IMSA GTP 101: On and Off Track Battery Charging Strategies

[@Casey_J96]

Loving this GTP 101 series, great work Marshall!

[@tomescover1166]

100% agree.

[@randyholbrook9609]

Great info Marshall. Thank you for explaining this stuff. It's going to make watching the series so much more enjoyable.

[@nickpappas4133]

Really enjoying the tech series of the hybrid GTP cars.Can’t wait for the 24hr.

[@beyond_the_infinite2098]

Great content. Hybrid cars are exciting to me. Fast, high tech, still have ICE with great sound. I've always been a gear head and race fan. I find the hybrid systems technology fascinating. More please!

[@WesllyOni]

So there's a HP cap on how much the GTPs can deploy at any given time, correct? either through the ICE or ICE + ESS, you can only deploy up to 670 HP, and if the ICE can put out more than those 670, some of that power can go to recharging the battery even at full throttle? That's pretty cool indeed. Thanks for this GTP 101 series, Marshall and Racer!

[@kitcat5455]

Does IMSA monitor the output of the engine and battery to make sure the combined output does not exceed the output limit?

[@rarewhiteape]

I’d love to know what this power sharing allowance means in terms of fuel efficiency savings if compared to other race cars who have similar systems but don’t have an extra allowance while charging. I’d predict it’s more efficient since the electric power delivery is almost lossless in terms of waste heat generation (i.e. charging the battery while driving at high speed while the ICE is already doing lots of hot work and converting a small amount of that inefficient work into more efficient reserve electricity for later use). Any insight there would be fantastic 👍

[@AutistaXR]

That is NICE!! Always running at 670 peak

[@Jt7166]

Very cool breakdown. Only other race car that I remember that could regen under power was the Porsche 919, but I believe they used a flywheel mechanism to do that.

[@ryanwhitlock7350]

That car had an MGU-H, similar to F1. Used exhaust gases to spin a turbine and charge the battery.

[@jimross5838]

@@ryanwhitlock7350 Thank you for sharing this. Considering manufacturers now want MGU-H out of F1 due to the cost, it really puts into perspective how much the top 3 really were spending to win Le Mans and why it was so unsustainable

[@ReXzz]

The 919 had a battery, Audi was using the flywheel. Toyota used a super capacitor. After 2015 they all realized batteries are unbeatable so Audi & Toyota switched to that type of energy store too. The 919 charged its batteries under braking and via an MGU-H (exhaust energy)

[@Dean0017]

Not even close. Research the "KERS" system used in formula 1....

[@ReXzz]

@@Dean0017 who is that addressed at?

[@davidhyson9910]

This is some new era Gold for us hybrid newbies. Well done Marshall, we can tell this trips all your racing triggers! Drinking through a fire hose but not drowning is how I prefer it! The potential drama of how this all hangs together on race day/night has me engaged. Thanks IMSA!

[@indopleaser]

great tech video explaining. gained a subscriber

[@thehansepeter]

Can you explain the benefit of the Hybrid System? It seems like it just adds weight an complexity, because the ICE can do everything alone.

[@MattLitkeRacing]

If I’m understanding this correctly if they need more than 670 for the charging plus driving the car the computer will turn up the horsepower? What’s the trade off between using more fuel to charge the battery and the extra power from the MGU after charging?

[@DonLee1980]

the whole point of using hybrid is to be more fuel efficient, but yeah that doesn't quite make sense... to charge the batteries by burning more fuel... The Porsche 919 and F1 cars today, use the exhausts and turbos to mechanically generate power thru the MGUH, energy that would have gone to waste. The only way that would have made sense is if cars were like the LMP1h cars, where they had 400+hp in electric power, by sacrificing top end speed for massive quick acceleration, but no, these cars are hard capped at 670hp. I mean, in theory, since the ICE can easily do 670hp, the cars would be faster just running the ICE and leaving the hybrid systems in the garage, but of course, there's weight limit. At the end, reliability will be a key factor of who will win, and not outright pace.

[@richardlong6097]

The point of a hybrid system is keep manufacters happy and their money flowing.

