EP3561280B1 - Carburettor and internal combustion engine with a carburettor - Google Patents

Carburettor and internal combustion engine with a carburettor Download PDF

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Publication number
EP3561280B1
EP3561280B1 EP18400011.5A EP18400011A EP3561280B1 EP 3561280 B1 EP3561280 B1 EP 3561280B1 EP 18400011 A EP18400011 A EP 18400011A EP 3561280 B1 EP3561280 B1 EP 3561280B1
Authority
EP
European Patent Office
Prior art keywords
fuel
chamber
enrichment
pump
internal combustion
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.)
Active
Application number
EP18400011.5A
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German (de)
French (fr)
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EP3561280A1 (en
Inventor
Philipp Kühnle
Klaus Geyer
Michael Grether
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.)
Andreas Stihl AG and Co KG
Original Assignee
Andreas Stihl AG and Co KG
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Application filed by Andreas Stihl AG and Co KG filed Critical Andreas Stihl AG and Co KG
Priority to EP18400011.5A priority Critical patent/EP3561280B1/en
Publication of EP3561280A1 publication Critical patent/EP3561280A1/en
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Publication of EP3561280B1 publication Critical patent/EP3561280B1/en
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Classifications

    • 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
    • F02M1/00—Carburettors with means for facilitating engine's starting or its idling below operational temperatures
    • F02M1/16—Other means for enriching fuel-air mixture during starting; Priming cups; using different fuels for starting and normal operation
    • 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
    • F02M1/00—Carburettors with means for facilitating engine's starting or its idling below operational temperatures
    • F02M1/08—Carburettors with means for facilitating engine's starting or its idling below operational temperatures the means to facilitate starting or idling becoming operative or inoperative automatically
    • F02M1/10—Carburettors with means for facilitating engine's starting or its idling below operational temperatures the means to facilitate starting or idling becoming operative or inoperative automatically dependent on engine temperature, e.g. having thermostat
    • 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
    • F02M17/00—Carburettors having pertinent characteristics not provided for in, or of interest apart from, the apparatus of preceding main groups F02M1/00 - F02M15/00
    • F02M17/02—Floatless carburettors
    • F02M17/04—Floatless carburettors having fuel inlet valve controlled by diaphragm

