F1 cars. BMW M3/M4. BMW M5. McLaren. Audi RS5. Those are just a few examples of cars whose noises lay victims in the path of turbocharging. But, they say the future is turbocharging. Or the present, really, if you look at how many cars already are turbo, some even base and optional engines. There are a lot of technical pros and cons to turbocharging, which I won't get into here. but one of the biggest subjective downsides is the noise. Some dismiss it, if the specs and the numbers are good. Some prefer all the whine, whooshing, and hissing. Some, however, mourn the death of N/A noise. Everyone who is even slightly familiar with what I like in cars knows I'm in the last group, and it turns out to be a special group because Ferrari engineers and/or their customers are in the group as well, because Ferrari is patenting a technology that makes turbo engines sound better.
The system is a hybrid (no pun intended) between an electric supercharger and a traditional turbo. An electric supercharger uses an electric motor driven compressor wheel to make boost on demand. Traditional turbos use a turbine wheel in the exhaust connected by a shaft to a compressor wheel in the intake, where the turbine wheel extracts energy from the exhaust stream and uses it to compress the intake charge. Ferrari's system uses a turbine wheel like a traditional turbo to extract energy from the exhaust, but instead of a direct mechanical connection (i.e. shaft) to the compressor wheel, it is connected to an electric motor that is used to charge a battery. Essentially, it turns the exhaust side of a traditional turbo into a small electric generator. The intake side is basically identical to an electric (centrifugal) supercharger, where there is an electric motor that is used to power a compressor wheel to generate boost when needed.
There are obvious benefits to this system compared to both of an electric supercharger and a traditional turbo. A pure electric supercharger does not capture any energy in the exhaust, letting it all go to waste through the tailpipe(s). If used with an electric/ICE hybrid powertrain, it can run more efficiently on energy captured through a regenerative braking system instead of power from the engine, but there is still no exhaust energy recovery. Here, the turbine wheel can capture exhaust energy and store it in a battery or a battery pack for later use. Compared to a traditional turbo, the main benefit is independent operation of turbine and compressor wheel. Energy can be captured from the exhaust whenever needed and boost can be made on demand as soon as required, so lag could be eliminated instead of having to wait for the engine to rev up, exhaust flow to build, and overcome compressor wheel mass (inertia).
The only downside? A little extra weight compared to both systems, but that's a (likely, small) penalty I'll happily take. The system may also be a little more complex, but we are into turbocharging and hybrid powertrains, so simplicity is thrown out the window. Adding a couple of electric motors (or one compared to electric superchargers) is a small added complexity that's worth the gains in my opinion, especially considering that electric motors are hugely reliable devices. So how, you might ask, is Ferrari changing the noise? This is where it gets even more creative.
Since the turbine and compressor wheel are independent, the speed of the turbine wheel and how much energy is extracted from the exhaust - both are factors directly related to noise - could be varied to control the exhaust noise without affecting the intake side. In other words, you could control the turbine wheel on the exhaust side to give you the noise you want while using energy from the battery to drive the compressor wheel and make the exact amount of boost you need. Of course, there should be an expected efficiency loss if you're not wasting exhaust energy to control noise. However,
Ferrari says in its filing that the “control method can only be used when desired,” so it "has no relevant negative effect on the overall energy efficiency.” Read that last bit again in an Italian accent and you'll believe it.
Joking aside, I do think that, overall, the system will definitely be more efficient than electric superchargers and perhaps even a little more efficient than traditional turbos. The noise? That alone is worth any downsides. The elimination of lag is icing on the cake. Just don't tell AMG's that they can make their engines sound even better, because they seem to rely on magic right now to continue to make their new V8's that are (twin) turbocharged sound as glorious as ever..
Source: US Patent & Trademark Office
Comments
Post a Comment