Latest news with #turbocharger
Motor 1
9 hours ago
- Automotive
- Motor 1
The Brilliance of Electric Turbochargers
What is a turbocharger's job? In essence, it's to increase thermal efficiency. An electric turbocharger does this and more, which is why I'm a big fan. Thermal efficiency is a measure of how much of the potential energy of a fuel is consumed to create power, versus how much of it is simply generating waste heat. In pure terms, an automotive internal-combustion engine is not very efficient. For example, Toyota made a big deal in the late 2010s when it achieved 40 percent thermal efficiency in its Dynamic Force four-cylinder engine. Meaning it was only wasting 60 percent of its potential energy. Welcome to The Rabbit Hole , a bi-weekly column where Senior Editor Chris Perkins explores his latest obsession with automotive technology. He speaks to the best in the business to understand how cars work and what the future of the automobile looks like. Incidentally, this is why EVs have an appeal beyond zero local emissions. Thermal efficiency doesn't apply to electric motors because they're not directly powered by a heat source. But in terms of electrical efficiency—the ratio of electrical energy a motor consumes to its useful output—an EV's motor is about 75 to 90 percent efficient, according to Renault , at least. So, in short, internal-combustion engines, especially on their own, aren't especially energy efficient. Electric motors are very energy efficient. Turbocharging can help narrow that gap. Mind you, it's still a big gap, but any little bit helps, right? This story was available to our newsletter subscribers before it hit the site. Want early access? Sign up below. back Sign up For more information, read our Privacy Policy and Terms of Use . Turbocharging 101: A turbocharger consists of a turbine in the exhaust system, a compressor in the intake, and a shaft connecting the two. The exhaust turbine spins up with the flow of exhaust gases, which in turn spins up the compressor, increasing the density of the air headed into the engine, boosting power. In terms of thermal efficiency, it takes energy that would otherwise be lost as heat and turns it into something useful. Photo by: Mercedes-Benz Turbocharging 201: An electric turbocharger adds a motor attached to the shaft between the turbine and compressor. This means you can spin up the turbocharger independent of exhaust-gas flow, which has all sorts of benefits. Most notable is the all-but-elimination of turbo lag, but also the lowering of boost threshold, and allowing for higher boost pressure. And simply knowing the shaft speed of a turbocharger—which admittedly can also be achieved with a simple speed sensor—allows the automaker to run the turbo more safely closer to its maximum speed. But an electric motor works backward too, generating electrical energy if you use it to brake the turbine. An engineer from Mercedes-AMG once told me that in some cases, an electric turbocharger can be energy neutral ; The energy the turbocharger's motor regenerates is enough to power the turbocharger itself. There are big thermal efficiency gains to be had using electric turbochargers. Mercedes-AMG said in 2017 its electric-turbocharged Formula 1 V-6 exceeded 50 percent thermal efficiency , which was one of the first times ever an automotive engine converted more of its fuel source into useful power than waste heat. Like all F1 engines, the AMG V-6 uses a Motor-Generator-Unit-Heat (MGU-H), which is simply another term for an electric turbocharger. AMG later became the first to offer electric turbochargers in a road car with the four-cylinder in the C43 and C63. Photo by: Mercedes-Benz Porsche then took things a step further with its hybrid system for the new 911 Carrera GTS . Its single BorgWarner turbocharger has a 14.7-horsepower electric motor on its shaft, and uniquely, no wastegate. Typically, a turbocharger uses a wastegate—a valve that opens to expel excess exhaust gas—to limit boost pressure. Porsche instead brakes the turbocharger's motor to control boost pressure, so it's not wasting any exhaust gas and generating additional electrical energy. That additional electrical energy can power either the turbocharger itself, or the 53.6-horsepower traction motor sandwiched between the engine and transmission. Photo by: Chris Perkins / Motor1 A Porsche engineer also tells Motor1 that using a large turbocharger and limiting its turbine speed with the motor reduces exhaust-gas temperature, and therefore, the temperature of the charge air going into the engine. That eliminates the need for fuel enrichment, which is often used to reduce combustion temperatures, but this practice now being banned with Euro 7 emissions regulations. Porsche's use of an e-turbo boosts the engine's thermal and fuel efficiency, and overall vehicle efficiency. Broadly speaking, going electric feels like a natural extension for turbocharging. If the point of turbocharging is to boost efficiency, why not go for a solution that furthers that aim? Well, electric turbochargers are expensive, complicated, and heavy. Ferrari is using electric turbochargers for its F80 hypercar, but its closest rival, McLaren, uses conventional turbos in the coming W1. McLaren engineers told Motor1 that they didn't want the extra weight electric turbos would bring, and that they'd rather use the car's electrical energy to power the traction motor. Adding weight and complexity is always a difficult decision for an automaker, one of the many compromises it must consider in the course of engineering a car. The complexity has to justify itself. McLaren might also have a point on the electrical energy side of things. In the past, I've written about interesting internal-combustion engine technologies, like Mazda's spark-controlled compression ignition and Nissan's variable compression . Both improve efficiency and performance, but not so much as augmenting internal combustion with a conventional hybrid system. Does electric turbocharging fall into the same category? Someone from