BOLT 2H3745 - Caterpillar

The engine can have a system that uses high pressure gas or low pressure gas.
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