4 cyl. crankshaft excitations.
4 cyl. crankshaft excitations.
(OP)
Hi guys,
I know this is trivial, but I need more information.
Was wondering if anyone knows of some technical papers that illustrate crankshaft angular excitations for a 4 cyl. IC engine. Preferably something that illustrate how much the excitations diminish with RPM.
Thanks!!
I know this is trivial, but I need more information.
Was wondering if anyone knows of some technical papers that illustrate crankshaft angular excitations for a 4 cyl. IC engine. Preferably something that illustrate how much the excitations diminish with RPM.
Thanks!!





RE: 4 cyl. crankshaft excitations.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: 4 cyl. crankshaft excitations.
This paper seems to indicate they decrease to an extent. http://papers.sae.org/2009-01-1938/
RE: 4 cyl. crankshaft excitations.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: 4 cyl. crankshaft excitations.
- Steve
RE: 4 cyl. crankshaft excitations.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: 4 cyl. crankshaft excitations.
It is the 2nd order (I presume 2E). That's useful information Steve. Are their any circumstances when it would not increase after 3000rpm?
RE: 4 cyl. crankshaft excitations.
The first is amplitude at given orders vs speed, where you can see 2E hitting a minimum.
The second is more interesting. It shows speed variation from mean through each engine cycle and (I think) you can see the 2E shape from gas forces decaying with speed as the 2E from inertia kind of rises out of the valleys. 2E is the dominant shape at each end, but there are two clearly unrelated sources.
You can see the point where the load goes on and also the shuffle it causes too, in the plots vs time. Nostalgia. I kind of miss those days. So much data to analyse. Matlab on hand to dig the story out of it.
- Steve
RE: 4 cyl. crankshaft excitations.
Seems to be dominated by 2nd order. I wonder how far the second plot's 2nd order slopes back up at sat 5000 rpm.
RE: 4 cyl. crankshaft excitations.
Cheers
Greg Locock
New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?
RE: 4 cyl. crankshaft excitations.
RE: 4 cyl. crankshaft excitations.
I need to know a representative (ballpark) maximum value of repetitive (vibratory) crankshaft angular acceleration (supercharged 3 liter inline four cylinder) at ~10,000 RPM (shooting for 725 HP @ ~9,000 RPM). The only "dampers" will be the vehicle drive off the flywheel end, and supercharger drive off the snout (a significant load- 30 PSI boost). Perhaps one of you can save me blindly buying SAE papers to look for this (I'm not an SAE member)? Or- to "cut to the chase"- are angular accelerations at least a factor of 100 smaller than the 8,500 G's radial acceleration of a point near the circumference of its counterweights?
RE: 4 cyl. crankshaft excitations.
Manolis has some nice tools on his site.
Engineering is the art of creating things you need, from things you can get.
RE: 4 cyl. crankshaft excitations.
I'd like to revive this thread for a moment. Any data for that same or similar engine above, but for C/S instantaneous torque?
I'm looking for the difference in mean torque in the rpm range and the instantaneous firing pulse torque.
Thanks,