Definitions

  • the invention relates to a carburetor of the type specified in the preamble of claim 1 and an internal combustion engine with a carburetor.
  • a carburetor which comprises a fuel pump, a feed pump to be operated by the operator and an enrichment device.
  • the enrichment device is used to feed an increased amount of fuel into the intake duct during start-up.
  • the enrichment device comprises an electromagnetically actuated valve which closes the flow connection into the intake channel as soon as a predetermined amount of fuel has been supplied via the enrichment device after starting.
  • a carburetor emerges which has a fuel pump, a feed pump to be operated by the operator, namely a purger, and an enrichment device, namely a primer.
  • the amount of fuel to be fed into the intake duct via the primer is taken from the fuel that is returned to the fuel tank by the purger.
  • the U.S. 5,711,901 A discloses a carburetor with a fuel pump, feed pump and enrichment device.
  • the pressure in the enrichment chamber is kept constant via a check valve.
  • From the EP 0 306 856 A2 shows a starting device with an electrically driven feed pump.
  • the pressure in the enrichment chamber is kept constant via a check valve.
  • an electromagnetic valve is opened in a fuel line that leads into the intake duct.
  • the invention is based on the object of creating a carburetor of the generic type which has a simple structure and in which a defined amount of fuel can be fed to an internal combustion engine via the enrichment device. Another object of the invention is to provide an internal combustion engine with which starting is facilitated.
  • this object is achieved by a carburetor having the features of claim 1.
  • the object is achieved by an internal combustion engine having the features of claim 12.
  • the carburetor has a fuel pump.
  • the fuel pump is the pump that supplies fuel to the internal combustion engine during operation.
  • the fuel pump advantageously supplies the fuel required for operation when the internal combustion engine is running.
  • the fuel pump can advantageously be driven by the fluctuating pressure in a crankcase interior of the internal combustion engine.
  • the carburetor advantageously has a feed pump that can be operated by an operator.
  • the feed pump is advantageously a so-called purger.
  • the feed pump is used in particular to manually flood the fuel system with fuel and gas bubbles or the like from the fuel system before the internal combustion engine is started to remove.
  • the feed pump is advantageously arranged in such a way that the feed pump feeds fuel from a fuel chamber of the carburetor into a fuel tank.
  • fuel is fed from the at least one fuel chamber into an intake duct section formed in the carburetor.
  • the fuel chamber of the carburetor is in particular a fuel chamber from which one or more fuel openings of the carburetor are fed.
  • the carburetor also has an enrichment device.
  • the enrichment device comprises, in particular, an enrichment pump that is separate from the feed pump.
  • the enrichment device has an enrichment chamber.
  • the enrichment device is designed to supply fuel from the enrichment chamber to the internal combustion engine.
  • the enrichment device is in particular a primer.
  • the enrichment chamber has a variable volume.
  • the feed pump and the enrichment device are preferably coupled in such a way that actuation of the feed pump leads to a change in the volume of the enrichment chamber. The actuation of the feed pump accordingly also leads to a pumping movement in the enrichment chamber.
  • the change in the volume of the enrichment chamber advantageously specifies the volume of fuel to be supplied to the internal combustion engine. With each complete pump stroke of the feed pump, a defined volume of fuel can accordingly be fed to the internal combustion engine via the enrichment device as soon as the fuel system is completely flooded. When the feed pump is fully actuated, a complete pump stroke of the feed pump is carried out.
  • the feed pump can in particular be a purger with an elastic pump bellows. Complete actuation of the feed pump is, in particular, actuation of the pump bellows up to a stop.
  • the number of pump strokes to be carried out with the feed pump is usually specified, for example in an operating manual or the like.
  • the amount of fuel supplied via the enrichment device is predefined, and it it can be ensured that a sufficient amount of fuel for starting the internal combustion engine is supplied to the internal combustion engine.
  • the fuel system is advantageously flooded by the feed pump and the enrichment device at the same time and a predefined amount of fuel is supplied to the internal combustion engine, in particular an intake duct.
  • the feed pump advantageously has a feed chamber.
  • the delivery chamber is partially delimited by an elastic pump bellows which is to be actuated by the operator.
  • the delivery chamber and the enrichment chamber are advantageously separate chambers.
  • the enrichment chamber is delimited by a movable element, for example by a movable stamp or an elastic membrane.
  • the feed pump preferably comprises an elastic element, in particular a pump bellows, the movement of the movable element being coupled to the movement of the elastic element via a coupling element.
  • the coupling element is in particular a rigid coupling element such as a coupling rod or the like.
  • the feed pump and the enrichment device are hydraulically coupled to one another.
  • the hydraulic coupling is advantageously designed in such a way that actuation of the feed pump leads to a change in the volume of the enrichment chamber.
  • the enrichment device and the feed pump are electrically coupled to one another.
  • the electrical coupling is advantageously designed in such a way that actuation of the feed pump leads to a change in the volume of the enrichment chamber.
  • the enrichment chamber is connected upstream of the feed pump.
  • the enrichment chamber is accordingly arranged upstream of the feed pump in relation to a flow direction to a fuel tank.
  • the volume of the enrichment chamber is first filled with fuel and then the volume of the feed pump.
  • the priming pump and the feed pump are filled when an elastic element such as a pump bellows is released by a negative pressure in causes a fuel line.
  • the elastic element is advantageously designed to be transparent. The operator can advantageously use the transparent elastic element to check whether gas bubbles are still present in the fuel system.
  • a first check valve is advantageously arranged in the flow connection from the enrichment chamber to the feed pump. The first check valve ensures that when the feed pump is actuated, no fuel can flow back from the feed chamber into the enrichment chamber.
  • the enrichment device conveys the fuel for the internal combustion engine from the enrichment chamber into a connecting line, in particular into a fuel line.
  • the connecting line is advantageously provided for connection to a crankcase of the internal combustion engine.
  • the connecting line opens in particular into a gas-carrying line which connects an intake duct of the internal combustion engine to a crankcase interior of the internal combustion engine.
  • a second check valve is preferably arranged in the connecting line.
  • the second check valve prevents fuel or air from being sucked into the enrichment chamber.
  • the opening pressure of the second check valve is advantageously lower than the opening pressure of the first check valve. This ensures that fuel is pumped into the connecting line.
  • the feed pump is advantageously arranged in the line path behind the fuel chamber in relation to the direction of flow.
  • the specified direction of flow relates to a suction stroke of the feed pump.
  • the feed pump is accordingly arranged downstream of the fuel chamber.
  • the feed pump is connected downstream of the fuel chamber in relation to the direction of flow.
  • the enrichment chamber is advantageously arranged downstream of the fuel chamber in relation to the flow direction in the line path.
  • the enrichment chamber is accordingly located downstream of the fuel chamber.
  • the enrichment chamber is advantageously arranged in the line path in relation to the direction of flow in front of the fuel chamber. In this configuration, the enrichment chamber is accordingly arranged upstream of the fuel chamber.
  • the enrichment chamber is arranged in the conduit upstream of the fuel chamber, the enrichment chamber is flooded before the fuel chamber when the feed pump is operated by the operator. As a result, after just a few pumping strokes of the feed pump, fuel is delivered to the internal combustion engine via the enrichment chamber.
  • the fuel chamber is advantageously a control chamber of the carburetor.
  • the fuel pump advantageously has a pump chamber which, in particular, is arranged upstream of the fuel chamber of the carburetor in relation to the direction of flow.
  • the fuel chamber is in particular a control chamber of the carburetor.
  • the enrichment chamber can advantageously be arranged in front of the pump chamber or behind the fuel chamber in relation to the direction of flow.
  • the pump chamber and fuel chamber are advantageously arranged directly following one another and separated from one another only by a valve.
  • the carburetor advantageously has two connections for connection to the fuel tank.
  • the enrichment chamber, the delivery chamber and the fuel chamber are arranged in a flow connection of the carburetor from one connection, which is provided in particular for the fuel inflow to the carburetor, to the other connection, which is in particular provided for the fuel outflow. Both Connections are connected to the fuel tank, with fuel being sucked in via one connection and fuel flowing back into the fuel tank via the other connection.
  • the delivery chamber is arranged downstream of the enrichment chamber in relation to the flow direction, that is, it is arranged downstream of the enrichment chamber, so that fuel from the fuel tank first enters the enrichment chamber and then into the delivery chamber.
  • the fuel chamber and the pump chamber can be connected downstream or upstream of the enrichment chamber, that is to say they can be arranged downstream or upstream of the enrichment chamber.
  • the enrichment chamber is flow-connected to a crankcase interior of the internal combustion engine.
  • the fuel is preferably supplied directly to the crankcase interior from the enrichment chamber.
  • the fuel is preferably supplied directly to the crankcase interior from the enrichment chamber.
  • the fuel is not supplied via an intake duct of the internal combustion engine.
  • a supply of fuel from the enrichment chamber into an intake duct of the internal combustion engine is preferably not provided.
  • a switching valve is advantageously arranged in the flow path from the enrichment chamber to the crankcase interior.
  • the fuel, which is additionally supplied via the enrichment chamber can be switched off via the switching valve in order, for example, to prevent the internal combustion engine from becoming too rich when the engine is warm.
  • the switching valve is temperature-actuated. If a warm start is carried out with the internal combustion engine, it is advantageously provided that the switching valve is closed so that no additional fuel is supplied from the enrichment chamber into the crankcase interior.
  • the switching valve is arranged directly on the crankcase. As a result, the temperature of the crankcase can be detected on the switching valve itself and the switching valve can be actuated depending on the temperature of the crankcase. An advantageous, simple design results when the switching valve is a temperature-actuated valve.
  • the switching valve comprises a bimetal.
  • a different design of the switching valve can also be advantageous.
  • Fig. 1 shows schematically an internal combustion engine 1.
  • the internal combustion engine 1 is advantageously a mixture-lubricated engine, in particular a two-stroke engine or a mixture-lubricated four-stroke engine.
  • the internal combustion engine 1 has a cylinder 2 in which a combustion chamber 3 is formed.
  • the combustion chamber 3 is delimited by a piston 5 which is mounted to reciprocate in the cylinder 2.
  • the piston 5 drives a crankshaft 6 in rotation via a connecting rod (not shown).
  • the crankshaft 6 is mounted in a crankcase 4 of the internal combustion engine 1 so as to be rotatable about an axis of rotation 7.
  • the crankcase 4 has a crankcase interior 8 in which the crankshaft 6 rotates.
  • the internal combustion engine 1 has a fuel system 26 which comprises a fuel tank 27 and a carburetor 9.
  • the carburetor 9 has a fuel pump 15 which, during operation, supplies fuel into an intake duct section 10 formed in the carburetor 9.
  • the main fuel opening 12 is arranged in the area of a venturi 11 in the intake duct section 10.
  • a throttle element, in the exemplary embodiment a throttle valve 13, is arranged downstream of the main fuel opening 12.
  • the intake channel section 10 is part of an intake channel 40 which opens into the crankcase interior 8.
  • the carburetor 9 has a feed pump 28 and an enrichment device 29.
  • the enrichment device 29 is designed as an enrichment pump.
  • the enrichment device 29 and the feed pump 28 are advantageously arranged in a housing 59 of the gasifier 9.
  • the enrichment device 29 and the feed pump 28 are shown outside of the gasifier 9 in the illustration for a better overview.
  • the fuel pump 15 sucks via a fuel line 52 from which in Fig. 1 schematically only a section is shown, fuel from the fuel tank 27 on.
  • the fuel line 52 is connected to the fuel tank 27, as in FIG Fig. 1 is shown schematically with a dashed line.
  • the carburetor 9 has two connections for fuel lines, namely a schematically illustrated fuel inlet 57 and a schematically illustrated fuel outlet 58.
  • the fuel line 52 is connected to the fuel inlet 57.
  • the fuel pump 15 is designed as a diaphragm pump and is driven by the fluctuating pressure in the crankcase interior 8.
  • the fuel pump 15 has an inlet valve 19 and an outlet valve 20, which in the exemplary embodiment are designed as check valves.
  • a pump chamber 18 is located between the inlet valve 19 and the outlet valve 20 in the flow direction 60.
  • the pump chamber 18 is delimited by a pump membrane 16.
  • the pump membrane 16 separates the pump chamber 18 from a pulse chamber 17.
  • the pulse chamber 17 is connected to the crankcase interior 8 via a pulse line 21.
  • the fluctuating pressure in the crankcase interior 8 that occurs during operation leads to deflections of the pump diaphragm 16, which thereby sucks in the fuel via the inlet valve 19 and conveys it out of the pump chamber 18 via the outlet valve 20.
  • a regulating valve 22 is arranged downstream of the fuel pump 15 in a flow direction 60 of the fuel from the fuel tank 27 to the intake duct section 10.
  • the control valve 22 is coupled to a control membrane 24 and is opened or closed depending on the position of the control membrane 24.
  • the control membrane 24 separates a fuel chamber 23, which forms the control chamber of the carburetor 9, from a compensation chamber 25.
  • the compensation chamber 25 is air-filled and can be closed or connected to the environment or the clean room of an air filter, through which combustion air is sucked into the intake duct 40 be. If the pressure in the fuel chamber 23 falls, the control valve 22 opens and fuel delivered by the fuel pump 15 continues to flow into the fuel chamber 23.
  • the fuel chamber 23 feeds the main fuel opening 12 and the secondary fuel openings 14.
  • a fuel line 42 leads from the fuel chamber 23.
  • the fuel line 42 connects the fuel chamber 23 to an enrichment chamber 30 of the enrichment device 29.
  • a check valve 43 is arranged in the flow path from the fuel chamber 23 to the enrichment chamber 30.
  • the check valve 43 opens in the flow direction 60 and closes in the opposite direction.
  • the direction of flow 60 is directed from the fuel chamber 23 to the enrichment chamber 30.
  • the enrichment chamber 30 has a variable volume. In the exemplary embodiment, the enrichment chamber 30 is delimited by an enrichment pump membrane 31 for this purpose.
  • the enrichment chamber 30 can alternatively also change the volume in a different form, for example by means of an adjustment of a side wall delimiting the enrichment chamber 30.
  • the enrichment chamber 30 is connected to a channel 38 via a connecting line 36.
  • the connecting line 36 is also advantageously a fuel line.
  • the channel 38 connects the intake channel 40 to the crankcase interior 8.
  • the channel 38 branches off from the intake channel 40 downstream of the throttle valve 13, based on the flow direction from the carburetor 9 to the crankcase interior 8. This can prevent the channel 38 from influencing the amount of air that is supplied to the internal combustion engine 1 when idling becomes.
  • the throttle valve 13 is in particular largely or completely closed, and the free flow cross-section results from an opening in the throttle valve 13.
  • a check valve 39 is arranged in the channel 38 in the flow direction from the intake channel 40 to the crankcase interior 8 upstream of the junction between the connecting line 36 and the channel 38.
  • the check valve 39 opens in the direction of flow from the intake duct 40 to the crankcase interior 8.
  • the channel 38 can advantageously be connected to the crankcase interior 8 via a switching valve 41.
  • the switching valve 41 is arranged in the flow path from the enrichment chamber 30 to the crankcase interior 8.
  • the switching valve 41 is arranged directly on the crankcase 4.
  • the switching valve 41 is advantageously a temperature-actuated valve which closes when a structurally predetermined temperature is exceeded. As a result, fuel is fed into the crankcase interior 8 via the channel 38 only at low temperatures. Another, for example electrical, actuation of the switching valve 41 can, however, also be advantageous.
  • the enrichment chamber 30 can be connected via an in Fig. 1 Connecting line 66 shown in dashed lines may be connected to intake duct 40.
  • a check valve 67 is advantageously arranged in the connecting line 66.
  • the fuel system 29 advantageously has a connecting line 36 and / or a connecting line 66.
  • the enrichment chamber 30 is connected to a delivery chamber 34 of the delivery pump 28 via a fuel line 44.
  • a check valve 45 which opens in flow direction 60, is arranged in fuel line 44.
  • the flow direction 60 runs from the enrichment chamber 30 to the delivery chamber 34.
  • the delivery chamber 34 is advantageously partially made up of an elastic pump bellows 33 limited.
  • a fuel line 46 preferably leads from the delivery chamber 34 to the fuel tank 27.
  • a check valve 47 is arranged in the fuel line 46 and opens in the flow direction 60.
  • the direction of flow 60 runs from the delivery chamber 34 to the fuel tank 27.
  • the fuel outlet 58 is located downstream of the check valve 47 and is shown in FIG Fig. 1 is shown on a schematically shown wall of the housing 59 of the carburetor 9.
  • the carburetor 9 is accordingly connected to the fuel tank 27 at the fuel inlet 57 and at the fuel outlet 58.
  • the fuel pump 15, the enrichment device 29 and the feed pump 28 are arranged one behind the other in the flow direction 60 in the line path from the fuel inlet 57 to the fuel outlet 58. Further elements can be interposed, such as the fuel chamber 23 of the carburetor 9.
  • the fuel chamber 23 of the carburetor 9 is arranged in the flow direction 60 between the fuel pump 15 and the enrichment device 29.
  • the pump bellows 33 which delimits the delivery chamber 34, is provided to be actuated by an operator in the direction of the arrow 54.
  • the pump bellows 33 is advantageously connected to an enrichment pump membrane 31 via a coupling element 35.
  • the coupling element 35 is a rigid, mechanical coupling element, for example a coupling rod made of metal or dimensionally stable plastic.
  • the fuel is advantageously conveyed via the channel 38 and / or the intake channel 40 and / or directly into the crankcase interior 8.
  • a connecting line 68 is shown schematically, via which fuel can be conveyed from the enrichment chamber 30 directly into the crankcase interior 8.
  • a check valve 69 is advantageously arranged in the connecting line 68.
  • a free travel can also be provided in the coupling of the pump bellows 33 and the enrichment pump membrane 31. As a result, the distance by which the pump bellows 33 is deflected is greater than the distance by which the enrichment pump membrane 31 is deflected by the structurally predetermined idle distance.
  • the feed pump 28 and the enrichment pump membrane 31 are coupled to one another so that a complete actuation of the feed pump 28 from the non-actuated state to the maximally actuated state leads to a reduction in the volume of the enrichment chamber 30 by a structurally predetermined volume.
  • a spring 32 is arranged in the enrichment chamber 30, which acts as a return spring and, as soon as the operator lets go of the pump bellows 33, returns the enrichment pump membrane 31 to its starting position.
  • the enrichment chamber 30 is connected to the crankcase interior 8.
  • the connecting line 36 can advantageously be provided in the flow path from the enrichment chamber 30 into the crankcase interior 8.
  • the connecting line 36 is a line in which advantageously only fuel flows.
  • the connecting line 36 opens into the channel 38, which transports the fuel from the connecting line 36 into the crankcase interior 8.
  • the channel 38 is designed as a gas-carrying, namely as an air-carrying or mixture-carrying channel. During operation, air is sucked into the crankcase interior 8 through the gas-carrying duct 38 when there is a negative pressure in the crankcase interior 8. In the exemplary embodiment, the air is drawn in from the intake duct 40 into the crankcase interior 8.
  • the intake duct 40 also opens into the crankcase interior 8, in particular via a valve (not shown).
  • the intake channel 40 on the cylinder 2 preferably opens into an area over which the piston 5 passes.
  • the valve which connects the intake duct 40 to the crankcase interior 8 is preferably formed by the piston 5.
  • the piston 5 opens and closes an inlet opening of the intake duct 40 on the cylinder 2 as it moves back and forth.
  • the internal combustion engine 1 is preferably an internal combustion engine that is slot-controlled by the piston 5.
  • the operator Before starting the internal combustion engine 1, the operator usually actuates the feed pump 28.
  • the feed pump 28 is advantageously actuated by pressing the pump bellows 33 several times in the direction of arrow 54. This causes fuel to be drawn from the fuel tank 27 via the fuel line 52, the pump chamber 18 of the fuel pump 15, the fuel chamber 23, the enrichment device 29 and the delivery chamber 34 are conveyed into the fuel tank 27 and the entire fuel system 26 is thereby flushed.
  • the pump bellows 33 is moved, the enrichment pump diaphragm 31 is simultaneously actuated via the coupling element 35 and fuel is thus conveyed from the enrichment chamber 30 into the connecting line 36 and via the channel 38 into the crankcase interior 8.
  • the check valves 37, 39, 43, 45 and 47 ensure that the fuel flows in the desired direction.
  • Fig. 2 shows an alternative embodiment.
  • the same reference symbols identify elements that correspond to one another in all figures.
  • the embodiment according to Fig. 2 corresponds essentially to the embodiment according to Fig. 1 , referring to the description for elements that are shown in both exemplary embodiments Fig. 1 is referred.
  • the enrichment device 29 is arranged in the flow path from the fuel tank 27 to the fuel pump 15.
  • the enrichment chamber 30 is accordingly located upstream of the fuel pump 15 and the fuel chamber 23.
  • the enrichment device 29, the fuel pump 15 and the feed pump 28 are arranged one behind the other in the line path from the fuel inlet 57 to the fuel outlet 58 in the flow direction 60.
  • the fuel chamber 23 of the carburetor 9 is arranged in the flow direction 60 between the fuel pump 15 and the feed pump 28.
  • the enrichment device 29 and the feed pump 28 are advantageously arranged in the housing 59 of the gasifier 9.
  • the enrichment chamber 30 is connected to the fuel tank 27 via a fuel line 48.
  • the non-return valve 37 is advantageously biased towards the closed position by a spring (not shown).
  • a check valve 49 which opens in flow direction 60, is arranged in fuel line 48. The direction of flow 60 runs from the fuel tank 27 to the enrichment chamber 30.
  • the fuel inlet 57 of the carburetor 9, shown schematically, is located between the check valve 49 and the fuel tank 27.
  • the enrichment chamber 30 is advantageously located in the direction of flow 60 behind the fuel inlet 57 of the carburettor 9
  • a fuel line 56 leads to the fuel pump 15 of the carburetor 9.
  • the fuel chamber 23 is connected to the delivery chamber 34 of the delivery pump 28 via a fuel line 50.
  • a check valve 51 which opens in flow direction 60, is arranged in fuel line 50. The flow direction 60 runs from the fuel chamber 23 to the delivery chamber 34.
  • the fuel line 56 is partially shown with a dashed line.
  • the check valve 47 is arranged upstream of the fuel outlet 58 of the carburetor 9 in relation to the flow direction 60.
  • the feed pump 28 is coupled to the enrichment chamber 30 via a hydraulic coupling 55. If the volume of the delivery chamber 34 decreases, the volume of the enrichment chamber 30 is reduced due to the hydraulic coupling 55.
  • the volume of the enrichment chamber 30 can be reduced by deflecting the enrichment pump membrane 31.
  • the path by which the enrichment pump diaphragm 31 is deflected from the non-actuated state to the fully actuated state when the pump bellows 33 is fully actuated is structurally predetermined, for example by means of corresponding stops.
  • Fig. 3 shows a further preferred embodiment.
  • the enrichment device 29 is arranged in the flow path from the fuel chamber 23 to the delivery chamber 34. This corresponds to the arrangement Fig. 1 , to the description of which reference is made.
  • the feed pump 28 is coupled to the enrichment device 29, preferably to the enrichment pump membrane 31, via an electrical coupling 65.
  • the coupling 65 is preferably designed such that actuation of the pump bellows 33 causes the volume of the enrichment chamber 30 to be reduced by a predetermined value.
  • the enrichment chamber 30 is connected to the crankcase interior 8 via a fuel line 53.
  • the fuel line 53 only carries fuel and no air during operation.
  • the fuel line 53 opens into the crankcase interior 8.
  • the fuel is not fed into a gas-carrying channel, but directly into the crankcase interior 8.
  • the switching valve 41 is arranged at the opening of the fuel line 53 into the crankcase interior 8.
  • the switching valve 41 is arranged directly on the crankcase 4.
  • the type of coupling of the feed pump 28 and the enrichment device 29 can take place mechanically, in particular via a rigid coupling element 35, hydraulically via a hydraulic coupling 55 or electrically via an electrical coupling 65 for each exemplary embodiment.
  • Other types of coupling can also be advantageous.
  • the fuel is supplied from the enrichment chamber 30 into the crankcase interior 8.
  • provision can be made for the fuel to be supplied from the enrichment chamber 30 via the intake duct 40 into the crankcase interior 8.
  • a fuel delivery is conceivable when actuated by means of mechanical coupling in the intake channel 40, as in FIG Fig. 1 shown schematically.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Control Of The Air-Fuel Ratio Of Carburetors (AREA)

Description

Die Erfindung betrifft einen Vergaser der im Oberbegriff des Anspruchs 1 angegebenen Gattung sowie einen Verbrennungsmotor mit einem Vergaser.The invention relates to a carburetor of the type specified in the preamble of claim 1 and an internal combustion engine with a carburetor.

