Latest news with #BoschMotorsport
Yahoo
13-06-2025
- Automotive
- Yahoo
Point 'Brake': The complexities behind Porsche's 963 hypercar braking system
Stopping an LMDh car is just as hard as getting it going. Sure, they've got four brakes, but these cars are hybrids, which means you also have regenerative braking. Plus adjustments for engine braking. This makes everything infinitely more complicated for teams, drivers, and suppliers, and frankly, a lot more interesting. Conceptually, the LMDh braking system is a lot like what's used in Formula 1. The front brakes are purely hydraulic. But since the hybrid system is at the back, LMDh cars use a brake-by-wire system, Bosch's Electronic Braking System (EBS) to manage the handoff between friction, regenerative, and engine braking at the rear of the car. Bosch also provides the Motor-Generator Unit (MGU), inverter, and control software for the spec hybrid system in LMDh. Advertisement (Le Mans Hypercar regulations allow for an electric front axle, so the braking system on the likes of the Ferrari 499P and Toyota GR010 are very different from what's described here.) 'With our EBS system, there are different modes and the one that's used in LMDh is pressure-based,' says Jordan Krell, senior calibration engineer for Bosch Motorsport. 'So they send a pressure request to us and that's what we hit at the brake perspective. So from the OEM perspective on LMDh, it gives them a lot of flexibility on braking strategies. It's a really open playbook for them to develop a lot of controls.' 'It's quite complex but it's where teams can make a difference because you can tune it for every single event,' says Porsche Penske Motorsportdriver Felipe Nasr. 'Depending on the grip level, if it's raining, if the track is evolving as the week goes on, you can always revisit those settings.' LMDh cars — like most every race car — have adjustable brake bias, which proportions the amount of braking front-to-rear. Under braking, the weight of the car shifts forward, increasing the load on the front tires and decreasing the load at the rear. With more front bias, that load shift is more prominent, giving the car a looser feel, more oversteer on corner entry and promoting rotation; with more rear bias, the shift is less dramatic, helping stabilize the car and inducing understeer. The brake discs glowing after a braking zone on the #5 Proton Competition Porsche 963: Neel Jani, Tristan Vautier, Nico Pino, Julien Andlauer The brake discs glowing after a braking zone on the #5 Proton Competition Porsche 963: Neel Jani, Tristan Vautier, Nico Pino, Julien Andlauer The use of brake-by-wire enables a really neat feature, brake migration. 'It's dynamic brake bias on the pressure side,' explains Krell. You can use the car's electronics to shift the brake bias as the car slows into a corner. Advertisement 'We have brake migration shaping,' Nasr says, 'which is either when you are in longitudinal braking or lateral braking. That affects how much the shift of the total bias is going rearwards as you steer the car.' That brake-migration shaping is cockpit-adjustable to suit both driver preferences and track conditions. Nasr says there are plus and minus settings for longitudinal braking, braking in a straight line, and lateral braking, braking with some steering dialed in. Throughout a lap, he'll make a handful of adjustments to overall brake bias and migration shaping tailored to each corner. But with LMDh, it's not just the shift from front to rear bias. Across the rear axle, the EBS is constantly juggling the braking force between the discs, MGU, and internal-combustion engine. There's no specific limits on the level of energy recuperation, but the amount of energy you can feed back into the battery depends on state of charge (SoC), and the limitations of the MGU itself, which is capable of about 180 kilowatts (241 horsepower) in total. Throughout the course of a lap, and a stint, the battery SoC changes almost constantly as you use the MGU to both propel and slow the car down. So there's no fixed level of regenerative vs friction vs engine braking. 'What's really unique about the LMDh platform is we put a lot of that into the team's hands,' says Krell. 'What they send to us is a braking torque request for how much negative torque you want to generate on the MGU, and they're able to control the pressure they want at the caliper…. That's something that, depending on your SoC, the balance they want between brake temp, SoC, and how they're using their energy-management strategy throughout a lap, they're able to blend that.' Advertisement There are cases where some of the braking at the rear is purely hydraulic if the battery SoC is particularly high. But you also might use a bit more regenerative braking to manage temperatures, as Krell says, or even to manage wear. Krell also notes that in some of the hardest braking events, like turn one at Indianapolis, you might see as much as 40 percent of the total braking at the rear come from the MGU. #6 Porsche Penske Motorsport Porsche 963: Mathieu Jaminet, Matt Campbell #6 Porsche Penske Motorsport Porsche 963: Mathieu Jaminet, Matt Campbell LMDh drivers have to think a lot about the braking system and understand how it works, but they ultimately need seamless, consistent performance. They need to be able to outbrake their rivals from 200 mph without the system doing anything funky or giving them miscues. If you've ever driven a hybrid or electric car with a brake-by-wire system, you know that the brake pedal can sometimes feel odd since it has to simulate what is otherwise done mechanically. Bosch offers a pedal-feel emulator, and it's down to the automaker to work with the supplier on tuning it to give drivers what they want. Advertisement 'When you're driving a purely hydraulic brake, you as the driver have the feeling that 'Ok, this is the maximum input, now I can feel the rear locking,' So what do you do? You just release the brakes at that point,' Nasr explains. 