and satisfactory eva ⁇ cuation of the burnt gases.
• Another object of the present invention is to provide a two-stroke engine capable of operating with a wide variety of fuels, and this with better characteristics of power, consumption and cost.
• the invention relates to a two-stroke engine comprising at least one cylinder having a combustion chamber supplied with fresh air by a positive displacement compressor and provided at its upper part with at least one inlet orifice cooperating with a valve d 'admission, two-stroke engine characterized in that its distribution is ensured, " independently of the geometry of the cylinder, by means of controlled distribution.
• FIG. 1 is a partial elevational view in section of a two-stroke engine according to the invention, the piston being in top dead center (TDC)
• FIG. 2 is a view of the motor according to Figure 1, in the scanning phase
• FIG. 3 is a view of the engine according to Figure 1, in the injection-compression phase -. -
• the two-stroke engine mainly comprises a block 1 associated with a cylinder 2 in which slides a piston 3.
• the latter is actuated by means of a connecting rod U cooperating with a crank pin 5 secured to the crankshaft (not shown) movable about its axis of rotation 6.
• the piston 3 actuated by the connecting rod-crank assembly constituted by the connecting rod 4 and the crankshaft slides in the cylinder 2 and moves, in known manner, between two extreme positions: a top dead center (TDC) corresponding to a zero angle of rotation of the crankshaft, and a bottom dead center (PMB) corresponding to a rotation angle of 180 degrees of the crankshaft .
• TDC top dead center
• PMB bottom dead center
• the circulation provided for gases is of the longitudinal type.
• the cylinder 2 has at its upper part 7 coinciding with the upper part 8 of the combustion chamber 9, one or more orifices 10 cooperating with valves 11 It also has orifices 12 located in the vicinity of the lower end 13 of the combustion chamber 9, and arranged in the side wall 1. of cylinder 2.
• the orifices 10 constitute orifices for the admission of fresh gases coming from a volumetric compressor (not shown) by means of a intake duct 15, while the orifices 12 constitute exhaust orifices.
• the two-stroke engine according to the invention is further provided at the upper part 7 of the cylinder 2, with a spark plug 16 intended in a known manner to ignite the mixture of fresh gas and fuel present in the combustion chamber 9.
• a spark plug 16 intended in a known manner to ignite the mixture of fresh gas and fuel present in the combustion chamber 9.
• One or more injectors 17 also placed in the upper part 7 of the cylinder 2, preferably near the intake orifices 10, and opening into the upper part 8 of the combustion chamber 9, allow to bring the fuel into it by direct injection.
• valves 11 ensuring the admission of the gases. fresh are ordered through a ca ⁇ tree 18 moved by. the crankshaft.
• the orifices 12 ensuring the exhaust of the used gases cooperate with exhaust valves 19 which are in particular slide valves actuated by means of a camshaft 20 and making it possible to open or close said exhaust orifices 12.
• the two-stroke engine includes controlled distribution means 21, the operation of which is independent of the geometry of the cylinder 2.
• These controlled distribution means 21 are constituted by the set of intake valves 11 and exhaust valves 1 9 controlled by the camshafts 18 and 20 respectively through the crankshaft, the piston 3 no longer providing the distribution function directly, as is the case in the current state of the art.
• this active work phase ends after a rotation of 135 degrees, of the crank pin 5. 'Then begins the exhaust phase 26 coinciding with the opening at point 23 of the slide valves 19 with which the cylinder 2 is provided, which amounts to clearing the exhaust orifices 12 so that the gases burn the. can escape.
• the intake phase 28 ends after a rotation of approximately 240 degrees of the engine, corresponding to position 33.
• the exhaust phase 26 begins before the intake phase 28, and also ends before it, which theoretically guarantees proper operation of the two-stroke engine. according to the invention. 5
• the distribution means selected namely the inlet 11 and outlet 19 exhaust ducts
• the setting of the operating points as described can be modified and is not dependent on the construction of the piston 3 and of the cylinder 2. It follows that this engine can operate with different fuels, in particular petrol, su ⁇ per, diesel, LPG, alcohol or "two-stroke mixture”.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Output Control And Ontrol Of Special Type Engine (AREA)
• Valve-Gear Or Valve Arrangements (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=9319021

Family Applications (1)

Country Status (4)

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• 1985
  • 1985-05-03 FR FR8506895A patent/FR2581422B1/fr not_active Expired
• 1986
  • 1986-04-25 WO PCT/FR1986/000142 patent/WO1986006789A1/fr active IP Right Grant
  • 1986-04-25 EP EP19860902435 patent/EP0220223B1/de not_active Expired
  • 1986-04-25 DE DE8686902435T patent/DE3665203D1/de not_active Expired

Non-Patent Citations (1)

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