RETAINER 6L2127 - Caterpillar

Introduction
This guide details maintenance procedures for emission control systems installed to Caterpillar Elphinstone equipment. For general machine maintenance information, see the Operation & Maintenance Guide for your machine. SMCS Code:1089Three types of emission control systems are covered by this maintenance guide. These emission control systems are the most common systems fitted to Caterpillar Elphinstone machines. The three systems are; water batch scrubber, catalytic exhaust purifiers and catalytic exhaust purifilters.In an ideal engine, fuel mixed with air burns completely to form nontoxic carbon dioxide and water vapour. Since this ideal engine does not exist, unburnt or partially burnt products are present in the exhaust of every engine.Exhaust emissions include: Carbon monoxide - a toxic gas which can cause headaches, nausea, unconsciousness and eventually death if present in sufficient quantities.Aldehydes/acroleins - in small quantities, these gases irritate eyes and nose.Unburnt fuel - can give ruse to odours, e.g. diesel.Depending on the type of system, emission control systems can be used to assist in reduction of noxious and toxic gases, reduction of noise pollution, reduction of exhaust gas temperatures, and reduction of particle carry-over.Water Bath Scrubbers
SMCS Code:1089The water bath scrubber is a simple, but effective method of emission control. The water bath scrubber is still used in some instances, but has been largely replaced by catalytic purifiers.Exhaust gas from the engine exhaust manifold is directed into the water bath through a submerged inlet pipe. The exhaust gases are distributed through the water. The gases are exposed to the water for as long as possible to provide maximum saturation. The exhaust gas is then discharged to atmosphere.The discharge method is either by a bottom outlet or a radiator discharge outlet. The latter allows the moisture-laden gases, much of which is in vapour form, to be dispersed by the flow of cooling air through the radiator.The level of water in the water bath scrubber must be maintained to a certain level. If the level of water is too low, the effectiveness of the water bath scrubber may be impeded.Catalytic Purifiers
SMCS Code:1089
Typical Purifier Arrangement(1) Outlet cone.(2) Silencer (muffler) section.(3) Purifier (catalyst section).(4) Back pressure port.(5) Inlet cone.(6) Outlet.(7) Inlet.Catalytic purifiers decrease carbon monoxide and hydrocarbon exhaust emissions by catalytic reaction.Catalytic purifiers have a honeycomb matrix of platinum catalyst which converts exhaust impurities at most exhaust temperatures.Catalytic purifiers do not provide significant noise reduction (muffling). The typical purifier arrangement fitted to Caterpillar Elphinstone equipment is equipped with a silencer to reduce noise pollution to an acceptable decibel level.Purifiers require limited maintenance. Regular cleaning is the main maintenance required and can extend the life of catalytic purifiers considerably. Poor quality fuel/and or smoky engines can shorten purifier life considerably. Sulphur and metallic compounds are not burned off in the purifier and will reduce its effectiveness and shorten its useful life.Catalytic Purifilters
SMCS Code:1089Catalytic purifiers are very efficient in converting unburnt fuel (hydrocarbons) and carbon monoxide to harmless gases, but do not provide protection from "black" smoke (or particulate) which is emitted by all diesel engines in varying