Despite their perfect design, the Mondeo engines are naturally not free from annoying defects: Ford certifies the power units for a mileage of 240,000 kilometers for at least ten years. Of course, it is better to hand over the in-depth adjustment work to a workshop. Trained "specialists in blue uniforms" have at their disposal the necessary specialist knowledge, they have practical experience and, as a rule, a large set of special tools to "get your Mondeo back on its feet".
For example, an improperly replaced camshaft timing chain can cause irreparable damage to pistons and valves. It is better not to demand that you perform any repairs to the cylinder head gaskets or valves, and sometimes high demands are placed on repairs to the crank mechanism when doing it yourself. If you are not so sure that you can professionally service or check the "insides" of your Mondeo, it is better to close the toolbox - for your own safety. However, do not "finally" close the engine compartment to yourself: there are enough checks and repairs that you can easily do yourself.
|
TECHNICAL DICTIONARY |
Engine parts
Engine cylinder block: all rotating and swinging elements of the crank mechanism and the oil supply system are collected here. In its periphery it also carries auxiliary units, such as the generator, servo pump, starter and ignition system. The cylinder blocks of Duratec engines are cast from aluminum, gray cast iron is held in high esteem by DuraTorg DI.
Cylinder head: in modern engines, it is generally made of light metal alloys today. The cylinder head covers the engine block from above, it has intake and exhaust channels, water channels, oil channels, insert rings of valve seats, valve guides, places for installing camshaft bearings and other valve drives, combustion chambers, as well as openings for spark plugs and injectors. The cylinder head gasket, located between the cylinder block and the cylinder head of the engine, seals from oil, coolant and "foreign" air from the inside and outside.
Cylinder: in it the piston moves between the lower dead center (UT) and the upper dead center (OT): the working surfaces of the cylinders are strictly matched in diameter to the diameter of the pistons and the surfaces are additionally specially treated. They are cooled indirectly through cooling channels or, in the case of wet cylinder liners, are directly washed by the cooling liquid.
Piston: moves in the cylinder and transmits combustion energy via the connecting rod to the crankshaft. Pistons are made of particularly light and heat-resistant alloys of light metals. Their main components are: bottoms, annular zones with piston rings, holes for the piston pin and guide part. The piston pin connects the piston to the connecting rod. The upper piston ring (sealing ring) seals the combustion chamber almost gas-tight from the crank mechanism. The lower ring (scraper oil scraper piston ring) removes excess lubricating oil from the cylinder walls to a collector for used oil (oil sump).
Connecting rod: connects the piston to the crankshaft. It consists of: the connecting rod head (leads the piston pin), the rod, the connecting rod base and the base cap (the base and cap surround the crankshaft connecting rod journals with bearing liners).
Crankshaft: by means of the "connecting element of the connecting rod" it converts kinetic energy (piston movement from TDC to BDC) into rotational energy (rotational movement). A modern crankshaft consists of a forged rod that rotates in the main bearing shells of the cylinder block. Depending on the number of cylinders with a strictly defined shift (angular degrees), each time two crank cheeks lead to the connecting rod journals (locations of the connecting rod bearings).
The four-cylinder Mondeo crankshafts have five main bearings and four connecting rod bearings eccentrically located at 90° angles. Replaceable three-piece plain bearings are "inserted" into all bearing locations. The V6 only needs four main bearings, here the connecting rod bearing locations are eccentrically located at 60° angles.
Valves: in a four-stroke engine, they are designed to control gas exchange (intake, compression, combustion, expulsion). In Mondeo engines, the valves "hang" in a V-shape at an angle of 42° under the camshafts. All moving parts in the cylinder head complete the valve drive.
Camshaft: opens and closes the valves – depending on the engine speed and the position of the pistons – in a strictly specified time sequence.
Basic concepts of engine technology
Four-stroke principle:
Intake (1st stroke): the piston slides from top dead center (TDC) to bottom dead center (BDC). The intake valve opens, the fuel-air mixture rushes into the cylinder.
Compression (2nd stroke): the piston slides from TDC to BDC and compresses the incoming fresh fuel mixture as it moves. The inlet valve and outlet valve are closed.
Combustion (3rd stroke): already at the beginning of TDC, the compressed fresh fuel mixture is ignited by the igniting sparks of the spark plugs: the mixture burns explosively, due to the increase in pressure, the piston moves to BDC. The connecting rod transmits energy further to the crankshaft and sets it in rotation.
Release (4th beat): the rotating mass of the flywheel moves the piston from the BDC position back to the TDC position. The exhaust valve is now open, so that the burnt gas (exhaust gas) exits into the exhaust system. Together, these four strokes in a four-stroke engine form the gas exchange cycle.
In general, a diesel engine operates on the same principle. However, during the intake stroke, it sucks in only clean air, compresses it much more strongly, so that the fuel (diesel fuel) injected at the end of the compression stroke can ignite independently in hot air without forced ignition (igniting sparks). The rest of the gas exchange cycle is identical to a carburetor engine.
Working volume: the space that the piston passes through when moving from BDC to TDC. The combustion chamber is not connected to the working volume in any way. The working volume and the combustion chamber together form the volume of the cylinder.
Compression ratio: a parameter that determines how much the fresh fuel mixture sucked into the combustion chamber is compressed. The size of the combustion chamber has a direct impact on the compression ratio. The compression ratio indicates what volume of the fuel mixture at 100% filling (the throttle valve is fully open) should be in the combustion chamber at the moment of ignition. DuraTorg engines have a compression ratio of 19.0. Duratec-HE engines operate with a compression ratio of 10.8:1, and the V6 compresses the fresh fuel mixture in a ratio of 9.8:1 (ST220 10.25:1).
The working volume 2 extends from the top 1 to the bottom dead center 3. Between the TDC, which in the right cylinder is limited directly by the piston bottom, and the deflection of the cylinder head 5, a combustion chamber 4 is formed. |
|
|
