A crank position pulse multiplier is something which converts the signal from a crank position sensor to the equivalent output of a 360p/r encoder.
Experimental measurements in engine combustion testing. For example, take measurements by mounting an optical encoder on the crankshaft.
But instead of a newly mounted optical encoder, by taking measurements using the signal from the crank position sensor on an actual vehicle, which is then input to an ECU, mounting an optical encoder is not necessary.
■ Output pulse cycles are corrected depending on fluctuations in the rotational speed
■ There are no output pulse errors
For every low-resolution pulse entered, the pulse multiplication method generally outputs the same number of pulses over a constant period as the multiplying ratio.
This method accumulates errors in the number of pulses output because the input and output phase are not synchronized with each other, producing a deviation in the angle.
On the other hand, since CPM-100 corrects the output pulse cycle depending on fluctuations in the rotational speed, the deviation in the angle does not occur.
● Further evolution of the conventional CPM-100 (360 pulse multiplier)
● Possible to select the pulse multiplier output as 720, 360, or 180 pulses per revolution
● High-resolution output of 1 pulse per every 0.5°
There are teeth missing in order to provide an angle reference for the crank position sensor.
As shown in the actual operating waveform in the figure below, CPM-100 continuously outputs a 360p/r signal even if there are missing teeth, and simultaneously outputs a 1p/r signal.
■ One spot with missing teeth/no missing teeth
Original number of teeth: 4, 6, 8, 12, 15, 20, 24, 36, 40, 60
Number of missing teeth: 0, 1, 2, 3, 4
■ One spot with additional tooth
Original number of teeth: 4, 6, 8, 12
Position of additional tooth: 1/3, 1/2, 2/3 of original number of teeth
■ Two spots with missing teeth
Original number of teeth: 36
Number of missing teeth: 3
■ Three spots with missing teeth
* Plates that have two or three spots with missing teeth are limited.
* Please contact us about other specifications.
Original number of teeth: 36
Number of missing teeth: 4, 6
| Display | |
|---|---|
| Displayed item: Display method | Rotational speed display: 6-digit x 1 row, character height approx. 14.2mm 7-segment LED, green |
| Settings display: 16-digit x 2 rows, character height approx. 5.6mm, character LED, green backlight | |
| Crank signal input | |
| Connector | BNC receptacle and screwless terminal block |
| Input frequency | 10 to 20,000Hz |
| Input signal | Sine wave (trigger level 0V)/square wave (trigger level +2.5V) |
| Trigger slope | Rising/Falling |
| LPF | OFF/20kHz (-3dB) |
| Pull-up | OFF/ON (terminal block only) |
| Sensor power supply | +12V (80mA) |
| Input resistance | 100KΩ |
| Input voltage | ±50V (maximum rating ±100V) |
| Wave shaping output voltage | TTL (0-5V) |
| Corresponding signal plates | ■ One spot with missing teeth/no missing teeth Original number of teeth: 4, 6, 8, 12, 15, 20, 24, 36, 40, 60 Number of missing teeth: 0, 1, 2, 3, 4 ■ One spot with additional tooth Number of original teeth: 4, 6, 8, 12 Position of additional tooth: 1/3, 1/2, 2/3 of original number of teeth ■ Two spots with missing teeth Number of original teeth: 36 Number of missing teeth: 3 ■ Three spots with missing teeth Original number of teeth: 36 Number of missing teeth: 4, 6 * Plates that have two or three spots with missing teeth are limited. * Please contact us about other specifications. |
| Multiplied pulse output | |
| Number of outputs | 2 outputs (BNC receptacle) |
| Output items | Angle output 180, 360, 720 p/r (CPM-100 is 360p/r only), TDC output (1p/r) |
| Output voltage | TTL (0-5V) |
| Output logic | Positive logic/Negative logic |
| F/V output | |
| Number of outputs | 1 output (BNC receptacle) |
| Output voltage | 0 to 10V |
| Refresh time | Every 1ms |
| Moving average | 1 to 500 |
| Arithmetic | |
| Frequency time resolution | 40MHz |
| Memory setting | EEPROM |
| General specification | |
| Input power supply voltage/(current) | DC9 to 32V (10W) |
| Insulation | DC power supply/crank signal input/F/V output/angle output, TDC output, wave shaping output |
| External dimensions | W: 184 D: 197 H: 70mm (excluding projecting parts) |
| Weight | Approx. 1kg |
| Operating temperature and humidity range | 0 to 40ºC/85%RH or less (with no condensation) |
| Accessories | AC adaptor, DC plug cable |
Multiplication of plate/crank position sensor
Flexible application for other than combustion analyses
No rotary encoder needed for the engine.