Design Features December 19, 1996

The High-Tech Race Car: A technological Road Warrior

Markus Levy, Technical Editor

Racing IndyCar or Formula 1 cars is the ultimate adrenaline-pumping, high-tech experience, for both the participants and spectators. Drivers risk their lives in cars that have been engineered to the outer limits of technology.

Picture yourself in a high-performance, high-tech race car. Your only protection is the helmet, gloves, and fireproof driving suit you're wearing. You're strapped in a cockpit so small, you had to remove the steering wheel just to get in. You're sitting, almost lying, two inches from the ground. Now imagine driving at 245 mph in this position, traveling the length of a football field in 0.8 seconds. Imagine doing 60 on a hairpin turn and feeling your body stress to 3Gs of lateral acceleration. Imagine making a small mistake that could be your last!

Most of us will only know an IndyCar or Formula 1 (F1) race as a two-hour sporting event broadcast on Sundays. We'll never experience the countless hours of practice and testing that the driver must endure. We'll never witness the enormous efforts and anxieties of the race team that must get the car and driver to the track. But, as engineers, we can certainly appreciate the technology that drives these exceptional cars. Today's IndyCar and F1 cars, most of which are designed and built using extensive CAD/CAM systems, are tight packages of high-tech components that consist of the aerodynamic chassis, a 600- to 850-hp engine, a precisely balanced suspension system, and enough electronic computing power to equal that of a small workstation.

The heart of the car

When you remove a car's rock-hard, carbon-fiber skin, you discover an intricate system of serpentine wires, precision sensors, LCDs, electronic black boxes, and spread-spectrum wireless communications equipment (Figure 1). Collectively, this system is called the electronic control management (ECM). Contained in one of those black boxes is the engine control unit (ECU). If the engine is the heart of the car, the ECU is the pacemaker.

ECU manufacturers often team up with specific engine manufacturers to provide custom, and very proprietary, implementations. For example, Motorola supplies ECUs for Honda's engine (Figure 2), and Delco supplies the ECU for the Mercedes Benz engine used in the Penske car. The ECUs typically used in IndyCar engines come from Delco and Motorola, and F1-engine ECUs come from companies that include Magneti Marelli, Pi Research, and Delco.

The basic functions of an ECU are fuel injection (air-fuel mixing) and spark timing, whether in a race car or street car. Whereas the street car's ECU enables an engine to deliver efficient performance with the least amount of pollution, the race car's ECU ensures that the engine cranks out maximum performance without blowing up. Obviously, in racing, ecology is not an issue. However, IndyCar regulations from CART (Championship Auto Racing Teams), the national governing body for race teams, limit the amount of fuel that a team can consume during a race (because of cost rather than pollution). This amount of fuel is enough to finish a race only if the car averages a whopping 1.8 miles per gallon. The car's electronics plays an active role in helping the driver maintain that fuel- consumption rate.

Similar to any computer-controlled car, the race car's ECU uses a fuel map to determine an uncorrected air-fuel ratio. A fuel map is a look-up table of engine rpm vs manifold pressure (where manifold pressure is a function of throttle position). To get the exact air-fuel ratio, the ECU takes the uncorrected value extracted from the fuel map and plugs it into an equation where the variables are the inputs from about 30 sensors. These sensors monitor air and engine temperature, barometric pressure, oxygen content in the exhaust, turbine speed, and selected gear.

Next time you're watching a race, you may see someone in the pit lane hold up a sign that says something such as, "MAP 3D 3." That person is telling his driver to change the fuel map. An eight-position rotator switch near the steering wheel allows the driver to select from eight fuel-consumption levels. When the driver selects a different level, he is actually shifting the fuel map so the air-fuel mixture runs leaner or richer, depending on the setting. So, when the track official waves the yellow flag during a track-hazard condition, the driver can switch the fuel map to extremely lean because he doesn't need much horsepower to follow a pace car. Alternatively, if the pit crew's data-acquisition system indicates that the car's fuel level is dropping too fast, the crew signals the driver to switch fuel maps to lower fuel consumption.

