SHAFT 2V5737 - Caterpillar

Fuel Consumption
Optimum fuel consumption can be obtained by fine tuning the air/fuel ratio and ignition timing. In order to make fine tuning feasible, the engine must have stable operating parameters. The parameters must not exceed the following tolerances.
Table 1
Performance Parameters of the Engine    
Parameter     Tolerance    
Jacket Water Coolant Temperature    
6 °C ( 10 °F)    
Inlet Manifold Air Temperature    
6 °C ( 10 °F)    
Temperature of the Gas    
6 °C ( 10 °F)    
Fuel Energy Content    
31.6 kJ ( 30 Btu)    
Load     5%    Air/Fuel Ratio
The correct air/fuel ratio is very important for the following considerations:
Margin of detonation
Control of emissions
Achieving optimum service life for the engineIf the air/fuel ratio is not appropriate for the fuel and the operating conditions, a failure of the engine may occur. The service life of the turbocharger, the valves, and other components may be reduced.Temperature of the Air Supply
Changes in the temperature of the air supply affects the air/fuel ratio. In addition to seasonal changes, the air temperature changes overnight. Control of the temperature in the engine room will help to maintain the air/fuel ratio.To optimize the inlet air temperature, use ducting and a heat exchanger. This will help to avoid exposure to hot air from a generator. For more information, see Application and Installation Guide, LEKQ7250, "Air Intake". Consult your Caterpillar dealer for assistance.Temperature of the Fuel Supply
Changes in the temperature of the fuel supply affects the air/fuel ratio. Warmer fuel is less dense than cold fuel. This results in a leaner mixture that causes a noticeable reduction of power. The recommended temperature differential of the air and the fuel is 2.8 °C (5 °F).The maximum fuel temperature depends on the temperature regulator (if equipped) of the aftercooler:
For engines with a 32 °C (90 °F) aftercooler, the maximum temperature of the air/fuel mixture is 43 °C (110 °F).
For engines with a 54 °C (130 °F) aftercooler, the maximum temperature of the air/fuel mixture is 65 °C (150 °F).For more information, see Application and Installation Guide, LEKQ7260, "Low BTU Engines". Consult your Caterpillar dealer for assistance.Fuel Supply Pressure
Fluctuations of the fuel pressure can change the air/fuel ratio. For low pressure gas fuel systems (10 kPa (1.5 psi) to 34.5 kPa (5 psi) fuel pressure into the regulator on the engine), the maximum fluctuation that is allowed in the fuel pressure is 1.7 kPa ( 0.25 psi). If more than one engine is using the fuel supply line, ensure a stable fuel pressure to the engine by installing a second gas pressure regulator prior to the gas pressure regulator on the engine.For high pressure fuel systems, the maximum fluctuation that is allowed in the fuel pressure is 6.9 kPa ( 1 psi).Gas Pressure Regulator