1. www.utm.my innovative ● entrepreneurial ● global 1 Detonation ● Produce multiple flame fronts within combustion chamber instead of a single flame kernel. ● When multiple flames collide, it produces sudden pressure rise accompanied by a sharp metallic pinging or knocking noise. ● The detonation shock waves cause the head gasket, piston, rings, and rod bearing to severe overloading. ● Occasional detonation usually causes no harm, but prolonged or heavy detonation can be very damaging Source: airbp

2. www.utm.my innovative ● entrepreneurial ● global 2 Detonation Things That Promote Detonation High Compression RatioHigh Compression Ratio Advanced Ignition TimingAdvanced Ignition Timing Wide Open Throttle SettingWide Open Throttle Setting Slightly Rich MixtureSlightly Rich Mixture High Air Inlet TemperatureHigh Air Inlet Temperature High Head TemperatureHigh Head Temperature Buildup of Deposits in Combustion ChamberBuildup of Deposits in Combustion Chamber

3. www.utm.my innovative ● entrepreneurial ● global 3 Concept question 1. What is the main reason for a black smoke coming out from a car exhaust: ● There is too much fuel for the air in the engine cylinder which results in rich mixture and incomplete combustion; ● There is not enough fuel for the air in the engine cylinder that result in weak mixture that cause poor combustion and loss of power. 2. Main reason for a white smoke? and blue smoke? coming out from a car exhaust: ● Caused by water and or antifreeze entering the cylinder, and the engine trying to burn it with the fuel; ● Caused by engine oil entering the cylinder area and being burned along with the fuel air mixture.

4. www.utm.my innovative ● entrepreneurial ● global 4 Fuel system are designed to provide engine with the fuel in different ways. There are 2 types of petrol fuel system: carburetor and electronic fuel injection (EFI). They all have subsystem including fuel supply, air supply and means of control In electronic fuel control, electronic control unit (ECU) is used to control and determines precisely how much fuel is needed and must be delivered by the injector. This is done through various engine sensors, fuel injector assemblies and related wires. The ECU control the injector for precise injection pulse width or injection duration for proper air fuel ratio mixture. Fuel Control

5. www.utm.my innovative ● entrepreneurial ● global 5 Carburetors were the predominant old method used to meter fuel on gasoline engines before 1980s The primary difference between carburetors and fuel injection is that a carburetor relies on suction created by intake air rushing through a venturi to draw the fuel into the airstream, while fuel injection atomizes the fuel by forcibly pumping it through a small nozzle under high pressure. Fuel Control

6. www.utm.my innovative ● entrepreneurial ● global 6 Electronic Fuel Control

7. www.utm.my innovative ● entrepreneurial ● global 7 Electronic Fuel Control

8. www.utm.my innovative ● entrepreneurial ● global 8 EFI is more efficient than the carburetor and can better operate at extreme temperatures while becoming more dependable at start up. EFI reacts better to situations such as high altitudes, extreme temperatures and variable fuel quality. EFI is an integral part of a modern vehicle's engine management system. The functional objectives for fuel injection systems can vary Electronic Fuel Injection (EFI) # power output # emissions performance # ability to accommodate alternative fuels # reliability # driveability and smooth operation# fuel efficiency automotive engineers strive to best satisfy a customer's needs competitively. The modern EFI system is far more capable at optimizing these competing objectives consistently than a carburetor.

9. www.utm.my innovative ● entrepreneurial ● global 9 Air enters engine through air induction system. air flow meter will measure the air flow. Fuel is mixed into the air by fuel injector located behind each intake valve in intake manifold. Use a high pressure injector, to inject fuel into an internal combustion engine. How EFI works Typical EFI components -Injectors -Fuel Pump -Wiring Harness -Various Sensors -Fuel Pressure Regulator - ECM : Engine Control Module; includes a digital computer and circuitry to communicate with sensors and control outputs.

10. www.utm.my innovative ● entrepreneurial ● global 10 How EFI works A fuel pump, usually located inside of the fuel tank, supplies pressurized fuel for the system. The fuel pressure is controlled by a pressure regulator according to demand on the vehicle ECU pulses injector by switching injector ground circuit on and off When injector is on, it opens and sprays atomized fuel Fuel will mix with incoming air and vaporize due to low pressure in intake manifold. ECU signal injector to send enough fuel to achieve ideal AFR ratio of 14.7:1 or stoichiometry value ECU determines injection quantity based upon intake air volume and engine RPM. Ultimately the amount of fuel that goes into the engine is determined by the engine management system according to information (feedback data) gathered by the sensors.

11. www.utm.my innovative ● entrepreneurial ● global 11 EFI use electronically controlled injectors to spray the fuel. Electronic Fuel Injection (EFI) Two main categories: 1.Single point injection – also known as throttle body fuel injection. 2.Multipoint injection – also known as port or sequential fuel injection. In order to provide correct amount of fuel for every operating condition, ECU monitors numbers of input. TwoTwo important input sensors are speed and load. Other sensors are: i. mass airflow sensor - tells ECU the mass of air entering the engine. ii. Oxygen sensor – monitor the amount of O 2 in the exhaust. Help ECU to determine how rich or lean the fuel mixture is.

