22844910 Volvo.Penta Arm

Illustration 1 g00776843
Diagram for a turbocharged air inlet and exhaust system with high pressure gas
(1) Gas pressure regulator
(2) Balance line
(3) Carburetor
(4) Air cleaner
(5) Turbocharger
(6) Gas supply
(7) Governor
(8) Aftercooler
(9) Air inlet manifold
(10) Cylinder
(11) Regulator
(12) Exhaust manifold
Illustration 2 g00776844
Diagram for a turbocharged air inlet and exhaust system with low pressure gas
(AA) Exhaust gas
(BB) Air and gas to cylinders
(CC) Gas supply
(DD) Low pressure gas
(EE) Air inlet
(1) Gas pressure regulator
(2) Balance line
(3) Carburetor
(4) Air cleaner
(5) Turbocharger
(6) Gas supply
(7) Governor
(8) Aftercooler
(9) Air inlet manifold
(10) Cylinder
(11) Regulator
(12) Exhaust manifold
Illustration 3 g00664642
Low pressure gas, air inlet and exhaust system without turbocharger
(1) Gas pressure regulator
(2) Balance line
(3) Carburetor
(4) Air cleaner
(6) Gas supply
(7) Governor
(9) Air inlet manifold
(10) Cylinder
(12) Exhaust manifoldFuel from gas supply (6) flows to pressure regulator (1). After the gas is reduced to the desired pressure by the regulator, the gas flows to carburetor (3).Inlet air is filtered by air cleaner (4).On high pressure gas fuel systems, turbocharger (5) delivers compressed air to the carburetor. Boost pressure is delivered to the gas pressure regulator through balance line (2) in order for the regulator to maintain the differential pressure between the gas and the inlet air.With low pressure gas, the air and the fuel are mixed in the carburetor and the mixture is compressed by the turbocharger.Governor (7) controls the opening of the throttle. The air and fuel is cooled in aftercooler (8) before entering air inlet manifold (9) and cylinders (10).Exhaust gas travels to exhaust manifold (12). Some of the exhaust gas drives turbocharger (5) before the exhaust gas exits through the exhaust outlet. If the boost pressure is excessive, some of the exhaust gas is diverted by regulator (11) (if equipped) to the exhaust outlet.Note: On some turbocharged engines, a boost control valve diverts excessive compressed air away from the air inlet manifold in order to control the boost pressure.Some systems have a gas shutoff valve in the supply line. This valve may be electrically operated from the ignition system. The valve can be operated manually in order to stop the engine. Manual resetting of the valve is needed in order to restart the engine.Engine installations that use dual fuel systems have components that are similar to the components in the above illustrations. However, an engine that uses a dual fuel system requires two gas pressure regulators. When the gas is changed, adjustments must be made for differences in the BTU content of the gas. An engine that has a dual fuel system can change fuels automatically. The engine timing must be adjusted when the fuel is switched. This can be accomplished with a magneto that is equipped for dual timing.Carburetor
The carburetor combines gas and air in order to establish a combustible mixture. The carburetor controls the flow of the mixture to the throttle. The carburetor also controls the exhaust emissions.The jets and the valves are interchangeable on the carburetor for low pressure gas. A change in the jets and the valves will allow the carburetor to burn a variety of fuels. The system can burn the following fuels: propane gas, natural gas and fuels with low Btu. The jets and the valves can also be changed in order to be used with an air/fuel ratio control when a catalyst is used.Carburetor (High Pressure Gas)
Illustration 4 g00664696
Cross section of the carburetor
(1) Diaphragm
(2) Sensing holes
(3) Spring
(4) Fuel valve
(5) Chamber
(6) Air horn
(7) Ring
(8) Outer chamber
(9) Fuel outlet port
(10) Inner chamber
(11) Fuel inlet port
(12) Idle adjustment
(13) Load adjusting valve
(14) Throttle plate
(15) Connection for the balance lineAir flows into the carburetor through air horn (6). The air fills outer chamber (8). Air moves diaphragm (1) away from ring (7). The air then flows into inner chamber (10) (mixing chamber).Fuel flows into the carburetor through fuel inlet (11). The fuel then flows by load adjusting valve (13) into the center of the carburetor and into fuel outlet port (9). Fuel valve (4) is fastened to diaphragm (1). While the diaphragm is moved away from ring (7), the fuel flows through fuel valve (4) into inner chamber (10). The air/fuel mixture flows through throttle plate (14) into the inlet manifold.When the engine is stopped, spring (3) holds diaphragm (1) against ring (7). This holds fuel valve (4) closed. No air or fuel can enter inner chamber (10). When the engine is started a vacuum in the cylinders is created by the intake strokes of the pistons. This creates low pressure in inner chamber (10). This low pressure is felt in chamber (5) behind the diaphragm through holes (2). This permits the pressure in chamber (5) to balance with the low pressure in the inner chamber. When the inlet pressure on diaphragm (1) becomes higher than the spring force, the diaphragm moves out.Fuel valve (4) moves out. This allows the air/fuel mixture to go into the inner chamber. A small volume of air is also measured into the inner chamber (10). This small volume of air is entered through the opening for idle adjustment (12).When the engine is operating at a constant load and speed, the position of the diaphragm is constant. The diaphragm only moves when the demand for fuel varies.Carburetor (Low Pressure Gas)
Operation of a carburetor with a single diaphragm is described below. Carburetors with more than one diaphragm operate in the same manner.
Illustration 5 g00812091
Flow of air and gas into the carburetor
(1) Filtered air
(2) Gas
Illustration 6 g00742168
Section view of the carburetor and the throttle
The carburetor and the throttle plate are in the open position.
(1) Filtered air
(2) Gas
(3) Spring
(4) Valve
(5) Jet
(6) Diaphragm
(7) Passage
(8) Load control valve
(9) Throttle bodyWhen the engine is stopped, spring (3) presses valve (4) against jet (5). No air or fuel can enter the mixing chamber of the car