[@Bahamuttiamat]

@@DonLee1980 Agreed. The explanation doesn't quite make sense. If the ICE can generate the capped hp then why add the heavy electric motor/battery.

[@absenttk4213]

Former Prototype engineer here. Thinking about this as only an energy saving feature isn’t quite right. Instead, this system basically means you have two hybrid modes available to you. If you only harvest through braking, then you extend fuel range and efficiency. If you opt to harvest on the straights, then you are spending fuel, but gaining energy to deploy for a faster lap. This is pretty cool because it means you can opt to use the hybrid system either to extend your stint length, or if stint time is not an issue, just use it to go faster.

[@Bahamuttiamat]

@@absenttk4213 ok but wouldn't these cars be better race cars with less weight and complexity? A lighter car is by definition more fuel efficient as it takes less energy to brake, corner and accelerate more mass? Here's my question, if the hp is capped and the ice is capable of achieving and maintaining that cap, what's the purpose of the e-motors?

[@RussellAutosport]

So… seems like the key would just be to build an engine that can make 800 hp, and neuter it so that you’re making 737 hp with the ICE (670 hp for powering along on the track, 67 hp for charging the MGU). Then using the MGU for powering out of slow corners where the power band of the engine puts you outside of 670 hp? Seems like a much more complicated, more expensive, and heavier solution than just making an engine with 670 hp to begin with…

[@rider65]

Exactly it is way more complicated and it is all about politics has nothing to do with the advancing of Motorsports. It has everything to do with advancing various political agenda by Corporatists

[@jims6614]

Did I understand the straight-line charging correctly.....essentially the engines make more power than the mandatory limit, the engine management system limits the engines max power, however under charging the extra power is used to charge the battery meaning only 670hp hits the road?

[@nickygray7066]

Great video and it answered some questions I had about the power split between the ICE and MGU. It's also the first time I have heard about the charging on the straight. However, the charging on the straight does seem to defeat the purpose of having a hybrid system. What is the point of having a hybrid system to save fuel when on the straight you are burning more fuel to charge it up? It just gives more credence to the accusation that putting a low powered electric motor in a race car is just greenwashing and manufacturer PR

[@absenttk4213]

Former Prototype engineer here. Thinking about this as only an energy saving feature isn’t quite right. Instead, this system basically means you have two hybrid modes available to you. If you only harvest through braking, then you extend fuel range and efficiency. If you opt to harvest on the straights, then you are spending fuel, but gaining energy to deploy for a faster lap. This is pretty cool because it means you can opt to use the hybrid system either to extend your stint length, or if stint time is not an issue, just use it to go faster.

[@The52car]

@@absenttk4213 thanks for the explanation!

[@djmohab2]

@@absenttk4213 How can you deploy it for a faster lap when you're capped at 675 HP regardless of distribution between ICE and MGH? Is it because you can have instantaneous torque from the MGH vs having to redline the ICE?

[@oddball0045]

@@djmohab2 Because the combustion engine can make more than 670 HP and use the extra power to charge the battery on the straights, while the electric motor helps give you a faster lap time out of the corners.

[@djmohab2]

@@oddball0045 cheers! Is there a maximum energy cap per lap like WEC?

[@prudenstoad]

Yes! I am no means a racing strategy guru but I can pretend while I watch these beasts race. Thanks for this insight!

[@charlesmeyer8951]

Formula 1 cars definitely harvest on the straight. They flash the rain light to let the following driver know that. It makes for great strategy and passing depending on where they harvest and deploy. If the GTP cars are always at peak horsepower the only advantage and strategy would be using the low end torque of the electric motor?

[@djmohab2]

But that's due to coasting, capturing the energy lost at the rear wheels as aerodynamics and engine braking take effect. This sounds like the ICE is directly driving the MGU to charge the battery .

[@charlesmeyer8951]

@@djmohab2 No, they often harvest on the straights at wide open throttle. Pay better attention.