12. www.utm.my innovative ● entrepreneurial ● global 12 Electronic Fuel Injection (EFI) Other sensors are: iii. Coolant temperature - helps ECU to determine when engine reach proper operating temperature. iv. Voltage sensor - monitor the voltage system in the car so the ECU can raise the idle speed if voltage is dropping. v. Throttle position sensor – monitor throttle valve position

13. www.utm.my innovative ● entrepreneurial ● global 13 Fuel Injection System Fuel metering is determined by a combination of the engine air charge, vacuum and speed. Some vehicles utilize a mass airflow sensor to determine engine air intake, other systems use a MAP sensor (manifold absolute pressure). Both utilize oxygen sensors to monitor emissions in the exhaust to help control mixture. A throttle position sensor located on the throttle body, is used to measure the load on the engine according to engine speed/vehicle speed/throttle position and other information gathered by the computer.

14. www.utm.my innovative ● entrepreneurial ● global 14 Concept question What happen if you use premium fuel to your car that does not require premium fuel? ● Wasting your money by burning premium fuel in a car that doesn't require it. Premium fuel (i.e. Higher-octane) fuel burns more slowly, and will actually give poorer performance when fed to engines that were designed to burn regular fuel. But what happens, if you use regular fuel in a car that really need a premium fuel? ● If the car is a late-model one, nothing will cause any permanent problems. The computer will adjust the ignition timing and other engine parameters to compensate for the lower-octane juice. You may notice a slight falloff in acceleration, but no engine damage or drivability problems should arise.

15. www.utm.my innovative ● entrepreneurial ● global 15 Single point injection (TBI) In single point injection: Acts like an electronic carburetor. Single injector sprays fuel into the air as it passes through the throttle body into intake manifold

16. www.utm.my innovative ● entrepreneurial ● global 16 Throttle body type

17. www.utm.my innovative ● entrepreneurial ● global 17 Throttle body type

18. www.utm.my innovative ● entrepreneurial ● global 18 Multipoint Injection In multipoint injection: Fuel injectors can all open at the same time; or each one can open just before the intake valve for its cylinder opens (called sequential injection).

19. www.utm.my innovative ● entrepreneurial ● global 19 Multipoint Injection In multipoint injection: Sequential injection: injection is timed to coincide with each cylinder's intake stroke Batched: fuel is injected to the cylinders in groups, without precise synchronization to any particular cylinder's intake stroke; or Simultaneous: fuel is injected at the same time to all the cylinders. The typical fuel pressure runs between 40-60 psi. Modern EFI systems utilize sequential MPI; however, in newer petrol engines, direct injection systems are beginning to replace sequential ones.

20. www.utm.my innovative ● entrepreneurial ● global 20 Direct Injection Direct fuel injection costs more than indirect injection systems: the injectors are exposed to more heat and pressure, so more costly materials and higher-precision electronic management systems are required. However, the intake is dry, making this a very clean system. In a common rail system, the fuel from the fuel tank is supplied to the common header (called the accumulator). This fuel is then sent through tubing to the injectors which inject it into the combustion chamber.

21. www.utm.my innovative ● entrepreneurial ● global 21 Direct Injection

22. www.utm.my innovative ● entrepreneurial ● global 22 Direct Injection The header has a high pressure relief valve to maintain the pressure in the header and return the excess fuel to the fuel tank. The fuel is sprayed with the help of a nozzle which is opened and closed with a needle valve, operated with a solenoid. When the solenoid is not activated, the spring forces the needle valve into the nozzle passage and prevents the injection of fuel into the cylinder.

23. www.utm.my innovative ● entrepreneurial ● global 23 Direct Injection The solenoid lifts the needle valve from the valve seat, and fuel under pressure is sent in the engine cylinder. Third-generation common rail diesels use piezoelectric injectors for increased precision, with fuel pressures up to 1,800 bar/26,000 psi. Gasoline engines incorporate gasoline direct injection engine technology.

24. www.utm.my innovative ● entrepreneurial ● global 24 Fuel Injector In trying to keep up with emissions and fuel efficiency laws, the fuel system used in modern cars has changed a lot over the years A fuel injector is nothing but an electronically controlled valve. It is supplied with pressurized fuel by the fuel pump and capable of opening and closing many times per second. When the injector is energized, an electromagnet moves a plunger that opens the valve, allowing the pressurized fuel to squirt out through a tiny nozzle.

25. www.utm.my innovative ● entrepreneurial ● global 25 Fuel Injector In trying to keep up with emissions and fuel efficiency laws, the fuel system used in modern cars has changed a lot over the years The nozzle is designed to atomize the fuel - to make as fine a mist as possible so that it can burn easily. The amount of fuel supplied to the engine is determined by the amount of time the fuel injector stays open. This is called the pulse width, and it is controlled by the ECU.

26. www.utm.my innovative ● entrepreneurial ● global 26 Fuel Injector The fuel injector nozzle directs liquid fuel into the engines intake air stream. The fuel system is controlled by a computer called a Powertrain Control Module (PCM). The PCM controls the fuel injection system by gathering and processing information from numerous sensors mounted into the system.

27. www.utm.my innovative ● entrepreneurial ● global 27 Advantages of EFI 1. Uniform Air fuel mixture distribution = improve cylinder to cylinder distribution 2. Accurate AFR control throughout all engine operating conditions = provides better drivability, fuel economyy and emision control 3. Superior throttle response and power = intake manifold design can be optimized to improve air velocity 4. Excellent fuel economy with improved emissions control = Improved cold engine startability and operation due to better fuel atomization and injection directly at the intake valve