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Carburettor fueling.ppt
- 1. Simple Carburettor Fuel System for a Piston Engine And how it works
- 2. Tank PISTON ENGINE – Carburettor Fuel System Exhaust Inlet
- 3. Tank Cavity Filler Cap Filler Neck E F 1/2 FUEL FUEL LEVEL SENSOR COCKPIT FUEL GAUGE PISTON ENGINE – Carburettor Fuel System - Tanks
- 4. PISTON ENGINE – Carburettor Fuel System - Tanks E F 1/2 FUEL E F 1/2 FUEL
- 5. Tank PISTON ENGINE – Carburettor Fuel System Cockpit Gauge Pump Exhaust Inlet
- 6. One-way Inlet Valve One-way Outlet Valve Diaphragm Driving Cam PISTON ENGINE – Mechanical Diaphragm Pump
- 7. One-way Inlet Valve One-way Outlet Valve Solenoid Windings Switch Mechanism Diaphragm Magnetic Plate PISTON ENGINE – Solenoid Diaphragm Pump
- 8. FLOW OUT ‘SPUR’ GEARS PUMP FLOW AND RESTRICTION TO FLOW IN CONTROLLER CAUSES PRESSURE TO INCREASE Flow Controller PISTON ENGINE – Gear Type Pump
- 9. Air Filter Tank PISTON ENGINE – Carburettor Fuel System Cockpit Gauge Pump Carburettor Exhaust Inlet
- 10. Air and Dirt Clean Air Filter element – corrugated breathable paper Dirt trapped by Filter element Basic Air Filter Operation PISTON ENGINE – Air Filter
- 11. Air Filter Tank PISTON ENGINE – Carburettor Fuel System Cockpit Gauge Pump Carburettor Exhaust Inlet
- 12. We are now going to look at how the carburettor controls the flow to the engine THE FLOAT CHAMBER This is done by the: -
- 13. SIMPLIFIED PISTON ENGINE FUEL SYSTEM FLOAT CHAMBER NEEDLE VALVE AIR VENT VENTURI FUEL FEED FUEL NOZZLE SIMPLIFIED PISTON ENGINE FUEL SYSTEM FLOAT FUEL LEVEL
- 14. AIR IS SUCKED THROUGH VENTURI BY….. A PISTON MOVING DOWN ON INDUCTION STROKE SIMPLIFIED PISTON ENGINE FUEL SYSTEM SIMPLIFIED PISTON ENGINE FUEL SYSTEM SIMPLIFIED PISTON ENGINE FUEL SYSTEM MOVING AIR HAS LOWER PRESSURE FUEL FLOW AIR FLOW AIR FLOW THE LOWER AIR PRESSURE PULLS FUEL THROUGH THE JET AIR/FUEL MIXTURE FLOWS TO ENGINE FUEL LEVEL DROPS
- 15. PULLING AIR INTO FLOAT CHAMBER SIMPLIFIED PISTON ENGINE FUEL SYSTEM FUEL LEVEL DROPS FUEL LEVEL DROPPING LOWERS FLOAT
- 16. AND ALLOWS FUEL TO ENTER FLOAT CHAMBER FROM PUMP SIMPLIFIED PISTON ENGINE FUEL SYSTEM FUEL LEVEL DROPS FUEL LEVEL RISING FORCES THE NEEDLE VALVE CLOSED FUEL LEVEL DROPPING LOWERS FLOAT
- 17. SIMPLIFIED PISTON ENGINE FUEL SYSTEM FUEL IS PULLED OUT OF THE FLOAT CHAMBER ONLY WHEN ONE OF THE PISTONS IS ON THE INDUCTION STROKE FUEL LEVEL RISING FORCES THE NEEDLE VALVE CLOSED
- 18. We now need to look at controlling the air/fuel mixture flowing into the engine THE THROTTLE Controlling the air/fuel mixture means controlling the engine The carburettor part which controls the flow is….
