Quote:
Originally Posted by serialk11r
What's wrong? Press the gas harder when it goes into V8 mode, then it'll be more efficient.
The point of a hybrid system or supercharger/turbocharger is to add power efficiently, but here you already have a lot of reserve power so that's not what you want.
|
That is not true. I cruise interstate a lot. That is where this system is to be used. Interstate cruising. Not 40mph country roads. Not during acceleration in town. When the truck kicks into V8 mode, I'm going up near 70mph. I can cruise at 70mph in v4 mode on the interstate unless there is any sort of incline or any sort of head wind. Even a slight breeze in the wrong direction will make it kick into V8 mode. My instantaneous mpg goes from a very stable 24mpg right on down to 17 as soon as the v8 mode kicks in. No change in speed. Just a little parasitic head wind that increased the load on the engine just slightly enough to cause the truck to kick into V8 mode.
So you go ahead and acclerate beyond 70mph in a truck thinking that will get you better mpgs, but you are wrong. The engine's thermal efficiency may increase under load, but the vehicle will also encounter exponentially higher parasitic losses from wind drag and road load when you accelerate any further. So, you get fewer mpg when you accelerate beyond the speed at which wind drag load causes this truck to kick into V8 mode.
The point of a hybrid system in this case is to harvest power from regenerative braking and use it to add power when the vehicle is nearing the upper limit of how much load it can work against while still staying in V4 mode. The truck gets its best gas mileage when in V4 mode, and it does not have much reserve power when in V4 mode, because it switches to V8 mode at the slightest hint of load onset. Instead of kicking the truck into V8 mode as a response to transient load onset, I will counteract that load with the electric motor. So the V4 is working as hard as it can, and the electric motor is taking up the rest of the work.
How much experience do you have with cylinder deactivation systems? Maximizing the use of that system is a crucial part of what I'm trying to accomplish with this project. The other crucial part is the fact that I'd be accomplishing that task purely with energy that was harvested through regenerative braking.