摘要:
A heating resistor type flow-measuring device is capable of adjusting heating temperature of a heating resistor according to the ambient temperature as well as making the initial adjustment. A heating resistor, a thermoresistance, a group of the resistors, and an amplifier constitute a bridge circuit, and leading terminals of the group of resistors are connected to one of input terminals of an amplifier for amplifying an error voltage through MOS transistors. The heating temperature of the heating resistor can be changed by selecting one of the MOS transistors and turning it on.
摘要:
A heating resistor type flow-measuring device is capable of adjusting heating temperature of a heating resistor according to the ambient temperature as well as making the initial adjustment. A heating resistor, a thermoresistance, a group of the resistors, and an amplifier constitute a bridge circuit, and leading terminals of the group of resistors are connected to one of input terminals of an amplifier for amplifying an error voltage through MOS transistors. The heating temperature of the heating resistor can be changed by selecting one of the MOS transistors and turning it on.
摘要:
A thermal air flowmeter having excellent temperature characteristics and improved measurement accuracy. The thermal air flowmeter includes a temperature sensor disposed in a casing of the air flowmeter, a computing unit for correcting a flow rate detection voltage from a measuring element by using the temperature sensor, and a heating temperature control disposed in a temperature control circuit for performing temperature control of a heating resistor to vary a temperature rise of the heating resistor relative to an air temperature depending on the air temperature. Flow rate detection errors of the thermal air flowmeter caused by an overall temperature change and a temperature change on an intake passage wall surface can be corrected simultaneously and a thermal air flowmeter having superior measurement accuracy can be realized.
摘要:
Conventional thermal flow measurement devices lack consideration for automobiles in severe environments. A detection element of the thermal flow measurement device according to the present invention is structured by the provision of a planar substrate made of a material having good thermal conductivity, such as silicon or ceramic, with a thin-walled portion (diaphragm). On the surface of the thin-walled portion, the detection element comprises a heat element as a heater heated to a temperature being different to a predetermined extent from the temperature of the air flow to be measured, temperature-detecting resistors as temperature-detecting means on both sides of the heat element, wiring portions formed of electrical conductors that draw signal lines from the heat element and the temperature-detecting resistors and that have a melting point of 2000° C. or higher, and pads.
摘要:
A thermal air flowmeter having excellent temperature characteristics and improved measurement accuracy. The thermal air flowmeter comprises a temperature sensor disposed in a casing of the air flowmeter, a computing unit for correcting a flow rate detection voltage from a measuring element by using the temperature sensor, and heating temperature control means disposed in a temperature control circuit for performing temperature control of a heating resistor to vary a temperature rise of the heating resistor relative to an air temperature depending on the air temperature. Flow rate detection errors of the thermal air flowmeter caused by an overall temperature change and a temperature change on an intake passage wall surface can be corrected simultaneously and a thermal air flowmeter having superior measurement accuracy can be realized.
摘要:
A heating resistance flow rate measuring apparatus which can use a power source of an ECU in an automobile without requiring an expensive protective circuit and regulator. Heating of temperature detecting resistors themselves causes temperature changes on the windward and leeward sides, and these temperature changes depend on the amounts of heat generated by the temperature detecting resistors. The amounts of heat generated by the temperature detecting resistors depend on a voltage value of the ECU power source applied to the temperature detecting resistors, and an error is caused in a sensor output depending on a variation in the voltage of the ECU power source. Based on the finding that suppressing the amount of heat generated by the temperature detecting resistors is effective in avoiding the sensor output error caused depending on a variation in the output voltage of the ECU power source, means for suppressing the amount of heat generated by the temperature detecting resistors is disposed.
摘要:
A heating resistance flow rate measuring apparatus which can use a power source of an ECU in an automobile without requiring an expensive protective circuit and regulator. Heating of temperature detecting resistors themselves causes temperature changes on the windward and leeward sides, and these temperature changes depend on the amounts of heat generated by the temperature detecting resistors. The amounts of heat generated by the temperature detecting resistors depend on a voltage value of the ECU power source applied to the temperature detecting resistors, and an error is caused in a sensor output depending on a variation in the voltage of the ECU power source. Based on the finding that suppressing the amount of heat generated by the temperature detecting resistors is effective in avoiding the sensor output error caused depending on a variation in the output voltage of the ECU power source, means for suppressing the amount of heat generated by the temperature detecting resistors is disposed.
摘要:
An IC power protection circuit functions as a surge protection circuit and reverse connection protection circuit. The IC power protection circuit includes an error amplification circuit, positioned and integrated within an integrated circuit and a transistor positioned as a stand-alone element that is separate from the integrated circuit. The integrated circuit includes a sensor signal processing circuit that processes a signal of a sensor. A transistor protects the integrated circuit against a surge voltage from a battery terminal. A resistor is positioned between an output terminal of an error amplifier and a base terminal of the transistor to provide reverse connection protection. Another resistor is connected between a ground and a connection point between the above resistor and the output terminal to provide overvoltage protection for the integrated circuit. A starting resistor is connected between a collector and base of the transistor.
摘要:
Conventional thermal flow measurement devices lack consideration for automobiles in severe environments. A detection element of the thermal flow measurement device according to the present invention is structured by the provision of a planar substrate made of a material having good thermal conductivity, such as silicon or ceramic, with a thin-walled portion (diaphragm). On the surface of the thin-walled portion, the detection element comprises a heat element as a heater heated to a temperature being different to a predetermined extent from the temperature of the air flow to be measured, temperature-detecting resistors as temperature-detecting means on both sides of the heat element, wiring portions formed of electrical conductors that draw signal lines from the heat element and the temperature-detecting resistors and that have a melting point of 2000° C. or higher, and pads.
摘要:
A thermal airflow meter excellent in flow-rate measurement accuracy is provided. The airflow meter has a flow-rate measuring element comprising a heat resistor and a temperature-compensating resistor which are formed on the a first base member. A second base member of the airflow meter, provided with a drive circuit and a signal processor, is housed in a casing holding the flow-rate measuring element. The flow-rate measuring element is disposed in an air passage. Of two temperature sensors for measuring temperature at each of two points in the thermal airflow meter, respectively, a first temperature sensor is provided on the fist substrate of the flow-rate measuring element, and a second temperature sensor is provided inside the casing. The signal processor has a function of computing an airflow rate, an air temperature, and an air passage wall face temperature on the basis of an output signal of the flow-rate measuring element and respective output signals of the first and second sensors.