COVER 1753721 - Caterpillar

The engine can be turbocharged and jacket water aftercooled (TA), or turbocharged and air-to-air aftercooled (ATAAC) with direct fuel injection.The 3406B PEEC is an electronically controlled, mechanically actuated unit injector diesel engine. Timing advance is achieved by precise control of injector firing. Engine speed is controlled by adjusting the firing duration. A pulse wheel provides information to the fuel cooled ECM (Electronic Control Module) for detection of cylinder position and engine speed.The programmable electronic engine control (PEEC) system was designed to provide electronic governing, automatic air-fuel ratio control, torque rise shaping, injection timing control and system diagnostics. Additional benefits such as cruise control, vehicle speed limiting, low and high gears engine rpm limiting (progressive shift engine speed control), PTO governor, data link and multi-torque ratings provide for additional engine fuel economy, driver comfort and serviceability.The fuel system is a mechanically actuated, electronically controlled unit injector combining the pumping, electronic fuel metering and injecting elements in a single unit to produce higher injection pressures. High injection pressures help to reduce fuel consumption and particulate emissions.The use of this type of unit injector provides total electronic control of injection timing. The injection timing is varied as a function of engine operating conditions. This optimizes the engine's performance for starting, emissions, noise, fuel consumption and driveability.A full range electronic governor controls the fuel injection pump output to maintain the engine rpm desired by the PEEC system. The governor functions like the Caterpillar mechanical governor in the mid-range, but includes additional features. These include programmable isochronous low idle and 20 rpm governor overrun.Individual injection pumps, one for each cylinder, meter and pump fuel under high pressure to an injection valve for eacy cylinder. Automatic timing advance provides the best fuel injection timing over the full range of engine speed.The 3406B PEEC has built-in diagnostics to assure that all components are functioning and operating properly. In the event of a system component deviation from programmed limits, the operator will be alerted to the condition by a dashboard mounted "Check Engine" light.A Caterpillar service tool is required to read the numerical code of the faulty component. Intermittent faults are logged and stored in the system memory.The cooling system consists of a gear driven centrifugal pump, with one thermostat which regulates the engine coolant temperature, an oil cooler and a radiator incorporating a shunt system.The engine lubricating oil, which is both cooled and filtered, is supplied by a gear-type pump. Bypass valves provide unrestricted flow of lubrication oil to the engine parts when oil viscosity is high, or if either the oil cooler or the oil filter elements should become plugged. Multi-Torque Rating (if equipped)This feature provides higher torque levels and better fuel economy while in top gear only. The 3406B PEEC electronics is able to determine when the vehicle is in top gear by calculating the engine rpm/vehicle speed ratio. A ratio of less than 26.6 will provide higher torque.Example: 1450 rpm/60 mph (96 km/h)=24.2The benefits of Multi-Torque are: * driver feel* less shifting