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| 3/4" piston travel | |
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| Tweet Topic Started: Apr 25 2014, 07:47 PM (726 Views) | |
| dayle1960 | Apr 25 2014, 07:47 PM Post #1 |
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Fastest Hampster EVER
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Today I noticed a fellow with a 2 seat Lotus and started a conversation with him. We talked about different kinds of high end cars (mostly Euro trash) but one thing he did say which stunned me was the engines in F-1 cars. He said their displacement was around 2L and they tuned about 17K rpm. But what really threw me for a loop was how far the pistons traveled. They only moved 3/4" in the cylinder. A very short throw. Also he stated that since the rpms were so extreme, the valve springs could not be used because they wouldn't close fast enough. So there are accutators which open and close the valves. Pretty heady stuff for a small engine, huh? |
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| AlexK | Apr 25 2014, 09:03 PM Post #2 |
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Advanced Member
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That sounded unbelievable so I googled it: http://en.wikipedia.org/wiki/Formula_One_car It says bore is 100mm and displacement is 2.4l and 8 cylinders. That gives 38mm stroke, about 1.5". So 3/4" is the throw on the crankshaft journal but piston stroke is double that. Still pretty small for a 4" diameter piston. Ducati has been doing the forced closed valves for a long time so it wouldn't surprise me F1 is doing that too. |
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| Metromightymouse | Apr 26 2014, 03:51 AM Post #3 |
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Powdercoat Wizard
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And the tolerances in the engine are so tight that when cold the engine is essentially "seized". They pump heated oil through the block to warm it up before they can start it. |
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| t3ragtop | Apr 26 2014, 06:55 AM Post #4 |
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Turbo3 and Twincam Tweaker
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if internal combustion engines continue, valve actuation will be done using compressed air systems and electronic controls which will supercede camshafts, valve springs and other types of power robbing mechanical valve actuation. there is a swedish high end car builder who pretty much robbed the now defunct saab automotive group of their best engineers who has working pneumatic valve actuation built into a saab inline 4 16 valve head. the technology is very trick. with individual control of valve timing you can do dynamic variable valve timing and have full programmable control of valve overlap, trim, etc. |
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| 3tech | Apr 26 2014, 09:12 AM Post #5 |
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Manufacturers have been trying to make that work since the 70's. I'll be surprised if we ever see that in production in our lifetime. |
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| perfesser | Apr 26 2014, 09:39 AM Post #6 |
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Elite Member - Former Metro owner
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The Cosworth GBA V6 had a 1.5L displacement. It was Cosworth's first V6 and their first turbo application for F1. The bank angle was 120 degrees. Due to the tight security they placed on these, I haven't been able to find the bore and stroke, but it would put out 1200+ HP at 12,000 RPM, which sounds awfully fast until you realize that the CA, a 3.0L V8, turned over 20,000 RPM on the track in 2006 before the FIA slowed engines down. |
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| perfesser | Apr 26 2014, 09:54 AM Post #7 |
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Elite Member - Former Metro owner
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Koenigsegg already has it in production. |
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| perfesser | Apr 26 2014, 10:05 AM Post #8 |
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Elite Member - Former Metro owner
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Koenigsegg is really close to production with theirs. He wouldn't talk about it in the video if he wasn't confident in it. If the article's video doesn't work, try this. He shows it in use in his Saab, where it's been used for 2-1/2 years. He's on the 5th generation of this now. |
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| 3tech | Apr 26 2014, 10:11 AM Post #9 |
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No they don't. They're still working on it, like most of the other auto manufacturers are, and have been for a long time. |
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| t3ragtop | Apr 26 2014, 10:24 AM Post #10 |
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Turbo3 and Twincam Tweaker
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that was the outfit i was talking about. it's not in production but it is running on their test mule. they have been driving it for over a year.
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| myredvert | Apr 26 2014, 10:28 AM Post #11 |
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myredvert
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The Koenigsegg video was fantastic. I had to force myself to watch that ugly slow red car at the beginning though. I wish he had talked more about the system they are using for bleed or compressed air to drive the valves. He talked about the power source only briefly and in very general terms, and neglected discussing specifics about the inherent power losses associated with providing various types of systems (bleed air, compressed air tanks, accumulators, etc.) to drive the valves. Which tells me that may very well be one of the main engineering issues they are trying to work out and optimize before it gets into production. |
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| punkozuna | Apr 26 2014, 11:10 AM Post #12 |
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A previous generation of F1 engines - 3 liter v10s, naturally aspirated - could turn 18K rpms and used pneumatically actuated valves. Some where thought to have 1.8:1 bore to stroke ratios with compression ratios of around 8:1, 5 or 6 valves per cylinder and up to 3 spark plugs per cylinder. This year's turbo v-6s are limited to 15k rpms and aren't allowed to use the pneumatic valves. They also have more strict fuel limitations. The total amount of fuel carried and the maximum allowed fuel flow rate is more limited than before. The Kinetic Energy Recovery Systems (KERS) are very interesting - they recover braking energy and excess energy from the turbo charger and can deliver short bursts of up to 200hp when they give back the recovered energy. The KERS systems are small and light and I can see that production versions in normal cars would be a very useful fuel saver. Beyond that I bet that, since the RPM and fuel is so limited, that the modern engine designs emphasize friction reduction and combustion efficiency. It's funny - I don't really follow the F1 races but I work with a guy that's an F1 nut and I'm interested in engine/car technology. F1 has a history of messing around with things and pissing off their competitors and fans. I'm old enough to remember the Tyrell 6 wheeled cars, the 1.5 liter turbo v12s that would make almost 1000 HP. The huge wings that created so much downforce that the suspension springs were so stiff that it was called the "1000 HP go kart era", the "beet juice" fuel era where the fuel handlers had to wear full hazmat suits (the mystery stuff was though to be very carcinogenic), the electronic controls era (ABS, traction control and ride height and aerodynamic stance all controlled by computer - all illegal now), the pneumatic valved cars and the current turbochargers plus KERS. Very interesting stuff. Mostly it is rule changes to make the racing safer or more competitive and the cleverness of the engineers to eventually make cars so fast using the current restrictions that they have to place more restrictions on them. |
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| Woodie | Apr 27 2014, 04:13 AM Post #13 |
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1000 HP was minimum just to get in during the 1.5 litre era. Qualifying engines put out more like 1300 HP. And yes, the V-8's of the last formula were doing 20,000 RPM and still climbing every year until the FIA put an 18K limit on them in the interest of reducing cost. Now they've made them throw out everything and come up with a new, unbelievably complex "power unit". So much for controlling casts, once again, the rich teams seem to have benefited. There's a KERS system on the turbocharger which turns exhaust energy into electricity and can also be used to spin up the turbocharger to minimize lag. Mercedes has split the turbocharger into two pieces, hot side behind the engine, cold side in front of the engine with the KERS-H motor/generator in the V of the engine connecting the two together, capable of spinning up just the intake side, let the exhaust side slow down if warranted. |
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