Re: Non-Audi Five Cylinder Engines, Honda!

[Igor Kessel <e6941tb@ix.netcom.com>]

Ian J Haseltine wrote:
> 
> > Gotta give honda a little credit with designing the ultimate nightmare, the
> > CVT (continually varying transmittion.)
> 
> Dont you mean VTEC?

No. Variable transmission changes the input-to-output shaft ratios monotoneously via 
a set of cones, unlike the conventional one, where a fixed number of gears provides 
a number of discrete torque transfer values.

VTEC, OTOH stands for Variable Intake blah blah something.
Valve/pistonstrokes have different frequency of operation across the engine's RPM 
band. It's a typical occillating sys that has it's unique natural frequency and 
harmonics thereof.
During the operation a phenomenon of standing waves occures. It is said that the 
engine gets filled by mixture more efficiently when the SWR (Standing Wave Ratio) is 
at a certain value, which depends on the resonant frequency. Now, that very 
frequency depends on the geometry and volume of the intake. For example, a 
particular configuration, that is ideal at 2000rpms (the intake length is equal to 
the even number of half-wavelengths) may be a real killer at 5000rpms (the intake 
length is equal to the odd number of half-wavelengths) and v.v. 

A number of companies have solved this problem in a first approximation, by changing 
the length of the intake depending on the rpms (Honda, VW to name a few).

-- 
Igor Kessel
'89 200TQ - 18psi (TAP)
'97 A4TQ - on the boat
Philadelphia, PA
USA