INSIGHT: IndyCar’s behind-the-scenes engine warfare
Because the NTT IndyCar Sequence and its engine suppliers put together to launch the 2021 season this weekend, the work will proceed behind the scenes by Chevy and Honda as they develop their new-for-2023 hybrid motor package deal.
That’s the norm when a racing sequence units an formidable change in movement for the longer term. Regardless of having a brand new season to run, Chevy’s companions at Ilmor Engineering and the Honda Efficiency Growth group stay entrenched in a second, non-public race away from the highlight to get their 2.4-liter twin-turbo V6s on the dyno and making huge, dependable energy.
Talking with Darren Sansum, IndyCar’s director of engine growth, there are a number of areas Chevy, Honda, and any new engine suppliers can play with on the design facet because the sequence appears to be like to retire its 2.2-liter twin-turbo V6s on the finish of 2022 and welcome the two.4s mated to kinetic vitality restoration programs.
“From a excessive stage, the two.4-liter is definitely not so completely different to the two.2,” Sansum informed RACER. “There have been some issues that have been open on the two.2 to homologate in the beginning in 2012, however we’ve really converged on one answer. So for instance, bore dimension was once a freedom, so long as the swept capability met the standards. We’ve really mounted the bore dimension for the two.4 on the request of the producers in order that they don’t must go and do loads of rig work with the intention to decide the optimum bore dimension.
“We simply stated, ‘Effectively, let’s simply agree on one after which it’s the identical for everyone.’ However there are freedoms on financial institution angle with the V, due to this fact crankshaft design and people such issues are open. The two.4 suits in the identical package deal as the two.2; it’s the identical size and it’ll match within the present automotive. Crank middle top’s the identical. What all meaning is, with a bigger capability engine in the identical dimensions of the two.2, it’s fairly a problem on the crankshaft design. You’re attempting to pack extra bang inside the identical bodily package deal.
“And these engines are already fairly extremely loaded. The underside finish is beneath fairly important stress, being a turbocharged engine with very excessive particular output. So the brand new engines are going to be a very good problem for the producers on getting that design proper.”
Within the decade or so for the reason that 2.2-liter V6 method was unveiled, new manufacturing applied sciences have reached the mainstream. One standard software could possibly be used with the 2023 motors, as 3D printing is on the record of permitted strategies for engine suppliers to make use of. The long-held and costly means of casting main engine parts may fall prey to cutting-edge additive manufacturing.
“The engine block, for instance, should stay aluminum, however it doesn’t essentially must be a casting anymore,” Sansum stated. “We’re permitting some completely different manufacturing methods for the cylinder block, which can permit some freedoms. Because the laws are written proper now, there’s nothing new and nothing particular about additive manufacturing, however we’re actively discussing with the producers on how one can tackle that sooner or later.
“We’re taking a look at these as a result of clearly there’s an enormous explosion within the space. There are parts from the engine now which might be additive, that’s no secret. You solely want to take a look at the exhaust programs to see that. There are exterior items that you would be able to see. However there are larger areas the place you can spend some huge cash on making additive elements and probably you get fairly good benefit, however we’re attempting to maintain that price capped.”
Sansum, Chevy, and Honda are engaged on a brand new minimal weight determine for the two.4 as nicely. Though the motors won’t be any bigger than the two.2s, a deliberate hike in horsepower to the 800-900 all through the two.4’s lifespan will doubtless see extra steel utilized in key areas so as to add energy and robustness.
“The two.2 is 112.5 kilos (247.5 lbs), and the two.4 is heavier than that by a bit bit,” he stated. “We’re near an settlement on the brand new quantity. And we’re sticking to the identical variety of engines in a lease per season, in order that they’ll not be allowed any additional engines, and the additional weight allowance does give them the liberty to make some elements stronger. It’s utterly as much as them on how they use that additional weight.
“Clearly once more, return to the crankshaft does get heavier as a result of it’s going to must be larger. In order that’s one of many most important issues that can get heavier.”
New turbos are a part of the two.4-liter package deal because the sequence and engine suppliers look to added enhance to help within the energy enhance.
“It’s a new turbo design for the brand new engine,” Sansum stated. “Due to the elevated air stream of the engine, we’ve received to reoptimize the turbo maps, so we’ll reoptimize the compressor and turbine dimension with the intention to be operated in a greater place. So that each one agreed to and prototypes can be found.
We’ve additionally gone up nominally on enhance so we’ll have an influence hike equal to the capability enhance. So our base enhance stage at street programs can be up from 1500 millibar (21.75 psi) to 1600 millibar (23.2 psi), which is simply the smidge beneath the place we at for the push-to-pass proper now.”
The largest piece of the 2023 hybrid 2.4-liter puzzle left to unravel is the introduction of harvesting and deploying electrical energy to enhance the twin-turbo V6’s output. Whereas IndyCar has settled on a KERS answer for street and avenue circuits, and for ovals as nicely, Sansum isn’t able to reveal their plans, however he was keen to share some basic insights.
“It’s fascinating, and you’ll be excited by it,” he stated. “The concept of utilizing the system for push-to-pass remains to be our major aim, and never having it routinely partaking and supplementing the interior combustion engine because it does in Method 1, however to primarily exchange what we do with the push-to-pass enhance proper now. So we’re trying to take away turbo enhance push-to-pass and exchange it with this.
“We’re unsure but the place we’re going to want to artificially restrict the quantity of use or simply permit it to organically play out. In order that’s on the facility facet. After which on the regeneration facet, we’re taking a look at plenty of completely different modes on how one can regenerate that. It’s a very fascinating subject. On the ovals, nobody has completed this but. We expect we’ll be the primary. And so clearly our greatest present is right here at Indy, and that’s the one the place focus is on how a lot vitality are you able to generate on the Speedway?”
Commonplace follow for race engine producers is to construct a take a look at a single-cylinder mannequin containing its concepts for how one can get probably the most out of a brand new method, and as soon as these ideas are confirmed or discarded, it’s time to maneuver onto constructing a full-size prototype. Each Chevy and Honda can be anticipated to have been working single-cylinder take a look at mules for some time now, and with the shift to 2.4-liter V6s as the subsequent step within the course of, Sansum will guarantee growth stays throughout the boundaries of the laws.
“We do stand again to some extent because the producers are extraordinarily non-public about what they’re doing,” he stated. “They’ll give a bit snippets away, however like, ‘Oh, now we have a prototype or we discovered one thing precious type of info,’ and it’s on the level now the place it’s no secret that they each, are within the means of testing issues. So very quickly as we begin going by the remainder of this 12 months, I can be inserting myself in and seeing what they’ve with the intention to make it possible for we don’t get any huge surprises when it comes round to homologation on the finish of 2022.
“We don’t need to discover their interpretation of the laws is completely different to my interpretation. So it’s undoubtedly time to be concerned in that loop now, and we are going to see the engines intimately from the within out to make it possible for they don’t get any surprises. You’ll be able to’t get so near the racing season after which discover out the mistaken path had been adopted.”