Aus der JP 2003-254162 A ist ein Vergaser bekannt, der eine Kraftstoffpumpe, eine vom Bediener zu betätigende Förderpumpe sowie eine Anreicherungseinrichtung umfasst. Die Anreicherungseinrichtung dient dazu, während dem Start eine erhöhte Menge an Kraftstoff in den Ansaugkanal zuzuführen. Die Anreicherungseinrichtung umfasst ein elektromagnetisch betätigtes Ventil, das die Strömungsverbindung in den Ansaugkanal schließt, sobald nach dem Starten eine vorgegebene Kraftstoffmenge über die Anreicherungseinrichtung zugeführt wurde.From the JP 2003-254162 A a carburetor is known which comprises a fuel pump, a feed pump to be operated by the operator and an enrichment device. The enrichment device is used to feed an increased amount of fuel into the intake duct during start-up. The enrichment device comprises an electromagnetically actuated valve which closes the flow connection into the intake channel as soon as a predetermined amount of fuel has been supplied via the enrichment device after starting.

Aus der US 7,210,441 B1 geht ein Vergaser hervor, der eine Kraftstoffpumpe, eine vom Bediener zu betätigende Förderpumpe, nämlich einen Purger, sowie eine Anreicherungseinrichtung, nämlich einen Primer, aufweist. Die über den Primer in den Ansaugkanal zuzuführende Kraftstoffmenge wird aus dem vom Purger in den Kraftstofftank zurückgeförderten Kraftstoff entnommen.From the US 7,210,441 B1 a carburetor emerges which has a fuel pump, a feed pump to be operated by the operator, namely a purger, and an enrichment device, namely a primer. The amount of fuel to be fed into the intake duct via the primer is taken from the fuel that is returned to the fuel tank by the purger.

Die US 5,711,901 A offenbart einen Vergaser mit Kraftstoffpumpe, Förderpumpe und Anreicherungseinrichtung. Der Druck in der Anreicherungskammer wird über ein Rückschlagventil konstant gehalten.The U.S. 5,711,901 A discloses a carburetor with a fuel pump, feed pump and enrichment device. The pressure in the enrichment chamber is kept constant via a check valve.

Aus der EP 0 306 856 A2 geht eine Startvorrichtung mit einer elektrisch angetriebenen Förderpumpe hervor. Der Druck in der Anreicherungskammer wird über ein Rückschlagventil konstant gehalten. Zur Zufuhr von Kraftstoff beim Starten ist das Öffnen eines elektromagnetischen Ventils in einer Kraftstoffleitung, die in den Ansaugkanal führt, vorgesehen.From the EP 0 306 856 A2 shows a starting device with an electrically driven feed pump. The pressure in the enrichment chamber is kept constant via a check valve. For the supply of fuel during starting, an electromagnetic valve is opened in a fuel line that leads into the intake duct.

Auch aus der US 4,735,751 A geht eine Anordnung mit einer Kraftstoffpumpe, einer vom Bediener zu betätigenden Förderpumpe und einer Anreicherungseinrichtung hervor.Also from the U.S. 4,735,751 A shows an arrangement with a fuel pump, a feed pump to be operated by the operator and an enrichment device.

Der Erfindung liegt die Aufgabe zugrunde, einen Vergaser der gattungsgemäßen Art zu schaffen, der einen einfachen Aufbau besitzt und bei dem über die Anreicherungseinrichtung eine definierte Menge an Kraftstoff einem Verbrennungsmotor zugeführt werden kann. Eine weitere Aufgabe der Erfindung liegt darin, einen Verbrennungsmotor anzugeben, mit dem das Starten erleichtert ist.The invention is based on the object of creating a carburetor of the generic type which has a simple structure and in which a defined amount of fuel can be fed to an internal combustion engine via the enrichment device. Another object of the invention is to provide an internal combustion engine with which starting is facilitated.

Diese Aufgabe wird bezüglich des Vergasers durch einen Vergaser mit den Merkmalen des Anspruchs 1 gelöst. Bezüglich des Verbrennungsmotors wird die Aufgabe durch einen Verbrennungsmotor mit den Merkmalen des Anspruchs 12 gelöst.With regard to the carburetor, this object is achieved by a carburetor having the features of claim 1. With regard to the internal combustion engine, the object is achieved by an internal combustion engine having the features of claim 12.

Es ist vorgesehen, dass der Vergaser eine Kraftstoffpumpe aufweist. Die Kraftstoffpumpe ist die Pumpe, die im Betrieb Kraftstoff zu dem Verbrennungsmotor zuführt. Die Kraftstoffpumpe liefert vorteilhaft bei laufendem Verbrennungsmotor den für den Betrieb notwendigen Kraftstoff. Die Kraftstoffpumpe kann vorteilhaft vom schwankenden Druck in einem Kurbelgehäuseinnenraum des Verbrennungsmotors angetrieben werden. Der Vergaser weist vorteilhaft eine von einem Bediener zu betätigende Förderpumpe auf. Die Förderpumpe ist vorteilhaft ein sogenannter Purger. Die Förderpumpe dient insbesondere dazu, vor dem Starten des Verbrennungsmotors das Kraftstoffsystem manuell mit Kraftstoff zu fluten und Gasblasen oder dergleichen aus dem Kraftstoffsystem zu entfernen. Die Förderpumpe ist vorteilhaft so angeordnet, dass die Förderpumpe Kraftstoff aus einer Kraftstoffkammer des Vergasers in einen Kraftstofftank fördert. Aus der mindestens einen Kraftstoffkammer wird im Betrieb Kraftstoff in einen in dem Vergaser ausgebildeten Ansaugkanalabschnitt zugeführt. Die Kraftstoffkammer des Vergasers ist insbesondere eine Kraftstoffkammer, aus der eine oder mehrere Kraftstofföffnungen des Vergasers gespeist werden.It is provided that the carburetor has a fuel pump. The fuel pump is the pump that supplies fuel to the internal combustion engine during operation. The fuel pump advantageously supplies the fuel required for operation when the internal combustion engine is running. The fuel pump can advantageously be driven by the fluctuating pressure in a crankcase interior of the internal combustion engine. The carburetor advantageously has a feed pump that can be operated by an operator. The feed pump is advantageously a so-called purger. The feed pump is used in particular to manually flood the fuel system with fuel and gas bubbles or the like from the fuel system before the internal combustion engine is started to remove. The feed pump is advantageously arranged in such a way that the feed pump feeds fuel from a fuel chamber of the carburetor into a fuel tank. During operation, fuel is fed from the at least one fuel chamber into an intake duct section formed in the carburetor. The fuel chamber of the carburetor is in particular a fuel chamber from which one or more fuel openings of the carburetor are fed.

Der Vergaser weist außerdem eine Anreicherungseinrichtung auf. Die Anreicherungseinrichtung umfasst insbesondere eine von der Förderpumpe separate Anreicherungspumpe. Die Anreicherungseinrichtung weist eine Anreicherungskammer auf. Die Anreicherungseinrichtung ist zur Zufuhr von Kraftstoff aus der Anreicherungskammer zu dem Verbrennungsmotor ausgebildet. Die Anreicherungseinrichtung ist insbesondere ein Primer. Um die Zufuhr eines konstruktiv vorbestimmten Volumens von Kraftstoff aus der Anreicherungseinrichtung zu dem Verbrennungsmotor zu ermöglichen, ist vorteilhaft vorgesehen, dass die Anreicherungskammer ein veränderliches Volumen aufweist. Vorzugsweise sind die Förderpumpe und die Anreicherungseinrichtung derart gekoppelt, dass eine Betätigung der Förderpumpe zu einer Veränderung des Volumens der Anreicherungskammer führt. Die Betätigung der Förderpumpe führt demnach auch zu einer Pumpbewegung an der Anreicherungskammer. Die Änderung des Volumens der Anreicherungskammer gibt vorteilhaft das dem Verbrennungsmotor zuzuführende Kraftstoffvolumen vor. Bei jedem vollständigen Pumpenhub der Förderpumpe kann demnach ein definiertes Volumen von Kraftstoff über die Anreicherungseinrichtung zu dem Verbrennungsmotor gefördert werden, sobald das Kraftstoffsystem vollständig geflutet ist. Bei einer vollständigen Betätigung der Förderpumpe wird ein vollständiger Pumpenhub der Förderpumpe ausgeführt. Die Förderpumpe kann insbesondere ein Purger mit einem elastischen Pumpenbalg sein. Eine vollständige Betätigung der Förderpumpe ist insbesondere eine Betätigung des Pumpenbalgs bis zu einem Anschlag. Die Anzahl der mit der Förderpumpe auszuführenden Pumpenhübe ist üblicherweise vorgegeben, beispielsweise über eine Betriebsanleitung oder dergleichen. Dadurch ist die über die Anreicherungseinrichtung zugeführte Kraftstoffmenge vordefiniert, und es kann sichergestellt werden, dass eine ausreichende Kraftstoffmenge für ein Starten des Verbrennungsmotors zum Verbrennungsmotor zugeführt wird. Vorteilhaft wird durch die Förderpumpe und die Anreicherungseinrichtung gleichzeitig das Kraftstoffsystem geflutet und eine vordefinierte Menge Kraftstoff dem Verbrennungsmotor, insbesondere einem Ansaugkanal zugeführt.The carburetor also has an enrichment device. The enrichment device comprises, in particular, an enrichment pump that is separate from the feed pump. The enrichment device has an enrichment chamber. The enrichment device is designed to supply fuel from the enrichment chamber to the internal combustion engine. The enrichment device is in particular a primer. In order to enable a structurally predetermined volume of fuel to be supplied from the enrichment device to the internal combustion engine, it is advantageously provided that the enrichment chamber has a variable volume. The feed pump and the enrichment device are preferably coupled in such a way that actuation of the feed pump leads to a change in the volume of the enrichment chamber. The actuation of the feed pump accordingly also leads to a pumping movement in the enrichment chamber. The change in the volume of the enrichment chamber advantageously specifies the volume of fuel to be supplied to the internal combustion engine. With each complete pump stroke of the feed pump, a defined volume of fuel can accordingly be fed to the internal combustion engine via the enrichment device as soon as the fuel system is completely flooded. When the feed pump is fully actuated, a complete pump stroke of the feed pump is carried out. The feed pump can in particular be a purger with an elastic pump bellows. Complete actuation of the feed pump is, in particular, actuation of the pump bellows up to a stop. The number of pump strokes to be carried out with the feed pump is usually specified, for example in an operating manual or the like. As a result, the amount of fuel supplied via the enrichment device is predefined, and it it can be ensured that a sufficient amount of fuel for starting the internal combustion engine is supplied to the internal combustion engine. The fuel system is advantageously flooded by the feed pump and the enrichment device at the same time and a predefined amount of fuel is supplied to the internal combustion engine, in particular an intake duct.

Die Förderpumpe besitzt vorteilhaft eine Förderkammer. Die Förderkammer ist in vorteilhafter Gestaltung teilweise von einem elastischen Pumpenbalg begrenzt, der vom Bediener zu betätigen ist. Die Förderkammer und die Anreicherungskammer sind vorteilhaft voneinander getrennte Kammern.The feed pump advantageously has a feed chamber. In an advantageous design, the delivery chamber is partially delimited by an elastic pump bellows which is to be actuated by the operator. The delivery chamber and the enrichment chamber are advantageously separate chambers.

