TIAGO TIGOR CNG - SERVICE MANUAL

1.2L REVOTRON Bi FUEL CNG ENGINE 87 FUEL SYSTEM COMPONENTS 1. Gasoline Fuel Injector The injector used in this engine is a piezo injector. This is controlled by the EMS ECU. The timing of injection and quantity is controlled by the EMS ECU. It operates at a pressure of 4 bar. It makes multiple injections. The piezo actuator is an electrically energized device that acts similar to a solenoid but is much more precise. A piezo actuator is a composition of piezo discs, that when electrically energized, cause the discs to deform resulting in an expansion. This expansion results in a longitudinal motion thus controlling the injector. When energized, the piezo actuator pushes downward against the valve piston. The piezo actuator is returned to its non-energized state via the ECU switching the polarity of the electrical feed to the injector. 2. Gasoline Fuel Rail It is a fuel reservoir where the fuel is maintained at a pressure of about 4 bar. The fuel is pumped into it from the pump and gets delivered to the injectors through the lines. 3. Fuel Tank and Fuel Tank Unit The Fuel tank assembly consists of the fuel tank and the Intank pump. The fuel tank is used to store the fuel. The Intank pump consists of float and a sensor. Fuel level sensor assembly provides the signal to indicate the fuel level in the tank. As the float arm assembly moves with respect to the fuel level in tank, resistance at sensor varies accordingly. 4. Tank Pressure Check Valve The tank pressure valve is provided to keep the pressure in the fuel tank constant. The valve operates according to the pressure inside tank. 1. The tank pressure valve opens out when pressure differential occurs between the tanks side and canister side ports and allows vapour from the tank to carbon canister. When the pressure inside the tank becomes positive and exceeds on established level of 1 – 1.5 Kpa valve opens out. 2. When the pressure in the fuel tank becomes negative (vacuum) and reaches it specified value it open the valve to let the air flow in the fuel tank via canister.