RENAULT MEGANE cars are equipped with three types of engines.
E type engine (1.4 liter E7J petrol engine)
This engine was put into operation in 1988 and received from the RENAULT developers the designation «Energie-Motor» (E-engine). The intake and exhaust valves of these engines are arranged in a V-shape relative to each other and are actuated by rocker arms from the camshaft.
The design of the cylinder head is based on the so-called transverse principle, when the air-fuel mixture is admitted from one side, and the exhaust gases are released from the opposite side into the exhaust manifold. This ensures rapid gas exchange.
Steel liners are inserted into the piston channels of the cast-iron cylinder block, washed by the coolant. In this regard, these sleeves received the designation «wet». In case of wear or grooves on the cylinder walls, the cylinders can be replaced with new ones. In this case, however, it will also be necessary to replace the pistons with new ones. At the bottom of the cylinder block on the main bearings is the crankshaft. Connecting to the pistons is provided by connecting rods mounted on crankpins with liners. The crankcase of the cylinder block is an oil bath, which contains the engine oil necessary for lubrication and cooling of the rubbing parts of the engine. The cylinder head is bolted to the block.
Engine lubrication is provided by a gear oil pump built into the cylinder block. The oil pump is driven from the crankshaft by means of a roller chain. The engine oil taken from the oil pan is fed through oil holes to the bearings on the crankshaft and camshaft, as well as to the cylinder liners and rocker arm bearings.
The water pump is also located on the cylinder block and is driven by a toothed belt from the camshaft. It must be remembered that in the cooling system all year round there should be a coolant, which is a mixture of antifreeze, anti-corrosion additives and distilled water.
The high-voltage distributor of the maintenance-free electronic ignition system is mounted on the cylinder head flange and is actuated by the camshaft.
F type engine (2 liter F3R/F3R petrol engine, 1.9 liter F8Q/F9Q diesel engine)
Various models of RENAULT vehicles have been equipped with this type of engine since 1983. The cylinder block for this type of engine is made of gray cast iron with non-removable cylinder liners. In this case, if they are worn or grooved, it is possible to perform honing in a specialized workshop, followed by the installation of oversized pistons.
The camshaft is located in the cylinder head, which is made of light metal, and is driven by a toothed belt from the crankshaft. The camshaft, in turn, drives the vertically positioned intake and exhaust valves through poppets. The valve clearance is adjusted using appropriately sized insert washers placed in the poppet tappets.
Engines with 1 b valves are equipped with two camshafts, respectively for intake and exhaust valves. Each cylinder has 4 valves - 2 intake and 2 exhaust. The valves are installed in a V-shape and actuated by hydraulic tappets. In this case, the valve clearance is adjusted automatically. Exhaust valves are filled with sodium, which increases their durability.
The oil pump located in the crankcase is driven from the intermediate shaft by means of a toothed belt, which is also installed on the camshaft.
The water pump is located on the cylinder block and is driven by a V-belt, which simultaneously rotates the generator.
The ignition and fuel systems are fully electronic and serviced by changing the spark plugs and filter.
K type engine (gasoline engine K4J / K4M / K7M with a displacement of 1.6 liters)
This engine is a modification of the E type engine and was put into operation in 1995. However, unlike the E-type engine, this engine has non-removable cylinder liners, which made it possible to reduce the distance between the cylinders and increase the diameter of the piston bore. This, in turn, provided an increase in displacement from 1.4 liters to 1.6 liters without changing the size of the engine.
The change in air-fuel mixture preparation, in combination with its multipoint injection using a distributorless ignition system, provided an increase in engine power characteristics.
Gasoline engines with a displacement of 1.4 and 1.6 liters with the designation K4J and K4M are the latest development designed for the second generation of MEGANE. Both models of these engines are 16-valve. The valves are driven by two overhead camshafts. The camshafts are driven by a toothed belt.
The ignition system of these engines is fully electronic and maintenance-free. Each cylinder has a separate ignition coil located directly on the corresponding spark plug. The wire that usually connects the spark plug and the ignition coil is missing in this case.
1.9 liter dCi engine (diesel engine with direct injection from the main fuel line)
The fuel pump in this type of engine takes diesel fuel from the tank and even at low engine speeds pumps it with a constant pressure of up to about 1350 bar.
From the fuel pump there is a main fuel line connected to each cylinder. The main fuel line is also an accumulator that maintains a constant fuel pressure and supplies it under this pressure to the fuel injectors.
The amount of fuel required for injection is set by the engine control unit and injected by electromagnetic injectors into each cylinder. As soon as the microprocessor of the control unit closes the nozzles, the fuel supply stops. In other words, pressurization and fuel injection are performed independently of each other, thereby optimizing fuel consumption and CO content in the exhaust gases, regardless of the engine speed.
Fuel injection is carried out in two stages by multi-jet injectors. First, a preliminary injection of a small amount of fuel is performed, the combustion of which creates the best conditions for igniting the main portion of the mixture. Thus, a soft and quiet combustion process is achieved, identical to the process that occurs when fuel is injected into the swirl chamber. Unlike other types of direct injection engines with cam distribution, the fuel supply to the combustion chambers of dCi engines can be changed according to the needs at a particular moment of movement.