Eine vollständige Betätigung der Förderpumpe aus dem unbetätigten Zustand der Förderpumpe führt zu einer Verringerung des Volumens der Anreicherungskammer um ein konstruktiv vorgegebenes Volumen. Bei jeder vollständigen Betätigung der Förderpumpe vom unbetätigten Zustand in den maximal betätigten Zustand wird, wenn die Anreicherungskammer vollständig mit Kraftstoff gefüllt ist, das gleiche Kraftstoffvolumen aus der Anreicherungskammer abgegeben. Bei teilweise leerer Anreicherungskammer, insbesondere nach der ersten Befüllung des Kraftstofftanks, kann das abgegebene Kraftstoffvolumen entsprechend geringer sein oder es wird zunächst nur Luft gefördert, bis die Anreicherungskammer vollständig mit Kraftstoff geflutet ist.Complete actuation of the feed pump from the non-actuated state of the feed pump leads to a reduction in the volume of the enrichment chamber by a structurally predetermined volume. With each complete actuation of the feed pump from the non-actuated state to the maximally actuated state, the same volume of fuel is generated when the enrichment chamber is completely filled with fuel released from the enrichment chamber. When the enrichment chamber is partially empty, in particular after the fuel tank has been filled for the first time, the volume of fuel dispensed can be correspondingly lower or only air is initially conveyed until the enrichment chamber is completely flooded with fuel.

Die Anreicherungskammer ist in vorteilhafter Gestaltung von einem beweglichen Element begrenzt, beispielsweise von einem beweglichen Stempel oder einer elastischen Membran. Die Förderpumpe umfasst vorzugsweise ein elastisches Element, insbesondere einen Pumpenbalg, wobei die Bewegung des beweglichen Elements über ein Koppelement an die Bewegung des elastischen Elements gekoppelt ist. Das Koppelelement ist insbesondere ein starres Koppelelement wie beispielsweise eine Koppelstange oder dergleichen.In an advantageous embodiment, the enrichment chamber is delimited by a movable element, for example by a movable stamp or an elastic membrane. The feed pump preferably comprises an elastic element, in particular a pump bellows, the movement of the movable element being coupled to the movement of the elastic element via a coupling element. The coupling element is in particular a rigid coupling element such as a coupling rod or the like.

In vorteilhafter alternativer Gestaltung ist vorgesehen, dass die Förderpumpe und die Anreicherungseinrichtung hydraulisch miteinander gekoppelt sind. Die hydraulische Kopplung ist vorteilhaft so gestaltet, dass eine Betätigung der Förderpumpe zu einer Veränderung des Volumens der Anreicherungskammer führt.In an advantageous alternative embodiment, it is provided that the feed pump and the enrichment device are hydraulically coupled to one another. The hydraulic coupling is advantageously designed in such a way that actuation of the feed pump leads to a change in the volume of the enrichment chamber.

In weiterer alternativer Gestaltung kann vorgesehen sein, dass die Anreicherungseinrichtung und die Förderpumpe elektrisch miteinander gekoppelt sind. Die elektrische Kopplung ist vorteilhaft so gestaltet, dass eine Betätigung der Förderpumpe zu einer Veränderung des Volumens der Anreicherungskammer führt.In a further alternative configuration, it can be provided that the enrichment device and the feed pump are electrically coupled to one another. The electrical coupling is advantageously designed in such a way that actuation of the feed pump leads to a change in the volume of the enrichment chamber.

In vorteilhafter Gestaltung ist vorgesehen, dass die Anreicherungskammer der Förderpumpe vorgeschaltet ist. Die Anreicherungskammer ist demnach bezogen auf eine Strömungsrichtung zu einem Kraftstofftank stromauf der Förderpumpe angeordnet. In anderen Worten wird bei einer Betätigung der Förderpumpe zuerst das Volumen der Anreicherungskammer mit Kraftstoff gefüllt und anschließend das Volumen der Förderpumpe. Das Befüllen der Anreicherungspumpe und der Förderpumpe wird beim Loslassen eines elastischen Elements wie eines Pumpenbalgs durch einen Unterdruck in einer Kraftstoffleitung bewirkt. Vorteilhaft ist das elastische Element durchsichtig gestaltet. Vorteilhaft kann der Bediener durch das durchsichtige elastische Element kontrollieren, ob noch Gasblasen im Kraftstoffsystem vorhanden sind. Dadurch, dass die Anreicherungskammer der Förderpumpe vorgeschaltet ist, ist sichergestellt, dass auch die Anreicherungskammer vollständig geflutet ist und Gasblasen vollständig entfernt sind, wenn an der Förderpumpe keine Gasblasen mehr auftreten. Vorteilhaft ist in der Strömungsverbindung von der Anreicherungskammer zu der Förderpumpe ein erstes Rückschlagventil angeordnet. Das erste Rückschlagventil stellt sicher, dass bei einer Betätigung der Förderpumpe kein Kraftstoff aus der Förderkammer zurück in die Anreicherungskammer strömen kann.In an advantageous embodiment it is provided that the enrichment chamber is connected upstream of the feed pump. The enrichment chamber is accordingly arranged upstream of the feed pump in relation to a flow direction to a fuel tank. In other words, when the feed pump is actuated, the volume of the enrichment chamber is first filled with fuel and then the volume of the feed pump. The priming pump and the feed pump are filled when an elastic element such as a pump bellows is released by a negative pressure in causes a fuel line. The elastic element is advantageously designed to be transparent. The operator can advantageously use the transparent elastic element to check whether gas bubbles are still present in the fuel system. The fact that the enrichment chamber is connected upstream of the feed pump ensures that the enrichment chamber is also completely flooded and gas bubbles are completely removed when no more gas bubbles occur at the feed pump. A first check valve is advantageously arranged in the flow connection from the enrichment chamber to the feed pump. The first check valve ensures that when the feed pump is actuated, no fuel can flow back from the feed chamber into the enrichment chamber.

In vorteilhafter Gestaltung ist vorgesehen, dass die Anreicherungseinrichtung den Kraftstoff für den Verbrennungsmotor aus der Anreicherungskammer in eine Verbindungsleitung, insbesondere in eine Kraftstoffleitung fördert. Die Verbindungsleitung ist vorteilhaft zur Verbindung mit einem Kurbelgehäuse des Verbrennungsmotors vorgesehen. Die Verbindungsleitung mündet dabei insbesondere in eine gasführende Leitung, die einen Ansaugkanal des Verbrennungsmotors mit einem Kurbelgehäuseinnenraum des Verbrennungsmotors verbindet. Durch die Zufuhr des Kraftstoffs in eine gasführende Leitung kann gewährleistet werden, dass auch geringe Mengen von Kraftstoff zuverlässig zum Kurbelgehäuseinnenraum transportiert werden, da die durch die gasführende Leitung strömende Luft auch geringe Mengen von Kraftstoff zum Kurbelgehäuseinnenraum mitnimmt. Dies ist insbesondere dann vorteilhaft, wenn der Leitungsweg zwischen der Anreicherungskammer und dem Kurbelgehäuseinnenraum vergleichsweise lang ist.In an advantageous embodiment, it is provided that the enrichment device conveys the fuel for the internal combustion engine from the enrichment chamber into a connecting line, in particular into a fuel line. The connecting line is advantageously provided for connection to a crankcase of the internal combustion engine. The connecting line opens in particular into a gas-carrying line which connects an intake duct of the internal combustion engine to a crankcase interior of the internal combustion engine. By supplying the fuel in a gas-carrying line, it can be ensured that even small amounts of fuel are reliably transported to the crankcase interior, since the air flowing through the gas-carrying line also takes small amounts of fuel with it to the crankcase interior. This is particularly advantageous when the line path between the enrichment chamber and the crankcase interior is comparatively long.

Bevorzugt ist in der Verbindungsleitung ein zweites Rückschlagventil angeordnet. Das zweite Rückschlagventil verhindert, dass Kraftstoff oder Luft in die Anreicherungskammer angesaugt werden können. Der Öffnungsdruck des zweiten Rückschlagventils ist dabei vorteilhaft kleiner als der Öffnungsdruck des ersten Rückschlagventils. Dadurch wird sichergestellt, dass Kraftstoff in die Verbindungsleitung gefördert wird.A second check valve is preferably arranged in the connecting line. The second check valve prevents fuel or air from being sucked into the enrichment chamber. The opening pressure of the second check valve is advantageously lower than the opening pressure of the first check valve. This ensures that fuel is pumped into the connecting line.

Vorteilhaft ist die Förderpumpe im Leitungsweg bezogen auf die Strömungsrichtung hinter der Kraftstoffkammer angeordnet. Die angegebene Strömungsrichtung bezieht sich dabei auf einen Saughub der Förderpumpe. Die Förderpumpe ist demnach stromab der Kraftstoffkammer angeordnet. Die Förderpumpe ist der Kraftstoffkammer bezogen auf die Strömungsrichtung nachgeschaltet. Die Anreicherungskammer ist im Leitungsweg bezogen auf die Strömungsrichtung vorteilhaft hinter der Kraftstoffkammer angeordnet. Die Anreicherungskammer befindet sich demnach stromab der Kraftstoffkammer. Die Anreicherungskammer ist in alternativer Gestaltung vorteilhaft im Leitungsweg bezogen auf die Strömungsrichtung vor der Kraftstoffkammer angeordnet. Bei dieser Gestaltung ist die Anreicherungskammer demnach stromauf der Kraftstoffkammer angeordnet. Ist die Anreicherungskammer im Leitungsweg stromauf der Kraftstoffkammer angeordnet, so wird die Anreicherungskammer beim Betätigen der Förderpumpe durch den Bediener noch vor der Kraftstoffkammer geflutet. Dadurch wird bereits nach wenigen Pumphüben der Förderpumpe Kraftstoff über die Anreicherungskammer zum Verbrennungsmotor gefördert. Die Kraftstoffkammer ist vorteilhaft eine Regelkammer des Vergasers.The feed pump is advantageously arranged in the line path behind the fuel chamber in relation to the direction of flow. The specified direction of flow relates to a suction stroke of the feed pump. The feed pump is accordingly arranged downstream of the fuel chamber. The feed pump is connected downstream of the fuel chamber in relation to the direction of flow. The enrichment chamber is advantageously arranged downstream of the fuel chamber in relation to the flow direction in the line path. The enrichment chamber is accordingly located downstream of the fuel chamber. In an alternative design, the enrichment chamber is advantageously arranged in the line path in relation to the direction of flow in front of the fuel chamber. In this configuration, the enrichment chamber is accordingly arranged upstream of the fuel chamber. If the enrichment chamber is arranged in the conduit upstream of the fuel chamber, the enrichment chamber is flooded before the fuel chamber when the feed pump is operated by the operator. As a result, after just a few pumping strokes of the feed pump, fuel is delivered to the internal combustion engine via the enrichment chamber. The fuel chamber is advantageously a control chamber of the carburetor.

Die Kraftstoffpumpe besitzt vorteilhaft eine Pumpenkammer, die insbesondere bezogen auf die Strömungsrichtung vor der Kraftstoffkammer des Vergasers angeordnet ist. Die Kraftstoffkammer ist insbesondere eine Regelkammer des Vergasers. Die Anreicherungskammer kann bezogen auf die Strömungsrichtung vorteilhaft vor der Pumpenkammer oder hinter der Kraftstoffkammer angeordnet sein. Pumpenkammer und Kraftstoffkammer sind bezogen auf die Strömungsrichtung vorteilhaft unmittelbar aufeinander folgend angeordnet und nur durch ein Ventil voneinander getrennt.The fuel pump advantageously has a pump chamber which, in particular, is arranged upstream of the fuel chamber of the carburetor in relation to the direction of flow. The fuel chamber is in particular a control chamber of the carburetor. The enrichment chamber can advantageously be arranged in front of the pump chamber or behind the fuel chamber in relation to the direction of flow. In relation to the direction of flow, the pump chamber and fuel chamber are advantageously arranged directly following one another and separated from one another only by a valve.

