Controles eletrônicos do motor – Veículos com: capacidade para etanol

Electronic Engine Controls – 2.5L Duratec-HE (122kW/165PS) 303-14A-11 303-14A-11 - MI4 DESCRIPTION AND OPERATION Electronic Engine Controls – Vehicles With: Ethanol Capability As a general rule, engine management works according to the same principles as for petrol operation. The PCM (powertrain control module), the sensors and the actuators are the same for petrol and for ethanol operation E100. For vehicles operated with ethanol, however, a fuel type determination and adaptation function is activated. This determines the fuel composition and adapts the control mode accordingly. Fuel type determination The mixture of fuel in the tank can vary from an ethanol share of 0% to 100%. This ethanol share is important for the engine management, as it has a strong influence on the engine running characteristics and the exhaust gas emissions. To determine the ethanol share in the fuel, the HO2S (heated oxygen sensor) and the fuel level sensor are used. Adaptation for ethanol operation The optimal fuel-air mixture for ethanol fuel E100 is 9.7 kg air per 1 kg E100. For petrol, the optimal fuel-air mixture is 14.5 kg air per 1 kg petrol. Ethanol operation therefore requires a richer mixture. To achieve this, injectors with a higher flow rate are used. In addition, the ignition time is "advanced", as the speed of transmission of the flame front of ethanol fuel E100 is lower. The requirements for petrol and ethanol operation are very different, which is why special characteristics maps have been saved in the PCM for both fuel types. Errors during fuel type determination and adaptation can have a significant influence on fuel consumption and the engine running characteristics. If a leak upstream of the HO2S causes the engine management to change the control mode to ethanol operation, the spark plugs may fail due to an excessive fuel supply and the engine will not run satisfactorily in the cold state. If the engine management switches to petrol during ethanol operation, the engine will run irregularly or will not start.