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The maximum piston speed decreases with shorter stroke engines. Less wear at high revs and higher bhp.
That is a bit cart before the horse. Long stoke engines are restricted to comparatively low revs vis-a-vis shorter stroke engines.
Mix that with a half of St Edmunds;)...
You'll need more then Aspirin;!..
They didnt so much use it, as get infltarted and funded by people with a political agenda that had almost nothing to do with ecology.
same as happened to te labour party in the 70s' - it ceased to be anythng to do with actually improvng the lot of the common man.
its ratrher that the stresses in a long stroke engine are higher at a given rev range.
I had an interesting discussion with someon about this,- we were discussing diesels and turbocharging - and he reckoned, and I agree - that turbocharging entirely changes the game, by taking the ability to 'breathe' well out of the design, so you can go for very high cylinder pressures and longish strokes and get alarming torque, as long as the engine is strong enough and the thing doesnt detonate.
more torque. less revs. unfortunately poweris torque time revs sqaured, so it generally means less power..
I had a dsucusson some years back with Brian Hart - the man who desiged F1 and endurance racing engines - and he said it was all down to breathing. The short stroke engines could rev like hell and there was room in the heads to make the heads pretty much 'all valves' ..and that was what you did. 4 valves pretty much was the biggest valve area you could get, so that the way it was done.
then it was all down to strong enough, light enough, cool enough, fast enough so ceramic pistons, titanium valves with sodium cooling in them..etc etc.
Rev limiters changed that a bit.
Next years turbo engines will be interesting, as are the crop of le mans winning diesels.
I cant remember the details, but the F1 engines are restricting fuel flow I think, so the prizes will go to whoever can screw the max out of the fuel and energy recovery systems. They are also rev limited to
15,000 rpm and a single turbo is specified BUT with modern variable gemoetry turbos that's no big deal. Peak power may well no longer be at peak RPM, though I suspect it probably will be.Cylinder pressures will be massively high - they are allowed up to 500 bar injection pressure straight into the cylnder, which gives an indication of what they will be doing there.
The races will probably be boring, but the engineering certainly won't be.
Monbiot is also pro nuclear.
They could hardly do otherwise, but that does not make him wrong about them.
Colin Bignell
No, the bore is cylindrical. The piston fits it when hot so reducing wear and tear. It expands more at the top as it is hotter. So it is made smaller at the top. (ie tapered)
The barrel shaped/ovality thing reduces wear on the skirt due to the angularity of the thrust. It is not even symmetrical, there is a thrust side to these pistons, (it only goes in one way round.
Common sense when you think. Obviously a lot more expensive to make. It amounts to a part worn piston in an unworn bore.
And applies equally to long and short stroke engines. The advantage of short stroke/over square engines were that they could work to higher speeds so delivering more power for a given engine capacity. But at a reduced lifespan/increased wear.
Enthusiasts used to "blueprint" engines to try and wring more power etc Nitraded crank/conecting rod and such crap.
Passed through that phase myself but it is a juvenile pursuit. I had one of these.
But unless you understand the theory of how engines work, all pretty futile
Actually, not really - it's just been massively superceded by hugely improved tolerances in any engine built since about the 1950s. Oh, and - in anything from the last couple of decades - far greater improvements available through twiddling the electronics.
A 1990s kit car based on a Triumph Herald? Did you really? Or do you mean one of these...?
One simple letter, but it illustrates so much.
I note nobody gives figures for the NG TD performance. However, if it was similar to the MG TD (a car I quite like, although TAs were more popular rebuild projects when I were a lad and, IMO, better looking), it is little wonder that Harry feels at home in an electric car.
Colin Bignell
It's a kit car. Almost certainly no two would have driven the same.
Actually, I do apologise. MGB based, not Herald.
But, no, nothing whatsoever like the almost-eponymous MG TD.
I think blueprinting is still done. After all you want the engine to be at the limits of the blueprint to get the maximum performance without being out of class and getting disqualified.
Yes, it is. But not by Joe Public for road motors.
Power-to-weight ratio is also of some interest...
It's probably no accident that the most efficient engines are in ships.
Andy
actually they are in power stations.
It wasn't by joe public for road use, they just bored it out as far as it was possible.
I'm sure there used to be a habit of manufacturers publishing 'typical' figures and reviewers giving figures 'in this configuration'.
Many years ago, a friend and I looked into building a copy of the MG TA. That would have used a Triumph engine as they were very willing to discuss supplying engines to a small manufacturer. They even gave us a tour of their engine plant, which was then working hard on a yet to be announced V8 engine, which later appeared in the Stag. The thing that really killed the project was the tyres. The only ones available for the size of wheel we wanted to use were Dunlop Fort tyres; an old design even then. We didn't think they were adequate for a car with 'modern' performance.
Colin Bignell
No,it was MG based with a 3.5 V8 engine.
It had a 3.5 V8 engine, slightly tweeked.
Engines have been made with only one valve per cylinder. Lots of valves may improve the perfomance of an engine but have only a sligh improvement on efficiency.
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