Not only does the air-fuel ratio have to be precise, but the fuel injection and spark ignition must occur at precise times. Delco's Gen IV ECU, for example, contains a Motorola 68332 derivative plus two Delco-developed timing processors. The timing processors, which offload the main processor, keep track of when the fuel injection and spark times occur. Unlike conventional engine controllers, Delco's Gen IV uses a capacitive discharge ignition module and replaces a mechanical distributor with a distributorless ignition module. This module sends an ignite signal to the engine's eight spark plugs 30 times per second at 13,500 rpm. Rather than having individual wires running to each plug, ignition coils are located at each plug, which increases reliability and performance.

The operation of the ECU is further complicated by the fact that the engine is turning at 13,500 rpm. With engine speeds this high, there is a precise balance between reliability and blowing up the engine. The car's engineers must be careful even when making subtle changes anywhere on the car, because surprising things can happen when the car hits 200 mph.

For example, let's say that a car is on the Indianapolis Speedway, and the driver reports that the car starts to drift when it reaches 230 mph. To compensate for the drift, the engineers change the wing position by a few millimeters to increase the downforce. The car goes back out, and, although it tracks well, the pit crew notices that the engine starts running warmer. That small aerodynamic change has diverted air away from the radiator. The ECU compensates for the hotter running temperature by making the air-fuel mixture richer (saturating the engine) and producing a suboptimal burn. This process in turn lowers the miles per gallon and may prevent the driver from finishing the race.

Another feature of race cars that you won't find in any street car is a custom steering wheel, which features molded comfort grips and costs between $2000 and $5000. In IndyCars, the buttons on the steering wheel include a radio-talk button, a passing switch that raises the revolution-limiter by 200 rpm, and a pit-lane limiter. With the pit-lane limiter activated, the driver can leave his foot flat on the throttle, and the ECM cuts engine power so the car maintains the preprogrammed pit speed limit (the speed limit imposed by track authorities to ensure pit safety). This technique works very well for leaving the pit, and, as long as the driver points the car in a straight line, the engine delivers the full horsepower when the driver releases the pit speed limit. Delco's pit-lane limiter also has a push-and-no-hold capability. Before the race, the pit team calibrates the distance in and out of the pit and programs it into the ECM. When the pit lane is over, the ECM's push-and-no-hold function automatically releases the pit-lane limiter.

Some of the F1 steering wheels are even more sophisticated. In addition to the functions on an IndyCar wheel, F1 steering wheels can include an integrated information display, a button that engages neutral in the transmission, a gear-change paddle, and the clutch. The wheel also has a set of sequential lights that indicate that the engine is approaching its maximum rpm, so the driver can be ready when the lights signal him to change gears. A knob at the bottom of the wheel controls brake bias toward the front or rear. Another knob selects different programs for the electronic throttle.

Another interesting innovation used in some F1 cars, such as the Tyrrell team car, is the "fly-by-wire" electronic throttle--there is no cable between the engine and throttle pedal. (Most teams use a hydraulic actuator.) The electronic throttle uses different pedal-position programs, so there doesn't have to be a constant relationship be-tween pedal and throttle amount, which mechanical linkage normally requires. The system uses two linear variable-displacement transponders (LVDTs) attached to the pedal. Information from the LVDTs is fed into the ECU, which determines how much throttle to apply based on the steering-wheel knob setting. This technique makes it easier for drivers to apply the throttle in adverse conditions, such as a wet track.

