Electric cars

[Linford]

Very economical 2 stroke engines?
Cheap to build, certainly. Economical to run? Far from it.
And as a consequence of the design, they pump unburnt fuel and oil into the air.
They were banned for very good reasons.

EDIT - IIRC, two-strokes aren't banned, as such. It's just that it's impossible to engineer one to get the emissions low enough...

The emissions are mostly 2 stroke oil in being a total loss system which produces unburnt oil itself and soot (which could be trapped). The petrol side can be made to be very efficient through supercharging. Many supertanker engines are 2T running on heavy oil and they have amazing efficiency given what they are asked to do as well as clean burning given what they are burning http://www.gizmag.com/go/3263/

2T petrol engines have the potential to be much more efficient than a 4T engine by virtue of the fact that every other stroke is a power stroke on a 2T as opposed to one in four.

Their day will come again..the engines have much less parts to fabricate, or wear out. their downfall is that they break rings regularly as they bulge into the ports on each stroke.

 

[TheDoctor]

To compare 2 stroke petrol engines with 2 stroke diesels is unrealistic.
They're not even close to being the same.
A 2T diesel has conventional sump lubrication and doesn't rely on crankcase scavenging using oil as a consumable. If you think, however, that the 2T diesel is a practical engine for a road vehicle, then best of luck with that. It's good for trains (Deltic, anyone?) and superb for ships, but for a motorbike? Not so much. It never caught on with lorries, let alone anything smaller.
As for petrol 2 strokes, an engine that is constantly running on the verge of oil starvation (seizing) strikes me as less than ideal. It has fewer parts, sure, but they need replacing so ruddy often. 2T petrol engines are inherently dirty and unreliable. It's just the way it is.

 

[slowmotion]

Is an electric car "energy efficient"? The electricity comes from somewhere, a power station, which uses fuel to generate it. It's just somewhere else. What is the embedded energy content of its manufacture and scrapping?
As somebody once said, " Driving an electric car and feeling good about it is rather like feeling smug about teaching your dog to crap on your neighbour's lawn"

 

[ufkacbln]

Is an electric car "energy efficient"? The electricity comes from somewhere, a power station, which uses fuel to generate it. It's just somewhere else. What is the embedded energy content of its manufacture and scrapping?
As somebody once said, " Driving an electric car and feeling good about it is rather like feeling smug about teaching your dog to crap on your neighbour's lawn"

It is all about comparison, and that is where the decisions lie.

A simple approach says that an electric vehicle in use is more efficient and produces less emissions than an internal combustion engine

However if you want to add the "cost" of producing that fuel then it becomes more complex. Do you add the production of petrol as well and compare the environmental cost of both?
It is whether one is less than the other.

 

[MontyVeda]

The almost silent is a down side

Many of the fleet operators noted that their electric vehicles were experiencing more accidents

This was shown to be because people listened for vehicles and no noise was assumed to mean no vehicle

Noise emitters are often fitted for this reason

I did that once... stepped out into the road without looking because my ears told me it was safe to cross and i quickly learned that bicycles don't make much noise until the rider goes "Whoahhhh!" Since then I've learnt that solely trusting my ears is not the best thing to do and i always look, especially when i hear nothing.

If people learn to look* first, will noise emitters be necessary?

*or trust their guide-dog.