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How does the CNG system work with your vehicles current fuel system without compromising the OEM fuel system?
Your Fuel injection system will sense changes with an installed CNG dual fuel system and create a new set of parameters for operation. These changes are passed through a central processing mechanism; this integrates individual signals and interprets the fuel systems requirements. These requirements are then transmitted by electrical, mechanical, and hydraulic systems to the pumping and metering devices, which distribute the correct quantity of natural gas to the Throttle Body.
When the vehicle is running on natural gas, the signals transmitted are different from the signals that are sent when the car is running on gasoline. These signals are interpreted as faults by the electronic control unit (ECU) and the light "CHECK-ENGINE" turns on in the dashboard. To prevent the ECU from reading those wrong signals, devices called Emulators are used.
There are three electronic control modules that work with your vehicles electrical control systems.
#1 The Lambda sensor emulator
This device sends modified signals to the ECU, which is interpreted by the fuel system as normal. This keeps the electronic control unit (ECU) detecting any fuel system faults and keeps the Check Engine light off.
#2 The Injector emulator
This device is used to cut the fuel injector activation signal, this stops the two fuels from mixing. In addition, it is no longer necessary to control the injector's polarization because the signal is cut and simulated individually to each injector. Two types of these emulators exist.
- Multipoint injector emulator:
Injectors positioned in each induction manifold branch pipe just in front of the inlet pipe. - Single point injector emulator:
This type of emulator is used in vehicles where the engine is fed by one injector.
#3 The Timing advance processor
Due to the fact that natural gas has different thermodynamic properties, (CNG has higher OCTANE) the timing must be modified in order insure safe combustion temperatures and performance.
The Anti-contaminating system
A mechanical devise driving a valve by a stepper motor that allows or does not allows natural gas to enter the mixer. This motor is governed by a module, which in turn receives the signal of the lambda sensor, which shows the presence of oxygen in exhaust gases. The system works balancing the mixture constantly in order to reduce the level of emissions.
The timing advance processor, the injector emulator, the lambda sensor emulator, an anti-contaminating system, CNG level sensor and fuel selector switch are all included.
