[Engineering Feature]
The Indianapolis 500 Electronic Edge
IndyCar Series race cars all must use the same engine and semi-automatic transmission, so teams look to electronics and telemetry to give them the extra advantage needed for a trip to victory lane.
The team can’t adjust the shifting mechanism and parameters, but it can modify the gear ratios. Changing the ratios takes five to 10 minutes. Teams often change them during practice sessions (but almost never during a race) to determine the optimal combination for a particular session, since everything such as humidity and temperature can affect how a car will handle. Selecting the right gear ratio is one way to improve a team’s chances of winning.
WHEEL WATCHING The IndyCar’s cramped interior is rather spartan, so simple and easy-to-read outputs are the norm (Fig. 2). In terms of complexity, the output is at the opposite end of the spectrum compared to a heads-up display in a fighter cockpit. It’s even simpler than the typical automobile.
Whereas a fighter pilot must analyze lots of data like positional threat information, an IndyCar driver wants minimal information and minimal distraction. Positional information is immediate and visual, including the track, the walls, and the other cars. Almost everything else is secondary.
Custom steering wheels do not necessarily mean complete customization. Many teams use steering wheel dashboards from companies like Pi Research. Its Pi Sigma Dash is easily incorporated into a custom wheel design (Fig. 3).
AJ Foyt Racing designed its steering wheel for its driver, Victor Meira (Fig. 4). Key controls are just inches away from gloved hands for easy access. The numeric displays provide basic details such as the current gear, while the longer but small display provides more detailed text messages for status or error conditions.
The text areas can display lap time, current or average speed, oil and water temperature, and the amount of fuel left in the tank. One bank of LEDs across the top of the steering wheel provides shift feedback. A full row of all-on LEDs indicates when it’s time to shift gears, just a paddle toggle away. It would be easy to display the engine RPM, but a row of LEDs makes for an easier to read meter, especially when the idea is to stay under the max RPM.
Two other dial adjustments on the wheel control the fuel mix and the suspension. The fuel mix helps control consumption and affects when cars need to pit. Telemetry information about fuel consumption and the amount of fuel onboard allows real-time feedback to the pit crew regarding when a car will have to stop in the pits to refuel.
The suspension control, or weight jacker, adjusts the setting of the cross weight pump connected to the hydraulic system. It adjusts the stiffness of the right rear shock, which in turn adjusts the pressure on the wheels. This is a dynamic adjustment the driver can make compared to the front and rear wings, which also affect weight distribution. The front wing can be quickly modified when the car comes into the pit using a simple adjustment.
Ron Ruzewski, technical director and race engineer #3 for Team Penske Dallara/ Honda, notes that each driver on the team has a backup steering wheel. Drivers also take their wheel with them when they drive a different car. Swapping a wheel is simple since there’s a common connector for the control and status information and a standard wheel mount.
These steering wheels are a bit more expensive than the typical steering wheel, even those with multiple controls found on high-end consumer vehicles. The wheels are custom-made, so backups are critical. Without them, a driver may have to work with unfamiliar equipment—not a good option in an environment where split-second operations are common.
OVER-THE-SHOULDER TELEMETRY The pit crew gets its hands on the car occasionally, but the tech crew monitors the car continuously during a race or a practice run. The telemetry information from a single car has real-time data from dozens of sensors, but only a subset will likely be monitored at one time from a handful of PC screens.
Adam Schaechter and one or two coworkers typically monitor this information during a race (Fig. 4). Everyone keeps an overall eye on the telemetry information, and even the pit crew will take a gander at the screens to get a general feel for how the car is performing. The crew in front of the displays keeps an eye out for trends or problems and provides feedback to the pit and the person communicating with the driver. The driver is the focal point and shouldn’t be distracted by a host of backseat drivers.
The software used to display the telemetry is normally custom and is designed to highlight trends in addition to providing alerts when thresholds are exceeded. The driver automatically sees these alerts if they’re very serious and might require immediate action. Typically, though, the tech pit crew takes these readings into account when providing recommendations to the driver and the pit crew.
For example, tires are a critical component that are often changed multiple times during a race. In the pits, changing a set of tires takes as little as six seconds. The type of tire and even the tire pressure for a replacement set are selections made well in advance of the car coming off the track.
Two Fig. 4's, and 2nd Fig. 4 and Fig. 5 should be 5 & 6.
Chip -May 08, 2009
In regards to automatic transmissions at Indy I remember that either A.J. Foyt and/or Dan Gurney used them in at least one race. I also remember that the Hall Chapparel (not Indy) race cars used automatic transmissions. This is not new technology just additional gears and better control in my opinion.
Anonymous -May 07, 2009
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