INTERNAL COMBUSTION ENGINES LECTURER PROF.Dr. DEMIR BAYKA

FUEL METERING IN SPARK IGNITION ENGINES FUEL IS MIXED WITH AIR : 1. OUTSIDE THE CYLINDER 2. INSIDE THE CYLINDER

FUEL MIXING OUTSIDE THE CYLINDER 1. CARBURETION 2. INJECTION SINGLE POINT INJECTION MULTIPLE POINT INJECTION

MIXTURE REQUIREMENTS OF SPARK IGNITION ENGINES AIR / FUEL RATIO OF A COMBUSTIBLE MIXTURE A/F = RICH MIXTURE LEAN MIXTURE

STOICHIOMETRIC FUEL AIR RATIO FOR GASOLINE : F/A = EQUIVALENCE RATIO    RICH MIXTURE STOICHIOMETRIC MIXTURE LEAN MIXTURE

INTAKE MASS FLOW RATE VARIATION OF THE EQUIVALENCE RATIO

MODES OF OPERATION 1. IDLING ……………..  > 1 (RICH MIXTURE) 2. COLD START.....…..  > 1 (RICH MIXTURE) 3. PART LOAD….……..  < 1 (LEAN MIXTURE) 4. ACCELERATION…..  > 1 (RICH MIXTURE) 5. FULL POWER ……..  > 1 (RICH MIXTURE)

CARBURETION AIR FILTER AIR FUEL MIX CARBURETOR INLET MANIFOLD ENGINE

INLET SECTION VENTURI THROAT FLOAT CHAMBER PRESSURE EQUALIZING PASSAGE CALIBRATED ORIFICE FUEL DISCHARGE TUBE THROTTLE VALVE FLOAT AIR AIR + FUEL

Po PTPT

NECESSARY MODIFICATIONS FOR THE ELEMENTARY CARBURETOR 1. MAIN METERING SYSTEM 2. IDLING SYSTEM 3. ENRICHMENT SYSTEM 4. ACCELERATION SYSTEM 5. COLD START SYSTEM 6. ALTITUDE COMPENSATION SYSTEM

MAIN FUEL METERING ORIFICE AIR-BLEED ORIFICE EMULSION TUBE OR WELL MAIN METERING SYSTEM FUEL AIR

INITIAL LEVEL FINAL LEVEL

UNRESTRICTED AIR BLEED RESTRICTED AIR BLEED

IDLING SYSTEM AIR IDLE AIR-BLEED ORIFICE IDLE MIXTURE ORIFICE IDLE THROTTLE SETTING ADJUSTING SCREW

TOYOTA LANDCRUISER

FUEL INJECTION IN SI ENGINES 1. INTO THE INTAKE SYSTEM a) MULTIPOINT PORT INJECTION b) SINGLE POINT THROTTLE BODY INJECTION 2. INTO THE CYLINDER

MULTIPOINT PORT INJECTION INJECTORS ARE POSITIONED AT EACH INLET PORT AS WELL AS ONE EXTRA INJECTOR POSITIONED CENTRALLY ON THE INLET MANIFOLD

MULTIPOINT PORT INJECTION ADVANTAGES : 1. IMPROVED VOLUMETRIC EFFICIENCY 2.MORE UNIFORM FUEL DISTRIBUTION 3.BETTER TRANSIENT RESPONSE

INDIRECT AIR FLOW CALCULATION

FUEL INJECTORS HAVE SOLENOIDS THEY ARE ELECTROMAGNETICALLY ACTUATED

SOLENOID COIL IS EXCITED THE PLUNGER IS ATTRACTED THE SPINDEL IS LIFTED (0.15 mm)

THE MASS OF FUEL INJECTED PER INJECTION IS CONTROLED BY VARYING THE DURATION OF THE CURRENT PULSE THAT EXCITES THE SOLENOID

TYPICAL INJECTION TIMES FOR AUTOMOBILE APPLICATIONS RANGE FROM ABOUT 1.5 TO 10 ms

DIRECT AIR FLOW CALCULATION

SIEMENS DEKO INJECTORS DEKA VII fuel injectors attain average particle sizes of less than 70 micrometers, depending on injection pressure and other conditions, and have a typical operating pressure of 3 to 5 bar.

SPREY TYPES SUPPLIED BY SIEMENS DEKO INJECTORS

FEEDBACK SYSTEMS OXYGEN SENSOR OR LAMBDA SENSOR

MECHANICAL MULTIPOINT INJECTION

SINGLE POINT THROTTLE BODY INJECTION ONE OR TWO INJECTORS

SINGLE POINT THROTTLE BODY INJECTION

ULTRA-LEAN COMBUSTION STRATIFIED CHARGE A/F =

The rich mixture is formed immediately before ignition, there is no time for the chemical reaction that causes knocking to take place.

SIEMENS PIEZO ELECTRIC INJECTORS FOR GASOLINE ENGINES System for spray-guided combustion has : 1.A piezo injector, 2.A newly developed high- pressure axial piston pump that delivers 200 bar injection pressure 3.32-bit engine control unit. 4.A largely free-definable needle stroke length and speed. 5.Multiple-injection control with up to three injection pulses per cylinder and working cycle.

The nozzle needle completes its full stroke in only 0.2 milliseconds. At the same time, the maximum deviation between individual injected quantities of fuel is 2 per cent Piezo injectors enable a very late moment of ignition in stratified charge operation without misfiring Piezo injectors allow precisely-timed, precisely-dosed multiple injections in the light and medium load range to ensure stable combustion with low cyclical fluctuations In stratified operation, the quality of the fuel feed is also enhanced by the piezo element's ability to open and close partially and completely the injector For cleaner combustion, it is important to ensure extremely fine atomisation of the fuel. At an injection pressure of approximately 200 bar, the average diameter of the fuel droplets is only 15 microns

ORBITAL INJECTOR