Dielectric constant detection apparatus for fuel
US5225783A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 27, 1992 |
| Grant date | Jul 6, 1993 |
| Priority date | — |
| Expiry date | Jan 27, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/221
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A detection apparatus for detecting a dielectric constant of fuel having an electrode disposed in a fuel passage and applied with an excitation signal, a monolayer-wound coil disposed in the vicinity of the electrode so that fuel is introduced in a space between the excitation electrode and the coil, a phase comparator which receives the signal to be applied to the excitation electrode and a signal induced in the coil to thereby compare the signals. The phase difference between both signals is detected using a low-pass filter to output the d.c. signal component of an output signal of phase comparator, a comparison integrator connected to the low-pass filter to output a controlled output signal so that the phase difference between the excitation signal and the induced signal in the coil becomes 90.degree., and a voltage controlled oscillator connected to the comparison integrator so that the frequency of a signal, to be applied to the electrode, of the voltage controlled oscillator is changed depending on the output signal of the comparison integrator. The dielectric constant of the fuel is detected on the basis of a voltage output signal from the comparison integrator, or a frequen…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.