Abstract: An apparatus for measuring an intake air flow of an internal combustion engine, wherein presence of a backflow is determined from a waveform of the electric signal of flow detecting unit. If a backflow is present, a kurtosis is calculated. A backflow ratio is calculated based on the relation obtained from the kurtosis and the backflow ratio. The mass of the flow obtained by converting electric signals from the flow detecting unit into flows are integrated or averaged. Then, the integrated value or the average value is compensated by the backflow ratio, and accumulate mass of the air flow is calculated.

Abstract: The output characteristics of the sensing device or the control quantity of the sensing element can be adjusted by extracting an adjusting terminal in addition to a power source terminal, a ground terminal, an output terminal and the like outside a housing containing and protecting an electronic circuit. Further, by arranging the adjusting terminal inside a connector housing containing terminals such as the power source terminal, the ground terminal, the output terminal and the like, it is possible to prevent contact of foreign objects to the adjusting terminal and to water-proof the terminals for preventing corrosion since an associated connector is attached to the connector when the sensing device is actually used.

Abstract: To offer a mass airflow measuring apparatus in which the effect of the adhesion onto the heating resistor caused while the engine is off is reduced and the measuring accuracy is improved. The apparatus measures the mass airflow of the air sucked into the internal combustion engine, using the heating resistor 1. The power control circuit 4 maintains the heating resistor 1 temperature equal to or higher than the temperature during the operation of the internal combustion engine after the internal combustion engine has stopped and until the temperature of the internal combustion engine and its apparatuses installed in the suction system has lowered below the generation temperature of volatile gas such as oil vapor.

Abstract: The output characteristics of the sensing device or the control quantity of the sensing element can be adjusted by extracting an adjusting terminal in addition to a power source terminal, a ground terminal, an output terminal and the like outside a housing containing and protecting an electronic circuit. Further, by arranging the adjusting terminal inside a connector housing containing terminals such as the power source terminal, the ground terminal, the output terminal and the like, it is possible to prevent contact of foreign objects to the adjusting terminal and to water-proof the terminals for preventing corrosion since an associated connector is attached to the connector when the sensing device is actually used.

Abstract: An airtight configuration for keeping down the permeation of corrosive gas from silicone adhesive, and for preventing corrosive gas from entering the case.

Abstract: An air flow rate measuring apparatus generates a flow rate signal with a nonlinear characteristic from a flow rate detecting unit provided with a heat generating resistor and converts that into a signal with a linear characteristic by a linearizing circuit. Then, the flow rate signal is smoothed by a filter circuit to obtain a signal in which the measurement error due to a flow rate ripple is suppressed. Thereafter, the flow rate signal is again formed into a signal with a nonlinear characteristic by a nonlinear-form converting circuit to suppress resolution lowering due to analog-to-digital conversion.

Abstract: The output characteristics of the sensing device or the control quantity of the sensing element can be adjusted by extracting an adjusting terminal in addition to a power source terminal, a ground terminal, an output terminal and the like outside a housing containing and protecting an electronic circuit. Further, by arranging the adjusting terminal inside a connector housing containing terminals such as the power source terminal, the ground terminal, the output terminal and the like, it is possible to prevent contact of foreign objects to the adjusting terminal and to water-proof the terminals for preventing corrosion since an associated connector is attached to the connector when the sensing device is actually used.

Abstract: A heating resistor type air flow rate measuring apparatus is provided with a couple of heating resistors placed at the positions where those resistors may each interfere thermally with respect to an air flow, and a couple of driving circuits for driving those heating resistors. The air flow rate signal is obtained by calculating the difference between the output signals of a couple of heating resistors in terms of heat radiation rate effected by an air flow, and adding the difference value onto the output signal of one of the heating resistors.

Abstract: The thermal-type airflow meter comprises airflow meter body 86 and measuring part 87. Both of the frame 31 of the housing 3 accommodating therein the electronic circuit 6 and the subpassage member 4 having the heating resistor 1 etc. positioned within a subpassage of air are arranged on the metallic base 5. Further, the frame 31, the subpassage member 4, the metallic base 5 and the cover 9 are adhered to respectively different member more than one. The connector 32 of the housing 3, the frame 31 and the subpassage member 4 are formed in a flat shape to form the measuring module 87. The measuring module 87 is inserted through the insertion hole 83 to locate the heating resistor 1 within the main air passage 81, and the fixing flange 36 of the housing 3 is fixedly attached to the airflow meter body 86.

