Developing powertrains for the next generation «fours», the manufacturer has worked hard to improve internal combustion engines. Their inventor, Otto, would certainly have liked it. For the first time in this series, two completely new gasoline engines with an aluminum crankcase are used: a four-cylinder in-line engine with a power of 96 kW (130 HP) with a displacement of 2.0 liters and a six-cylinder V-engine with a power of 162 kW (220 HP) with a working volume of 3.0 liters. The proven 110 kW Turbo engine completes the petrol engine program (150 HP) with a displacement of 1.8 liters and a revised engine with a power of 75 kW (102 HP) with a working volume of 1.6 liters.
The Avant large-capacity variant was powered by 2.4L engines until the premiere of the new model in July 2001 (165 HP) and 2.8 l (193 HP). Now, the new A4 Avant uses the same petrol engines as the sedans that received them in October 2000, meaning the Avant comes with a new 1.6L engine.
With the exception of this 1.6-litre base engine, Audi relies on five-valve technology to speed up gas exchange in petrol engines. Two intake and three exhaust valves are designed to provide better gas flow. It is clear that more gas mixture passes through three valves at the same time than through two or one valve. Cylinder filling per intake stroke is greatly improved.
3.0L ASN 6-cylinder V-engine
Details of the six-cylinder five-valve V-twin engine with a displacement of 3.0 liters: 1 - rod oil level indicator, 2 - pulley for driving the steering pump, 3 - V-ribbed belt, 4 - generator, 5 - toothed belt, 6 - vibration damper, 7 - oil pan, B - oil filter, 9 - pulley for the compressor air conditioner, 10 - crankshaft, 11 - exhaust camshaft, 12 - single spark ignition coil, 13 - intake camshaft, 14 - oil filler neck, 15 - variable geometry intake gas pipeline.
If we ignore the main concept, i.e. arrangement of rows of cylinders at an angle of 90" relative to each other and the identical bore of the cylinders, it can be said that the new best engine uses not so many components from the previous engine with a displacement of 2.8 liters. The six-cylinder V-shaped five-valve engine accelerates the A4 front-wheel drive sedan with a five-speed manual transmission from 0 to 100 km / h in 6.9 seconds. Top speed is 245 km/h, average fuel consumption for this version is only 9.5 liters.
The most important innovation in this engine is the aluminum cylinder block (thanks to this, the engine weighs only 163 kg), lighter pistons, balance shaft, continuously variable intake camshaft, variable exhaust camshaft, new variable geometry two-stage gas line and Bosch-Motronic ME 7.1.1 engine control with electronic accelerator pedal.
Power and torque vs. RPM of a 3.0L six-cylinder, V-shaped, five-valve engine
The intake camshaft can be continuously adjusted up to 42' in the pre-ignition direction. On the exhaust side, if necessary, the camshaft can be adjusted by 22' in the direction of late ignition. Already at 1900 rpm, the system sets the maximum overlap, this allows you to achieve the maximum possible torque. The maximum torque of 300 Nm in this case is already generated at 3200 rpm. In the range from 2200 to 5200 rpm, 90% of the maximum torque is provided.
Along with ingenious camshaft adjustment, the ASN engine features a newly designed two-stage variable geometry intake manifold. Starting from 4200 rpm, the resonant intake manifold switches to a short path. Maximum power 162 kW (220 HP) provided at 6300 rpm.
2.0L ALT engine
2.0L Engine Parts (5V): 1 - single spark ignition coil, 2 - intake camshaft, 3 - hydraulic tappet, 4 - toothed belt tensioner, 5 - toothed belt, 6 - piston, 7 - vibration damper (crankshaft pulley), 8 - V-ribbed belt, 9 - steering pump pulley, 10 - crankshaft, 11 - variable geometry intake gas line, 12 - oil level gauge, 13 - injector, 14 - intake camshaft drive chain, 15 - exhaust camshaft, 16 - spark plug
As the second newcomer to the range of petrol engines, Audi has introduced the 1984 cc3 inline engine. This five-valve engine with an aluminum cylinder block and counterbalance shafts for improved running accelerates the A4 Sedan from 0 to 100 km/h, also in less than 10 seconds. The maximum speed is 212 km / h. Considering that the fuel consumption is only 7.9 liters, it can be argued that this engine will compete with other power units. Testers commend this engine for revving very well, and revs are not accompanied by unpleasant vibrations.
Key technical innovations highlighted by the manufacturer include continuous intake camshaft adjustment to achieve optimal engine filling, a program-controlled cooling system to increase efficiency, a new two-stage intake gas line with variable duct geometry to provide more torque and high power, as well as balancing shafts to improve engine performance.
2.0L FSI engine with gasoline direct injection
The 2.0-litre four-cylinder engine has been selected by Audi to move to a new generation of gasoline direct injection engines (FSI). The cylinder block and dimensions of the FSI engine correspond to those of a conventional engine with the same displacement. New is only that it has a fuel injection system with a common fuel line and a single-plunger injection pump. In the cylinder head, unlike Audi engines with injection into the intake manifold, there are not five, but four valves. This freed up space for the injector, which dispenses fuel with millisecond precision at an injection pressure of 110 bar. The four-valve cylinder head has a gas distribution mechanism with valve drive through rocker arms and roller tappets. The variable geometry inlet gas line in the FSI engine is also two-stage, that is, the intake tract can have different lengths for high and low speeds. The constant adjustment of the intake camshaft in this engine also ensures proper control of the valve opening times.