Vorteilhaft besitzt der Vergaser zwei Anschlüsse zur Verbindung mit dem Kraftstofftank. In einer Strömungsverbindung des Vergasers von dem einen Anschluss, der insbesondere für den Kraftstoffzufluss zum Vergaser vorgesehen ist, zu dem anderen Anschluss, der insbesondere für den Kraftstoffabfluss vorgesehen ist, sind die Anreicherungskammer, die Förderkammer und die Kraftstoffkammer angeordnet. Beide Anschlüsse sind dabei mit dem Kraftstofftank verbunden, wobei über einen Anschluss Kraftstoff angesaugt wird und über den anderen Anschluss Kraftstoff zurück in den Kraftstofftank fließt. Die Förderkammer ist bezogen auf die Strömungsrichtung nachgeschaltet zur Anreicherungskammer angeordnet, also stromab der Anreicherungskammer angeordnet, so dass Kraftstoff aus dem Kraftstofftank zunächst in die Anreicherungskammer und dann in die Förderkammer gelangt. Die Kraftstoffkammer und die Pumpenkammer können der Anreicherungskammer nachgeschaltet oder vorgeschaltet sein, also stromab oder stromauf der Anreicherungskammer angeordnet sein.The carburetor advantageously has two connections for connection to the fuel tank. The enrichment chamber, the delivery chamber and the fuel chamber are arranged in a flow connection of the carburetor from one connection, which is provided in particular for the fuel inflow to the carburetor, to the other connection, which is in particular provided for the fuel outflow. Both Connections are connected to the fuel tank, with fuel being sucked in via one connection and fuel flowing back into the fuel tank via the other connection. The delivery chamber is arranged downstream of the enrichment chamber in relation to the flow direction, that is, it is arranged downstream of the enrichment chamber, so that fuel from the fuel tank first enters the enrichment chamber and then into the delivery chamber. The fuel chamber and the pump chamber can be connected downstream or upstream of the enrichment chamber, that is to say they can be arranged downstream or upstream of the enrichment chamber.

Für einen Verbrennungsmotor mit Vergaser ist vorteilhaft vorgesehen, dass die Anreicherungskammer mit einem Kurbelgehäuseinnenraum des Verbrennungsmotors strömungsverbunden ist. Bevorzugt wird der Kraftstoff aus der Anreicherungskammer dem Kurbelgehäuseinnenraum unmittelbar zugeführt. Bevorzugt wird der Kraftstoff aus der Anreicherungskammer dem Kurbelgehäuseinnenraum direkt zugeführt. Mit anderen Worten wird der Kraftstoff nicht über einen Ansaugkanal des Verbrennungsmotors zugeführt. Eine Zufuhr von Kraftstoff aus der Anreicherungskammer in einen Ansaugkanal des Verbrennungsmotors ist bevorzugt nicht vorgesehen. Im Strömungsweg von der Anreicherungskammer zu dem Kurbelgehäuseinnenraum ist vorteilhaft ein Schaltventil angeordnet. Über das Schaltventil kann der zusätzlich über die Anreicherungskammer zugeführte Kraftstoff abgeschaltet werden, um beispielsweise bei warmem Motor ein Überfetten des Verbrennungsmotors zu vermeiden.For an internal combustion engine with a carburetor, it is advantageously provided that the enrichment chamber is flow-connected to a crankcase interior of the internal combustion engine. The fuel is preferably supplied directly to the crankcase interior from the enrichment chamber. The fuel is preferably supplied directly to the crankcase interior from the enrichment chamber. In other words, the fuel is not supplied via an intake duct of the internal combustion engine. A supply of fuel from the enrichment chamber into an intake duct of the internal combustion engine is preferably not provided. A switching valve is advantageously arranged in the flow path from the enrichment chamber to the crankcase interior. The fuel, which is additionally supplied via the enrichment chamber, can be switched off via the switching valve in order, for example, to prevent the internal combustion engine from becoming too rich when the engine is warm.

In bevorzugter Gestaltung ist das Schaltventil temperaturbetätigt. Wird ein Warmstart mit dem Verbrennungsmotor durchgeführt, ist vorteilhaft vorgesehen, dass das Schaltventil geschlossen ist, so dass kein zusätzlicher Kraftstoff aus der Anreicherungskammer in den Kurbelgehäuseinnenraum zugeführt wird. In bevorzugter Gestaltung ist das Schaltventil unmittelbar am Kurbelgehäuse angeordnet. Dadurch kann am Schaltventil selbst die Temperatur des Kurbelgehäuses erfasst und in Abhängigkeit der Temperatur des Kurbelgehäuses das Schaltventil betätigt werden. Eine vorteilhafte, einfache Gestaltung ergibt sich, wenn das Schaltventil ein temperaturbetätigtes Ventil ist.In a preferred embodiment, the switching valve is temperature-actuated. If a warm start is carried out with the internal combustion engine, it is advantageously provided that the switching valve is closed so that no additional fuel is supplied from the enrichment chamber into the crankcase interior. In a preferred embodiment, the switching valve is arranged directly on the crankcase. As a result, the temperature of the crankcase can be detected on the switching valve itself and the switching valve can be actuated depending on the temperature of the crankcase. An advantageous, simple design results when the switching valve is a temperature-actuated valve.

Das Schaltventil umfasst in bevorzugter Gestaltung ein Bimetall. Auch eine andere Gestaltung des Schaltventils kann jedoch vorteilhaft sein.In a preferred embodiment, the switching valve comprises a bimetal. However, a different design of the switching valve can also be advantageous.

Ausführungsbeispiele der Erfindung werden im Folgenden anhand der Zeichnung erläutert. Es zeigen:

Fig. 1 bis 3
schematische Darstellungen von Ausführungsvarianten eines Verbrennungsmotors mit einem Kraftstoffsystem, wobei das Kraftstoffsystem einen Vergaser umfasst.
Embodiments of the invention are explained below with reference to the drawing. Show it:
Figs. 1 to 3
schematic representations of design variants of an internal combustion engine with a fuel system, the fuel system comprising a carburetor.

Fig. 1 zeigt schematisch einen Verbrennungsmotor 1. Der Verbrennungsmotor 1 ist vorteilhaft ein gemischgeschmierter Motor, insbesondere ein Zweitaktmotor oder ein gemischgeschmierter Viertaktmotor. Der Verbrennungsmotor 1 besitzt einen Zylinder 2, in dem ein Brennraum 3 ausgebildet ist. Der Brennraum 3 ist von einem Kolben 5 begrenzt, der im Zylinder 2 hin- und hergehend gelagert ist. Der Kolben 5 treibt über ein nicht gezeigtes Pleuel eine Kurbelwelle 6 rotierend an. Die Kurbelwelle 6 ist in einem Kurbelgehäuse 4 des Verbrennungsmotors 1 um eine Drehachse 7 drehbar gelagert. Das Kurbelgehäuse 4 besitzt einen Kurbelgehäuseinnenraum 8, in dem die Kurbelwelle 6 rotiert. Fig. 1 shows schematically an internal combustion engine 1. The internal combustion engine 1 is advantageously a mixture-lubricated engine, in particular a two-stroke engine or a mixture-lubricated four-stroke engine. The internal combustion engine 1 has a cylinder 2 in which a combustion chamber 3 is formed. The combustion chamber 3 is delimited by a piston 5 which is mounted to reciprocate in the cylinder 2. The piston 5 drives a crankshaft 6 in rotation via a connecting rod (not shown). The crankshaft 6 is mounted in a crankcase 4 of the internal combustion engine 1 so as to be rotatable about an axis of rotation 7. The crankcase 4 has a crankcase interior 8 in which the crankshaft 6 rotates.

Der Verbrennungsmotor 1 besitzt ein Kraftstoffsystem 26, das einen Kraftstofftank 27 sowie einen Vergaser 9 umfasst. Der Vergaser 9 weist eine Kraftstoffpumpe 15 auf, die im Betrieb Kraftstoff in einen im Vergaser 9 ausgebildeten Ansaugkanalabschnitt 10 zuführt. Vorzugsweise münden in den Ansaugkanalabschnitt 10 eine Hauptkraftstofföffnung 12 sowie Nebenkraftstofföffnungen 14, über die der Kraftstoff im Betrieb in den Ansaugkanalabschnitt 10 zugeführt wird. Die Hauptkraftstofföffnung 12 ist im Bereich eines Venturis 11 im Ansaugkanalabschnitt 10 angeordnet. Stromab der Hauptkraftstofföffnung 12 ist ein Drosselelement, im Ausführungsbeispiel eine Drosselklappe 13, angeordnet. Der Ansaugkanalabschnitt 10 ist Teil eines Ansaugkanals 40, der in den Kurbelgehäuseinnenraum 8 mündet.The internal combustion engine 1 has a fuel system 26 which comprises a fuel tank 27 and a carburetor 9. The carburetor 9 has a fuel pump 15 which, during operation, supplies fuel into an intake duct section 10 formed in the carburetor 9. A main fuel opening 12 and secondary fuel openings 14, via which the fuel is fed into the intake channel section 10 during operation, preferably open into the intake channel section 10. The main fuel opening 12 is arranged in the area of a venturi 11 in the intake duct section 10. A throttle element, in the exemplary embodiment a throttle valve 13, is arranged downstream of the main fuel opening 12. The intake channel section 10 is part of an intake channel 40 which opens into the crankcase interior 8.

Der Vergaser 9 weist eine Förderpumpe 28 sowie eine Anreicherungseinrichtung 29 auf. Die Anreicherungseinrichtung 29 ist im Ausführungsbeispiel als Anreicherungspumpe ausgebildet. Die Anreicherungseinrichtung 29 sowie die Förderpumpe 28 sind vorteilhaft in einem Gehäuse 59 des Vergasers 9 angeordnet. Die Anreicherungseinrichtung 29 und die Förderpumpe 28 sind zur besseren Übersicht in der Darstellung außerhalb des Vergasers 9 dargestellt.The carburetor 9 has a feed pump 28 and an enrichment device 29. In the exemplary embodiment, the enrichment device 29 is designed as an enrichment pump. The enrichment device 29 and the feed pump 28 are advantageously arranged in a housing 59 of the gasifier 9. The enrichment device 29 and the feed pump 28 are shown outside of the gasifier 9 in the illustration for a better overview.

Die Kraftstoffpumpe 15 saugt über eine Kraftstoffleitung 52, von der in Fig. 1 schematisch nur ein Abschnitt dargestellt ist, Kraftstoff aus dem Kraftstofftank 27 an. Die Kraftstoffleitung 52 ist hierzu mit dem Kraftstofftank 27 verbunden, wie in Fig. 1 schematisch mit gestrichelter Linie dargestellt ist. Der Vergaser 9 weist im Ausführungsbeispiel zwei Anschlüsse für Kraftstoffleitungen auf, nämlich einen schematisch dargestellten Kraftstoffeinlass 57 sowie einen schematisch dargestellten Kraftstoffauslass 58. Die Kraftstoffleitung 52 ist am Kraftstoffeinlass 57 angeschlossen. Die Kraftstoffpumpe 15 ist im Ausführungsbeispiel als Membranpumpe ausgebildet und wird vom schwankenden Druck im Kurbelgehäuseinnenraum 8 angetrieben. Die Kraftstoffpumpe 15 besitzt ein Einlassventil 19 sowie ein Auslassventil 20, die im Ausführungsbeispiel als Rückschlagventile ausgebildet sind. In Strömungsrichtung 60 zwischen dem Einlassventil 19 und dem Auslassventil 20 liegt eine Pumpenkammer 18. Die Pumpenkammer 18 ist von einer Pumpenmembran 16 begrenzt. Die Pumpenmembran 16 trennt die Pumpenkammer 18 von einer Impulskammer 17. Die Impulskammer 17 ist über eine Impulsleitung 21 mit dem Kurbelgehäuseinnenraum 8 verbunden. Der sich im Betrieb einstellende, schwankende Druck im Kurbelgehäuseinnenraum 8 führt zu Auslenkungen der Pumpenmembran 16, die dadurch den Kraftstoff über das Einlassventil 19 ansaugt und über das Auslassventil 20 aus der Pumpenkammer 18 fördert.The fuel pump 15 sucks via a fuel line 52 from which in Fig. 1 schematically only a section is shown, fuel from the fuel tank 27 on. For this purpose, the fuel line 52 is connected to the fuel tank 27, as in FIG Fig. 1 is shown schematically with a dashed line. In the exemplary embodiment, the carburetor 9 has two connections for fuel lines, namely a schematically illustrated fuel inlet 57 and a schematically illustrated fuel outlet 58. The fuel line 52 is connected to the fuel inlet 57. In the exemplary embodiment, the fuel pump 15 is designed as a diaphragm pump and is driven by the fluctuating pressure in the crankcase interior 8. The fuel pump 15 has an inlet valve 19 and an outlet valve 20, which in the exemplary embodiment are designed as check valves. A pump chamber 18 is located between the inlet valve 19 and the outlet valve 20 in the flow direction 60. The pump chamber 18 is delimited by a pump membrane 16. The pump membrane 16 separates the pump chamber 18 from a pulse chamber 17. The pulse chamber 17 is connected to the crankcase interior 8 via a pulse line 21. The fluctuating pressure in the crankcase interior 8 that occurs during operation leads to deflections of the pump diaphragm 16, which thereby sucks in the fuel via the inlet valve 19 and conveys it out of the pump chamber 18 via the outlet valve 20.