- 19. SIMPLIFIED PISTON ENGINE FUEL SYSTEM LINK TO THROTTLE LEVER/PEDAL THROTTLE VALVE VALVE SPINDLE VALVE DISC
- 20. SIMPLIFIED PISTON ENGINE FUEL SYSTEM THROTTLE VALVE THIS WOULD BE A HIGH THROTTLE SETTING OR ‘FULL –POWER’ OPEN THROTTLE ALLOWS VENTURI TO WORK AT MAXIMUM EFFICIENCY
- 21. LOW THROTTLE SETTING - CALLED ‘IDLE’ OR ‘TICK-OVER’ ALMOST CLOSED THROTTLE MEANS THE VENTURI DOES NOT WORK VERY WELL LOW AIR FLOW MEANS VERY LITTLE OR NO FUEL/AIR MIXING IN THE VENTURI SO AN ALTERNATIVE AND EFFECTIVE VENTURI NEEDS TO BE FOUND SIMPLIFIED PISTON ENGINE FUEL SYSTEM SIMPLIFIED PISTON ENGINE FUEL SYSTEM
- 22. T CONTROLS FUEL FLOW SIMPLIFIED PISTON ENGINE FUEL SYSTEM SIMPLIFIED PISTON ENGINE FUEL SYSTEM LOW THROTTLE SETTING - CALLED ‘IDLE’ OR ‘TICK-OVER’ EDGE GAPS BECOME THE VENTURI FOR THE LOW AIR FLOW AT IDLE - SLOW RUNNING JET
- 23. BALANCED AIR PRESSURE AT THE MAIN JET
- 24. SIMPLIFIED PISTON ENGINE FUEL SYSTEM SIMPLIFIED PISTON ENGINE FUEL SYSTEM THE AIR FILTER CAN ALSO CAUSE RESTRICTION TO AIR FLOW THIS WOULD CREATE A PRESSURE DIFFERENCE BETWEEN:- HERE AND HERE AND THEREFORE A SLIGHT VACUUM BEFORE CARB FLOAT CHAMBER VENT
- 25. SIMPLIFIED PISTON ENGINE FUEL SYSTEM SIMPLIFIED PISTON ENGINE FUEL SYSTEM SIMPLIFIED PISTON ENGINE FUEL SYSTEM EQUALISING THE PRESSURE AT LOW SPEED THEREFORE PREVENTING TOO MUCH FUEL MIXING WITH THE AIR AND THE FLOAT CHAMBER IS CONNECTED TO THE CARB AIR INTAKE SO THE VENT TO THE FLOAT CHAMBER IS CLOSED OFF FLOAT CHAMBER VENT
- 26. MORE EFFICIENT MIXING OF AIR AND FUEL
- 27. MORE EFFICIENT MIXING OF AIR AND FUEL IS ACHIEVED BY FITTING A DIFFUSER TUBE SIMPLIFIED PISTON ENGINE FUEL SYSTEM HERE, ABOVE THE MAIN JET LET’S TAKE A CLOSER LOOK AT THIS AREA
- 28. IDLE SETTING FUEL SUPPLIED VIA IDLE JET OPEN THROTTLE IDLE JET STOPS WORKING CRUISE SETTING HIGH POWER SETTING AIR INLET DIFFUSER TUBE INCREASED FLOW OF MIXED AIR/FUEL FUEL FEED FROM FLOAT CHAMBER MAIN JET AIR MIXES WITH FUEL AIR/FUEL MIXING IN DIFFUSER TUBE FUEL LEVEL IN FLOAT CHAMBER SIMPLIFIED PISTON ENGINE FUEL SYSTEM
- 29. AUTOMATIC MIXTURE CONTROL This is required to take into account that at higher altitude there is less air, so therefore less fuel is required. It is called a pressure bellows or pressure capsule. This change in fuel flow is controlled by a device that can sense the change in air pressure.
- 30. SIMPLIFIED PISTON ENGINE FUEL SYSTEM SIMPLIFIED PISTON ENGINE FUEL SYSTEM SIMPLIFIED PISTON ENGINE FUEL SYSTEM FIXED END MOVING END NEEDLE VALVE CAPSULE EXPANDS IN LOWER PRESSURES AND CONTRACTS IN HIGHER PRESSURES PRESSURE CAPSULE
- 31. SIMPLIFIED PISTON ENGINE FUEL SYSTEM SIMPLIFIED PISTON ENGINE FUEL SYSTEM SIMPLIFIED PISTON ENGINE FUEL SYSTEM AT LOW ALTITUDE – HIGHER ATMOSPHERIC PRESSURE CAPSULE CONTRACTED HIGH FUEL FLOW AT HIGH ALTITUDE – LOWER ATMOSPHERIC PRESSURE CAPSULE EXPANDS
- 32. SIMPLIFIED PISTON ENGINE FUEL SYSTEM SIMPLIFIED PISTON ENGINE FUEL SYSTEM SIMPLIFIED PISTON ENGINE FUEL SYSTEM AT HIGH ALTITUDE – LOWER ATMOSPHERIC PRESSURE CAPSULE EXPANDS CLOSING FUEL ORIFICE E AND REDUCING FUEL FLOW
- 33. AUTOMATIC MIXTURE CONTROL This is required to take into account that at higher altitude there is less air, so therefore less fuel is required. It is called a pressure bellows or pressure capsule. This change in fuel flow is controlled by a device that can sense the change in air pressure.
- 34. Battery Fuel Tank Pump Warm Up Regulator Fuel Accumulator Ignition Switch Filter Primary Pressure Valve Air Sensor Plate Mixture Control Unit (Fuel Distributor Valve) Auxiliary Air Device Cold Start Valve Idle Speed Adjuster Fuel Injector Throttle Valve Engine Temp Sensor Safety Relay Air Inlet High Pressure Fuel Low Pressure Fuel Supply Pressure Fuel Servo Pressure Fuel Electrical Signal Legend PISTON ENGINE – Hydro-Mechanical Fuel Injection System (from Air Filter)
- 35. Air Filter PISTON ENGINE – Electronic Fuel Injection System Engine ECU Tank Pump Cockpit Gauge Pressure Regulator Injection Control Unit Engine Temp Engine RPM/TDC Exhaust Temp Throttle Position Forward Speed Air Temps – Inlet & Ambient Fuel Injectors ‘Common Rail’ Throttle