Recent content by fredric21

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    Automotive Can You Turbocharge a 62 cc Two-Stroke Engine?

    Hi Bluechpx. I thought I would keep you up to date on progress with my own radical two-stroke design. At long last I have completed the prototype and it is installed on the test bed. I have had some problems with oil supply which have now been sorted, but I still need to sort out the...
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    Two-Stroke Engine Tuning: Maximizing Performance

    If only life was that simple for the two-stroke! The problem with poppet exhaust valves is two-fold. a) the tremendous amount of heat that needs to be dealt with at high bmep's, due to the extra power strokes, and b) inertia loading on the valve train, limiting rpm.
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    Two-Stroke Engine Tuning: Maximizing Performance

    If it were only so simple, then we would have Saab two-strokes, Trabants, Warburgs, and NSU's dominating the Automotive market, but we don't, because direct injection is not the magic wand for the genre. We don't have any two-stroke motorcycles being manufactured currently, not even for racing.
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    Two-Stroke Engine Tuning: Maximizing Performance

    It's the actual time available for injection that's the problem. I have discussed this with Siemens technical staff.
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    Automotive Can You Turbocharge a 62 cc Two-Stroke Engine?

    Hi bluechipx, This was meant to be a reply to chkneater posted on Jan 10th. this year. But, as we are on the subject, check out the Chrysler Two-stroke engine developed for the Neon. See:http://www.allpar.com/neon/stroke.html Are you still sceptical?
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    Automotive Can You Turbocharge a 62 cc Two-Stroke Engine?

    What on Earth are you talking about when you say that superchargers are "overkill" for two-stroke engines? If, as you suggest, we are to keep the two-stroke engine "simple", by which I assume you mean piston-ported and crankcase scavenged, then you are stuck with resonating pressure pulses to...
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    Automotive Can You Turbocharge a 62 cc Two-Stroke Engine?

    I must correct you here. The RR Crecy was most definitely a two-stroke and had Ricardo-type sleeve valves. If you don't believe me, I suggest you read the book on the Crecy by Nahum, Foster-Pegg and Birch, which is the definitive work on this engine. On a further note, the prototype of my...
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    Which Engine Type Should Car Manufacturers and Buyers Choose?

    The smaller engine would have to win every time. Because the parts are smaller, raw material costs are lower. Smaller bores and strokes mean less friction and less total area for heat flux into the coolant. The entire engine will be lighter and more responsive due to less part inertia. Higher...
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    Automotive Can You Turbocharge a 62 cc Two-Stroke Engine?

    Excuse me, but a supercharger for scavenging and a turbo for boosting the charge pressure is the only way to go in two-stroke development. Get rid of piston-controlled porting and you have a winner. 460 psia BMEP's are easily possible with such a set up. Check out the Rolls Royce Crecy from 1944.
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    Two-Stroke Engine Tuning: Maximizing Performance

    Yes, direct fuel injection would indeed appear to be the answer. The problem is, however, that at high speeds, there is very little time available after exhaust closing to allow sufficient fuel to be injected before the point of ignition, (typically less than 2msec.) in a conventional, piston...
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    Automotive Can You Turbocharge a 62 cc Two-Stroke Engine?

    My old-time colleague, Peter Halman who now is a partner with Ripmax Ltd, has produced a 2.5cc, 0.15cu.in. glow motor that actually produces 2.5BHP at 40,000 rpm on methanol only...no nitromethane or other oxygen-bearing additive. I believe the bore to be about 14mm, giving a piston area of...
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    Automotive Can You Turbocharge a 62 cc Two-Stroke Engine?

    Yes, of course this is pure theory...what else! However, the prototype is under construction and I will let you know the real world results in due course, when I get it on the test bed.
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    Automotive Can You Turbocharge a 62 cc Two-Stroke Engine?

    Ok, here's the maths. Total mass flow through engine is 18,750 litres/min. for bmep 460 psia at n=12 Piston area = 25.136 Stroke = 0.1ft. rpm = 12,500 Using formula BHP = PLAN/33,000 = 431 At 17,550rpm, BHP= 605 for piston speed of 58ft/sec.
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    Automotive Can You Turbocharge a 62 cc Two-Stroke Engine?

    Yes, this is fairly impressive, but my 500cc twin is designed for 605bhp at 12,500rpm and uses 3.7 bar pressure at induction, with no detonation. BMEP's up to 460psia. Piston speed 12m/sec. It also utilises dry sump lubrication with cooling and plain bearings, with oil supplied at 3.2 bar and...
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    Two-Stroke Engine Tuning: Maximizing Performance

    Your idea for a valve in the exhaust in the form of a fenestrated disc is a poor one I'm afraid. You would have major problems with both sealing, friction and lubrication. You would also have to deal with uneven heat distribution within the disc itself, not to mention the problem of carbon...
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