Abstract: A heating resistor type air flow rate measuring apparatus is provided with a couple of heating resistors placed at the positions where those resistors may interfere thermally each other with respect to an air flow, and a couple of driving circuits for driving those heating resistors. The air flow rate signal is obtained by calculating the difference between the output signals of a couple of heating resistors in terms of heat radiation rate effected by an air flow, and adding the difference value onto the output signal of one of heating resistors.

Abstract: An object of the present invention is to provide an air flow rate measuring apparatus of a heat generating resistor type in which it is possible to adequately take the advantage of the air flow rate measuring apparatus of a heat generating resistor type and to obtain a high control precision when the air flow rate measuring apparatus is applied to the engine control.

Abstract: The object of this invention is to provide a heated type air flow rate sensor for measuring an air flow rate using heat generating resistive element or resistor formed within a diaphragm of which periphery is fixed, in which diaphragm destruction due to the collusion of dust is adapted to be prevented.

Abstract: The present invention provides an air flow measuring device comprising a housing with a sub-passage having a inlet and a outlet for air flow formed in the housing, the sub-passage further having a predefined curvature with a maximum downstream point and a flow measuring element located in the sub-passage at a position at least further downstream from the point.

Abstract: The output characteristics of the sensing device or the control quantity of the sensing element can be adjusted by extracting an adjusting terminal in addition to a power source terminal, a ground terminal, an output terminal and the like outside a housing containing and protecting an electronic circuit. Further, by arranging the adjusting terminal inside a connector housing containing terminals such as the power source terminal, the ground terminal, the output terminal and the like, it is possible to prevent contact of foreign objects to the adjusting terminal and to water-proof the terminals for preventing corrosion since an associated connector is attached to the connector when the sensing device is actually used.

Abstract: In flow detection by a thermal-type flow measuring instrument, a flow rate valve with reduced measurement error due to temperature variation can be obtained even under environment where a fluid temperature and a circuit temperature are different. A measurement error due to temperature variation of the fluid of the thermal-type flow measuring instrument can be corrected on the basis of a temperature of the fluid by adjusting the measurement error to be constant ratio irrespective of the flow rate. On the other hand, a temperature characteristic of the circuit is adjusted to be substantially zero %.

Abstract: A thermal type air flow measuring instrument is mounted to a main passage forming an intake air passage of an internal combustion engine and is provided. with an auxiliary passage which includes a heating resistor and a temperature sensing resistor therein and an electronic circuit which is electrically connected to the heating resistor and the temperature sensing resistor. The auxiliary passage is a passage including at least one bent portion composed of a first path substantially parallel to the main passage and a second path having a path different in flow direction from the first path. A member forming the auxiliary passage is fixed in a united form to only a case member for interiorly protecting the electronic circuit, and the case member is fixed to the outer wall surface of the intake air passage.

Abstract: A thermal-type airflow meter comprises an airflow meter body and a measuring part. Both of the frame of a housing which accommodates the electronic circuit, and a sub-passage member which has the heating resistor positioned within a sub-passage, are arranged on a metallic base. Further, the frame, the sub-passage member, the metallic base and the cover are each fixedly attached to at least two respective different members. A connector of the housing, the frame and the sub-passage member are formed in a flat shape to form the measuring module. The measuring module is inserted through an insertion hole to locate the heating resistor within the main air passage, and the fixing flange of the housing is fixedly attached to the airflow meter body.

Abstract: An air flow rate measuring device for an internal combustion engine is disclosed. The air flow rate measuring device has a casing provided downstream from an air cleaner element for purifying intake air to the internal combustion engine, a duct connected fluidly to and downstream from the casing, and an air flow meter provided in said duct, for measuring an air flow rate taken into the internal combustion engine. A cross-sectional area of a connection portion between the casing and the duct, taken perpendicularly to the direction of air flow is the minimum cross-sectional area in the duct.

Abstract: The output characteristics of the sensing device or the control quantity of the sensing element can be adjusted by extracting or leading an adjusting terminal in addition to a power source terminal, a ground terminal, an output terminal and the like outside a housing containing and protecting an electronic circuit. Further, by arranging the adjusting terminal inside a connector housing containing terminals such as the power source terminal, the ground terminal, the output terminal and the like, contact of foreign objects with the adjusting terminal is prevented and the terminals are waterproofed for preventing corrosion since an associated connector is attached to the connector when the sensing device is actually used.