Abstract: A mass fluid flow sensor includes an internal bypass passage characterized by a first section that converges along a first axis to define a nozzle, and a radially-expanded generally-cylindrical second section immediately adjacent to and coaxial with the first section so as to define a radial step at the nozzle exit. The passage further includes a semispherical third section adjacent to the second section having the same nominal diameter, a converging fourth section whose nominal axis is disposed at a right angle to the nominal axis of the first and second sections, and a fifth section adjacent to the fourth section that includes a further ninety degree bend. The resulting U-shaped passage features reduced pressure losses and an improved velocity profile, whereby the performance of a sensing element disposed in the passage proximate to the radial step is improved.

Abstract: A device for detecting a mass of a flowing fluid is disclosed. The device includes a housing having a fluid sampling portion and a circuit cavity portion. The fluid sampling portion is positionable within a fluid carrying duct and includes a flow passage. A nozzle is in fluid communication with the flow passage, wherein the nozzle has a nozzle exit. An electrical element is disposed in the flow passage proximate to the nozzle exit. Further, a circuit module is in communication with the electrical element and disposed in the circuit cavity portion for detecting a change in an electrical property of the electrical element, wherein the detected change in the electrical property is used to determine the mass of the flowing fluid. Finally, a homogenous lead frame having a connector pin portion and an electrical attachment portion for providing an electrical path from the electrical element and circuit module to the connector pin portion is provided.

Abstract: A mass fluid flow sensor includes an internal bypass passage characterized by a first section that converges along a first axis to define a nozzle, and a radially-expanded generally-cylindrical second section immediately adjacent to and coaxial with the first section so as to define a radial step at the nozzle exit. The passage further includes a semispherical third section adjacent to the second section having the same nominal diameter, a converging fourth section whose nominal axis is disposed at a right angle to the nominal axis of the first and second sections, and a fifth section adjacent to the fourth section that includes a further ninety degree bend. The resulting U-shaped passage features reduced pressure losses and an improved velocity profile, whereby the performance of a sensing element disposed in the passage proximate to the radial step is improved.

Abstract: A device for detecting a mass of a flowing fluid is disclosed. The device includes a housing having a fluid sampling portion and a circuit cavity portion. The fluid sampling portion is positionable within a fluid carrying duct and includes a flow passage. A nozzle is in fluid communication with the flow passage, wherein the nozzle has a nozzle exit. An electrical element is disposed in the flow passage proximate to the nozzle exit. Further, a circuit module is in communication with the electrical element and disposed in the circuit cavity portion for detecting a change in an electrical property of the electrical element, wherein the detected change in the electrical property is used to determine the mass of the flowing fluid. Finally, a homogenous lead frame having a connector pin portion and an electrical attachment portion for providing an electrical path from the electrical element and circuit module to the connector pin portion is provided.

Abstract: This invention includes straightening and curving air flow within an environmental test chamber so as to improve the testing of a mass air flow meter by maintaining a uniform air flow velocity profile and constrain the size of the environmental test chamber. Such size constraint facilitates the task of maintaining a desired environment within the chamber.

Abstract: A mass air flow sensor calibration air flow stand is tested during production by substituting a nozzle supplying a predetermined amount of air flow for a mass air flow sensor in the production line. The calibration air flow stand is supplied air from the nozzle. If the calibration air flow stand is operating properly the flow in the air flow stand is the same as the predetermined amount of air flow.

Abstract: A carrier for the assembly, test and calibration of a mass air flow sensor on a production line. The support carrier consists of a structure having a well for receiving a first portion of the sensor head of the mass air flow sensor and a transverse air flow passage provided through the support structure aligned with the well and parallel to the top surface of the support structure. A clearance aperture connects the bottom of the well with an air flow passage and permits the sensor elements of the mass air flow sensor to be centrally disposed in the air flow passage. Sealing surfaces provided at the opposite ends of the air flow passage permit the carrier to be connected to a controlled source of air. Locating pins align the mass air flow sensor on the carrier with the sensor elements accurately positioned in the air flow passage.

Abstract: A response time test apparatus for a mass air flow sensor (10) mounted on a sensor manifold (12) connectable to the air intake manifold of an internal combustion engine. The test apparatus has a connector member (28) to which the sensor manifold (12) may be attached and a primary manifold (30) connected between a vacuum source (46,48) and the connector member (30). The primary manifold (30) has a first branch (32) and a parallel second branch (38). The first branch (32) has a first sonic nozzle (34) and a first valve (38) controlling the air flow through the first branch (32). The second branch (38) has a second sonic nozzle (40) and a second valve (42) controlling the air flow through the second branch (32). The first and second sonic nozzles (34,40) producing substantially different air flow rates in the primary manifold (30).

Abstract: An air flow manifold system for a production line calibration station. The air flow manifold system has a connector manifold connected to the production line calibration station, a vacuum source, a first manifold and a second manifold. The first and second manifolds connect the connector manifold to a vacuum source. The first and second manifolds each have a shut-off valve and a sonic nozzle controlling the mass air flow therethrough. The mass air flow through the first and second sonic nozzles are selected to have an optimal value for the calibrations to be conducted by the calibration station. An electrical controller sequentially activates the first and second valves sequentially supplying the specified mass air flow rates through the calibration station. Pressure and temperature sensors disposed upstream of the sonic nozzles permit an accurate determination of the mass air flow rates through the sonic nozzles.

Abstract: A two temperature test apparatus for a mass air flow sensor having a cold test station disposed in a cold test chamber and a hot test station disposed in a hot test chamber. A first air manifold connects the cold test chamber with a vacuum chamber. The first air manifold includes a sonic nozzle controlling the air flow through the first air manifold. A second air manifold connects the cold test station to the hot test station. A third air manifold connects the hot test station to an air filter within the hot test chamber. The mass air flow sensor is mounted on a production carrier having a transverse air passage receiving the sensing head of the mass air flow sensor. The transverse air flow passage of the carrier in the cold test station connects the first air manifold to the second air manifold and the transverse air flow passage of the carrier in the hot test station connects the second air manifold to the third air manifold.

Abstract: An O-ring test apparatus for a mass air flow sensor having a lift mechanism for lifting the mass air flow sensor and its production line carrier from the production line to a test location. In the test location, a clamping mechanism clamps the mass air flow sensor to the carrier compressing the O-ring. A seal mechanism blocks one end of an air flow passage provided in the production line carrier and connects an air inlet member to the other end. The air inlet member is connected by a manifold to a source of pressurized air through a solenoid valve. A pressure sensor connected to the manifold generates at least a first pressure signal in the manifold which rises to a pressure indicating that the O-ring is properly mounted on the mass air flow sensor. A control circuit activates the lift mechanism, the seal mechanism and the solenoid valve in a predetermined sequence and generates a fail signal in the absence of the first pressure signal when the solenoid value is open.