F1 cars also use a semiautomatic gearbox; the driver shifts using the gear-change paddle on the steering wheel. The shifting mechanism, which is linked to the ECM, allows the driver to shift without lifting the throttle as the ECM momentarily cuts power to the engine during the gear change. The mechanism also prevents mis-shifts; on downshifts, the semiautomatic gearbox denies shifts if the car speed is too high for the requested gear. The shifting mechanism works with the fly-by-wire throttle to automatically "blip" the throttle (a quick rev) to the correct engine-revolution limit, thereby preventing damaged cogs and minimizing tire chirp on a downshift. F1 cars used to have a feature that allowed the engineering team to program the race course into the car's computer, which would then automatically select the gear based upon track location. However, the International Motor Sports Federation (FIA), the F1 regulations committee, banned this feature, along with other innovations, because it seemed that the car was driving the driver.

IndyCar regulations do not permit semiautomatic gearboxes because of the cost. Instead, IndyCar drivers must manually shift gears on the $100,000 gearbox (about half the cost of an F1 gearbox). As with F1 cars, IndyCar drivers can shift without using the clutch and with the throttle on; a shift takes about 100 milliseconds. When the driver pulls on the shifter, a proximity switch cuts the ignition and unloads the engine, letting the gearbox components move into place.

Today's IndyCar and F1 cars are also equipped with two-way voice-communications systems, and they can transmit real-time performance data back to pit row. These cars are essentially wireless computer networks that collect data from more than 100 electronic engine and chassis sensors. Typically, one race weekend can produce as much as one gigabyte of data per car, from qualifying rounds up to the finish.

Pi Research is the primary supplier of data-acquisition hardware and software for the racing community (Figure 3). The company's tools include chassis sensors, transmitters, receivers, the motor racing computer (MRC), and the dashboard display. Chassis sensors monitor functions such as airflow; loading and wheel speed for each wheel; wheel-bearing temperature (especially important on high-speed ovals where outer-wheel pressure is excessive); shock deflection; ride height; steering input; brake pressure; forward and lateral gravitational pull; and miscellaneous temperatures, including brake and tire temperatures. The Pi system has a connector that allows the car's engineers to plug in signals coming from the engine. The system generates more than 1000 direct and derived parameters that allow the engineers to continually monitor and fine-tune the car. This fine-tuning may improve the car's speed by as much as 0.1 seconds per 2.5-mile lap--the difference between first and second place.

Data-acquisition systems use two types of telemetry to transmit data from the car back to the pit: real time and burst. The systems typically use spread spectrum in the 900-MHz range for interference-immune, real-time data transfers (critical engine and chassis functions); however, a few F1 cars are starting to use microwave for higher bandwidth. The real-time telemetry system continuously transmits data as the car goes around the track and uses sophisticated error-correction algorithms to ensure reliability.

The burst telemetry system transfers data to an infrared beacon receiver when the car passes the pit lane. The system automatically sets up the Pi data-system marker when the car first passes the pit-lane beacon. From then on, the system knows within a certain window when the beacon is present to receive the burst data. The pit team plots this data using Pi analysis software to determine functions such as the aerodynamic downforce as the car goes around the track. Finally, when the car comes into the pit at the end of a race, engineers rush out to the car and plug in their notebook computers to download information from onboard RAM. They will use this information to scrutinize every possible action of the car to help improve performance.

Although the general public only sees the sporting side of racing, behind every successful IndyCar and F1 race team is a successful, highly technical business. Besides the driver and car, this business includes, but is not limited to, a marketing department; manufacturing, research, and development; pit crews; mechanics; and perhaps most important, sponsors. (The Benetton F1 team even employs 11 additional people to clean the factory floor.) Furthermore, as the IndyCar and F1 businesses get more high tech, so too do the sponsors. Sponsorships are evolving from cigarette manufacturers (which laws may eventually force out) to high-tech companies that include Motorola, Hewlett-Packard, Sun Microsystems, and Delco.

In addition to financial backing, these high-tech sponsors are playing an active role in providing the support and technology that help drive the cars. For example, Motorola sponsors the Brix Comptech Race team and provides many of the car's electronic components. These components, leveraging Motorola's expertise in com- munication equipment, include the car-to-trackside data- and voice-communication equipment, a wireless LAN PDA (personal digital assistant), and an alphanumeric pager.

