Question on ICE warm-up

I do know why it warms up the catalytic converter. What I object to is the assertion that the car does not use the mechanical output of the engine for the first 57 seconds that it is running. On the face of it that would be a waste of fuel. What benefit would there be in it?

 

<div class='quotetop'>QUOTE(richard schumacher @ May 19 2007, 12:05 AM) [snapback]444851[/snapback]</div>

Ignition timing.
During the first 57 seconds, the ignition timing is very late, about 9 degrees ATDC.
This causes very hot exhaust gas, almost flame, to warm up the catalizer.
At this point, we can't expect good output torque from engine, thus Prius uses electric only to drive it.
If you listen the engine sound carefully, you'll notice the ignition timing change point just after 57 seconds from start. It is well-known S1a to S1b transition of warming up stages.

As everyone said, it's for reducing emissions.

Ken@Japan