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Six-cylinder diesel engines
| Fig. 4.5. Engine compartment with a diesel engine 300 D: 1 - cooled box made of plastic for electronic controllers and relay blocks; 2 - intake grille interior ventilation; 3 - the case of the pressure control valve; 4 - compartment lid injectors and spark plugs; 5 - drive the wiper; 6 - the oil filter; 7 - the inlet manifold; 8 - the brake fluid reservoir with the main brake cylinder and brake booster; 9 - the fuse and relay; 10 - expansion tank; 11 - air filter; 12 - bypass valve exhaust system; 13 - the dipstick; 14 - oil filler cap; 15 - the fuel filter; 16 - the spare capacity of the hydraulic oil to the servo; 17 - washer tank (front - for headlamps, rear - for wiper); 18 - brake unit
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Together with five-cylinder turbo engines Mercedes offers 6-cylinder diesel engine having a cylinder capacity of 3 liters (OM 606) (Fig. 4.5). Technically OM 606 model almost entirely correspond to the OM 604 and OM 605 with a smaller number of cylinders (2.5 L, 5 cyl.). It is equipped with cylinder head prechamber and four valves per cylinder, electronically controlled in-line injection pump, dual mass flywheel (for models with a manual transmission). Crankshaft 6-cylinder engine is mounted on seven journal bearings. The exclusive feature of the OM 606 is adjustable along the length of the intake manifold in the form of a three-stage resonance intake manifold with flaps.
| Fig. 4.6. Engine compartment with a diesel engine 320 CDI: 1 - a broad tank; 2 - the air filter; 3 - air intake of the turbocharger; 4 - cooled housing for electronic controllers and relay blocks; 5 - oil filler cap; 6 - intake grille interior ventilation; 7 - a cover of the engine; 8 - a cover of the intake manifold; 9 - the brake fluid reservoir with the main brake cylinder and brake booster; 10 - the dipstick; 11 - audible alarm; 12 - protective grille; 13 - radiator hose; 14 - a cover of the fuel filter; 15 - washer tank (front - for headlamps, rear - for the windscreen wiper); 16 - it controls the braking system; 17 - the spare capacity of the hydraulic oil from the servo; 18 - fuse and relay box
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Since August 1999, the Mercedes cars began to install the engine 320 CDI (Fig. 4.6) with the system Common Rail, which replaced the E 300 D. All the CDI engines are carried out on a modular system, they have identical cylinder spacing (97 mm) and the same diameter and stroke (88 x 88.34 mm). This CDI engines have a new cylinder head with four valves, tsentralnoraspolozhennymi injectors and an aluminum structure.
| Fig. 4.7. The distribution of fuel in the combustion chamber
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| Fig. 4.8. Multivalve system
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| Fig. 4.9. Piston rod: 1 - the piston with three piston rings; 2 - rod; 3 - Cover support bearing
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| Fig. 4.10. DMF: 1 - the crankshaft; 2 - the front part of the flywheel; 3 - torsional vibration damper; 4 - rear flywheel
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| Fig. 4.11. Longitudinal section of a 4-cylinder diesel engine with pre-chamber injection (OM 604): 1 - fan with viscous coupling; 2 - dipstick; 3 - circuit timing; 4 - oil filler cap; 5 - the inlet manifold; 6 - pipe from the control valve body; 7 - the oil filter; 8 - starter; 9 - two-mass flywheel; 10 - a rod with a piston; 11 - the crankshaft; 12 - receiving funnel oil pump; 13 - the oil pump; 14 - chain drive oil pump
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| Fig. 4.12. Cross-section of a 4-cylinder diesel engine with pre-chamber injection (OM 604): 1 - a reception pipe intake system; 2 - the inlet manifold; 3 - glow; 4 - gear pump; 5 - Connecting rod shaft of the crankshaft; 6 - the oil pump drive gear; 7 - the oil level sensor; 8 - thermostat cooling system; 9 - an outlet; 10 - channel EGR; 11 - the EGR valve; 12 - the control valve
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| Fig. 4.13. Five-cylinder diesel engine CDI (OM 612)
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| Fig. 4.14. The six-cylinder diesel engine CDI (OM 613)
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| Fig. 4.15. Teamwork camshaft and valves 1 - head cover; 2 - the housing of the cylinder head; 3 - exhaust camshaft; 4 - tappets with hydraulic clearance adjustment; 5 - injection nozzle; 6 - exhaust valve; 7 - pre-chamber with the inlet to the combustion chamber; 8 - the inlet channel; 9 - nozzle; 10 - the inlet camshaft
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| Fig. 4.16. The pistons: 1 - top dead center; 2 - stroke; 3 - bottom dead center; 4 - the combustion chamber; 5 - cylinder head