In einer Strömungsrichtung 60 des Kraftstoffs vom Kraftstofftank 27 zum Ansaugkanalabschnitt 10 ist stromab der Kraftstoffpumpe 15 ein Regelventil 22 angeordnet.A regulating valve 22 is arranged downstream of the fuel pump 15 in a flow direction 60 of the fuel from the fuel tank 27 to the intake duct section 10.

Das Regelventil 22 ist an eine Regelmembran 24 gekoppelt und wird in Abhängigkeit der Position der Regelmembran 24 geöffnet oder geschlossen. Die Regelmembran 24 trennt eine Kraftstoffkammer 23, die die Regelkammer des Vergasers 9 bildet, von einer Kompensationskammer 25. Die Kompensationskammer 25 ist luftgefüllt und kann geschlossen oder mit der Umgebung oder dem Reinraum eines Luftfilters, über den Verbrennungsluft in den Ansaugkanal 40 angesaugt wird, verbunden sein. Sinkt der Druck in der Kraftstoffkammer 23, so öffnet das Regelventil 22 und von der Kraftstoffpumpe 15 geförderter Kraftstoff strömt in die Kraftstoffkammer 23 nach. Die Kraftstoffkammer 23 speist die Hauptkraftstofföffnung 12 sowie die Nebenkraftstofföffnungen 14.The control valve 22 is coupled to a control membrane 24 and is opened or closed depending on the position of the control membrane 24. The control membrane 24 separates a fuel chamber 23, which forms the control chamber of the carburetor 9, from a compensation chamber 25. The compensation chamber 25 is air-filled and can be closed or connected to the environment or the clean room of an air filter, through which combustion air is sucked into the intake duct 40 be. If the pressure in the fuel chamber 23 falls, the control valve 22 opens and fuel delivered by the fuel pump 15 continues to flow into the fuel chamber 23. The fuel chamber 23 feeds the main fuel opening 12 and the secondary fuel openings 14.

Aus der Kraftstoffkammer 23 führt eine Kraftstoffleitung 42. Die Kraftstoffleitung 42 verbindet die Kraftstoffkammer 23 mit einer Anreicherungskammer 30 der Anreicherungseinrichtung 29. Im Strömungsweg von der Kraftstoffkammer 23 zur Anreicherungskammer 30 ist ein Rückschlagventil 43 angeordnet. Das Rückschlagventil 43 öffnet in Strömungsrichtung 60 und schließt in Gegenrichtung. Die Strömungsrichtung 60 ist von der Kraftstoffkammer 23 zur Anreicherungskammer 30 gerichtet. Die Anreicherungskammer 30 besitzt ein veränderliches Volumen. Im Ausführungsbeispiel ist die Anreicherungskammer 30 hierzu von einer Anreicherungspumpenmembran 31 begrenzt. Die Anreicherungskammer 30 kann alternativ auch in anderer Form das Volumen ändern, beispielsweise mittels einer Verstellung einer die Anreicherungskammer 30 begrenzenden Seitenwand.A fuel line 42 leads from the fuel chamber 23. The fuel line 42 connects the fuel chamber 23 to an enrichment chamber 30 of the enrichment device 29. A check valve 43 is arranged in the flow path from the fuel chamber 23 to the enrichment chamber 30. The check valve 43 opens in the flow direction 60 and closes in the opposite direction. The direction of flow 60 is directed from the fuel chamber 23 to the enrichment chamber 30. The enrichment chamber 30 has a variable volume. In the exemplary embodiment, the enrichment chamber 30 is delimited by an enrichment pump membrane 31 for this purpose. The enrichment chamber 30 can alternatively also change the volume in a different form, for example by means of an adjustment of a side wall delimiting the enrichment chamber 30.

Die Anreicherungskammer 30 ist im Ausführungsbeispiel über eine Verbindungsleitung 36 mit einem Kanal 38 verbunden. Auch die Verbindungsleitung 36 ist vorteilhaft eine Kraftstoffleitung. Der Kanal 38 verbindet den Ansaugkanal 40 mit dem Kurbelgehäuseinnenraum 8. In vorteilhafter Gestaltung zweigt der Kanal 38 bezogen auf die Strömungsrichtung vom Vergaser 9 zum Kurbelgehäuseinnenraum 8 stromab der Drosselklappe 13 aus dem Ansaugkanal 40 ab. Dadurch kann vermieden werden, dass der Kanal 38 die Luftmenge beeinflusst, die dem Verbrennungsmotor 1 im Leerlauf zugeführt wird. Im Leerlauf ist die Drosselklappe 13 insbesondere weitgehend oder vollständig geschlossen, und der freie Strömungsquerschnitt resultiert aus einer Öffnung in der Drosselklappe 13. In der Verbindungsleitung 36 ist ein Rückschlagventil 37 angeordnet, das in Strömungsrichtung von der Anreicherungskammer 30 zum Kurbelgehäuseinnenraum 8 öffnet. Im Kanal 38 ist in Strömungsrichtung vom Ansaugkanal 40 zum Kurbelgehäuseinnenraum 8 stromauf der Verbindungsstelle der Verbindungsleitung 36 mit dem Kanal 38 ein Rückschlagventil 39 angeordnet. Das Rückschlagventil 39 öffnet in Strömungsrichtung vom Ansaugkanal 40 zum Kurbelgehäuseinnenraum 8.In the exemplary embodiment, the enrichment chamber 30 is connected to a channel 38 via a connecting line 36. The connecting line 36 is also advantageously a fuel line. The channel 38 connects the intake channel 40 to the crankcase interior 8. In an advantageous embodiment, the channel 38 branches off from the intake channel 40 downstream of the throttle valve 13, based on the flow direction from the carburetor 9 to the crankcase interior 8. This can prevent the channel 38 from influencing the amount of air that is supplied to the internal combustion engine 1 when idling becomes. When idling, the throttle valve 13 is in particular largely or completely closed, and the free flow cross-section results from an opening in the throttle valve 13. In the connecting line 36 there is a check valve 37 which opens in the direction of flow from the enrichment chamber 30 to the crankcase interior 8. A check valve 39 is arranged in the channel 38 in the flow direction from the intake channel 40 to the crankcase interior 8 upstream of the junction between the connecting line 36 and the channel 38. The check valve 39 opens in the direction of flow from the intake duct 40 to the crankcase interior 8.

Der Kanal 38 kann vorteilhaft über ein Schaltventil 41 mit dem Kurbelgehäuseinnenraum 8 verbunden sein. Das Schaltventil 41 ist im Strömungsweg von der Anreicherungskammer 30 zu dem Kurbelgehäuseinnenraum 8 angeordnet. Im Ausführungsbeispiel ist das Schaltventil 41 unmittelbar am Kurbelgehäuse 4 angeordnet. Das Schaltventil 41 ist vorteilhaft ein temperaturbetätigtes Ventil, das bei Überschreiten einer konstruktiv vorgegebenen Temperatur schließt. Dadurch wird über den Kanal 38 nur bei niedrigen Temperaturen Kraftstoff in den Kurbelgehäuseinnenraum 8 zugeführt. Auch eine andere, beispielsweise eine elektrische Betätigung des Schaltventils 41 kann jedoch vorteilhaft sein.The channel 38 can advantageously be connected to the crankcase interior 8 via a switching valve 41. The switching valve 41 is arranged in the flow path from the enrichment chamber 30 to the crankcase interior 8. In the exemplary embodiment, the switching valve 41 is arranged directly on the crankcase 4. The switching valve 41 is advantageously a temperature-actuated valve which closes when a structurally predetermined temperature is exceeded. As a result, fuel is fed into the crankcase interior 8 via the channel 38 only at low temperatures. Another, for example electrical, actuation of the switching valve 41 can, however, also be advantageous.

In vorteilhafter alternativer Ausführung kann die Anreicherungskammer 30 über eine in Fig. 1 gestrichelt eingezeichnete Verbindungsleitung 66 mit dem Ansaugkanal 40 verbunden sein. Vorteilhaft ist in der Verbindungsleitung 66 ein Rückschlagventil 67 angeordnet. Vorteilhaft weist das Kraftstoffsystem 29 eine Verbindungsleitung 36 und/oder eine Verbindungsleitung 66 auf.In an advantageous alternative embodiment, the enrichment chamber 30 can be connected via an in Fig. 1 Connecting line 66 shown in dashed lines may be connected to intake duct 40. A check valve 67 is advantageously arranged in the connecting line 66. The fuel system 29 advantageously has a connecting line 36 and / or a connecting line 66.

Im Ausführungsbeispiel ist die Anreicherungskammer 30 über eine Kraftstoffleitung 44 mit einer Förderkammer 34 der Förderpumpe 28 verbunden. In der Kraftstoffleitung 44 ist ein Rückschlagventil 45 angeordnet, das in Strömungsrichtung 60 öffnet. Die Strömungsrichtung 60 verläuft von der Anreicherungskammer 30 zur Förderkammer 34. Die Förderkammer 34 ist vorteilhaft teilweise von einem elastischen Pumpenbalg 33 begrenzt. Aus der Förderkammer 34 führt vorzugsweise eine Kraftstoffleitung 46 zum Kraftstofftank 27. In der Kraftstoffleitung 46 ist ein Rückschlagventil 47 angeordnet, das in Strömungsrichtung 60 öffnet. Die Strömungsrichtung 60 verläuft von der Förderkammer 34 zum Kraftstofftank 27. Stromab des Rückschlagventils 47 befindet sich der Kraftstoffauslass 58, der in Fig. 1 an einer schematisch dargestellten Wand des Gehäuses 59 des Vergasers 9 dargestellt ist. Der Vergaser 9 ist demnach am Kraftstoffeinlass 57 und am Kraftstoffauslass 58 mit dem Kraftstofftank 27 verbunden. Im Ausführungsbeispiel sind im Leitungsweg vom Kraftstoffeinlass 57 zum Kraftstoffauslass 58 in Strömungsrichtung 60 hintereinander die Kraftstoffpumpe 15, die Anreicherungseinrichtung 29 und die Förderpumpe 28 angeordnet. Dabei können weitere Elemente zwischengeschaltet sein wie beispielsweise die Kraftstoffkammer 23 des Vergasers 9. Im Ausführungsbeispiel ist die Kraftstoffkammer 23 des Vergasers 9 in Strömungsrichtung 60 zwischen der Kraftstoffpumpe 15 und der Anreicherungseinrichtung 29 angeordnet.In the exemplary embodiment, the enrichment chamber 30 is connected to a delivery chamber 34 of the delivery pump 28 via a fuel line 44. A check valve 45, which opens in flow direction 60, is arranged in fuel line 44. The flow direction 60 runs from the enrichment chamber 30 to the delivery chamber 34. The delivery chamber 34 is advantageously partially made up of an elastic pump bellows 33 limited. A fuel line 46 preferably leads from the delivery chamber 34 to the fuel tank 27. A check valve 47 is arranged in the fuel line 46 and opens in the flow direction 60. The direction of flow 60 runs from the delivery chamber 34 to the fuel tank 27. The fuel outlet 58 is located downstream of the check valve 47 and is shown in FIG Fig. 1 is shown on a schematically shown wall of the housing 59 of the carburetor 9. The carburetor 9 is accordingly connected to the fuel tank 27 at the fuel inlet 57 and at the fuel outlet 58. In the exemplary embodiment, the fuel pump 15, the enrichment device 29 and the feed pump 28 are arranged one behind the other in the flow direction 60 in the line path from the fuel inlet 57 to the fuel outlet 58. Further elements can be interposed, such as the fuel chamber 23 of the carburetor 9. In the exemplary embodiment, the fuel chamber 23 of the carburetor 9 is arranged in the flow direction 60 between the fuel pump 15 and the enrichment device 29.

