Tom wrote:Rotary valves themselves are at least 50 years old and have been used by Mercedes in Grand Prix racing before.This has been discussed before and I'm pretty sure we discovered it was against the regulations. I'm sure there's an even better system out there too.
Please direct me to the link of the better system?
Conceptual wrote:Please direct me to the link of the better system?
topgear.com wrote:Frankfurt show: Mercedes F700
[url=http://www.topgear.com/content/news/stories/2220/]September 12, 2007[/url]
One of the undoubted stars of the Frankfurt show isn't a car at all, but rather an engine: the DiesOtto in the Mercedes F700.
Not that the F700 is anything less than imposing (and more about that in a tick). But if the DiesOtto's performance and economy turns out to be even close to what Merc is quoting, well, it could revolutionise the combustion engine.
In brief, the DiesOtto is a 1.8-litre, four-cylinder petrol engine. That might sound small in a car the size of the F700 - which is longer than an S-Class - but Merc reckons that it'll produce comparable performance to the current 3.5-litre V6 in the S: 238bhp and a 0-60mph time of 7.5 seconds.
And all that with consumption of just 44.3mpg and CO2 emissions of 127g/km - astonishing figures for such a big car.
It's all down to the DiesOtto's ingenious ignition system, which combines the best bits of a petrol and diesel engine. On start-up, the engine runs in standard petrol mode, with spark plugs igniting petrol injected directly into the cylinder.
But once the engine is warm and cruising, it switches to a more efficient 'diesel mode', raising the compression ratio and deactivating the spark plugs.
modbaraban wrote:This may be interesting
Tom wrote:Please direct me to the link of the better system?
Ciro Pabón wrote:... the forum agreed on four "problems":
- no variable timing (that's perhaps the answer to the thread's question)
- poor sealing (worse at high RPM)
- oil leaking (idem)
- position of spark plug is not optimal
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