Audi A4

since 1994 release

Manual of the car

In 1972 the Audi 80 model was for the first time presented. Since then came 4 generations of models from Ingolstadt to the market. All of them could win the strong place in the market thanks to solid technology and unostentatious appearance, it is proved also by statistics of the admission of vehicles. A4 in any relation is the proof of it and the worthy successor.

The tradition obliges

In 1972 automobile plant in Ingolstadt, having released Audi 80 which thanks to the easy design and the compact sizes, comfortableness and spaciousness of salon and a luggage carrier, and also to modern engines and a model running gear established the high standard of the car of middle class. The Audi A4 which is carrying on traditions of Audi 80 came to the market in November, 1994. In the following Audi model consciously refused the large-size external sizes. Nevertheless thanks to skillful use of space, increase in a track and wheel base it was succeeded to improve considerably for sitting in salon the attitude of internal length of a body towards base.

Engines

Along with two new five-valve engines with a working volume of 1,8 l, in Audi A4 the processed four-cylinder two-valve engine with a working volume of 1,6 l with newly the head of the block of cylinders designed for A4 with the cross movement of a stream of air is offered. Besides, also two engines already known on Audi 80 are used: V6 with a working volume of 2,6 l and 2,8 l. Everyone it:

• the four-cylinder engine with the 74 kW working volume of 1,6 l
• the four-cylinder five-valve engine with the 92 kW working volume of 1,8 l
• the four-cylinder five-valve engine with a working volume of 1,8 l and with the 110 kW turbo-supercharging
• V6 with a working volume of 2,6 l and 110 kW
• V6 with a working volume of 2,8 l and 128 kW

At such gradation the possibility of the choice between two power plants of identical power because as the four-cylinder engine with a working capacity of 1,8 hp a turbo-supercharging, and V6 with a working volume of 2,8 l have with an identical capacity of 110 kW is of interest. At the identical power there are distinctions in conceptual characteristics: depending on what for the buyer is priority in the engine a choice between the increased profitability or bigger comfortableness and smoothness of the course can be made.

Technology of the five-valve engine

Engine capacity along with various parameters, for example working volume and speed, considerably depends on that, gas exchange how fast can be carried out. The more fresh gas for the same unit of time can get to the combustion chamber, the more intensively a power exit. The majority of Audi engines has the long course, it means that the piston stroke is more, than diameter of the cylinder. Engines with the long course allow to create short designs, they it is easier than engines with the short course, have smoothness in work, especially idling, and differ, first of all, in the fact that already on low turns reach the maximum torque.

Filling of the combustion chamber depends, first of all, on the opening and closed valves and sections through passage in valves and channels of a head of the block of cylinders.

Three inlet and two final valves, i.e. in the sum five on each cylinder, provide the maximum section through passage. It follows from the area of a plate of the valve and size of the course of its opening. In comparison with widespread multivalvate concepts the five-valve technology in engines with the long course gives the greatest possible advantages from the point of view of intensity of filling of cylinders.

At the same time the technology of the five-valve engine allows a combustion chamber form with the central arrangement of a spark plug, and at the expense of it the short way of a spark of ignition for ensuring bystry, effective combustion of working mix is possible. At the same time also danger of a detonation decreases, and at the expense of a high compression there is possible an intensive use of fuel. Combustion of working mix in the five-valve engine is carried out "more softly", than in two - and four-valve engines. As because of the bigger cross section of valves of force, putting them in action, much more weakly, in general during the operation of the five-valve engine pleasant acoustics is created.

Five valves are put in action by two cam-shafts directly by means of hydraulic tarelochny pushers. How long it is accepted in Audi, the gap of valves is not regulated.

The inlet cam-shaft serves three valves on each cylinder, a final cam-shaft – on two. Both cam-shafts are connected among themselves by means of a chain, the drive from the crankshaft is provided with a gear belt.

Philosophy of adjustment of the engine

The high density of traffic on our streets demands other concept of the engine different from that that existed in the 80th: not the size of the maximum power, but balance of fuel consumption, the range of the offered capacities, character of exhaust gases and noise is in demand. The engine design chosen by Audi with powerful torque in the lower range of frequency of rotation allows the movement on low turns and, therefore, noticeable decrease in fuel consumption.