Oak Ridge National Lab Prius Evaluation

This is a very thorough and detailed article explaining the function of the hybrid system of the Prius...43 pages, but quite impressive.

 

do not know guys, seems to work fine for me.

 

I don't know if it's so much 'ominous' as maybe a noteable area for potential future improvement. There are lot of gears and thus a lot of contact and friction which will, obviously, result in losses. If an improved PSD (power split device) could be designed that could 1)Handle the torque and 2)lower frictional losses, you could have a marked improvement in efficiency.

 

That was the first time I'd heard that mentioned too:

From: http://www.gmpperformance.com/products/eng...perchargers.htm

Supercharging is also known as forced induction. When an engine is normally aspirated (draws in air without assistance) it relies on atmospheric pressure (at sea level approx 14.7 pounds or 1 bar) to push the air into the manifold (running under vacuum) and into the combustion chambers (cylinders). Due to internal restrictions along the air path, the normally aspirated cylinder is never able to completely draw in a full charge of air/fuel mix. In general a supercharger is anything that will force more air, or air/fuel mixture, into the cylinders of an engine at a faster rate than would be drawn naturally by the suction of the pistons during the intake stroke (putting the engine into positive pressure). This process is used to increase power and torque of an engine.

Types of supercharger?
There are several fundamental designs of superchargers (roots, screw, vane, rotary, axial flow and centrifugal). Each design has its advantages and each are differently suited to different types of application. The most commonly used today for aftermarket supercharger kits are the roots and centrifugal. The roots units, ideally need to be mounted on the plenum chamber but the centrifugal type is not restricted in this way. However all supercharger units need to be mounted to take a drive from the engine crank pulley by a serpentine belt.

Parameters of supercharging?
Performance modifications /customization to a vehicle are termed as 'Aftermarket' or 'Retro-fitting'. When retro fitting a supercharger, an important factor is the natural compression ratio of an engine. Supercharging as an aftermarket technique is typically setup to create a 40% power increase. More power can be produced if the compression ratio is suitable.

Why supercharge?
Compressed air contains a greater amount of oxygen molecules which improves the fuel combustion cycle. However this requires that the fuel mixture and ignition cycles be altered / increased to suit the increased volume of oxygen. Retro-fitting a supercharger usually provides a much larger power gain compared to other aftermarket modifications such as capacity increasing which is also expensive. Supercharging with a centrifugal supercharger is less obtrusive to the vehicle and reversibility is simple to incorporate into its design.

Fuel Efficiency
A centrifugally supercharged engine will operate under vacuum until the ECU determines the motor is at wide open throttle (full throttle). At this point the engine goes into positive pressure (onto boost). Upto this point the fuel consumption is not affected. When driving hard and on full throttle the supercharged engine will be creating more power and hence using a greater amount of fuel. Fuel consumption usually increases in the region of about 10% depending upon how often you drive under boost and the type of supercharger you have fitted.


Also, Adobe 6 IS completely compatible with FireFox, it's my browser and every pdf opens fine.

 

Foxfire 1.0
Acrobat 6.0.2xxx