12 replies to this topic

[kike]

I wanted to know if V10 F1 engines use balance shafts. Alternative unbalanced forces are very big at so high speeds. I know that degree of unbalance depends on the V angle and the firing order (optimum or not). Help me please if you know things about it.

[marion5drsn]

Kike; In regards to the Primary and Secondary Shake there should not be any of this present on a 72 degree bank angle as with this angle the two pistons on opposite banks arrive at the same position at the same time, thus no secondary shake. Also the cranks have 10 counterweights as shown on desmos pictures of a Judd crankshaft, thus no Primary Shake! This particular crank has a place for what I assume to be a pendulum type vibration damper. V-10 cranks also need 10 counterweights to balance the crankshaft in the fore to aft direction due to the crank being asymmetrical. As I have stated before it is my belief that the only reason for the use of crank throws being off of the 72 degrees in small amounts is the desire to widen the bank angle for clearance of the intake stacks and to obviate the vibrations that show up no matter how much effort you have made in balancing the Primary and Secondary Shakes. I am also beginning to believe that much of the “odd” vibrations are in the camshafts and valve areas. Also the engines might require dual coolant pumps, alternators and hydraulic pumps that can multiply the vibration problem. These are a few of the reasons I am very suspicious of the claimed “odd” engine bank angles! One must also remember that these engines are dry sumped and might have as many as five suction pumps and one high-pressure pump.
As to balance shafts I doubt that anyone would use them, as the weight penalty is too great. Tuned Lanchester vibration dampers might be much superior in this respect and add to the flywheel effect.This style should cover a somewhat larger range than a balance shaft. The balance shaft usually just rids the engine of a particular type of shake as the one in the Honda four cylinders. The problem here is one of not knowing anything about the balance problems of the V-10 for absolute, as no book I know of covers all the aspects of this. Books as Taylor’s and Bosch and others just don’t have any great degree of coverage if anything at all!
You might punch in V-10 balance in the search area and see what comes up. There has been a lot of discussion on this matter

[desmo]

Amazingly, the Honda-Mugen V-10 did have a balance shaft. I suspect but don't know that the current engines do not.

[marion5drsn]

Mugen-Honda; Since I haven’t any information on this engine I don’t know the bank angle. If the bank angle is other than 72 degrees I’ll just have make a guess! If for an example the bank angle is 108 degrees they will still have no Primary Shake as the Primary Shake is balanced by the 10 counterweights. However the Secondary is another matter, as the pistons will arrive at different positions in the cylinders at the exact wrong time. Therefore it will have in my opinion all the Secondary Shake you can take.
Any deviation from the 72 “Normal”(?) angle is subject to additions of Secondary shake. This is assuming that the crank is still 72 degrees. (Not Likely) Does anyone know the bank angle and the crank angle of the Mugen-Honda V-10?
One thing to consider in the Secondary Shake is the fact that if the pistons are not at the same position in the cylinder as the opposite piston the accelerations are different! Yours M. L. Anderson

[Alvega]

I remember reading an interview with Osamu Gotto back in '89, where he confirmed that the Honda V10 used a balancing shaft. The Mugen V10 being a derivative of that engine probably explains it's presence.

[Ray Bell]

Just a thought... What stresses do these shafts raise inside the block?

[kike]

Marion, when you talk about secondary shake, is the same of second harmonic in development of alternative force?. If so do, I think is not possible to balance it with counterbalance. In V90º, second harmonic in each couple of pistons (on the same pin), creates horizontal force,and depending number of cylinders exist possibility of getting them balanced (i.e. eight cylinders). Fourth harmonic creates vertical force in this V90º. This vertical force is typical thing in some Harleys.
Could anyone tell me a possible firing order for RS2 Renault F1 engine?

[marion5drsn]

Kike; One of the problems in this problem is the lack of like descriptions of actions of the crankshaft, a common phrase or word. In Taylors book he uses the phrase Primary Shake, but the Bosch handbook uses the phrase Free forces of the 1st order.In respect to the Secondary Shake the Bosch book uses the phrase Free forces of the 2nd order. The way I see it these are the same types of action. If you go to the Ludvigsens(sp) post in the Nostalgia section you will find that what you say seems to be true. I hope I have not said anything that one can misconstrue to be that it has been done , that is the balancing of a crankshaft in Secondary Shake. As I know of no case where it has been done successfully. In the V-10 I have found the worst case of Secondary Shake is at 108 degrees Vee bank angle. I haven't made any sketches of a V-8 at any other bank angle except V-8 90 degreees with a 180 degree crankshaft. I am hoping that the fourth harmonic is not very powerfull as this would only aggravate the problem they have now. As soon as I get my WinWord correctly fixed I might expand this further. Yours. M. L. Anderson

[Ray Bell]

Which thread of Karl Ludvigsen's, Marion?

[marion5drsn]

Kike and Ray Bell; Sorry about the error. The post of karlcars is under Flat plane crank and under The Technical forum. Marion L. Anderson.

[kike]

Where could I find Bosch handbook (editorial, year)?. And Marion, how have you found the worst V angle for 10 cylinders second shake?. Thanks.

[marion5drsn]

Kike; In regards to the purchase of BOSCH AUTOMOTIVE HANDBOOK the only place I know of that deals in this book is
Classic Motorbooks,
PO Box 1,
Osceola WI USA
54020-0001
Phone # 1-800-826-6600
FAX 1-715-294-4448
E-Mail: mbibks@motorbooks.com
Website: www.motorbooks.com The Book is listed under Carburetion & Fuel systems. USA $34.95 Order number 107984B
The worst bank angle is 108 degrees with a 72 degree five pin crankshaft. Almost impossibe to achieve.
Yours, Marion L. Anderson

[marion5drsn]

Kike; In regards to the Primary and Secondary shake: The Primary is a 360 degree centrifugal force and the Secondary is an intermittent centrifugal force usually at 180 degrees and twice each revolution. In the case of the V-8 180 degrees crankshaft the force is horizontal. The problem in the V-10 is that the firing spacing is 72 degrees and the normal bank angle is the same. Since the Primary Shake is nullified by the 10 counterweights this need not concern us. The reason I believe that the Secondary shake is at its worst at 108 degrees is the piston that should be “boxing” with it is out of phase by ½ of the “Normal” bank angle. 72 degrees divided by 2 is 36 degrees, 72 degrees plus 36 is 108 degrees and according to my sketches this is the condition that the opposing piston is about halfway up the cylinder and its acceleration is at its greatest. This may or may not be somewhat modified by the fact that a piston is not perfectly halfway up the stroke at 90 degrees crankshaft angle. I’m sure the engineers know which way this affects the Shake. So I believe that the 108 degrees is close enough. Altho one may make a case of this if that much accuracy is necessary. M. L. Anderson