ADVANCES IN IC ENGINES

Limitations of Carburetion Non-homogenous air fuel mixture supply to each cylinder Rely upon the pressure difference which is not reliable Needs compensating devices which makes system complex Purely a mechanical machine with little or no intelligence More pollution

Electronic Injection Systems or Fuel Injection Systems in SI Engine Classification according to type of arrangements: Port Injection Throttle Body Injection(Single Point Injection)

Port injection(MPFI for Multicylinder)

Port injection(MPFI for Multicylinder)

Multi Point Fuel Injection Engine (MPFI) Components: Air Intake System Fuel Delivery System Electronic Control System Emission Control System

1. Air intake system : Throttle body consists Main bore, air bypass passage, Throttle valve TP sensor (which detects the throttle valve opening and sends a signal to ECM) Idle air control valve(IAC) valve controls opening of the bypass air passage. Opening and closing of the valve itself is determined by operation of the magnet, which is connected to it. The magnet operates according to electric current from ECM.

2. Fuel Delivery System Fuel pump Pressure regulator system Injector

3. Electronic control system Fuel injection control system Idle speed control system Fuel pump control system Ignition control system Radiator fan control system,

4. EMISSION CONTROL SYSTEM Catalytic converter Catalytic oxidizers Evaporative emission control system (prevent emission of fuel vapour)

Sensors Used In MPFI Manifold absolute pressure (MAP) sensor Throttle position sensor Intake air temperature sensor Engine coolant temperature sensor Oxygen sensor Vehicle speed sensor Camshaft position sensor Crank shaft position sensor

Multi Point Fuel Injection Engine (MPFI) Classification: Depending upon the working, there are further two types D-MPFI system L-MPFI system

D-MPFI Measure intake manifold vacuum using manifold pressure sensor and engine speed using speed sensor Air Injection Injector Petrol Intake Manifold A/F Mixture Injection volume control ECU Engine RPM Sensor

L-MPFI Measure engine speed and the amount of air actually entering in the engine. Air Intake Air Volume Detection Air Meter Intake Manifold Injector Engine ECU

Advantages of MPFI System: Cleaner exhaust emission 2. Economical fuel consumption 3. Improved drivability 4. Better ‘power balance’ amongst the cylinders 5. Higher output (and torque) from each cylinder 6. Faster throttle response 7. Supplies optimized air/fuel mixture ratio under widely varying driving conditions 8. More uniform A/F mixture will be supplied to each cylinder; hence the difference in power developed in each cylinder is minimum. Vibration from the engine equipped with this system is less, due to this the life of engine components is improved.

9. No need to crank the engine twice or thrice in case of cold starting as happens in the carburetor system. 10. Immediate response, in case of sudden acceleration / deceleration. 11. Since the engine is controlled by ECM* (Engine Control Module), more accurate amount of A/F mixture will be supplied and as a result complete combustion will take place. This leads to effective utilization of fuel supplied and hence low emission level. Improved mileage. Improved Volumetric Efficiency.

2. Throttle body injection

Timed and continuous injection: Classification type which is based upon the injection action: Timed injection system Fuel is injected in the form of pulse Continuous injection system: fuel is continuously injected

Gasoline direct injection (GDI) GDI: Gasoline Direct Injection (GDI), also known as Petrol Direct Injection or Direct Petrol Injection or Spark Ignited Direct Injection (SIDI) or Fuel Stratified Injection (FSI) The gasoline is highly pressurized, and injected via a common rail fuel line directly into the combustion chamber of each cylinder 3. GDI enables a stratified fuel charge (ultra lean burn) combustion for improved fuel efficiency, and reduced emission levels at low load.

Injector Spark Plug

Direct injection may also be accompanied by other engine technologies such as variable valve timing (VVT) or continuous variable cam phasing, variable length intake manifolding (VLIM, or VIM), and turbocharging. Water injection or (more commonly) exhaust gas recirculation (EGR) may help reduce the high nitrogen oxides (NOx) emissions

Advantages of GDI Increased fuel efficiency High power output Controlled Emissions levels Injection timings that are varied according to engine load Reduced 'pumping losses' in engines without a throttle plate. Engine speed is controlled by the engine control unit/engine management system (EMS), which regulates fuel injection function and ignition timing.

Additives or Dopes Tetraethyllead (Still in use as a high octane additive) Methylcyclopentadienyl manganese tricarbonyl (MMT) Ferrocene Iron pentacarbonyl Toluene Isooctane

Additives or Dopes 1. TEL: Tetraethyllead (common name tetraethyl lead) An organolead compound with the formula (CH3CH2)4Pb It was mixed with gasoline (petrol) beginning in the 1920s as an inexpensive octane booster engine compression to be raised substantially increased vehicle performance and fuel economy an effective antiknock agent and prevented exhaust valve and seat wear neurotoxicity and its damaging effect on catalytic converters Banned in India from 2000

2. MMT Methylcyclopentadienyl manganese tricarbonyl (MMT): boost octane MMT impairs the effectiveness of automobile emission controls and increases pollution from motor vehicles. 3. FERROCENE Ferrocene is the organometallic compound with the formula Fe(C5H5)2 4. IRON PENTACARBONYL: also known as iron carbonyl, is the compound with formulaFe(CO)5. Iron pentacarbonyl has been found to be a strong flame speed inhibitor in oxygen based flames.

5. TOLUENE Toluene is a clear, water-insoluble liquid with the typical smell of paint thinners due to the density of the fuel and other factors, the fuel does not vaporize easily unless preheated to 70 degrees Celsius it eats through standard rubber fuel lines and has no lubricating properties 6. TRIMETHYLPENTANE (ISOOCTANE)

FUEL RATING IN INDIA India: India's Ordinary And Premium Petrols are of 91 RON.(Range: 85-91) Two variants, "Speed 93" and "Speed 97", were launched, with RON values of 93 and 97. India's economy-class vehicles usually have compression ratios under 10:1, thus enabling them to use lower-octane petrol without engine knocking.

Octane rating Isooctane (upper) has an octane rating of 100 whereas n-heptane has an octane rating of 0. Measurement methods Research Octane Number (RON) (600 rpm) Motor Octane Number (MON)(900 rpm) MON of a modern gasoline will be about 8 to 10 points lower than the RON

Anti-Knock Index (AKI)/Pump Octane Number (PON) (R+M)/2 Fuel's Sensitivity: Difference between RON and AKI Observed Road Octane Number (RdON) derived from testing gasolines in real world multi-cylinder engines, normally at wide open throttle Aviation gasoline octane ratings This utilizes a supercharger, and uses a significantly richer fuel/air ratio for improved detonation resistance

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