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Fuel Injection Learning Process Under Way

Deb Williams | Senior Writer, RacinToday.com Tuesday, October 18 2011

An engine with electronic fuel injection sits on a stand at Charlotte Motor Speedway during Monday's test session. (Photos courtesy of NASCAR)

By Deb Williams | Senior Writer
RacinToday.com

CONCORD, N.C. – NASCAR Sprint Cup cars equipped with an electronic fuel injection system sounded no different Monday at Charlotte Motor Speedway than those that raced in Saturday’s Bank of America 500, but everyone admitted there was still much to be learned before the 2012 season opening Daytona 500.

“There is a learning curve, a communication curve between what the driver is feeling, what the engineers are hearing and what the engine tuners are hearing,” said Jeff Burton, one of a dozen drivers who participated in the test. “We didn’t really have any mechanical issues with the system. It feels the same as it’s always felt. The big difference to me is the ability to communicate about what the engine is doing and then how they tune it. I think that will be important moving into the future, marrying the car guys and the engine guys as to what we’re looking for. There are a lot of issues we still have to figure out.

“We focused (today) on the tune ability of the system and having the engine tuners interface with the software. We don’t want to take the engine tuners we had today and replace them. We want to take the engine tuners we had today and train them to operate this system.”

NASCAR began working on a plan to switch from carburetors to an electronic fuel injection system five to six years ago. A move that Roush Yates Engines CEO Doug Yates maintains

Chad Knaus, crew chief for Jimmie Johnson, checks under the hood during EFI test on Monday.

will help put the “stock” back into stock car racing since almost all modern passenger vehicles have electronic fuel injection. However, unlike passenger cars, stock cars produce conditions that aren’t conducive to electronics, such as extreme heat under the hood for 500 miles.

Prior to Charlotte, EFI tests were conducted at Kentucky and Phoenix. There will be another test at Talladega on Thursday and at Martinsville the day after that track’s Sprint Cup race. NASCAR Vice President of Competition Robin Pemberton said one of the biggest software changes came before the Phoenix test.

“The first three or four tests we’re solving problems,” NASCAR Sprint Cup Series Director John Darby said. “The fuel delivery system created and gave us some headaches early on with fluctuating fuel pressures and just some of the unknowns that we probably didn’t address as well as we should have walking in. After Kentucky, everyone went back to work and the engine groups gave us a list of problems and how to resolve them.

“We’ve done a lot of work inside the cell with the slosh pots, the lift pumps and everything to supply a good, steady fuel supply to the engine. The Phoenix test was probably the first where we weren’t fighting off problems. We had one small programming issue with the ECU on the Michael Waltrip car that was there, but beyond that the teams that were at Phoenix, as the teams are today, have been able to focus more on the actual tuning parts of the engines and making sure they like the way they feel. It’s a good place to be right now.”

With NASCAR’s EFI system the intake manifold rules will remain the same as will the engine sizes, compression ratios and all of the rules surrounding the engine’s internal structure. Each cylinder will have an electronically controlled fuel injector. There will no longer be a carburetor and a distributor, but air will go through the throttle body, which will continue to be made by Holley.

“The switch to electronic fuel injection gives you the ability to better set the fuel and the

NASCAR's John Darby explains the components of the electronic fuel injection system.

timing for the engine,” Yates explained. “That will allow us to cut all the fuel when we’re off throttle, so you don’t have that wasted, unburned gas that you see flaming out the pipes. It will give us a better environmentally friendly engine. It will also give us more precise control of the fuel and the spark for the engine.”

The system has an engine control unit, microcontroller and microprocessor. The ECU is a Freescale microprocessor that determines the amount of fuel, ignition timing and other parameters an internal combustion engine needs to continue running. One thousand times a second, the MCU collects data from the sensors on the engine and calculates the amount of fuel needed, when it should be injected into the manifold and when the air/fuel mixture needs to be ignited. Officials said the system is designed to be completely secure where any modification is traceable and detectable.

Darby said restrictor plates would still be used at Talladega and Daytona since they control air flow to the engine.

The move to an EFI system, which possesses a high up front cost, comes just a year after teams had to make a sizeable investment to switch to fuel that is 15 percent ethanol. For Roush Yates Engines, it was described as a “hefty financial investment.” Darby said each system costs a team about $25,000 per engine. Software licenses are separate.

No live telemetry will be allowed on race weekends, but each car’s engine may be tuned

A old-style carburetor viewed from above.

throughout it, virtually up until the event starts, since tuning will be done via a laptop/PC. Tuning, however, won’t be allowed during competition. NASCAR also can spot check an engine at any time, as well as show data to viewers during the race telecasts. Similar data can be applied to NASCAR racing video game engine setups.

The EFI system allows mapping of the fuel and timing to be tailored for each competitor’s driving style within parameters set by NASCAR.

“A map is like an excel spread sheet,” explained Ted Harbour, chief fuel injection engineer for Roush Yates Engines. “On one side you have throttle position. On the other side is rpm. So at every point in the rpm curve the engine wants a certain amount of fuel to run efficiently. (A map) is the table the ECU uses to look up how much fuel it squirts out of the injectors and when to fire the spark plug.”

Yates noted the EFI system might allow the fuel’s ethanol percentage to be increased in the future. He also said it would allow a faster transition to new fuels because engine builders can now understand exactly what it’s doing, control the engine and adjust for the different fuels.

“We’ll be in a lot better position in the future to change fuels,” Yates commented

Darby said the EFI system might make the Sprint Cup Series a little more attractive to other manufacturers, but the basic push-rod design of the engine was still a “huge separator between NASCAR racing and a lot of other forms of motorsports.”

“It’s easy to overcome and the fuel injection puts us much closer, but that’s hard to speculate if it will bring them in,” Darby said.

– Deb Williams can be reached at dwilliams@racintoday.com

Deb Williams | Senior Writer, RacinToday.com Tuesday, October 18 2011
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