A few years ago,Renault running their 111 degree engine. It provide a lower gravity centre and offer a good aerodynamics to the rear end of their car. But, I had read that they have a problem with that engine. Is vee angle influence the horsepower output?
Location: Covilhã, Portugal (and sometimes in Évora)
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According to what I know/think (I might be wrong ) the vee angle itself does and does not influence the power output!
Theoreticly if you didn't have friction, vibration, combustion time, engine efficiency (if it was 100%), etc you would have around 4 times (or more) the power output that you have! The thing is that friction (though the friction level doesn't raise a whole lot with a increased vee angle, but it counts in any case) and vibration is directly linked to the vee angle of the engine.....engine efficiency and combustion time are associated with engine/component materials and fuel caracteristics!
So the vee angle is responsable for a few of the problems that reduce the power output, the other problems are associated with things that are harder to control!
The ideal vee angle to have ideal friction is 90º, cause no one is using 0º! (according to Steve Matchett, ex-mechanic), the ideal vee angle to reduce vibration is 78º (according to ex-Renault engine guru, Jean Jaques His) the best power output vee angle is between 72º and 78º (according to Peter Wright, ex-F1 Technical Director).
Renault gambled with the wide vee angle...the main problem of it was the vibration it caused, if I'm not mistaken.
I agree with you. Bigger vee angle may cause piston's weight more to the wall of the cylinder,as the result friction is increase( I might be wrong also). The combustion output also has to reduce. Although this is not a main problem,it might be a reason why this kind of cause of a problem.
Selection of vee angle maybe different due to engine manufacturer. Subaru is sucessfully in WRC with their boxer engine (180 degree). Low gravity centre offer stability and less vibration. According to physics theory,I can't rememeber well,the vector explains how we can combine two or more force on different angle to create an output force. Maybe it can help to choose the right vee angle. Same amount of force with different angle,cause different force to act.
However, I always look at Ferrari as a benchmark in engine manufacturing.Although I'm a fan of McLaren Mercedes.They run with 90 degree and very succes. I just give my opinion.
One more thing,how about the engine operating temperatures. Was it linked to the fuel ingredient combination? or material that they use to built that engine?
Location: Covilhã, Portugal (and sometimes in Évora)
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Anonymous wrote:in qualification villeneuve´s engine hit 20000 rpm
If you came to this forum frequently you'd see in other topics that we explained that the number shown on tv isn't the real number! It's a computer acoustic analysis program that analysis the sound that the car is producing and gives a rough figure of the rpm. F1 teams probably have quite acurate programs...but the rpm meter shown on the telly is just a marketing manouver and probably has a very high error (anywhere between 5 to 15%). So don't believe all you see. Besides that the program can be precisly calibrated for a determined engine....but other engines at the same rpm might send diferent frequencies....so don't trust everything they show you! When Williams passed the 19000 rpm barrier it was public....have you seen anyone coment on the 20000 rpm barrier? So if it was true everyone would be talking about it.
Another thing the tv program cannot be acurate cause teams/engine builders wouldn't like it if their "enemies" got acurate data from their engine...
The V-angle has two main influences regarding power output and two regarding chassis integration.
Power output:
1) The admission chamber acoustics are influenced by the "rythm" the strokes happen. More regular strokes help more constant air aspiration and enable better control of how the acoustic waves behave. For that, in a V10 engine, the ideal V-angle is 72º. The bigger the actual difference is from this value, the harder is to obtain good cylinder filling in all conditions (rpm's). This lack of regularity also induce more vibrations that may have to be reduced by the use of auxiliary shafts (taking power from the engine).
2) The more the cylinder rows are away from the vertical, more difficult it is to lubricate evenly the cylinders and heads. Usually, the pump must be more powerful and take more power away from the output. Some lack of reliability of the 111º Renault engines I think was caused by lubrication problems (see also the BMW 4-inline instalation in the Brabham BT55 of 1986, that suffered from lack of power and terrible reliability, because of the instalation od the engine with an inclination of 72º).
Chassis integration:
1) Wider angles mean lower heads and lower CG. I've always thought that Renault's angle was an antecipation of possible new solenoid distribution, in order to avoid the extra weight from being placed too high.
2) Reduced V-angle mean higher compaticity and rigidity of the engine, meaning higher overall stiffness of the chassis.
In terms of potential or theoretical BMEP the v angle has little influence, however in real terms the wider and inherently unbalalanced angle used by Renault was frought with problems. These are soem points I picked up from the engineers At renault onboth the chassis and engine side.
Casting integrity
The early wide angle engines (2001 2002) had intrisic problems wit the bottom end, leadign to failure sint he casting, I beleive this was down to the vibrations and loads passed thorough from the chassis.
Water cooling
again the second engine (2002) had an intrinsic water coolign problem, I do not know of any related oil cooling lubrication problems.
Valve gear vibrations
Valve gear vibrations along the long cams were killing the 2002 engien and limiting its revs even after the other problems were cured. For 2003 Renault adopted a cam gear drive, driving one cam from the forn of the engien and form the rear and interconnecting the cams, this heavier set up reduced the torsionalstresses and lead the best performance from any of the wide angle engines.
airbox accoustics
both ackonwledged and denied by the engineers was the impac tof the spaced inlet tracts, as the wngien was wider the ideal inlet tract routign moves the pair of inlet runners apart, this limited the accoustics possible compared to a conventional engine. Instead Renault installed a tall square ridge in between the inlet runners to help boost the accoustic effect.
Chassis
The low line engine had several (3-4) Cms advantage in terms of Cof G height. this was offset by the added weight the engien needed to offset the vibrations. It was also handicapped by the width which placed the exhaust routing into the area of the sidepod uses for sidepod cooling, further exacerbating the coolign problem of the early engines. The side angle helped in terms of lateral stiffness but was weaker in beam stiffness, it is commonly beleived that the reinforcing strut was a later ad don but was in fact par tof the design. the simple strut was adopte din place of alrger more heavier structure, helping keep the CofG low.
With the engine failing in relaibility and revs, plus the advantage of a low CofG beign offset by the addition of ballast to artificially lower the CofG, renault adopted a new engien for the one per weekend rule based on a 72 degree design, which by detail devleopment was only slightly higher in Cof G than the wide angle unit, plus was free of vibrations alloiwing to to rev higher and weigh less.
Has anyone used a boxer engine in F1. that would lower the cog greatly, and, correct me if i am wrong, but i dont think that they suffer from so many of the problems that Renaults wide angled engine had.
Source Enrico Benzing’s book “Dall’aerodinamica alla potenza in F1”.
Obviously since the discovery that what happens under the car is more important than what happens above it (from an aerodynamic point of view) in late 70s, the flat engine was basically killed and in fact only Motori Moderni tried that route in the modern era.
With the stepped bottom rules a flat (or Boxer) engine would be impractical, already (with a 90-degree engine) the exhuast ports are inline with the raised floor of the car, creating a flat V angle would only point them through the floor (...!)
) the vee angle itself does and does not influence the power output!