'Whereas in the brake-by-wire, the system is also trying to compensate, so it's best that the driver has more control over the brake pedal than anything else, you're trying to minimize those interferences.' Nasr says the 963 has gotten easier to drive thanks to a few years of development since its 2023 competition debut. But big braking zones are still a challenge. 'The longer brakes are always the trickiest because there's a lot more going on the system trying to read all that, and at the same time combining the transition phase of the braking, and the diff, and the MGU, and trying not to lock any of the tires,' he says. 'The bigger the braking, the trickier it gets for us drivers and the system.' Also tricky was making it work in the first place. One would think that of all of the LMDh constructors, Porsche would have a leg-up in making this braking system work, since it did blended braking in the 919 LMP1 car. But Stefan Moser, technical director for the Porsche LMDh program said it wasn't so easy. Advertisement 'Obviously, when we started this project, we thought we kind of knew how to integrate the hybrid into such a race car, but, we really learned that there are a lot of differences,' Moser says. 'It's a lot of paying attention to the details if the [MGU] is on the front axle or on the rear axle. We did a significant part of the code over again.' There's a complexity here that's hard to wrap your head around, and it's proof that despite LMDh cars all using the same hybrid hardware, each car is very different from one another. It's also proof that LMDh racers are among the true elites, both in understanding how the system works, and the many, many ways they can manipulate it across a lap, a stint, a race distance to get different results. And if this is hard for Porsche, imagine the challenge for all the others joining the LMDh field in the coming years. Read Also: The near-supernatural racing talent of Porsche's Kevin Estre To read more articles visit our website.
Yahoo
30-05-2025
- Automotive
- Yahoo
Wickens proves he's ready for his new challenge
Robert Wickens went into his first race of the season in the IMSA WeatherTech SportsCar Championship at Long Beach with a simple goal: 'To leave with our heads held high.' The Canadian undoubtedly did that over the course of his maiden event aboard a Chevrolet Corvette Z06 GT3.R specially adapted to allow him to drive with hand controls. But there was also a feeling of what might have been for Wickens and team-mate Tommy Milner. Advertisement The positives included the 2nd generation electronic brake system developed by Bosch Motorsport proving 'flawless from start to finish' during the 100-minute race. It allowed him to show his pace competing at this level of motorsports for the first time since returning into professional racing after his life-changing accident in IndyCar back in 2018. Wickens ended up fastest in second free practice as he threaded his GT Daytona class DXDT Racing Chevy between the walls on the daunting 1.97-mile Long Beach Grand Prix Circuit. He then ended up just over half a second from pole position in qualifying despite a side-swipe from another car on his hot lap — he completed his lap with damaged suspension. 'It was all sunshine and rainbows going into qualifying,' says Wickens, a driver who has always felt an affinity with street circuits. 'We thought if we do everything right and play our cards right, we have a shot at pole on debut. Frankly, if you had told me that last week, I would have said you are dreaming. 'But we ended up eighth. The electronic hand control system from Bosch was doing everything I needed it to do. That's why it hurts that we didn't get to maximise my qualifying.' Advertisement Wickens regards the system developed by Bosch for the Corvette as a breakthrough that has allowed him to take the next step of his racing comeback with a programme in the five IMSA sprint races aboard the Corvette. It is, says Jordan Smart, motorsport application engineer at Bosch Motorsport, 'deeply integrated with the car'. The brakes on the Hyundai TCR car in which Wickens returned to competition in IMSA's Michelin Pilot Challenge support series were based on hydraulic braking. Now, the Bosch Electronic Brake System (EBS), explains Smart, allows the inputs Wickens makes on the controls on the steering wheel to create 'a little electrical signal that is converted into brake pressure' at the wheel. 'It's true brake-by-wire.' Wickens and Milner went into the Long Beach race on 12 April with ambitions to improve on eighth place on the grid, though with one proviso. Driver changes are an integral part of the IMSA series and DXDT knew that come the race it would lose time to its rivals in the pits. Advertisement 'It just takes a little more time currently with the position we are in with Robert having to be lifted out of the car,' says Bryan Sellers, DXDT's programme manager on the IMSA team. 'We have a lot of moving pieces with getting Robert out, with getting the next driver in.' That loss of time resulted in Milner falling to P10 from the seventh position out of which Wickens ducked into the pits. The longtime factory Corvette driver made it as high as fifth, but as he passed a BMW for that position he receives a tap on the rear that dislodges the bodywork. Race control demands Milner pits to have the errant bodywork properly secured, the delay resulting in a 15th- place finish in class for the DXDT Chevy. 'Safety is the top priority and after having some contact our rear bumper was a little bit loose, and they gave us a black flag to pit for repairs,' explains Wickens. 'Our race was more or less over at that point, so we finished whatever it was. I don't think it tells the whole story.' Advertisement 'That's racing,' says Smart. 'The system we have developed gave Robert the potential and the pace was there. That was the key takeaway for us: we provided him the tool to get to that level.' To read more articles visit our website.
