Engine - Td5 (Description): Description and operation

Description

General

The Td5 diesel engine is a 2.5 litre, 5 cylinder, in-line direct injection unit having 2 valves per cylinder, operated by a single overhead camshaft. The engine emissions, on pre EU3 models, comply with ECD2 (European Commission Directive) and on EU3 models, comply with ECD3 legislative requirements. Both models employ electronic engine management control, positive crankcase ventilation and exhaust gas recirculation to limit the emission of pollutants. The unit is water cooled and turbo-charged and is controlled by an electronic engine management system.

The engine is a monobloc cast iron construction with an aluminium stiffening plate fitted to the bottom of the cylinder block to improve lower structure rigidity. The cylinder head and sump are cast aluminium. An acoustic cover is fitted over the upper engine to reduce engine generated noise.

The engine utilises the following features: l Electronic Unit Injectors (EUI's) controlled by an Engine Management System for precise fuel delivery under all prevailing operating conditions. l Turbocharging which delivers compressed air to the combustion chambers via an intercooler for improved power output. l Fuel Cooler l Oil Cooler l Centrifuge Oil Filter l Hydraulic Lash Adjusters with independent finger followers

Cylinder block components

The cylinder block components are described below:

Cylinder Block The cylinders and crankcase are contained in a single cast iron construction. The cylinders are direct bored and plateau honed with lubrication oil supplied via lubrication jets for piston and gudgeon pin lubrication and cooling. It is not possible to rebore the cylinder block if the cylinders become worn or damaged. Three metal core plugs are fitted to the three centre cylinders on the right hand side of the cylinder block.

Lubrication oil is distributed throughout the block via the main oil gallery to critical moving parts through channels bored in the block which divert oil to the main and big-end bearings via oil holes machined into the crankshaft. Oil is also supplied from the cylinder block main gallery to the five lubrication jets which cool and lubricate the piston and gudgeon pins. Plugs are used to seal both ends of the main oil gallery at front and rear of the engine block. An oil cooler is fitted to the LH side of the engine block; ports in the oil cooler assembly mate with ports in the cylinder block to facilitate coolant flow. Oil is diverted through the oil cooler, centrifuge filter and full-flow filter before supplying the main oil gallery. A tapping in the oil filter housing provides a lubrication source for the turbocharger bearings and an oil pressure switch is included in a tapping in the oil cooler housing which determines whether sufficient oil pressure is available to provide engine lubrication and cooling.

Cylinder cooling is achieved by water circulating through chambers in the engine block casting. A threaded coolant jacket plug is located at the front RH side of the cylinder block.

Cast mounting brackets are bolted to both sides of the engine block for mounting the engine to the chassis on the LH and RH hydramount studs.

The gearbox bolts directly to the engine block; a gearbox shim plate is located between the adjoining faces of the gearbox and the flywheel side of the engine block and is fixed to the rear of the engine block by two bolts. Two hollow metal dowels locate the rear of the cylinder block to the gearbox shim plate. The gearbox casing provides the mounting for the starter motor.

A port is included at the rear left hand side of the cylinder block which connects to the turbocharger oil drain pipe to return lubrication oil to the sump.

A plug sealing the lubrication cross-drilling gallery is located at the front right hand side of the cylinder block and plugs for the main lubrication gallery is included at the front and rear of the cylinder block.