Der Pumpenbalg 33, der die Förderkammer 34 begrenzt, ist dazu vorgesehen, von einem Bediener in Richtung des Pfeils 54 betätigt zu werden. Der Pumpenbalg 33 ist vorteilhaft über ein Koppelelement 35 mit einer Anreicherungspumpenmembran 31 verbunden. Im Ausführungsbeispiel ist das Koppelelement 35 ein starres, mechanisches Koppelelement, beispielsweise eine Koppelstange aus Metall oder formstabilem Kunststoff. Bei einer Betätigung des Pumpenbalgs 33 durch einen Bediener wird die Anreicherungspumpenmembran 31 über das Koppelelement 35 vorteilhaft um den gleichen Weg ausgelenkt wie das Koppelelement 35. Dadurch wird Kraftstoff in die Verbindungsleitung 36 und über die Verbindungsleitung 36 in den Kanal 38 und/oder über die Verbindungsleitung 66 in den Ansaugkanal 40 gefördert. Der Kraftstoff wird vorteilhaft über den Kanal 38 und/oder den Ansaugkanal 40 und/oder unmittelbar in den Kurbelgehäuseinnenraum 8 gefördert. In Fig. 1 ist schematisch eine Verbindungsleitung 68 eingezeichnet, über die Kraftstoff aus der Anreicherungskammer 30 unmittelbar in den Kurbelgehäuseinnenraum 8 gefördert werden kann. Vorteilhaft ist in der Verbindungsleitung 68 ein Rückschlagventil 69 angeordnet. In alternativer Ausführung kann auch ein Leerweg in der Kopplung von Pumpenbalg 33 und Anreicherungspumpenmembran 31 vorgesehen sein. Dadurch ist der Weg, um den der Pumpenbalg 33 ausgelenkt wird, um den konstruktiv vorgegebenen Leerweg größer als der Weg, um den die Anreicherungspumpenmembran 31 ausgelenkt wird. Die Förderpumpe 28 und die Anreicherungspumpenmembran 31 sind so miteinander gekoppelt, dass eine vollständige Betätigung der Förderpumpe 28 aus dem unbetätigten Zustand bis in den maximal betätigten Zustand zu einer Verringerung des Volumens der Anreicherungskammer 30 um ein konstruktiv vorgegebenes Volumen führt. In der Anreicherungskammer 30 ist eine Feder 32 angeordnet, die als Rückstellfeder wirkt und, sobald der Bediener den Pumpenbalg 33 loslässt, die Anreicherungspumpenmembran 31 in ihre Ausgangsstellung zurückstellt.The pump bellows 33, which delimits the delivery chamber 34, is provided to be actuated by an operator in the direction of the arrow 54. The pump bellows 33 is advantageously connected to an enrichment pump membrane 31 via a coupling element 35. In the exemplary embodiment, the coupling element 35 is a rigid, mechanical coupling element, for example a coupling rod made of metal or dimensionally stable plastic. When the pump bellows 33 is actuated by an operator, the enrichment pump membrane 31 is advantageously deflected via the coupling element 35 by the same path as the coupling element 35. As a result, fuel enters the connecting line 36 and via the connecting line 36 into the channel 38 and / or via the connecting line 66 conveyed into the intake duct 40. The fuel is advantageously conveyed via the channel 38 and / or the intake channel 40 and / or directly into the crankcase interior 8. In Fig. 1 a connecting line 68 is shown schematically, via which fuel can be conveyed from the enrichment chamber 30 directly into the crankcase interior 8. A check valve 69 is advantageously arranged in the connecting line 68. In an alternative design A free travel can also be provided in the coupling of the pump bellows 33 and the enrichment pump membrane 31. As a result, the distance by which the pump bellows 33 is deflected is greater than the distance by which the enrichment pump membrane 31 is deflected by the structurally predetermined idle distance. The feed pump 28 and the enrichment pump membrane 31 are coupled to one another so that a complete actuation of the feed pump 28 from the non-actuated state to the maximally actuated state leads to a reduction in the volume of the enrichment chamber 30 by a structurally predetermined volume. A spring 32 is arranged in the enrichment chamber 30, which acts as a return spring and, as soon as the operator lets go of the pump bellows 33, returns the enrichment pump membrane 31 to its starting position.

Zur Zufuhr von Kraftstoff aus der Anreicherungskammer 30 in den Kurbelgehäuseinnenraum 8 ist vorgesehen, dass die Anreicherungskammer 30 mit dem Kurbelgehäuseinnenraum 8 verbunden ist.In order to supply fuel from the enrichment chamber 30 into the crankcase interior 8, it is provided that the enrichment chamber 30 is connected to the crankcase interior 8.

Vorteilhaft kann im Strömungsweg von der Anreicherungskammer 30 in den Kurbelgehäuseinnenraum 8 die Verbindungsleitung 36 vorgesehen sein. Die Verbindungsleitung 36 ist im Ausführungsbeispiel eine Leitung, in der vorteilhaft ausschließlich Kraftstoff strömt. Die Verbindungsleitung 36 mündet im Ausführungsbeispiel in den Kanal 38, der den Kraftstoff aus der Verbindungsleitung 36 in den Kurbelgehäuseinnenraum 8 transportiert. Der Kanal 38 ist als gasführender, nämlich als luftführender oder gemischführender Kanal ausgebildet. Im Betrieb wird durch den gasführenden Kanal 38 Luft in den Kurbelgehäuseinnenraum 8 gesaugt, wenn im Kurbelgehäuseinnenraum 8 ein Unterdruck herrscht. Im Ausführungsbeispiel wird die Luft aus dem Ansaugkanal 40 in den Kurbelgehäuseinnenraum 8 angesaugt. Der Ansaugkanal 40 mündet ebenfalls in den Kurbelgehäuseinnenraum 8, insbesondere über ein nicht dargestelltes Ventil. Bevorzugt mündet der Ansaugkanal 40 am Zylinder 2 in einen Bereich, der vom Kolben 5 überfahren ist. Das Ventil, das den Ansaugkanal 40 mit dem Kurbelgehäuseinnenraum 8 verbindet, ist vorzugsweise durch den Kolben 5 gebildet.The connecting line 36 can advantageously be provided in the flow path from the enrichment chamber 30 into the crankcase interior 8. In the exemplary embodiment, the connecting line 36 is a line in which advantageously only fuel flows. In the exemplary embodiment, the connecting line 36 opens into the channel 38, which transports the fuel from the connecting line 36 into the crankcase interior 8. The channel 38 is designed as a gas-carrying, namely as an air-carrying or mixture-carrying channel. During operation, air is sucked into the crankcase interior 8 through the gas-carrying duct 38 when there is a negative pressure in the crankcase interior 8. In the exemplary embodiment, the air is drawn in from the intake duct 40 into the crankcase interior 8. The intake duct 40 also opens into the crankcase interior 8, in particular via a valve (not shown). The intake channel 40 on the cylinder 2 preferably opens into an area over which the piston 5 passes. The valve which connects the intake duct 40 to the crankcase interior 8 is preferably formed by the piston 5.

Insbesondere ist vorgesehen, dass der Kolben 5 bei seiner Hin- und Herbewegung eine Einlassöffnung des Ansaugkanals 40 am Zylinder 2 öffnet und schließt. Der Verbrennungsmotor 1 ist vorzugsweise ein durch den Kolben 5 schlitzgesteuerter Verbrennungsmotor.In particular, it is provided that the piston 5 opens and closes an inlet opening of the intake duct 40 on the cylinder 2 as it moves back and forth. The internal combustion engine 1 is preferably an internal combustion engine that is slot-controlled by the piston 5.

Vor dem Start des Verbrennungsmotors 1 betätigt der Bediener üblicherweise die Förderpumpe 28. Vorteilhaft erfolgt die Betätigung der Förderpumpe 28 durch mehrmaliges Drücken des Pumpenbalgs 33 in Richtung des Pfeils 54. Dadurch wird Kraftstoff aus dem Kraftstofftank 27 über die Kraftstoffleitung 52, die Pumpenkammer 18 der Kraftstoffpumpe 15, die Kraftstoffkammer 23, die Anreicherungseinrichtung 29 und die Förderkammer 34 in den Kraftstofftank 27 gefördert und dadurch das gesamte Kraftstoffsystem 26 gespült. Über das Koppelelement 35 wird bei der Bewegung des Pumpenbalgs 33 gleichzeitig auch die Anreicherungspumpenmembran 31 betätigt und dadurch Kraftstoff aus der Anreicherungskammer 30 in die Verbindungsleitung 36 und über den Kanal 38 in den Kurbelgehäuseinnenraum 8 gefördert. Die Rückschlagventile 37, 39, 43, 45 und 47 stellen sicher, dass der Kraftstoff in der gewünschten Richtung strömt.Before starting the internal combustion engine 1, the operator usually actuates the feed pump 28. The feed pump 28 is advantageously actuated by pressing the pump bellows 33 several times in the direction of arrow 54. This causes fuel to be drawn from the fuel tank 27 via the fuel line 52, the pump chamber 18 of the fuel pump 15, the fuel chamber 23, the enrichment device 29 and the delivery chamber 34 are conveyed into the fuel tank 27 and the entire fuel system 26 is thereby flushed. When the pump bellows 33 is moved, the enrichment pump diaphragm 31 is simultaneously actuated via the coupling element 35 and fuel is thus conveyed from the enrichment chamber 30 into the connecting line 36 and via the channel 38 into the crankcase interior 8. The check valves 37, 39, 43, 45 and 47 ensure that the fuel flows in the desired direction.

Fig. 2 zeigt ein alternatives Ausführungsbeispiel. Gleiche Bezugszeichen kennzeichnen dabei in allen Figuren einander entsprechende Elemente. Das Ausführungsbeispiel nach Fig. 2 entspricht im Wesentlichen dem Ausführungsbeispiel nach Fig. 1, wobei zu Elementen, die bei beiden Ausführungsbeispielen gezeigt sind, auf die Beschreibung zu Fig. 1 verwiesen wird. Beim Ausführungsbeispiel nach Fig. 2 ist die Anreicherungseinrichtung 29 im Strömungsweg vom Kraftstofftank 27 zur Kraftstoffpumpe 15 angeordnet. Die Anreicherungskammer 30 befindet sich demnach stromauf der Kraftstoffpumpe 15 und der Kraftstoffkammer 23. Im Ausführungsbeispiel nach Fig. 2 sind im Leitungsweg vom Kraftstoffeinlass 57 zum Kraftstoffauslass 58 in Strömungsrichtung 60 hintereinander die Anreicherungseinrichtung 29, die Kraftstoffpumpe 15 und die Förderpumpe 28 angeordnet. Dabei können weitere Elemente zwischengeschaltet sein wie beispielsweise die Kraftstoffkammer 23 des Vergasers 9. Im Ausführungsbeispiel ist die Kraftstoffkammer 23 des Vergasers 9 in Strömungsrichtung 60 zwischen der Kraftstoffpumpe 15 und der Förderpumpe 28 angeordnet. Die Anreicherungseinrichtung 29 sowie die Förderpumpe 28 sind vorteilhaft in dem Gehäuse 59 des Vergasers 9 angeordnet. Die Anreicherungskammer 30 ist über eine Kraftstoffleitung 48 mit dem Kraftstofftank 27 verbunden. Um zu vermeiden, dass Druck im Kraftstofftank 27 zu einer ungewollten Förderung von Kraftstoff in den Kanal 38 führt, ist das Rückschlagventil 37 vorteilhaft von einer nicht dargestellten Feder in Richtung auf die geschlossene Stellung vorgespannt. In der Kraftstoffleitung 48 ist ein Rückschlagventil 49 angeordnet, das in Strömungsrichtung 60 öffnet. Die Strömungsrichtung 60 verläuft vom Kraftstofftank 27 zur Anreicherungskammer 30. Zwischen dem Rückschlagventil 49 und dem Kraftstofftank 27 befindet sich der schematisch dargestellte Kraftstoffeinlass 57 des Vergasers 9. Vorteilhaft liegt die Anreicherungskammer 30 in Strömungsrichtung 60 hinter dem Kraftstoffeinlass 57 des Vergasers 9. Von der Anreicherungskammer 30 führt eine Kraftstoffleitung 56 zur Kraftstoffpumpe 15 des Vergasers 9. Die Kraftstoffkammer 23 ist über eine Kraftstoffleitung 50 mit der Förderkammer 34 der Förderpumpe 28 verbunden. In der Kraftstoffleitung 50 ist ein Rückschlagventil 51 angeordnet, das in Strömungsrichtung 60 öffnet. Die Strömungsrichtung 60 verläuft von der Kraftstoffkammer 23 zur Förderkammer 34. Fig. 2 shows an alternative embodiment. The same reference symbols identify elements that correspond to one another in all figures. The embodiment according to Fig. 2 corresponds essentially to the embodiment according to Fig. 1 , referring to the description for elements that are shown in both exemplary embodiments Fig. 1 is referred. In the embodiment according to Fig. 2 the enrichment device 29 is arranged in the flow path from the fuel tank 27 to the fuel pump 15. The enrichment chamber 30 is accordingly located upstream of the fuel pump 15 and the fuel chamber 23. In the exemplary embodiment according to FIG Fig. 2 the enrichment device 29, the fuel pump 15 and the feed pump 28 are arranged one behind the other in the line path from the fuel inlet 57 to the fuel outlet 58 in the flow direction 60. Further elements can be interposed, such as the fuel chamber 23 of the carburetor 9. In the exemplary embodiment the fuel chamber 23 of the carburetor 9 is arranged in the flow direction 60 between the fuel pump 15 and the feed pump 28. The enrichment device 29 and the feed pump 28 are advantageously arranged in the housing 59 of the gasifier 9. The enrichment chamber 30 is connected to the fuel tank 27 via a fuel line 48. In order to avoid that pressure in the fuel tank 27 leads to an undesired delivery of fuel into the channel 38, the non-return valve 37 is advantageously biased towards the closed position by a spring (not shown). A check valve 49, which opens in flow direction 60, is arranged in fuel line 48. The direction of flow 60 runs from the fuel tank 27 to the enrichment chamber 30. The fuel inlet 57 of the carburetor 9, shown schematically, is located between the check valve 49 and the fuel tank 27. The enrichment chamber 30 is advantageously located in the direction of flow 60 behind the fuel inlet 57 of the carburettor 9 A fuel line 56 leads to the fuel pump 15 of the carburetor 9. The fuel chamber 23 is connected to the delivery chamber 34 of the delivery pump 28 via a fuel line 50. A check valve 51, which opens in flow direction 60, is arranged in fuel line 50. The flow direction 60 runs from the fuel chamber 23 to the delivery chamber 34.