one automaker might say yes, but then why would engineering powerhouses like Mercedes, Porsche, and Ferrari all embrace it? Photo by: Porsche Ironically, for a technology that was developed in Formula 1, the sport will soon abandon electric turbocharging. To attract more engine suppliers, F1 is changing its engine formula for next year to abandon the MGU-H, deeming it too expensive and not relevant to road cars… just as more road cars are embracing this technology. F1 is also upping the electric portion of its hybrid powertrain to achieve about a 50/50 split between engine and motor power. And hey, F1 is expanding its engine supplier base with Audi, Ford, and GM all joining the fray. F1 is a sport and a business, not simply a technological proving ground. In any case, turbocharging is, in spirit, about not leaving energy on the table. An internal-combustion engine is going to produce a ton of exhaust gas that is pure waste. Why not make something useful out of that? And why not generate additional electrical energy from it while you're at it? Engineering at its best maximizes the potential of what you have in front of you. This isn't to say that cars that don't use electric turbochargers are bad, or that there aren't legitimate reasons to skip out on this piece of tech. It's possibly something that only justifies itself in higher-end performance-car applications. There's an admirable engineering ideal with electric turbochargers that satisfies the nerd in me. Isn't maximizing potential something we should all strive for? Further Down the Rabbit Hole Why Carbon-Ceramic Brakes Are Expensive. And Why They Might Be Worth It Why BMW's B58 Is a True Successor to the Toyota 2JZ Share this Story Facebook X LinkedIn Flipboard Reddit WhatsApp E-Mail Got a tip for us? Email: tips@ Join the conversation ( )
Yahoo
18-05-2025
- Automotive
- Yahoo
This hybrid with its tiny battery is the most exciting car I've driven all year
When you buy through links on our articles, Future and its syndication partners may earn a commission. When the 922-generation Porsche 911 arrived back in 2018, there were whispers that its platform was designed to accommodate a future hybrid system. It was thought Porsche had carved out space for a battery, an electric motor and all the other hardware needed to make its iconic sports car compliant with upcoming emissions regulations. Would this be the end of the 911 as we knew it? Would the facelifted 992.2 model be forced to carry a big battery and a charging socket to silence its engine and drive as an EV for a few dozen miles? As it turns out, the answer is no and no. I've just spent a week with the new 911 GTS and, in all honesty, you'd struggle to tell that it's a hybrid at all. The high-voltage battery is tiny, at just 1.9 kWh (compared to 97 kWh for an EV like the Porsche Taycan) and it sends power to two motors, one in the eight-speed gearbox and one inside the engine's single turbocharger. The motor fitted between the gearbox and the engine provides an extra 40 kW (54 PS) and 150 Nm of torque, on top of the engine's own 357 kW (485 PS) and 570 Nm, and also acts as the starter motor and alternator. The second, smaller motor is fitted to the turbo, which now spools up instantly without any lag. Once spinning, the turbo also generates up to 11 kW of electrical power, which is then sent to the other motor or fed back into the battery. The engine itself is all-new. It retains the 911's flat-six configuration, but capacity is now 3.6 litres and there's a single turbocharger in place of the twin-turbo system still used by other variants. And the result of all this? The GTS hybrid is currently the quickest and most powerful 911 Porsche makes. It produces a combined 541 PS and even in two-wheel-drive form sprints to 60 mph in just 2.9 seconds, and 100 mph in 6.8 seconds. The hybrid system not only eliminates turbo lag, but also helps deliver extra power the moment the driver asks for it. In any gear, the GTS's power response is both extraordinary and thoroughly addictive. The soundtrack of the sports exhaust helps, naturally. As well as boosting performance, the hybrid system also improves efficiency. Despite the extra power – the GTS has an extra 147 PS over the base-level 911 Carrera – Porsche states an efficiency figure of up to 27.2 MPG. I actually saw over 28 on a motorway run, matching Porsche's own best-case figure for the standard, far less powerful, Carrera. Apart from the extra performance, the driver is mostly unaware of the hybrid trickery going on around them. There's a new readout on the rev counter that shows when the battery is being used and charged, along with a dial showing current capacity. The system is almost constantly working to spend and generate electricity, but without the graphics you'd really have no idea. It's not as if the electric motor launches the car off the line like an EV, or that it somehow outshines the engine. Instead, the motor makes the engine feel even more potent, and with a far more linear power and torque delivery than you'd expect from a turbocharged 911. It doesn't have the heavily boosted character of the previous generation 911 Turbo, yet feels every bit as quick. For now, only the GTS variant of 992.2 is a hybrid. All the modes below it use twin-turbocharging, while the GT3 remains normally aspirated. The upcoming 992.2-generation Turbo and Turbo S will also use the T-hybrid system, but likely with a more powerful engine. A week with the 911 GTS taught me that calling a car 'a hybrid' is really only half the story. Some hybrids have giant batteries and can go for dozens of miles without using their engine at all, while others combine both to be as efficient as possible, especially in town and city driving, with no need to plug in and charge. Others still, like the Porsche, demonstrate how hybrid tech can make a sports car quicker and more efficient. The GTS T-hybrid suggests electrification is not necessarily a zero-sum game, and that with clever engineering, there's still plenty of life in icons like the 911.