Power and torque versus speed for a 5-valve FSI engine with a displacement of 2.0 liters
The MSI engine also uses two catalytic converters to clean the exhaust gases. Behind the exhaust manifold near the engine is a three-way staged catalytic converter, and in the lower part of the body is a storage catalytic converter, in which nitrogen oxides are accumulated and converted. The storage converter is designed to meet the special requirements associated with the characteristics of a direct injection engine. This neutralizer binds nitrogen oxides in the barium layer.
1.8L AVJ turbocharged engine
Proven 1.8L turbocharged engine
The 1.8-litre turbocharged four-cylinder engine, which is the classic engine of the previous generation, has also been taken into account in the creation of the new A4 models. The engine has been tested a thousand times. This unit is valued for its high torque (210 Nm), which, thanks to the turbocharger, is already created at low speeds (1750 min-1). Up to 4600 rpm, this moment does not change. In this way, the maximum torque is ensured throughout the entire rev range, which is mainly used during driving. This power development is usually found only in engines with large displacement.
The high torque of the 1.8 liter turbocharged engine is ensured by the turbocharger even at low engine speeds
Front-wheel drive A4 1.8T with manual gear shifting consumes only 8.2 liters of gasoline per 100 km «Super» (95 octane unleaded gasoline). Acceleration from 0 to 100 km/h with this engine is achieved in just 8.9 seconds. The maximum speed is 222 km/h.
ALZ engine with a working volume of 1.6 liters
High-torque, eco-friendly engine: 1.6L base engine (general view of the engine compartment)
A large amount of mental labor was required to create the base engine with a displacement of 1.6 liters. Thanks to a new low-friction roller rocker valve train and the fine grinding of many components, the two-valve engine is more powerful and less polluting. The four-cylinder in-line engine has an overhead camshaft, the maximum power is 102 hp and the maximum speed is 190 km/h. Like the 8 other motors controlled by Bosch Motronic ME, ME 7 is now used for electronic motor control. Earlier ALZ models are equipped with the proven Simos 3.4 from Siemens.
Model | Working volume (see3) | Power (kW/hp) |
4-cyl. 2-valve ALZ 1.6L engine | 1595 | 75/102 |
4-cyl. 5-valve AVJ 1.8L turbo engine | 1781 | 110/150 |
ALT 2.0 l | 1984 | 96/130 |
6-cyl. V-shaped 5-cl. ASN 3.0L engine | 2976 | 162/220 |
Engine identification
You can find out which engine your car is equipped with from the table with the characteristics of the vehicle, which is available in the service book, and, of course, from the official documents for the car. The most reliable way to identify an engine is to look for the engine code on the cylinder block or where the engine and gearbox are separated (i.e. ASN, ALT, AVJ or ALZ). Somewhere in these places you will definitely find embossed letters. For complete identification, the serial number of the unit is also required. The following sketches show where to look.
Engine number (engine code and serial number) in a four-cylinder engine with two valves, it is located at the front left at the junction of the engine and gearbox.
Engine number for a four-cylinder engine with five valves (displacement 1.8 turbo or 2.0 L) located on the rear left side of the cylinder block.
Engine number for a six-cylinder engine with five valves (3.0 l) embossed on top front (between cylinder head and hydraulic pump). In addition, the letter designation is located on the left rear of the cylinder head. The ASN designation can only be seen after some manipulations. To do this, you must at least remove the front engine cover. There is a sticker with letters and a number on the housing of the vacuum diaphragms for adjusting the intake gas line. If not, remove the rear engine cover so you can see the lettering on the cylinder head. If you need to know the full engine number, after unscrewing the two screws and removing the pressure spring, remove the vacuum diaphragms and set them aside with the pipes attached. After that, the corresponding designation can be seen on the cylinder block.
Engine parts
Cylinder block. Moving parts are placed in the cylinder block. In addition, the cylinder block serves as a support for such units as the generator, starter and ignition system.
Cylinder head. The cylinder head covers the cylinders from above. It contains intake and exhaust passages, water passages, valve seats, bearings and guides for valve timing parts, as well as spark plug threads and a combustion chamber. The gasket between the metal surfaces of the cylinder head and the cylinder block prevents air and coolant from entering the cylinders.
Cylinders. The cylinders together with the cylinder head form the combustion chamber (working cavity). They are polished smooth (honed) and precisely matched to the piston diameter. Cooling is provided by water that flows through the channels that are present in the cylinder wall.
Pistons. The pistons take the combustion pressure and transfer it through the connecting rods to the crankshaft. The main parts of the piston include the piston crown, the piston ring belt and the piston pin boss. Two top piston rings (O-rings) prevent gas from escaping from the combustion chamber into the cylinder block. bottom ring (oil scraper ring) diverts excess lubricating oil from the cylinder wall back into the oil pan.
Connecting rods. The connecting rod connects the piston to the crankshaft. Connecting rod components: connecting rod head (covers the piston pin), connecting rod, connecting rod end and connecting rod cap (covers the crankpin).
Crankshaft. Converts the up and down movement of the pistons into rotational movement. Crankshaft parts: main journals (to support the cylinder block), connecting rod journals, cheeks of the crankshaft (connect the connecting rod journals to the main journals).
Valves. Fresh gas enters the cylinders through the intake valves, and exhaust gases are released into the exhaust pipe through the exhaust valves. The set of all the parts that are involved in opening and closing the valves is called the valve mechanism.
Camshaft. The camshaft opens and closes the valves at the appropriate time. Each valve is cam driven via a poppet or roller rocker. The camshaft is driven by a toothed belt from the crankshaft.
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