In der schematischen Darstellung in Fig. 2 ist die Kraftstoffleitung 56 der besseren Übersicht halber teilweise mit gestrichelter Linie dargestellt. In der Kraftstoffleitung 46, die die Förderkammer 34 mit dem Kraftstofftank 27 verbindet, ist das Rückschlagventil 47 bezogen auf die Strömungsrichtung 60 vor dem Kraftstoffauslass 58 des Vergasers 9 angeordnet.In the schematic representation in Fig. 2 For the sake of clarity, the fuel line 56 is partially shown with a dashed line. In the fuel line 46, which connects the delivery chamber 34 to the fuel tank 27, the check valve 47 is arranged upstream of the fuel outlet 58 of the carburetor 9 in relation to the flow direction 60.

Die Förderpumpe 28 ist mit der Anreicherungskammer 30 über eine hydraulische Kopplung 55 gekoppelt. Verringert sich das Volumen der Förderkammer 34, so wird aufgrund der hydraulischen Kopplung 55 das Volumen der Anreicherungskammer 30 verringert.The feed pump 28 is coupled to the enrichment chamber 30 via a hydraulic coupling 55. If the volume of the delivery chamber 34 decreases, the volume of the enrichment chamber 30 is reduced due to the hydraulic coupling 55.

Beispielsweise kann durch Auslenkung der Anreicherungspumpenmembran 31 das Volumen der Anreicherungskammer 30 reduziert werden. Vorteilhaft ist der Weg, um den die Anreicherungspumpenmembran 31 bei einer vollständigen Betätigung des Pumpenbalgs 33 aus dem unbetätigten Zustand bis in den vollständig betätigten Zustand ausgelenkt wird, konstruktiv vorgegeben, beispielsweise durch entsprechende Anschläge.For example, the volume of the enrichment chamber 30 can be reduced by deflecting the enrichment pump membrane 31. The path by which the enrichment pump diaphragm 31 is deflected from the non-actuated state to the fully actuated state when the pump bellows 33 is fully actuated is structurally predetermined, for example by means of corresponding stops.

Fig. 3 zeigt ein weiteres bevorzugtes Ausführungsbeispiel. Beim Ausführungsbeispiel nach Fig. 3 ist die Anreicherungseinrichtung 29 im Strömungsweg von der Kraftstoffkammer 23 zur Förderkammer 34 angeordnet. Dies entspricht der Anordnung nach Fig. 1, auf deren Beschreibung hierzu verwiesen wird. Die Förderpumpe 28 ist im gezeigten Ausführungsbeispiel über eine elektrische Kopplung 65 mit der Anreicherungseinrichtung 29, bevorzugt mit der Anreicherungspumpenmembran 31, gekoppelt. Die Kopplung 65 ist vorzugsweise so ausgeführt, dass eine Betätigung des Pumpenbalgs 33 eine Verringerung des Volumens der Anreicherungskammer 30 um einen vorgegebenen Wert bewirkt. Fig. 3 shows a further preferred embodiment. In the embodiment according to Fig. 3 the enrichment device 29 is arranged in the flow path from the fuel chamber 23 to the delivery chamber 34. This corresponds to the arrangement Fig. 1 , to the description of which reference is made. In the exemplary embodiment shown, the feed pump 28 is coupled to the enrichment device 29, preferably to the enrichment pump membrane 31, via an electrical coupling 65. The coupling 65 is preferably designed such that actuation of the pump bellows 33 causes the volume of the enrichment chamber 30 to be reduced by a predetermined value.

Im Ausführungsbeispiel nach Fig. 3 ist die Anreicherungskammer 30 über eine Kraftstoffleitung 53 mit dem Kurbelgehäuseinnenraum 8 verbunden. Die Kraftstoffleitung 53 führt im Betrieb nur Kraftstoff und keine Luft. Die Kraftstoffleitung 53 mündet in den Kurbelgehäuseinnenraum 8. Der Kraftstoff wird dabei nicht in einen gasführenden Kanal zugeführt, sondern unmittelbar in den Kurbelgehäuseinnenraum 8. An der Mündung der Kraftstoffleitung 53 in den Kurbelgehäuseinnenraum 8 ist das Schaltventil 41 angeordnet. Auch beim Ausführungsbeispiel nach Fig. 3 ist das Schaltventil 41 unmittelbar am Kurbelgehäuse 4 angeordnet. Bezüglich der Beschreibung der weiteren Komponenten wird auf die vorangegangenen Ausführungsbeispiele verwiesen.In the embodiment according to Fig. 3 the enrichment chamber 30 is connected to the crankcase interior 8 via a fuel line 53. The fuel line 53 only carries fuel and no air during operation. The fuel line 53 opens into the crankcase interior 8. The fuel is not fed into a gas-carrying channel, but directly into the crankcase interior 8. The switching valve 41 is arranged at the opening of the fuel line 53 into the crankcase interior 8. Also in the embodiment according to Fig. 3 the switching valve 41 is arranged directly on the crankcase 4. With regard to the description of the further components, reference is made to the preceding exemplary embodiments.

Weitere vorteilhafte Ausführungen ergeben sich durch beliebige Kombination der Elemente der Ausführungsbeispiele miteinander. Insbesondere die Art der Kopplung von Förderpumpe 28 und Anreicherungseinrichtung 29 kann für jedes Ausführungsbeispiel mechanisch, insbesondere über ein starres Koppelelement 35, hydraulisch über eine hydraulische Kopplung 55 oder elektrisch über eine elektrische Kopplung 65 erfolgen. Auch andere Arten der Kopplung können vorteilhaft sein. In den Ausführungsbeispielen erfolgt die Zufuhr des Kraftstoffs aus der Anreicherungskammer 30 in den Kurbelgehäuseinnenraum 8. In vorteilhafter alternativer Gestaltung kann vorgesehen sein, den Kraftstoff aus der Anreicherungskammer 30 über den Ansaugkanal 40 in den Kurbelgehäuseinnenraum 8 zuzuführen. So ist beispielsweise eine Kraftstoffförderung bei Betätigung mittels mechanischer Kopplung in den Ansaugkanal 40 denkbar, wie in Fig. 1 schematisch dargestellt.Further advantageous designs result from any combination of the elements of the exemplary embodiments with one another. In particular the type of coupling of the feed pump 28 and the enrichment device 29 can take place mechanically, in particular via a rigid coupling element 35, hydraulically via a hydraulic coupling 55 or electrically via an electrical coupling 65 for each exemplary embodiment. Other types of coupling can also be advantageous. In the exemplary embodiments, the fuel is supplied from the enrichment chamber 30 into the crankcase interior 8. In an advantageous alternative configuration, provision can be made for the fuel to be supplied from the enrichment chamber 30 via the intake duct 40 into the crankcase interior 8. For example, a fuel delivery is conceivable when actuated by means of mechanical coupling in the intake channel 40, as in FIG Fig. 1 shown schematically.

Claims (15)

  1. Carburettor for supplying fuel/air mixture to an internal combustion engine (1) having a fuel pump (15), a feed pump (28) designed for operation by an operator and an enrichment device (29), wherein the carburettor (9) has at least one fuel chamber (23) into which the fuel pump (15) delivers fuel, wherein in operation fuel is fed from the at least one fuel chamber (23) into an intake duct section (10) formed in the carburettor (9), wherein the feed pump (28) is designed to deliver fuel from the at least one fuel chamber (23), wherein the enrichment device (29) has an enrichment chamber (30), and wherein the enrichment device (29) is designed to deliver fuel from the enrichment chamber (30) to the internal combustion engine (1),
    characterised in that the enrichment chamber (30) has a variable volume and in that the feed pump (28) and the enrichment device (29) are coupled in such a way that a complete operation of the feed pump (28) from the non-operated state of the feed pump (28) results in a reduction of the volume of the enrichment chamber (30) by a constructively predetermined volume.
  2. Carburettor according to claim 1,
    characterised in that the enrichment chamber (30) is bounded by a movable element, in that the feed pump (28) comprises a pump bellows (33), and in that the movement of the movable element is coupled to the movement of the pump bellows (33) by way of a coupling element (35).
  3. Carburettor according to claim 1 or 2,
    characterised in that the feed pump (28) and the enrichment device (29) are hydraulically or electrically coupled to each other in such a way that an operation of the feed pump (28) results in a change of the volume of the enrichment chamber (30).
  4. Carburettor according to any of claims 1 to 3,
    characterised in that the enrichment chamber (30) is located upstream of the feed pump (28).
  5. Carburettor according to claim 4,
    characterised in that a first non-return valve (45) is located in the flow connection from the enrichment chamber (30) to the feed pump (28).
  6. Carburettor according to claim 5,
    characterised in that the enrichment device (29) delivers the fuel for the internal combustion engine (1) from the enrichment chamber (30) into a connecting line (36), the connecting line (36) being provided for connection to a crankcase (8) of an internal combustion engine (1).
  7. Carburettor according to claim 6,
    characterised in that a second non-return valve (37) is located in the connecting line (36).
  8. Carburettor according to claim 7,
    characterised in that the opening pressure of the second non-return valve (37) is lower than the opening pressure of the first non-return valve (45).
  9. Carburettor according to any of claims 1 to 8,
    characterised in that the feed pump (28) is located downstream of the fuel chamber (23) in the routing with respect to the flow direction (60).
  10. Carburettor according to any of claims 1 to 9,
    characterised in that the enrichment chamber (30) is located downstream of the fuel chamber (23) in the routing with respect to the flow direction (60).
  11. Carburettor according to any of claims 1 to 9,
    characterised in that the enrichment chamber (30) is located upstream of the fuel chamber (23) in the routing with respect to the flow direction (60).
  12. Internal combustion engine with a carburettor (9) according to any of claims 1 to 11,
    characterised in that the enrichment chamber (30) is flow-connected to a crankcase interior (8) of the internal combustion engine (1).
  13. Internal combustion engine according to claim 12,
    characterised in that a switching valve (41) is located in the flow path from the enrichment chamber (30) to the crankcase interior (8).
  14. Internal combustion engine according to claim 13,
    characterised in that the switching valve (41) is temperature-actuated and in particular located directly at the crankcase (4).
  15. Internal combustion engine according to any of claims 1 to 14,
    characterised in that the enrichment chamber (30) is flow-connected to an intake duct (40) of the internal combustion engine (1).
EP18400011.5A 2018-04-24 2018-04-24 Carburettor and internal combustion engine with a carburettor Active EP3561280B1 (en)

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Application Number Priority Date Filing Date Title
EP18400011.5A EP3561280B1 (en) 2018-04-24 2018-04-24 Carburettor and internal combustion engine with a carburettor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP18400011.5A EP3561280B1 (en) 2018-04-24 2018-04-24 Carburettor and internal combustion engine with a carburettor

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EP3561280A1 EP3561280A1 (en) 2019-10-30
EP3561280B1 true EP3561280B1 (en) 2021-01-06

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Publication number Priority date Publication date Assignee Title
CN112377334B (en) * 2020-10-29 2022-04-15 浙江瑞星化油器制造有限公司 Pure gasoline engine assembly

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4735751A (en) * 1986-05-27 1988-04-05 Tecumseh Products Company Primer system and method for priming an internal combustion engine
JPS6466455A (en) * 1987-09-07 1989-03-13 Walbro Far East Fuel supply starting device for internal combustion engine for hand carrying working machine
EP0786591A3 (en) * 1996-01-29 1997-08-13 WCI OUTDOOR PRODUCTS, Inc. Fast start fuel system for an internal combustion engine
US5711901A (en) * 1996-06-05 1998-01-27 Walbro Corporation Carburetor having temperature-compensated purge/primer
DE19941697A1 (en) * 1999-09-02 2001-03-08 Stihl Maschf Andreas Membrane carburetor for IC engine, has regulating chamber bounded by membrane and impeller piston stroke limited by stop
JP2003254162A (en) 2002-02-26 2003-09-10 Zama Japan Kk Starting fuel supplying device for carburetor
US7210441B1 (en) 2005-04-14 2007-05-01 Walbro Engine Management, L.L.C. Priming and purging system and method for an internal combustion engine
US7690342B2 (en) * 2007-01-05 2010-04-06 Walbro Engine Management, L.L.C. Priming circuit for a fuel system

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
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