Common-rail injection or distributor injection are adopted in recent diesel engines, nowadays. This application shows how to measure the diesel engine rotation by using the engine vibration. This is also effective way for reciprocating engine which vibrates along to the piston movement.
Mount the NP-3331B accelerometer on the engine chassis to detect the engine vibration. On performing FFT analysis, the FT-2500 advanced tachometer can decompose the complicated signals with periodically into the basic (1st) order frequency and integral multiple of the high-order frequency. And then the engine rotation speed can be calculated by the basic frequency.
Configuration
| Model | Product name | Reference | |
|---|---|---|---|
| 1 | NP-3331B | Accelerometer | Floating and water resistant, operating temperature range:-20 to+110℃ |
| 2 | FT-2500 | Tachometer | 1024 points FFT calculation method |
| Measurement principle | |
|---|---|
|
The FFT processing
decomposes a complicated waveform with a certain periodicity
into basic frequency (1st-order) and high order frequency of
the integral multiple. Thereby the power spectrum is
obtained at every order of the frequency.
The FT-2500 advanced
tachometer is developed by applying this FFT processing
technology, which enables to obtain the following power
spectrum of the signal from an accelerometer even though it
is complicated and minute. With this 1st-order or high order
components, the rotation speed can be obtained.
|
Measurement point
The vibration components of an engine differ in horizontal or vertical direction. It needs to find out the most suitable mounting position of the accelerometer for the each engine.
Revised:2011/07/01
