48V Automotive - Electric Compressors and Superchargers
2020-05-01 | 5 min read
Last year I blogged about The 48V/Ethernet Powered Automotive Future, addressing how automotive ethernet is bringing big savings and better capabilities while on the powertrain side of things 48V architectures were helping car makers do a better job with automatic engine start and other tasks.
Now the world of mild hybrids, where the hydrocarbon burning engine is augmented by an electrical engine, it undergoing some interesting changes.
Car makers are under intense competitive and regulatory pressure on a number of fronts, including performance and drivability, fuel consumption and emissions. There is the constant demand to do more with less.
Consumers, on the other hand, have traditionally wanted the responsiveness and drivability of a large displacement, normally aspirated (non-turbo) motor but have also desired the fuel economy of a small displacement motor.
One compromise that has been partially effective has been to use relatively small displacement motors with small turbos. Because a small turbo can spool up faster than a larger turbo can, it can help add power at relatively low RPM, in many cases making a small engine feel like a larger engine. While effective and popular with manufacturers, the small turbo 4 cylinder reduces but does not eliminate turbo lag – the delay in power delivery that happens between the gas pedal going down and the engine responding with power.
The turbocharger’s near cousin, the supercharger, has long been viewed as an effective way to make a smaller engine act and feel like a larger one without the lag of exhaust driven turbochargers. Unfortunately, most traditional supercharger implementations have involved some sort of belt drive, leading to parasitic loses even when the supercharger was not in use.
Enter the 48V Electric Compressor, which is another name for what could be called an electric supercharger. When deployed in conjunction with a turbocharged mild hybrid, the electric supercharger, an electrically driven air compressor, kicks in to cover low rpm and transient needs when transitioning from off boost to on boost. With the ability to spool in as little as 300ms, electric superchargers combine the lack of parasitic loss that you get with a turbo with the near instant response of a belt driven supercharger.
By masking some of the shortcomings of a traditional small displacement turbo, the combination of electrical compressor with turbo allow for an end package that can be smaller in displacement, run at lower RPM with a larger turbo, effectively delivering the response and feel of a larger, normally aspirated motor. Think of a little four cylinder that feels like a big V8 and gets good gas mileage.
Anyway, technology and its perception can be a funny thing. Not long ago (even now) you can find bros in Hemi-powered muscle cars scoffing at hybrids. However, the bros may discover that the guy with the hybrid has more horsepower. Jaguar Land Rover is now offering a hybrid inline six with turbo and electric supercharging putting out 395 HP and 406 ft/lbs of torque.
Looking for a sportier alternative? Here is an interesting demonstration of how a BorgWarner eBooster helps transform a 2.3L turbocharged Mustang from a cost-effective compromise into something even burlier and torquier than their highly regarded 5.0L V8.
Need to test? Check out the Ixia Automotive Ethernet Testing page. Our parent company, Keysight, also has a number of solutions for automakers covering everything from electrics and batteries to IoT and more.