A thermal flow sensor chip has a heater part, and a pair of thermopiles provided so as to be opposite each other across the heater part. The heater part is famed by doping silicon with an impurity that reduces the electrical resistance. In each of the thermopiles: a silicon region is formed by doping silicon with an impurity that reduces the electrical resistance; the concentration of the impurity in a heater main part, including the lengthwise center of the heater part extending in the first direction, is lower than the concentration of the impurity in a heater outer peripheral part, the heater outer peripheral part being different from the heater main part and including a lengthwise end part of the heater part; and the concentration of the impurity in the heater main part is the same as the concentration of the impurity in at least part of the silicon region of the thermopile.

The invention comprises a thermal flow sensor for determining the temperature and the flow velocity of a flowing measuring medium, comprising: a functional element which is configured to determine the temperature of the measuring medium and to influence the temperature of the measuring medium; and a control and evaluation unit which is configured to determine the temperature of the measuring medium in a first interval of time by means of the functional element and to determine the flow velocity of the measuring medium in a second interval of time following the first interval of time, and a method for determining the temperature and the flow velocity of the measuring medium by means of the thermal flow sensor according to the invention, and a sensor system comprising such a thermal flow sensor and a further sensor type.

The invention comprises a thermal flow sensor for determining the temperature and the flow velocity of a flowing measuring medium, comprising: a functional element which is configured to determine the temperature of the measuring medium and to influence the temperature of the measuring medium; and a control and evaluation unit which is configured to determine the temperature of the measuring medium in a first interval of time by means of the functional element and to determine the flow velocity of the measuring medium in a second interval of time following the first interval of time, and a method for determining the temperature and the flow velocity of the measuring medium by means of the thermal flow sensor according to the invention, and a sensor system comprising such a thermal flow sensor and a further sensor type.

In order to provide a correction device that enables the accuracy of the linearity between sensor output values and flow rate values in a flow rate sensor, there are provided a sensitivity correction function storage unit that stores a sensitivity correction function in which at least a portion of sensitivity correction values are set to different values in accordance with the sensor output values output from a flow rate sensor in an initial state in which the sensitivity coefficient is set to an initial value, a sensitivity setting unit that sets the sensitivity coefficient based on the initial values and on the sensitivity correction function, and then adjusts the sensitivity of the flow rate sensor, and a coefficient calculation unit that calculates a post-correction flow rate characteristic function based on function correction values that are decided in accordance with the flow rate values output post sensitivity correction.

In order to provide a correction device that enables the accuracy of the linearity between sensor output values and flow rate values in a flow rate sensor, there are provided a sensitivity correction function storage unit that stores a sensitivity correction function in which at least a portion of sensitivity correction values are set to different values in accordance with the sensor output values output from a flow rate sensor in an initial state in which the sensitivity coefficient is set to an initial value, a sensitivity setting unit that sets the sensitivity coefficient based on the initial values and on the sensitivity correction function, and then adjusts the sensitivity of the flow rate sensor, and a coefficient calculation unit that calculates a post-correction flow rate characteristic function based on function correction values that are decided in accordance with the flow rate values output post sensitivity correction.

A thermal, flow measuring device for determining and/or monitoring a mass flow of a measured medium, comprising a sensor element (1, 11, 21) having a measuring tube (2, 12, 22) with a tube wall (7, 17, 27) and with at least a first and a second temperature sensor element, which are especially embodied as resistance thermometers (3, 13, 23, 33), wherein at least one of the temperature sensor elements is heatable, wherein the measuring tube (2, 12, 22) has a longitudinal axis (A) and a tube contour (8, 18, 28) with a first tube cross section in the end regions of the measuring tube (2, 12, 22), wherein the measuring tube (2, 12, 22) includes a narrowing having a second tube cross section, which differs in form and/or area from the first tube cross section, wherein the narrowing is divided into at least two segments (6, 16, 26), wherein at least one of the segments (6, 16, 26) is angled relative to the longitudinal axis (A) of the measuring tube (2, 12, 22) by an angle (α) of at least 5° and wherein, in each case, one of the temperature sensor elements is arranged in a respective one of the two segments (6, 16, 26) externally on the tube wall (7, 17, 27) of the measuring tube (2, 12, 22) and is located in thermal contact with the measured medium.

The design and structure of a vortex flow meter with large dynamic range utilizing a micro-machined thermal flow sensing device for simultaneously measurement of volumetric flowrate via vortex street frequency as well as mass flowrate is exhibited in this disclosure. The micro-machined thermal flow sensing device is placed at the central point of a channel inside the bluff body where the channel direction is not perpendicular to the direction of fluid flow in the conduit. The thermal flow sensing device is operating in a time-of-flight principle for acquiring the vortex street frequency such that any surface conditions of the device shall not have significant impact to the measured values. With a temperature thermistor on the same micro-machined thermal flow sensing device, the vortex flow meter shall be able to output the fluid temperature as well as the fluid pressure.

A sensor device for determining at least one parameter of a fluid medium flowing through a duct, e.g., an intake air mass flow of an internal combustion engine, includes: a sensor housing, e.g., a sensor plug that is placed or that can be placed into a flow tube, in which the duct is fashioned; and at least one sensor chip situated in the duct for determining the parameter of the fluid medium. The sensor chip has a sensor area. The sensor housing has an inlet into the duct that is oriented opposite a main direction of flow of the fluid medium, and has at least one outlet from the duct. The sensor area is covered at least partly by an electrically conductive layer.

A sensor device for determining at least one parameter of a fluid medium flowing through a duct, e.g., an intake air mass flow of an internal combustion engine, includes: a sensor housing, e.g., a sensor plug that is placed or that can be placed into a flow tube, in which the duct is fashioned; and at least one sensor chip situated in the duct for determining the parameter of the fluid medium. The sensor chip has a sensor area. The sensor housing has an inlet into the duct that is oriented opposite a main direction of flow of the fluid medium, and has at least one outlet from the duct. The sensor area is covered at least partly by an electrically conductive layer.

A cooling circuit for a fuel cell includes at least one channel, a mechanical support, a first sensor, and a second sensor. Each channel is formed in a bipolar plate of the fuel cell, and is adapted to permit a cooling fluid to flow. The first sensor senses a flow rate of the cooling fluid. The second sensor senses an electrical conductivity of the cooling fluid. Both the first sensor and the second sensor are installed on the mechanical support.