HEAD 7J4718 - Caterpillar

Proper operation and maintenance are key factors in obtaining the maximum life and economy of the engine. If the directions in the Operation and Maintenance Manual are followed, costs can be minimized and engine service life can be maximized.The time that is needed for the engine to reach normal operating temperature can be less than the time taken for a walk-around inspection of the engine.The engine can be operated at the rated rpm after the engine is started and after the engine reaches operating temperature. The engine will reach normal operating temperature sooner during a low engine speed (rpm) and during a low-power demand. This procedure is more effective than idling the engine at no load. The engine should reach operating temperature in a few minutes.Avoid excess idling. Excessive idling causes carbon buildup, engine slobber and soot loading of the Diesel Particulate Filter (DPF). These issues are harmful to the engine.Gauge readings should be observed and the data should be recorded frequently while the engine is operating. Comparing the data over time will help to determine normal readings for each gauge. Comparing data over time will also help detect abnormal operating developments. Significant changes in the readings should be investigated.Engine Operation and the Aftertreatment System
The exhaust gases and hydrocarbon particles from the engine first pass through Diesel Oxidation Catalyst (DOC). Some of the gasses and matter are oxidized as they pass through the DOC. The gasses then pass through the Diesel Particulate Filter (DPF). The DPF collects the soot and any ash that is produced by the combustion in the engine. During regeneration, the soot is converted into a gas and the ash remains in the DPF. The gasses finally pass through the Selective Catalytic Reduction (SCR). Before the gasses pass through the SCR, Diesel Exhaust Fluid (DEF) is injected into the gas stream. The DEF is stored and controlled by the Pump Electronic Tank Unit (PETU). The mixtures of DEF and the exhaust gas pass through the SCR reducing the NOx in the exhaust emissions.The DPF may require the exhaust gas temperature to rise in order to remove the soot. If necessary, the back pressure valve operates in order to create the rise in temperature. In some applications, the operation of the back pressure valve will make the engine tone different.The engine software will control the amount of DEF that will be required in order to keep the exhaust emission compliant.This design of DPF will not require a service maintenance interval. The DPF can be expected to function properly for the useful life of the engine (emissions durability period), as defined by regulation, subject to prescribed maintenance requirements being followed.