[@basedgodstrugglin]

The energy deployment makes sense considering how LMH cars deploy their electric energy in a similar fashion. My only snagging point, I’ve been heard somebody call an ICE engine an “ice” engine lol I don’t know how I feel about that

[@8power0]

THIS IS FANTASTIC ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, I COME FROM A LONG LINE OF AUTOMOTIVE TECHNICIANS ,,,, SO THESE HIGH-TECH VIDEOS ARE LIKE CATNIP TO ALL US AND THANKS SO MUCH FOR YOUR TIME !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[@X8X8X8X8X8X8X8X8X8X]

I struggle to think of something more ironic than a hybrid racing car charging its batteries with its internal combustion engine during warmup.

[@giuseppepuglisi3980]

As long as the fuel efficiency and performance out on track aren't affected then any kind of power generation makes sense.

[@X8X8X8X8X8X8X8X8X8X]

@@giuseppepuglisi3980 No conversion of energy makes sense, as it is always associated with losses!

[@The52car]

Yeah, this part I don't get...

[@ReXzz]

@@giuseppepuglisi3980 they are affected

[@ReXzz]

First of all: the hybrid unit in these cars is very much a marketing tool. That is probably its main purpose. It could have added to the performance of the cars, but that's not really what it is supposed for. Always consider this: the main targets for the new regulations were keeping the costs down and attracting manufacturers. That's why these are spec parts. Another guy asked a similar question and an engineer gave an interesting answer which I will just paste as here: From AbsentTK421: "Former Prototype engineer here. Thinking about this as only an energy saving feature isn’t quite right. Instead, this system basically means you have two hybrid modes available to you. If you only harvest through braking, then you extend fuel range and efficiency. If you opt to harvest on the straights, then you are spending fuel, but gaining energy to deploy for a faster lap. This is pretty cool because it means you can opt to use the hybrid system either to extend your stint length, or if stint time is not an issue, just use it to go faster" Makes a lot more sense this way. So the impact of this unit may not be huge, but could still be race deciding!

[@ktwei]

Now this is quality content, any word on the battery pack capacity?

[@flavortown3781]

judging by the size of the actual box maybe maybe 10 amp hours

[@GregReinacker]

If you look at 0:43 in the video, there's a label on the side of the battery...looks like it says 1.35 kWh.

[@ktwei]

@@GregReinacker Less than I expected. I understand output is the main consideration but still....

[@jimross5838]

@@ktwei More capacity = more weight and cost.

[@bukwok]

race car hybrid power trains just so complicated and expensive , those number just theory ,battery strategies kind of things only way to learn is in racing condition , i bet next season team know how to make it work ,getting better efficiency . lot of people dont like hybrid engine, to me hybrid engine very cool very interesting.

[@Todis51]

That’s wild stuff!

[@reactor4]

what kind of mileage gain are these cars getting?

[@andrewahern3730]

They’ve gone from 2 MPG to 3.

[@shaunguanco2764]

@@andrewahern3730 So a 50% increase in gas mileage!

[@andrewahern3730]

@@shaunguanco2764 honestly, probably close to that. Usually 100% of the energy is lost during braking. OTOH It’s a low power electric motor (relative to the ICE) and it charges on the straights, so it might be worse. I wonder if there’s an eco map if they’re trying to stretch pit window?

[@neilbardsley]

Honestly sounds like the hybrid is getting in the way. Weights lots, must use the ice to charge and can't be used in slow corners. The cars would be quicker without

[@pedroferrari1]

I doubt that hybrid system really saves much fuel over the weekend. 😅 why dont they charge the battery on the plug in the garage?? Seems nonsense to charge it with the engine on

[@absenttk4213]

Hi! Former Prototype Engineer here. I can confirm that yes it saves a lot of fuel, and as for charging there is an interesting reason why it is smart. All prototype cars have engines that require a warmup process before they can be run on track. This is to properly heat all the seals and components. Usually between 3 and 10 minutes of running through various RPM ranges. So, if you can adjust your warmup to also charge the battery at the same time, then its pretty handy.

[@The52car]

Wait... WHAT??

[@otanica]

Great videos but stop saying the 4 manufactures names all the time.