3850095 Volvo.Penta Fitting

Illustration 1 g02192355
Fuel system schematic
The fuel supply circuit is a conventional design for engines that use fuel injectors. The fuel supply circuit uses a fuel transfer pump to deliver fuel from the fuel tank to the electronic fuel injectors. The transfer pump is a fixed displacement gear pump.The fuel flows then through a fuel filter before entering the fuel supply manifold. A fuel priming pump is on the fuel filter base to fill the system. The system must be primed after the filter changes. The system must be primed after draining the fuel supply and return manifolds, when the fuel injectors are replaced.The fuel flows continuously from the fuel supply manifold through the fuel injectors. The fuel flows when either the supply or the fill port in the injector is not closed by the injector body assembly plunger. The fuel that is not injected into the cylinder is returned to the tank through the fuel return manifold.A pressure regulating valve is at the end of the fuel return manifold. The pressure regulating valve controls the entire fuel system pressure. The regulation provides proper filling of the fuel injectors.The electronically controlled mechanically actuated fuel injector system provides total electronic control of injection timing. The injection timing is varied to optimize the engines performance.The timing ring is part of the rear gear group. A signal is generated by the engine speed/timing sensor. This information is for detection of crankshaft position and for engine speed. Other information and these data allow the ECM to send a signal to the injector solenoids. The fuel injector solenoid is energized to begin fuel injection. The fuel injector solenoid is de-energized to end fuel injection. Refer to Systems Operation, "Fuel Injector".Gas System
System Operation
Cat® Large Mining Truck (LMT) products powered by diesel and liquid natural gas (LNG) fuels are equipped with fully integrated diesel and LNG fuel tanks located in the same space claim as the standard diesel tank. In the pump-less LNG system designed for the Cat LMT, the bulk temperature of the LNG fuel in the tank effectively determines the tank pressure driving natural gas to the engine. The system is designed to operate at 8.6 bar (125 psi). The system contains an economizer which will automatically select between the vapor space and liquid space, allowing the continuous flow of fuel to the engine. LNG out of the tank flows through a tank isolation valve (used during service of the system) to a heat exchanger (referred to as "vaporizer"), in which the LNG is warmed into natural gas. Cat LNG LMT is equipped with a 3-micron gaseous fuel filter at the outlet of the vaporizer heat exchanger on its way to the engine.Clean LNG fuel that meets Caterpillar fuel recommendations provides outstanding engine service life and performance. As per fuel cleanliness standard ISO 4406, the LNG fuel needs to meet or exceed a standard of ISO 18/16/13 cleanliness. Fuels not meeting Caterpillar’s minimum specifications will adversely affect the perceived performance of the combustion system, fuel filters, and the service life of the gaseous fuel injection system, valves, pistons, liners, and bearings.Refer to Application & Installation Guide, LEBT0003, "Liquefied Natural Gas (LNG) Powered Dynamic Gas Blending™ (DGB™) Large Mining Trucks", for more information on LNG fuel specifications and LNG fueling station specifications. The publication is available from the Electronic Media Center.The LNG system is equipped with multiple safety features including a tank isolation valve, vent valve, defuel valve, excess flow valve, check valves, and fill isolation valve all provide the abilitytosafely control the flow of fuel internal and external to the tank. In addition, there are multiple pressure relief valves that safely control the pressure internal and external to the tank including a 1586 kPa (230 psi) primary relief valve, 1724 kPa (250 psi) secondary relief valve, 2413 kPa (350 psi) tertiary relief valve, a 2413 kPa (350 psi) fill line relief valve with a manual lift to safely service the fill line, and a 3 2413 kPa (350 psi) defuel relief valve.If at any time the tank pressure rises above 1586 kPa (230 psi), the primary relief valve will protect the system from overpressure by opening and transferring fuel into the vent circuit directed safely away from the truck. If the pressure rises above 1724 kPa (250 psi), the secondary relief valve will also open to protect the system from overpressure by transferring fuel through a secondary vent circuit. If at any time liquid fuel becomes trapped, the 2413 kPa (350 psi) tertiary relief valve will open to allow the expanding fuel to expel safely into the vent circuit.In addition to the tank safety features, the DGB product is equipped with multiple mechanical and electronic safety features on the chassis including ECM events and diagnostics for the gas system, a methane detection system with alarm and sensors in the engine compartment and cab, a system manual vent valve to depressurize the gas supply line, a 1586 kPa (230 psi) primary relief valve, and a 104° C (219° F) Pressure Relief Device (PRD) thermal relief valve.If at any time the pressure or temperature in the chassis gas supply line to the engine exceed the 1586 kPa (230 psi) setting of the primary relief valve or the 104° C (219° F) setting of the PRD thermal relief valve, these devices will open and allow the flow of fuel through the vent circuit directed safely away from the truck.On-Truck Gas System
Illustration 2 g06444357
(1) Check valve (Fill Line)
(2) Fill isolation valve
(3) Fill receptacle and strainerLiquid Natural gas flow into the tank through the fill receptacle and strainer (3), through the normally open fill isolation valve (2), and through the fill check valve (1).
Illustration 3 g06444376
(4) Vapor outlet
(5) Pressure regulator primary (Economizer)
(6) Vapor shutoff (OPEN)When the Engine reaches operating temperature and load, the system will open the gas shutoff valve allowing fuel to flow from the Tank to the engine. Vapor only flows from the tank when tank pressure is greater than the economizer set pressure. The vapor will flow out the