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, Tue, 2 Dec 2014 00:25:08
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I used to feel that Saab engine technology was very special. But not now. Today you can purchase many affordable vehicles with high compression engines that use regular gas, direct injection, direct ignition, performance is very good, high MPG's and variable valve technology on the intake and exhaust valve trains.
Note that [modified] Atkinson cycle engine require direct [fuel] injection and cannot be done with port injection.
Years ago, if you wanted variable valve technology, you needed to purchase a BMW M3.
Engine technology is evolving. This seems to be driven by the costs of highly taxed fuel in Europe and the USA regulations driving higher MPG's.
There are many turbo engine options now. With water cooled turbo bearings, these should be reliable.
Saab DIC technology: The use of knock sensing via spark plugs was a great technological leap. But if more conventional methods produce better engines, the reason to be may not exist today. I think that some other systems are using some aspects of Saab DIC, ignition detection, multi-spark etc.
Saab spent a lot of time and money exploring variable compression technology and seemed to have become frozen in that moment. Modified Akinson cycle engines to achieve variable compression engine features, but at the cost of lower energy density. [This seems to be compensated by implementing aggressive transmission downshifting and higher engine RPM's.]
There are also many turbo charged performance oriented engines that deliver better MPG's. These do require premium fuel. There is a limit to what one can do with a modified Atkinson cycle engine with its higher compression ratios [for efficiency] and supercharging that requires lower compression ratios to avoid knock at high boost pressures. By applying diesel engine fuel injection techniques, these engines may be able to achieve high power density with lower octane requirements. [http://www.wired.com/2014/10/volvo-turbo-engine-concept/] There are 2 liter I4 engines that develop high power outputs on 87 octane fuel, not prototypes, these are at the dealers now.
posted by 108.207.11...
https://en.wikipedia.org/wiki/Atkinson_cycle#Vehicles_using_Atkinson_cycle_engines
, Mon, 1 Dec 2014 12:12:27
, Tue, 2 Dec 2014 11:54:47
, Thu, 4 Dec 2014 12:25:11, Mon, 8 Dec 2014 08:06:08, Tue, 9 Dec 2014 06:59:51, Fri, 5 Dec 2014 19:22:45
, Wed, 3 Dec 2014 14:28:59, Thu, 4 Dec 2014 17:19:28, Wed, 3 Dec 2014 14:48:58, Wed, 3 Dec 2014 19:01:35, Wed, 3 Dec 2014 17:35:12, Tue, 2 Dec 2014 18:34:45, Tue, 2 Dec 2014 19:36:18, Tue, 2 Dec 2014 12:39:12, Tue, 2 Dec 2014 18:06:16
, Tue, 2 Dec 2014 12:19:00, Mon, 1 Dec 2014 21:37:57, Mon, 1 Dec 2014 18:18:50, Mon, 1 Dec 2014 15:18:21, Tue, 2 Dec 2014 00:25:08, Tue, 2 Dec 2014 18:04:43
, Tue, 2 Dec 2014 12:18:02
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