You may wonder why Brix Comptech's driver, Parker Johnstone, needs a pager. According to IndyCar regulations, all teams must use the same channel for radio communication--hardly a way to send strategic messages during a race. Using the alphanumeric pager taped to the cockpit display, the pit team can send Johnstone a message, such as "Pit next lap" or "Increase rpm limit."

Hewlett-Packard (HP) is another high-tech company that plays a hands-on role in racing. The sophistication of data processing and the growing use of CAD for car development have required race teams to install complex computer networks and servers. HP provides Team Rahal (IndyCar) and, to a greater extent, Team Jordan (F1), with a highly integrated, custom communications infrastructure that links laptops and desktop units at headquarters, trailers, and trackside pits into a cohesive client/server environment containing both Unix and NT servers. HP's commitment to these teams also includes around-the-clock support services to maintain and upgrade the equipment, as well as an engineer on site during a race.

When HP began its sponsorship of the Jordan team, it immediately noticed that the team's CAD equipment was inadequate to keep up with the quick time-to-market needs of F1 teams (this time can be as little as two weeks--the time between races). For example, when an engineer was developing a new part, the server would have to run computations for three hours. So HP installed its K420 multiprocessing server (about $110,000) so that Jordan's engineers could more efficiently run a program called Fluent. Fluent is aerodynamics software that simulates a three-dimensional wind tunnel. The software, which requires a massive amount of computing power, takes into account properties such as surface frictions, turbulent flow, and other aerodynamic qualities. If you consider all the aerodynamic components of an F1 car, they represent an incredible amount of data to process. Fluent saves the team many hours in the wind tunnel (at $40,000 an hour) and reduces the number of hard models they must build and test.

Every year, CART and FIA impose more restrictions on race cars in an attempt to slow the cars down and, therefore, make them safer. However, racing is racing, and engineers will always rise to the challenge of exploiting the rules to design the best of class. As long as there is car racing, there will always be improvements in technology. So, next time you see a driver zoom around a track at breakneck speeds and capture a new world record, remember that the both the driver and the car's engineers deserve the credit.

Satisfy Your Need For Speed

Formula 1 (F1) and IndyCar racing is an elite sport that only a handful of drivers will ever experience. After all, not many people have the nerve or the annual budget of at least $10 million (some top F1 teams budget over $100 million annually). Put another way, it costs about $40,000 an hour to run one of these high-tech cars. But there is a way for you to become more than just a passive observer, and for only a fraction of the cost of professional racing. The Skip Barber and Jim Russell racing schools will put you behind the wheel of a Formula Ford-style car. Although it's a low-tech vehicle, it's enough to let you feel a few Gs as you whip through the turns. Both schools offer half- and three-day race classes that cost $500 to $2500. You'll learn techniques for cornering, braking, and balancing the car (a lesson I learned the hard way when the car I was driving plowed into the tire barrier). Even if you decide not to pursue racing as a career, these classes will give you a deep appreciation of what the F1 and IndyCar drivers experience. Be careful, though--this sport is addictive. Skip Barber School Lakeville, CT (800) 221-1131 www.albany.edu/~gr643 /index.html Jim Russell School Sonoma, CA (709) 939-7600 www.russellracing.com

References

1. Sakkis, Tony, Anatomy and Development of the Indy Car, Motorbooks International, Osceola, WI, 1994.
2. Bennett, Chris, with Oliver Holt, Behind the Scenes with Benetton Formula 1 Racing Team, Motorbooks International, Osceola, WI, 1995.

Acknowledgments
Special thanks to Dan Levens of the Brix Comptech Motorola team, who spent countless hours explaining every nook and cranny of the IndyCar to me. Thanks to Geoff Banks of Hewlett-Packard for his knowledge of F1 cars. Thanks to the Skip Barber and Jim Russell racing schools for the opportunity to experience the race-car thrill.

You can reach Technical Editor Markus Levy at (916) 939-1642, fax (916) 939-1650, e-mail markuslevy@aol.com.

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