From cul-de-sacs to racetracks: Hybrid-car tech heads to Indy

The most exciting part of the Indianapolis 500, the nail-biting dash to the finish line, stands to get even more tension-filled in 2023 thanks to a rare instance where a technology created for everyday family cars — the gasoline-electric hybrid powertrain — migrates to the track.

From paddle shifters to active suspension systems, the list of modern technologies pioneered on the racetrack before moving to regular production cars is long and well documented. But sometimes automotive technology travels the other way. And that is happening now as race car engineers figure out how to make a new "push to pass" system work safely and efficiently for the open-wheel cars that race in the Indy 500.

By pressing a button on or near the steering wheel, IndyCar's 2023 push-to-pass technology will give the driver a quick, perhaps 15- to 20-second jolt of about 100 hp from an electric motor. Drivers can use that burst of horsepower strategically — to fend off challengers, pass other cars and get to the finish line faster.

Open-wheel race cars in the IndyCar Series have used push to pass on road and street courses since 2009, but the system has not been electric and it has not been used on oval courses such as the Indianapolis Motor Speedway. Instead, the output pressure of the twin turbochargers on today's IndyCars is increased briefly, which boosts horsepower.

Mass-produced hybrids, of course, have been in showrooms for more than two decades, starting with such vehicles as the Honda Insight, which arrived in late 1999, the 2000 Toyota Prius, 2004 Chevrolet Silverado, 2005 Ford Escape and 2011 Chevrolet Volt.

So, it seems fitting that the two automakers that build all the engines for the NTT IndyCar Series, Honda and Chevrolet, also have encyclopedic knowledge of hybrid systems.

One of Honda's goals in engineering its racing hybrid system is to make it behave much like the ones in its production vehicles, David Salters, Honda Performance Development president and chief engineer, told Automotive News. Honda engineers can tap into what the company has learned with such vehicles as the Acura NSX, which has three electric motors, along with its gasoline engine.

"This learning is available to us, such as how to harvest the maximum energy during the braking/regeneration phase whilst maintaining car stability, making this seamless to the driver," Salters said.

He said some of the same engineers who are working on Honda's high-performance production vehicles will also be working on the racing hybrid system.

When slowing down to enter the pit or sometimes when cornering, the heat generated by brakes is wasted in most race vehicles. Engineers have sought to capture that energy to make cars faster and more fuel- efficient and to make the races more exciting. IndyCar's use of an electric hybrid system will also reduce CO2 emissions.

European Formula 1 race cars have had energy recovery systems for years to capture that wasted heat — from the brakes or the exhaust — and convert it to electricity that powers a slightly different version of push to pass. Or, they have stored kinetic energy in ultrafast spinning flywheels.

The introduction of an electric motor to IndyCars is just one of two planned changes coming for 2023. The other: new and larger engines from Chevrolet and Honda.

The twin-turbo Honda and Chevrolet V-6 engines used in the NTT IndyCar Series are increasing the displacement to 2.4 liters from 2.2 liters. Combined with the hybrid system, horsepower will jump from around 700 in today's IndyCar to 900 — 100 from the larger engine and another 100 on tap from the push-to-pass system.

"The hybrid element is important for every racing series as you go through this decade, to have some level of electrification," said Rob Buckner, Chevrolet's program manager for the NTT IndyCar Series.

Buckner says Chevrolet engineers working with their counterparts at Ilmor Engineering in Plymouth, Mich., are building on the experience gained from General Motors producing millions of gasoline directed- injected turbo passenger-vehicle engines, nearly two decades of hybrid production and a decade of wringing more efficiency out of the current 2.2-liter engine.

"We can do a lot of simulation and analysis using both Ilmor and GM's tools on how that [hybrid system] would affect the rotating assembly of our engines," Buckner said. "A lot of the early-on work is to try and mitigate risk and make sure our engine will be able to handle the system, but right now we don't foresee any big problems there. We have a lot of modeling tools and bright people to make sure everything functions as it should."

Officials have not released much technical information on the hybrid system; that's coming this year.

IndyCar engineers — with input from race teams, Honda and Chevrolet — are still working on the details of the layout of the hybrid system. "There are very open channels of communication with IndyCar management, from the top of the organization on down, and they are constantly looking for our feedback," said Mike Shank, co-owner of Meyer Shank Racing.

"Everything has to be considered, and it is a big balancing act for IndyCar to make good decisions for manufacturers, fans, teams and drivers. They also have to keep a big eye on what the racing product looks like and how it's being delivered to the fans," he added.

The electric motor is expected to be sandwiched between the engine and the transmission. But the rest of the integration has engineers working overtime. Instead of a battery pack, for instance, it could use supercapacitors, which are smaller and lighter and designed to release a massive amount of electrical power quickly.

Replacing the turbocharger as the source of extra push-to-pass power with an electric motor presents race car engineers with a major headache: adding weight. Some estimates peg the weight of the electric motor and batteries at about 100 pounds. Depending on the race circuit, an IndyCar weighs 1,655 to 1,700 pounds, so adding 100 pounds is a big deal. Other issues include figuring out where to place the batteries in the car so that they run cool, not upsetting the car's handling and not detracting from its crashworthiness.

Here's another: Running an IndyCar with the new hybrid system will make it difficult for drivers to replenish their batteries after using push to pass — the cars don't brake often on oval tracks.

No cars have yet been built that use the new hybrid push-to-pass system, but early testing is underway. In late March, two Honda and two Chevrolet IndyCars that use the older turbo-boosted push-to-pass system ran at the Brickyard's 2.5-mile, four-turn oval to simulate how drivers would use it on this type of racetrack — the first of several scheduled tests.

"From an oval perspective, it's never been done, and we're excited for what's coming," Jay Frye, IndyCar president, told Racer.com.