CVT

All cars are an exercise in compromise. A major limitation of the internal combustion engine is that it has a fairly narrow rev range where it is efficient in terms of power output for fuel used. Anything outside that band and you start to lose efficiency. This is why electric cars, electric trains and boats are efficient transport. The engine spins at close to it's ideal rev range almost all of the time because they have flexibility built into the drivetrain.

Cars on the other hand, have to vary their speed significantly and often and have a rigid connection between the engine and the tyres on the road. So gears were added. These allow cars to keep their rev range somewhere around their most efficient level but still be able to vary their speed. This applies to both manual and automatic transmissions.

A new kind of transmission has been developed. CVTs (Continuously Variable Transmission) have a theoretically infinite number of gear ratios, allowing the engine to stay in it's most efficient rev range regardless of the road speed. It's a great technology.

You know how lots of automatics now have that 'semi-automatic' mode that allows you to change the gear up or down by moving the transmission selector to the side and moving it forwards or backwards? This always seemed odd to me, because why not get a manual and enjoy the improved efficiency.

So here's the funny part. Yet another example of marketers taking a great engineering idea and weirding it. Nissan has released a car with CVT and they've put in this 'manual' mode. They've taken a masterpiece of engineering that allows an infinite number of transmission ratios and they've deliberately hobbled it by forcing the transmission to stick at certain pre-defined ratios! It's like developing a new, propellent-free rocket, but NASA deciding that the big flames coming out of the space shuttle were more 'dramatic' and putting a rocket engine on the back to produce the flames.

A glimpse into the future

The guys at Pointless waste of time have done it again. There's a hilarious and well written prediction piece about how virtual reality will become the preferred place to live. Click here to read.

He raises some interesting questions. I don't know the answers, but I enjoyed pondering as I read.

Gyroscopes

Check out the gyro car and the gyro train.

They are two wheeled vehicles like motorbikes that use gyroscopes and precession to stay upright, even when they're stationary. They work by having a reasonably sized gyroscope mounted in the vehicle. Tilt sensors detect the vehicle starting to tip over and apply a force to the spin axis of the gyroscope. Precession causes this force to be translated by 90 degrees, righting the vehicle.

More (and probably better) information is provided by HowStuffWorks.

Extra Value Pack!

I went shopping at coles today. I went to grab my normal-sized container of stuff when I noticed a larger "Extra Value Pack". I figured, cool, it has to be cheaper because it's "Extra Value".

But then I decided to check. Of course, the larger pack wasn't any logical multiple larger than the small one (that would have made it easy), so I had to use a calculator.

It turned out that the "Extra Value" pack actually cost more per gram than the regular size! Damn marketing lies!

"Extra Value" my ass.