A turbocharger that would have a small clutch between the compressor wheel and the turbine wheel to disengage them one from another, allowing them to rotate independently. It might also have a small flywheel on the turbine shaft (I know this would be the opposite of what most people do to reduce the spooling time of turbochargers).
When the vehicle is stopped, the turbo's clutch would be disengaged. The engine would be running naturally, and the turbine and flywheel would still be rotating by the engine. When the vehicle starts to go the turbo’s clutch will be engaged, instantly rotating the compressor. By revving up the engine before you are ready to go, it would spin the turbine faster and cause it to have more rotational momentum, which will create more boost when activated.
The clutch could possibly be controlled by connecting it to the transmission's clutch pedal, or brake pedal (I'd have to think about it a little more), or it could maybe be manually controlled with a button.
(This might also make the engine slightly less inefficient when idling than a normal turbo.)-- BJS, May 31 2006 this wouldnt really work. Turbo lag is a direct corolation to the mass of the turbine. Heavier Turbine(with flywheel) means greater turbo lag, this could even decrease the ultimate speed of the Turbo. I suspect more power is used in pumping the air than is lost in coming up to speed. a Better solution would be a super light ceramic Turbine rather than in a flywheel/clutch system-- jhomrighaus, May 31 2006 I know that this would actually create lag while running, but the the point of this is to be able to accelerate faster from a stop or coasting. And this isn't about efficiency either.-- BJS, May 31 2006 When the clutch engages, the momentum is conserved, and the turbine will quickly slow down as its energy goes to the compressor. You'll accelerate quite a bit more slowly because the efficiency will drop during this momentary phase and the clutch and flywheel will add weight.-- kevinthenerd, May 31 2006 Nice attempt, I believe BMW had some racecars that bridge the turbogap by using a second tiny turbine that kicks in at lower RPM and supercharger the motherturbine. Yet another option would be to use fit a hybrid car like the Toyota Prius with a turbo and have the electrical engine charging the turbo.-- jvanguts, May 31 2006 the change in the rate of exhaust flow is an important component of turbo performance. a supercharger is the best option for getting around this problem and has been used in combination with turbos.(or a superlight rotor)-- jhomrighaus, May 31 2006 Okay, you add the weight of the clutch to the rotating mass of the turbine, there's a lag between applying gas and the activation of the clutch, then there's lag as the clutch drags the blower up to speed, then there's more lag as the blower and turbine together speed up enough to start doing something useful. KISS - adding steps and parts won't add functionality in this case. It's just one more bit to break.
The bit about using a tiny turbo was right on. Nissan had a variable vanes on the input side of an 80's model to keep the turbo revs up, too. Whether that worked well is questionable, as I don't think they offer that on any model now. I like the hybrid approach, in this case not from the Prius philosophy but the Honda Accord philosophy. Honda has positioned their Accord Hybrid as the premier model, and the motor assist adds gobs of torque at ZERO revs. Turbos can't touch that, and it makes the Accord H a surprisingly quick ride that gets impressive mileage. Points for trying. I'm not boning it, but not bunning it either.-- elhigh, Jun 07 2006 random, halfbakery