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LPG Engine Control Units - ECUs
Sequential injection system is the latest generation of LPG injection systems. It is the most effective system that ensures the best results in terms of driving conditions and performance. The enriching strategies and consumption and emissions optimisation strategies generated by the petrol CPU are indeed unaltered in each cylinder. This system is compatible with the original OBD system (On Board Diagnosis) of the vehicle.
The Sequential system for LPG is a specific one for catalyst vehicles and therefore has an ECU (Electronic Control Unit) that commands the gas electro-injectors in the rail, guaranteeing the perfect stoichiometric ratio of the mix by processing the signal of the pressure sensor and the injection timing of the petrol injectors.
The sequential ECU is connected in parallel to the original petrol cpu. The petrol injection timing and engine rpm signals are processed by the sequential ECU and transformed into electric signals to command the injectors on the rails, thus optimising the driving conditions and fuel consumption levels of the vehicle.
The principle used by the LPG ECU to calculate the injection timing applied to the LPG
injectors, is based on the acquisition of the petrol injection timing by LPG ECU during LPG mode.
The engine management is, therefore, mainly left to the petrol ECU whilst the LPG control unit translates petrol actuations into an appropriate control for LPG injectors.
In order to maintain the coherence with the petrol system, the LPG ECU drives LPG injectors in the same sequence as petrol injectors.
Roughly, the LPG ECU converts an amount of energy that should be actuated by the petrol into an equivalent amount of energy that LPG has to release in order to compensate the differences between the two fuels.
When the vehicle is running on lp gas, the switch-over to petrol is intercepted by an electronic device (emulator) built-in the actual ECU, which cuts-out the original petrol electro-injectors.
The user can choose which fuel to use (LPG or PETROL) using the change-over switch fitted in a handy position inside the vehicle compartment. The change-over switch comes complete with fuel indicator .