1st & 2nd order
1st & 2nd order
(OP)
1.what is the first order, second order in terms of NVH?
2.In auto industry, what do you mean by " any order peak at certain frequency at certain rpm?"
could you just explain me details.
3.does this statement is correct - If vehicle is at 1000 rpm at idele means it is at 17 HZ?
Please rectify it if necessary.
2.In auto industry, what do you mean by " any order peak at certain frequency at certain rpm?"
could you just explain me details.
3.does this statement is correct - If vehicle is at 1000 rpm at idele means it is at 17 HZ?
Please rectify it if necessary.





RE: 1st & 2nd order
2) If you have a waterfall plot look up the line for a given rpm. It is asking for the highest peak along that line
3) At 1000 rpm, first order s at 17 Hz, 2nd order is at 33 Hz, 3rd order is at 50 Hz, 2.5 order is at 2.5*1000/60 Hz etc
Cheers
Greg Locock
RE: 1st & 2nd order
Could you explain me the physical significance of 1st,2nd order frequency at 1000 rpm?
RE: 1st & 2nd order
Second order is typically caused by the non sinusoidal motion of the pistons, due to the L/r ratio, which rarely cancel internally except with straight six or boxer engines.
Cheers
Greg Locock