The 2014 Audi R18 e-tron quattro is the most complex race car created in Ingolstadt and Neckarsulm to date. This not only applies to the mechanics as the electronics of the most recent LMP1 race car to wear the four rings is more sophisticated than ever before.
Audi first used electronic data transmission from the race car on track began in 1989. At that time, an Audi 90 quattro in the IMSA GTO series radioed eight parameters to the garage where engine speeds and a few pressures and temperatures were plotted on printouts – a tiny step from today’s perspective, but one that provided important insights at the time.
Today, an Audi R18 e-tron quattro generates data of crucial importance to a staff of engineers at Audi Sport on more than a thousand channels, in cycles that in some cases only amount to only milliseconds. At Le Mans, the engineers constantly monitor their race cars for 24 hours. Whether it concerns the functionality of the systems, compliance with the regulations or information that is important for strategic reasons, the race car – similar to a medical EKG system – continually diagnoses its condition and reports its health and operation to the team garage.
To achieve this, the R18 is equipped with an array of CAN-Bus systems which interlink a wide range of electronic control units (ECUs). Sophisticated digital sensors measure parameters, such as suspension and acceleration data, temperatures and pressures, or information regarding energy management in line with the new regulations, to generate a database for the ECUs. The R18 e-tron quattro has a master system control unit that is primarily responsible for engine and hybrid control and additionally communicates with the other control units in the race car – such as the ECUs for the transmission, clutch actuators, windscreen wipers (yes, they really DO have sensors on the wipers!) and the laser beam headlights.
The race car has a direct online connection to the computers in the team garage. This facilitates high-speed data transmission in real time for operating conditions, such as temperatures, that do not require a high transfer rate. This makes it possible to effectively transfer limited data volumes for a general assessment of the car’s condition. In contrast, during each race lap the car gathers detailed data and then transmits it via a burst signal as it drives past the pit lane. Data volumes of more than 20 megabytes are generated per lap, depending on the measurement configuration – equating to more than 10,000 A4 size pages.
Bi-directional data transmission is prohibited by the regulations, data may be transmitted from the car to the pits, but not vice versa. Radio communications with the race driver in the car is the only way which the team has to influence the car. If there is a need for action based on the engineers’ data analysis this information – such as brake balance, engine control or hybrid system settings – is communicated to the driver by radio. If necessary, alternative program versions stored in the car may be selected by the driver.
In addition to all of this technical data, there is a telemetry system for the officials of the FIA (Fédération Internationale de l’Automobile), which together with the ACO (Automobile Club de l’Ouest) monitors compliance with the regulations: Is the hybrid system within the prescribed amounts of energy? Is the energy consumption of the race car within the prescribed range? Are the boost pressure parameters correct? Does the cockpit temperature remain within the permissible limits?
In addition to the telemetry, and new for 2014, the FIA uses a GPS system to measure whether or not a race driver complies with the speed limit in critical situations, such as caution periods at the scene of an accident and the position of the race car can be tracked on a map of the circuit in real time. Activities of the marshals (in marshaling areas to secure accident scenes, for example) are also displayed in the cockpit. This provides the driver with assistance that enhances the safety of all the participants. Consequently, a modern LMP1 race car is constantly and comprehensively connected with the team and with race control.