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Technical Dictionary Multivalve system Cylinder four-valve heads. Motor power depends not only on the volume of cylinders and number of revolutions, but also on the rate of supply of air-fuel mixture in the combustion chamber and exhaust velocity. Therefore, compared with the two-valve system 4, the valve may improve filling of the combustion chamber (Fig. 4.7). In addition, four valves a smaller diameter have a much larger opening area than the two - of larger diameter (Fig. 4.8). Combustion engines with four-valve system is "softer" than in engines with two-valve, since less inertia valve. This helps to reduce the noise level during operation. Details of the engine The cylinder block. In this very large and heavy site is a crank mechanism. The cylinder block is made of cast iron. Inside the unit there are channels for cooling water. Bottom block - air bearings for the crankshaft. Power for the new 5- and 6-cylinder CDI engines made of cast iron. Because of the increased mechanical stress (direct injection) blocks have complementary ribs and thicker walls. Cylinder head. Closes the top unit. It made of light alloy. As compared with a head made of gray cast iron are more likely to warp due to insufficient cooling, incorrect mounting or dismounting still hot from previous engine, but it is lighter and has higher heat transfer into the cooling system. In the cylinder head there are channels for cooling, lubrication, intake system and exhaust system. Also, it mounted seats for glow plugs, injectors, valves and tappets. The camshafts are located on top of the cylinder head. Nozzles are mounted externally on the cylinder head. On the left are the various sensors, switches and valves. Valve seats are made of hard metal. The cylinder head is made of aluminum for the engine CDI models differ, among other things by the presence of two spiral inlets. One of them is for swirls, another - for filling. Both channels correspond symmetrically made the combustion chamber and provide for a strong air turbulence before the cylinder, which helps create an optimal mixture of fuel forced air. For uniform distribution of fuel within the combustion chambers are new design nozzles located in the middle of the cylinder. Cylinders. The cylinders are embedded in the block and, together with the combustion chambers of the cylinder head form displacement. The inner walls of the cylinder hone the so-called method of grinding mesh. Bore performed on 0.02 mm larger than the respective pistons. At overhaul the engine cylinders can be sanded up to an additional 3 times, providing the appropriate repair size. Pistons. They take the pressure of the mixture and burned down by a rod transmitting force to the crankshaft. They are made of light metal. In the upper third piston disposed piston rings. Two upper ring (compression) prevent the penetration of the gases in the crankcase. Bottom (scraper) ring removes the oil from the cylinder wall. Cranks. Connecting the pistons to the crankshaft (Fig. 4.9). The head of a rod with bronze liner is connected by a free piston finger landed. The base of a rod is fixed via a support bearing cap to the crankshaft. Crankshaft. It converts the reciprocating motion of pistons into rotary. To prevent vibration during operation knee shaft have counterweights. To prevent uncontrolled oscillation or deflection at the support shaft journal bearings are mounted on the engine block. Rear (in the direction of movement) at the end of the crankshaft bearing ring is set with the ring gear to eliminate the runout of the shaft. At the front end of the crankshaft mounted gears to drive the camshaft and the oil pump and a pulley for accessory drive belt. |
Technical Dictionary Details of the engine Dual-mass flywheel. In cars with manual gearbox installed dual-mass flywheel (Fig. 4.10). It smoothes the crankshaft torsional vibrations occurring during engine operation. The front of the flywheel firmly bolted to the crankshaft 1. It is installed vibration damper 3, consisting of a system of springs and dampers. The back of the flywheel fastened to torsional vibration dampers and has no rigid connection with the front part and the crankshaft. Valves. Through them injects the fuel mixture and exhaust system. Camshaft. With four valves per cylinder and two camshafts are installed in an enclosure. A camshaft is used to drive the valve in a particular order. The moment of opening and closing is set by setting the crankshaft into position (Fig. 4.15). Timing chain is carried out by the crankshaft. Both camshafts gear are engaged with each other. The gear on the camshaft is twice teeth than the gear on the crankshaft. Accordingly, the number of cylinders camshafts have different lengths. To save weight the hollow shafts. |
Technical Dictionary Basic concepts of the engines The four principle. Inlet (Step 1): the piston goes down to the lower dead point; the inlet valve opens, air is injected into the cylinder. Compression (Step 2) extends from the piston bottom dead point to the top; the inlet valve is closed; pressurized piston compresses the air. Combustion (3rd cycle): Temperature of compression ignites the fuel, the fuel mixture by the combustion pushes the piston to the bottom dead center, the connecting rod and cranks the crankshaft. Release (4th cycle): the piston goes back up, the exhaust valve is opened, and the exhaust gases go into the exhaust system. Cylinder capacity. The volume of the cylinder in which the piston passes by the bottom dead point to the top, called the working volume. Upon reaching the top dead center of the piston remains a small space of the combustion chamber. The combustion chamber and displacement are shown in Fig. 4.16. The compression ratio. It is a characteristic relationship between stroke volume and the volume of the combustion chamber. It shows how many times the fuel-air mixture is compressed before ignition. |
A WARNING Repair of components and parts on engines require high qualifications and special tools. All work should be carried out solely on the specialized workshop. |
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