Vagueness and the Aftermath - A sporadic diary

[bobby1]

Phil. Where has your gay Spiderman gone?

oh no, he appears to have left me. Will have to find a replacement toot sweet.

On the subject of eating out why do restaurants serve their clients with a chunk of bread to eat before they eat the food they have actually ordered?

Are they not just filling up their customers with very cheap or in some cases free food and minimizing the courses they sell to those customers?

[RED-DOG]

Phil. Where has your gay Spiderman gone?

oh no, he appears to have left me. Will have to find a replacement toot sweet.

On the subject of eating out why do restaurants serve their clients with a chunk of bread to eat before they eat the food they have actually ordered?

Are they not just filling up their customers with very cheap or in some cases free food and minimizing the courses they sell to those customers?

I don't know, but I do lurrve the bread and eat far too much while waiting for my meal.

[Redsgirl]

It's some kind of engine isn't it? I can see a spark plug and a piston and an exhaust?  

Well done.

Yes, it's an engine, but what kind? Look at what happens during each stroke of the piston.

Erm, I'm not sure, fuel goes in, spark plug lights it (internal combustion) gas pushes piston down, turns crank, fumes come out?
That about covers all of them dosent it?  

Excellent!

Now compare these models. What is different?

There are two valves controlling the fuel input? Not sure if that would change how it works.

There is also a big counter weight on that one.  

[EvilPie]

Is one a 2 stroke and the other a 4 stroke? Also known as the otto cycle if I remember correctly from school?

[Redsgirl]

Hang on, is one going round more times on less fuel?

[EvilPie]

Or is it a rotary (Wankel) engine?

[Skippy]

Is it... a one stroke engine?

[EvilPie]

 

One's got fuel injectors the other is standard carbs?

[RED-DOG]

Is one a 2 stroke and the other a 4 stroke? Also known as the otto cycle if I remember correctly from school?

Correct Matt.

A 4 stroke engine uses one downward  stroke to draw in a fuel and air mix, this is called the intake stroke. The next upward stroke, the 'compression' stroke squeezes the fuel / air mix to the top of the chamber where it is ignited by a spark. Now the piston is driven down again in what is known as the 'power' stroke, and then the final 'exhaust' stroke pushes out the burned gasses. So 4 strokes = one cycle.


Now, look how cleverly the other engine accomplishes all that with only two strokes.


Now look again at the four stroke engine. All the fuel and exhaust gasses are confined to the top of the piston, thereby allowing everything below the piston i.e. little end, con rod, big end, crank etc to sit in a nice bath of oil. That's not possible in a two stroke engine because the fuel / air intake is below the piston.

What simple but ingenious solution to that problem did they come up with?

[pokerfan]

They've reinvented the crankshaft.

[RED-DOG]

They've reinvented the crankshaft.

Nope! That would be too easy.

[david3103]

They ran it on 'mixture'.

[Mohican]

Two stroke?

[RED-DOG]

They ran it on 'mixture'.

That's right. they put the oil into the fuel, usually at a ratio of 50 / 1.

That way, every time fuel is drawn into the engine, the moving parts get a fresh coat of oil.

Two stroke engines are noisy and dirty but wonderfully efficient and reliable, and because they don't have a crank case full of oil to spill, they work just as well upside down. (Which is great for chainsaws).

 

[RED-DOG]

Two stroke?

Yes. The mixture is usually referred to as "Two stroke".