1. Four-cylinder engine with a displacement of 2.0 liters and a power of 66 kW (90 l. With.)
2. Four-cylinder engine with a displacement of 2.0 liters and a power of 85 kW (115 l. With.)
3. Five-cylinder engine with a displacement of 2.3 liters and a power of 98 kW (133 HP)
4. Six-cylinder engine with a displacement of 2.6 liters and a power of PO kW (150 HP)
5. Six-cylinder engine with a displacement of 2.8 liters and a power of 128 kW (174 HP)
Four-cylinder engines are a modification of the previous models of power units installed on earlier AUDI cars. The increase in the working volume of these engines to two liters favorably affected the torque. Both engines differ in the way they prepare and inject the fuel-air mixture. If the engine is 66 kW (90 HP) consumes unleaded gasoline with an octane rating of up to 92 according to the research method, and the injection is made through a single nozzle under the throttle valve, then its 85 kW variant (115 HP) has a Digifant injection system. In this case, Euro Super gasoline is injected into the combustion chamber of each cylinder by valve injectors. The selective control of the knocking combustion of the air-fuel mixture in the combustion chamber of each cylinder of this engine allows the use of conventional gasoline with an octane rating of up to 92 according to the research method without damage to the engine.
In addition, there were some innovations. This time it is a tensioner pulley that is resistant to changes in engine temperature and holds the toothed belt at a constant tension. The valves of both engine models are driven by maintenance-free hydraulic tappets.
Four-cylinder engines have an overhead camshaft. The valves are driven through poppets. The oil pump is driven by an intermediate shaft. The drive is carried out from the camshaft and intermediate shaft by means of a toothed belt.
The five-cylinder in-line engine with a volume of 2.3 liters has become more perfect. It is also equipped with a toothed belt tensioner that is resistant to changes in engine temperature. This engine has a KE-III-Jetronic fuel injection system and an ignition system controlled by an electronic unit, which contains the nominal values determined during the tests. Selective control of the knocking combustion of the air-fuel mixture allows optimal consumption of gasoline with an octane rating of 96 - 98 according to the research method at a compression of 10.0: 1. It is allowed to refuel with gasoline with an octane rating of up to 92 according to the research method.
The camshaft is driven by a toothed belt, as with four-cylinder engines. The valve drive is also performed by poppet pushers. A toothed belt also drives the water pump.
Of particular interest is the design of the crankshaft of a five-cylinder engine. The connecting rod journals of the crankshaft are located at an angle of 72°relative to each other, and the shaft itself has two counterweights for each cylinder. In addition, a special unbalance on the flywheel and a vibration damper located next to the flywheel provide damping of residual vibrations.
The V6 engine has an automatic multiport fuel injection system and a filament air mass meter. The system injects fuel into the combustion chamber of each cylinder, which ensures economical fuel consumption and reduces the content of harmful substances in the exhaust gases. Selective air-fuel combustion control is monitored by two knock sensors, which in turn prevents engine damage when lower octane fuel is used.
The V6 engine has two overhead camshafts driven by toothed belts. The camshaft valves are controlled by poppets. A sufficiently large intake manifold is located in the space between both rows of cylinder heads.
A feature of the 2.8L V6 engine is the intake manifold with a variable internal cavity configuration, which provides high torque over a fairly wide range of engine speeds. For this purpose, six dampers are installed in the intake manifold of the V6 engine, driven by reduced pressure and, depending on the number of engine revolutions, closing or opening the openings of the manifold pipes and thereby changing their active length. At engine speeds up to 4000 rpm, the flaps remain open, forming a so-called long intake manifold to ensure high torque. At engine speeds above 4000 rpm, the dampers close, as if shortening the intake manifold pipes, which at the same time increases the effective engine power (see illustration 2.0). The maximum torque of 245 Nm is achieved by the V6 engine at 3000 rpm with Euro Super petrol. When refueling with Super Plus petrol, the maximum torque is 250 Nm.
The ignition system of the V6 engine does not have a mechanical ignition distributor and is controlled by an electronic unit.
Exhaust gases from the left and right rows of cylinders are fed to two independent catalysts. Two heated lambda probes, also functioning independently of each other and included, respectively, in the left and right rows of cylinders, ensure the emission of exhaust gases with a minimum content of harmful substances.
