Engine design K9K Renault Megane-2

Engine characteristics:

• compression ratio — 18.25;
• cylinder bore — 76 mm;
• piston stroke — 80.5 mm;
• engine displacement — 1461 cm³.

Design features:

• The cylinder head is made of aluminium alloy.
• The cylinder head gasket is made of metal, thanks to which it is more resistant to high temperature and pressure.
• The cylinder block is cast of grey iron with already formed cylinder liners.

Crankshaft:

• The crankshaft bearings have cast-iron caps forming part of the block, including the bolts.
• In both halves of the bearings are inserted shells with tab locks and lubricating grooves.
• The axial movement of the crankshaft is limited by two half-rings installed in the grooves of the seat of the middle main bearing.
• The oil channels to the bearings are made transversely (diagonally).
• The flywheel, cast of iron, is installed on the rear end of the crankshaft and secured by six bolts.

Connecting rod and piston assembly:

• The pistons are made of aluminium castings with a graphite coating of the skirt to reduce friction.
• In the piston crown there is a recess with a guide rib to ensure turbulent air movement.
• The piston pins are press-fitted with an interference fit into the upper ends of the connecting rods.
• The connecting rods are steel, forged, with an I-section shank. The cap and the connecting rod are machined as a single unit — fitting the cap to another connecting rod is inadmissible.

Features of the lubrication system:

• The oil pump with an excess pressure valve is driven by a roller chain from the crankshaft sprocket.
• Under the crankshaft there is an oil deflector.
• The engine sump of aluminium alloy is combined with the front and rear covers.
• The oil heat exchanger (6) and the oil filter (3) are integrated into the lubrication system.
• The oil filter is provided with a replaceable paper filter element.

Features of the cooling system:

• The cooling system is sealed, with an expansion tank.
• Forced circulation is provided by a centrifugal water pump driven from the crankshaft by the auxiliary drive belt.
• The thermostat closes the large circuit of the system when the engine is not warmed up.

Turbocharging:

• The exhaust manifold is attached to the turbocharger flange by nuts.
• Lubrication of the turbine bearings is included in the general engine lubrication system.
• The turbocharging system is complemented by an exhaust gas recirculation system.
• The quantity of gases supplied is regulated by an electromagnetic recirculation valve.

Operating principle of the diesel engine:

• Pure air is drawn into the cylinders. During compression the pressure and temperature rise sharply (to 700–900 °C).
• Before TDC diesel fuel is injected into the cylinder, which self-ignites.
• For cold starting glow plugs are installed in the combustion chamber, which heat up before the starter is switched on.
• After the plugs have heated up the indicator in the instrument cluster goes out and the engine can be started.

Fuel system:

• The injection pump is driven by the toothed belt from the crankshaft pulley.
• An electromagnetic valve is installed in the injection pump — to stop the engine the voltage supply is interrupted, the valve closes the fuel channel.
• The fuel before the injection pump passes through the fuel filter for cleaning from contaminants and water.

Note: for the bolts securing the oil sump and some other connections, the description of the procedure should be consulted in the corresponding sections of the manual.