How APG Works:
The American Power Group (APG) Dual-Fuel system is a patented aftermarket upgrade system which seamlessly meters Compressed Natural Gas (CNG) from CNG fuel tanks into the induction system of a diesel engine.
The Dual-Fuel configuration does not change any of the OEM diesel engine components and monitors compliance with OEM system parameters like oil pressure, coolant temp, exhaust gas temp, manifold air pressure, diesel fuel pressure, etc., either through the Communication Area Network (CAN) system or installed sensors.
The Dual-Fuel controller will not allow CNG to flow unless the base engine parameters are within standard operating range (i.e., the CNG does not flow until the engine coolant temp and exhaust gas temps are at “normal” operating values, therefore “cold” engine start-up is on 100% diesel fuel). The conventional diesel engine governor controller acts to reduce diesel fuel flow as CNG is introduced to maintain requested engine speed/load.
The OEM diesel engine control system remains unchanged in APG systems. If for any reason, the engine parameters are not within standard operating range or the CNG fuel storage pressure falls below 150 PSI, the Dual-Fuel system turns off the CNG flow and seamlessly returns the engine back to 100% diesel fuel operation. Also if the CNG fuel supply is depleted, the system automatically returns to 100% diesel fuel.
From the CNG fuel tank, the APG Dual-Fuel system gas-train is comprised of an electronic shutoff valve, high pressure regulator, low pressure regulator and variable fuel metering valve. The regulated CNG gas then goes to an induction system mounted venturi mixer, upstream of the diesel engine turbocharger and intake manifold.