[CL9] What is harmonic engine resonance?

[unity]

Hi, I was just wanting to know what it means when people talk about harmonic engine resonace?
Is this a feature or is this experienced by Euro owners out there?
Thank you.

[NSPYRE]

first u need to understand the basics... in every cylinder firing cycle, torque is transferred to the crankshaft. the crankshaft deflects under this torque, which sets up vibrations when the torque is released. at a certain given engine speed the torque transferred by the cylinders are in synch with the vibrations in the crankshaft, which results in resonance.

here is where a harmonic balancer comes into play. the harmonic balancer prevents this vibration from occuring by absorbing the vibratin energy

[unity]

Thank you for that very clear and easy to understand explanation. Do you have any idea at what engine speeds this occurs in the Euro? I am finding that I am getting a slight but noticable vibration in my car when under light acceleration (ie trying to maintain speed or going up a slight incline) when in the range of 1500RPM to 2300RPM.

[NSPYRE]

hmm.. i doubt its related to resonance since you have such a new car. usually happens to older cars as the absorbing material begins to deteriorate.

the reason ur getting this vibration sounds like is because ur revs are too low - that is ur labouring the engine. do u drive manual or auto?

[unity]

Mine is automatic. Usually feel it most in 5th gear when travelling in 60, 70 and 80km/hr speed zones.

[trism]

yeah, its the engine lagging

not really to do with harmonic resonances like said :)

[unity]

So what can I do about this? I can push on the accelerator a bit harder and increase my rpms but then it takes me over the speed limit. Obviously the computer is controlling everything else.

[trism]

drop it back a gear?

if it is being weird when changing gears, maybe the trans fluid needs some changing....

[NSPYRE]

ur gears will change according to how much pressure u apply to the throttle. obviously its not shifting down automatically cause ur not applying that much more throttle so its assuming u only want to increase ur speed a little bit... does it really bother u that much?

[unity]

Yes that helps but the car is auto and I should not have to keep adjusting my gears manualy. It's not like it just happens here or there. It's noticeable almost all the time.
At 60km/hr the car is in 5th gear and travelling along a straight road the RPMs are usually sitting at about 1500RPM. If I tap the gas pedal a bit to maintain speed the RPMs might only jump to say 2000RPM and this is the range I feel the roughness/vibration.
I will bring it up with the roaming Honda technician that has agreed to inspect my car for other problems as well.

[unity]

ur gears will change according to how much pressure u apply to the throttle. obviously its not shifting down automatically cause ur not applying that much more throttle so its assuming u only want to increase ur speed a little bit... does it really bother u that much?

Yes when driving in traffic I find that I only need to hit the throttle a little to maintain my speed in traffic say when I am travelling behind another car. It is annoying because at higher RPMs the engine and response is really smooth. But when you do most of your driving in the suburbs and you are cruising at the speed limit then the RPMs are sitting in that lower range most of the time. I just wished it felt smoother in those lower ranges.