Mass Air Flow Sensor                                                                      home

Production System


SYSTEM REQUIREMENTS

» Vacuum Flow at Nominal Flow Rates ranging from 1 to 1023 Kg/hr with a minimum step size of 1 Kg/hr 
» Unit Under Test (UUT) Power Cycling, Communication and Programming Capabilities
» Part Fixturing, including air flow inlet and exit tubes and a UUT mechanical/electrical mating connector
» Fully integrated into the continuous-flow manufacturing line
» Meet Production Line Cycle Time Goals of 1 part every 28 sec.
» Expandable and Flexible Data Acquisition and Control sub-system
» Expandable Air-Flow metering system and Instrumentation
» Operator Safety Interlock devices to comply with all regulatory requirements
» User-friendly Test System Controller Software for Operator, Maintenance and Engineering personnel.
DESCRIPTION

An Automotive OEM Parts Supplier required a flexible, automated in-line production test system to provide an accurate metered air flow supply through a new generation of automotive engine Mass Air Flow Sensors. The workstation would need to power and communicate and perform final programming of the Unit-Under-Test (UUT) while concurrently setting mass flow points. Additionally this workstation had to be fully integrated into a production line that was being simultaneously designed and installed. 

Accuracy, repeatability, throughput and availability were also critical elements in the design of the Test System.

SOLUTION

This workstation presented several challenges to the FLOW SYSTEMS Design Team. This stand was highly automated, and included functional requirements beyond that of simply “flowing” a UUT. The workstation had to communicate with the manufacturing line that it was integrated into to receive production data, as well as interface with the UUT to set parameters during the UUT flow test and to perform final UUT programming after flow testing.

FLOW SYSTEMS designed and manufactured an Air Flow system that employed a binary set of ten (10) Sonic Nozzles (Critical Flow Venturis ) housed in a common chamber to meter the air flow through each UUT. The Test System controller uses the current ambient conditions and a desired flow rate as inputs to compute the required nozzle pattern to set and then to open the nozzles.FLOW SYSTEMS also sized and provided the complete Vacuum System required to meet the workstation flow range and capacity.

FLOW SYSTEMS also designed and implemented a custom UUT interface using a Commercial Off-The-Shelf (COTS) microcontroller board. This product provided the necessary digital I/O and serial communication channels to effectively interface with the UUT. The product provided a cost effective, field proven and tested hardware and software solution that allowed FLOW SYSTEMS' personnel to focus on solving the problem rather than trying to design a “blank-sheet” hardware/software solution. The UUT also required additional instrumentation to operate and for measurement. The workstation included a Precision Dual Output Power Supply for powering the UUT. An 8˝ digit multimeter was also integrated into the test system for reading output voltages from the UUT at various flowrates.

Part Fixturing included air flow inlet and exit tubes that mechanically held the UUT in the proper horizontal orientation and a mechanical/electrical mating connector that held the UUT in the proper vertical orientation as well as providing the necessary electrical signals to the UUT.

As with all FLOW SYSTEMS' Test System designs, the Test System controller, data acquisition and control subsystems, and all instrumentation are standard, readily available Commercial Off-The-Shelf (COTS) items. This ensures that servicing or replacement of any item can be achieved in a timely manner, providing for a high-availability for the Test System. This includes all of the UUT related instrumentation that was explicitly specified by the customer

 
SYSTEM SCHEMATICS 

The following illustrates the Pneumatic and Instrumentation Diagram (P&ID) of the test system.


 

 
SOFTWARE OPERATOR INTERFACE 

The following image shows the Operator Interface to the Test System. 


 

 
SPECIFICATIONS

» Flow Elements: Eleven (11) Critical Flow Venturis (Sonic Nozzles), Two (2) spare positions for expansions
» Flow Range: 1 to 1023 Kg/hr, 1 Kg/hr resolution
» Accuracy: +/- 0.3 % of reading, traceable to NIST standards
» Repeatability: +/-0.08 % or better 
» Cycle Time: < 28 sec.

 
SYSTEM LAYOUT

The following diagram illustrates the physical layout of the test system.



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