The 2.6L six-cylinder engine with a modified MPFI fuel injection system has an intake air mass meter that is structurally different from the 2.8L engine. In addition, it does not have a reconfigurable intake gas line. However, with regard to power characteristics, these differences did not affect them in any way and amount to 110 kW at 5750 rpm, and the torque is 225 Nm at 3500 rpm.
All AUDI 80 vehicles are fitted as standard with a five-speed manual gearbox. Four models with front-wheel drive and gasoline engine are equipped as a special equipment with a four-speed automatic transmission with two programs: «E» (economy mode) And «S» (sports mode).
All AUDI power units provide mileage over 100,000 km without any problems. For diesel engines, mileage can be at least 130,000 km, especially if operating conditions allow for a minimum of cold engine starts and the owner does not abuse high speeds. Driving style and engine care also affect the service life. With regard to care, regular replacement and the use of only the engine oil prescribed by the manufacturer are of particular importance. If no mechanical damage was observed on the diesel engine during operation (destruction of the valve, piston, connecting rod), then with the approach to the above run, one should reckon with the appearance of difficulties when starting the engine during the cold period of operation.
An internal combustion engine operates at maximum efficiency only at a certain number of revolutions - the so-called nominal speed. Exceeding the rated engine speed has no effect. The increased engine speed is only useful when shifting to a higher gear.
AUDI engines are designed to withstand high engine speeds. The valves are actuated by poppets directly from the overhead camshaft. This means that relatively small masses are involved in the gas distribution process and, therefore, high revolutions are quite easily tolerated by the engine if this occurs for a short time. The engine speed can be brought up to 6300 rpm for a while. In this state, the noise from the engine becomes unbearable.
The engine speed limit is limited to approximately 6700 rpm. Going beyond this value leads to such an increase in the oscillations of the valve springs, which excludes the perfect opening and closing of the valves. The valve spring may break and the corresponding valve may break the piston.
For this reason, all AUDI engines are equipped with a speed controller, which, when the engine reaches a certain speed range, limits its further increase by cutting off the fuel supply. Therefore, if at high speeds the engine suddenly starts to work with gaps, then the reason for this is not a malfunction of the engine, but the operation of the protection, namely, the engine speed controller.
The crankshaft of a four-cylinder engine has five main bearings, while a five-cylinder engine has six. The crankshaft mount for six-cylinder engines has its own features due to space savings. The crankshaft of this engine has four main bearings, which means that between the two bearings there are two connecting rod journals, and not one like in four-cylinder engines.
Gasoline engines of cars with a manual transmission are started using a starter, the gear of which engages with the teeth of the flywheel gear. In connection with the flywheel, the clutch mechanism and gearbox work. Vehicles with automatic transmission have a clutch disc with a torque converter instead of a flywheel. At the front end of the crankshaft are the toothed belt drive gear and belt pulley.
2.0a Four-cylinder gasoline engine in section
1 - Camshaft
2 - Hydraulic pushers
3 - Toothed belt tensioner
4 - Piston
5 - Toothed belt
6 - Intermediate shaft
7 - Belt pulley of the crankshaft
8 - Water pump
9 - Cylinder head cover
10 - Spark plug of the fourth cylinder
11 - Ignition distributor
12 - Connecting rod
13 - Oil pump
2.0b Five-cylinder gasoline engine in section
1 - Piston
2 - Valve
3 - Hydraulic pusher
4 - Camshaft drive gear
5 - Camshaft
6 - Cylinder head
7 - Cylinder block
8 - Oil pan
9 - Crankshaft
10 - Intake pipe of the oil pump
11 - Oil pump
12 - Crankshaft timing gear
13 - V-belt pulley of the crankshaft with vibration damper
2.0v Six-cylinder V-shaped gasoline engine in section
1 - Intake manifold pipe
2 - Ignition coils
3 - Toothed belt
4 - Ribbed belt
5 - Belt pulley of the crankshaft with vibration damper
6 - Oil pump
7 - Intake pipe of the oil pump
8 - Crankshaft
9 - Connecting rod
10 - Piston
11 - Hydraulic pusher
12 - Valve
13 - Camshaft
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