przez Wilu » wtorek, 4 mar 2003, 23:31
wyczytałem właśnie, że jest szybsza od octavi na asfalcie 2 s/km co hyba już w fazie testów jest niezłym wynikiem. czesi testowali auto w tunelu aerodynamicznym, i kształt zderzaka przedniego jest wymuszony czystą aerodynamiką i zapewnia odpowiednią wentylację brejków jak i komory silnika. boczne szyby podgrzewane, silnikowo nic się nie zmienia, no może oprucz elektroniki
zresztą czytajcie:
Škoda Fabia RS - the base for the new WRC car
To have a rally car homologated for the World Rally Championship (WRC), at least 25,000 production cars of the basic model range, with a minimum length of 3,750 mm, and at least 2,500 cars of the model from which the rally car has been derived, with a minimum length of 4,000 mm and a wheelbase of 2,440 mm, must be produced. With the Fabia WRC, this condition will be met by the production of the Škoda Fabia RS that is presented for the first time at the Geneva MotorsShow. The actual WRC rally car is then made from the basic model by carrying out extensive modifications to almost all sections. These modifications are precisely specified in the FIA regulations that are binding for all car manufacturers who enter the Championship.
Modified body
When the body of the Škoda Fabia WRC was designed, great attention was paid to giving it maximum rigidity, which significantly influences the characteristics of a rally car. The torsional rigidity of the WRC car is several times higher than that of production cars, which is, to a great extent, caused by the installation of the roll cage in the interior.
The skeleton of the Fabia WRC’s self-supporting monocoque body and its outer parts are derived from the production Fabia RS. However, they have been modified to accommodate wider tyres and to extend the wheel track of both axles, so that the car has the maximum admissible width of 1,770 mm. Also, the floorpan has been modified to enable the installation of the four-wheel drive system. Its large central tunnel has the maximum admissible dimensions and, in addition to a connecting drive shaft, it contains a heat-insulated exhaust pipe. Fuel tanks are installed under the car in the same position as in standard cars but, compared to the standard Fabia, they have double the volume (90 litres).
All aerodynamic elements such as the front bumper and the rear spoiler have been greatly modified compared to the Fabia RS. Their design is based purely on functionality and is a result of careful, extensive work in a wind tunnel. Both bumpers are made from an extremely light material and designed for the vehicle’s greater width. The size and design of the inlets in the front bumper, as well as ventilating the engine compartment, have also been optimised in the wind tunnel where the most extreme climatic conditions that can appear during a rally were simulated.
The windscreen, rear window and door windows appear to be the same as in the standard car, but all the glass has been weight-optimised. In addition, the windscreen and the front door windows are electrically heated. Heated windows are necessary in rally cars to provide perfect exterior visibility for the driver no matter what the climatic conditions.
The engine
The new Škoda Fabia WRC is driven by a later version of the engine that is used in the Škoda Octavia WRC. As with all competitors in the WRC category, it is a four-cylinder, turbocharged engine with a displacement of 2,000 cm3. The power unit used for the Škoda WRC cars is derived from the well-known turbocharged, five-valve 1.8-litre engine produced by the company. The output of engines of all car manufacturers participating in the world championship is approximately 221 kW (300 bhp). This conformity is produced by a restricting device with a diameter of 34 mm, as prescribed by the regulations, that must be assembled on the turbocharger and limits the volume of intake air. This then limits the maximum output and torque. A key criterion is the production of the highest possible output and torque in the maximum possible speed range with optimised driving response and flexibility.
An important factor is to eliminate turbo lag” i.e. reducing the engine's response time to pressing the accelerator pedal. This is carried out, among other things, by the ALS system (Anti Lag System). With the additional combustion of unburned fuel in the exhaust gas collector, the ALS system maintains the operating revolutions of the turbocharger even if the driver takes his foot off the accelerator. This sophisticated process is controlled by an engine control unit taking into account many parameters, including the revolutions of the engine and the turbocharger, temperature, ignition timing, the volume of injected fuel, ignition pressure, throttle valve position, etc. The electronic engine management system carries out many operations that are not used in standard cars. Many other operations used with standard engines have been further modified to suit the specific requirements of a rally car. These include a system of regulating engine knock designed especially for competition purposes that provides the control unit with information allowing the engine to continue making use of its maximum output without damaging it. All these sophisticated processes take place within a few milliseconds.
In order to keep the output at the maximum in extreme climatic conditions, the pressurised air cooler is sprayed with water. The water, evaporating on the cooler's surface cools the air entering the engine and helps the engine to maintain the maximum output. A tank containing 20 litres of water is installed in the car for this purpose.
The exhaust pipe, designed with the help of computer simulation and optimised on the test bench, also helps to produce the optimum output and torque. According to FIA regulations, Škoda Fabia WRC rally cars are equipped with special sports catalytic converters that keep the engines at their optimum output parameters while complying with the exhaust standards
Transmission and 4x4 drive with three active differentials
The special six-gear transmission is connected to a four-wheel drive system. The inter-axle differential and the front differential are installed in the gearbox and are electronically controlled, as is the rear axle differential. The control of the entire driving system for all wheels is carried out by a separate electronic unit that takes into account the steering angle, the speed of the car, the revolutions of individual wheels, brake pressure, throttle valve position and other parameters. Electronic communication with the engine control unit takes place through the CAN-Bus electronic interface. All data on the performance of the four-wheel drive control system received during the timed stages of a rally are stored and analysed during service intervals. Based on these results, possible imperfections can be corrected or the system can be modified according to the character of the rally.
The rally gearbox is equipped with semi-automatic gearing controlled by buttons on the steering wheel. This system allows the gears to be changed with minimum interruption of the driving force and the minimum idle period. The co-ordination of the gearing process is the responsibility of a separate electronic control unit that is also connected to the engine-management system through the CAN-Bus interface. The car also has a conventional gear lever that can be used for manual gear changes if the semi-automatic gearing malfunctions.
Next to the gear lever is the hand brake lever, which is significantly longer than the standard design and is positioned very close to the driver's hand. The difference in the actual function of the hand brake is even more significant. In addition to braking the rear wheels, using the hand brake activates a hydraulic system in the drive management of all the wheels, and the inter-axle disconnects the drive between the axles. This causes the intentional instability of the car's tail that is used, for instance, when taking S bends at high speed - in other words, for rallying’s famous hand-brake turns.
Robust chassis
The rally chassis is appropriately strengthened and reinforced with both axles supported on auxiliary frames and independent McPherson strut suspention. The front axle has robust lower triangular arms. The rear axle has a multi-member suspension that includes two cross beams and one longitudinal arm. The suspension upright is a sophisticated welded element made of strong titanium (for rallies on asphalt roads) or steel. (for rallies on gravel surface). Both axles are fitted with adjustable anti-roll bars. The suspension system includes individually adjusted shock absorbers that can be varied according to the type of roads the rally takes place on. The coil springs, consisting of main and auxiliary springs, have individually adjustable rigidity and suspension characteristics and can be changed as needed. The clearance height of the Fabia WRC can be adjusted according to the character of individual competitions and varies from 80 to 240 mm.
Ventilated brake discs, 378 mm in diameter and 32 mm thick in the front and 355 x 28 mm in the rear are used for competitions on asphalt roads. The discs used for competitions on gravel are 304 x 28 mm in the front and 304 x 25 mm in the rear. Magnesium 8.0 J x 18" wheels are used for asphalt roads, 7.0 J x 15" for gravel and 5.5 J x 16" for snow. At each service stop during the competition, the team engineers and tyre technicians, together with the drivers, select from the many tread patterns and mixtures of the special Michelin motorsport tyres.