A fluid sensing system includes a sensing element having a positive temperature coefficient of resistance. The system also includes a switch which is switchable between an open position which prevents current from passing and a closed position which permits current to pass. An inductor is connected electrically in series between the switch electric output and the sensing element and a diode is connected electrically in series between the sensing element and the inductor such that an output of the diode is between the switch and the inductor. A hysteretic controller changes the switch from the open position to the closed position when current passing to the sensing element falls to a lower current threshold and changes the switch from the closed position to the open position when current passing to the sensing element rises to an upper current threshold. A voltmeter measures voltage across the sensing element.

Methods and systems are provided for improving engine oil level sensing while a vehicle is moving. The output of a hot wire sensor partially immersed in an engine oil well is sampled during selected vehicle moving conditions when lateral and longitudinal acceleration is limited and the vehicle is driving in a straight line. A transfer function is used to correlate a rate of change in sensor output, sampled during the selected vehicle operating conditions, with engine oil level.

A liquid level detection device detecting a liquid level of a liquid in a container includes a heater configured to heat the container, a plurality of temperature sensors provided at different heights of the container, and configured to detect a surface temperature of the container, and a controller configured to detect the liquid level of the liquid in the container, based on the surface temperature of the container detected by the plurality of temperature sensors when the heater is caused to heat.

In some examples, a liquid container comprises a chamber forming a volume containing a liquid, an elongated strip extending into the volume containing the liquid, the strip supported along a side of the volume such that a face of the strip adjacent the side of the volume is not opposed by the liquid, a plurality of heaters supported by the strip along the strip, and a plurality of temperature sensors supported by the strip along the strip.

A fluid characteristic sensing device has a projection. The fluid characteristic sensing device receives current pulses and directs the received current pulses through the projection. The received and directed current pulses enable determination of a resistance of the projection and a rate of change of temperature.

A fluid sensing system includes a sensing element having a positive temperature coefficient of resistance. The system also includes a switch which is switchable between an open position which prevents current from passing and a closed position which permits current to pass. An inductor is connected electrically in series between the switch electric output and the sensing element and a diode is connected electrically in series between the sensing element and the inductor such that an output of the diode is between the switch and the inductor. A hysteretic controller changes the switch from the open position to the closed position when current passing to the sensing element falls to a lower current threshold and changes the switch from the closed position to the open position when current passing to the sensing element rises to an upper current threshold. A voltmeter measures voltage across the sensing element.

The invention relates to devices for detecting media.

These are distinguished, in particular, by the fact that simply the medium can be detected and/or properties of the or a medium can be determined or monitored.

For this purpose, a heating sensor comprising a heating device and at least one p-n junction operated in the forward direction and a reference sensor comprising at least one p-n junction operated in the forward direction are spaced apart from one another. The heating device and the p-n junctions are connected to a control device, which is a control device ascertaining the presence and/or at least one property of the medium from the thermal properties of the medium.

The invention relates to devices for detecting the fill level of media in containers.

The devices are distinguished, in particular, by a simple and reliable detection of the fill level.

For this purpose, multiple measuring points, each consisting of a series circuit of a resistor and a p-n junction, are spaced apart from one another. Each measuring point is connected, on the one hand, to an input of a multiplexer. On the other hand, the measuring points are connected to a reference potential. The output of the multiplexer is connected to a control device, wherein the control device is a control device periodically supplying a voltage to the measuring point connected to the control device via the multiplexer and measuring the voltage drop, a control device determining the medium from the temperature-dependent forward voltages resulting from the different thermal properties of the medium and a control device ascertaining the fill level from the consecutive measuring points.

A liquid level detection system for determining a liquid level includes a level sensor configured to be at least partially disposed in a liquid storage vessel and exposed to liquid. A first optoelectronic interface is operatively connected to the level sensor for providing power thereto. A second optoelectronic interface is operatively connected to the first optoelectronic interface. A fiber optic cable optically connects the first optoelectronic interface to the second optoelectronic interface to provide photonic power to the first optoelectronic interface and to transmit data from the first optoelectronic interface to the second optoelectronic interface.

In a method for operating a heating device, fluid is initially introduced into a fluid chamber, then the heating elements of the heating device are switched on and a leakage current is detected as a temperature-dependent current flow through a dielectric insulation layer. A supply voltage of the heating devices is measured and is taken into account in an evaluation of the temperature at the fluid chamber as a function of the leakage current. The leakage current is converted into a leakage voltage by means of a resistor, which is then divided by the measured supply voltage. Subsequently, the quotient obtained may be multiplied by a compensation value in order to obtain a normalized leakage signal, which is normalized to a base value of the supply voltage. The normalized leakage signal is used, if a particular absolute value of the leakage signal is exceeded or if a particular slope of the profile of the leakage signal is exceeded, in order to top up the fluid chamber with more fluid and/or to reduce the heating power of at least one heating element.