Response time test apparatus for a mass air flow sensor

A response time test apparatus for a mass air flow sensor mounted on a sensor manifold comprising attachable to the air intake manifold of an internal combustion engine, said sensor manifold having an air inlet end and an air outlet end, said test apparatus comprising:

• a connector member having a first end connectable to said air outlet end of said sensor manifold and a second end;
• a vacuum source;
• a primary air flow manifold connected between said vacuum source and said second end of said connector;
• at least a first sonic nozzle disposed in said primary air flow manifold between said vacuum source and said connector member, said first sonic nozzle having a first mass air flow rate therethrough under sonic air flow conditions;
• at least a first valve disposed in said primary air flow manifold, said first valve having an open state permitting air to flow through said first sonic nozzle and a closed state preventing an air flow through said first sonic nozzle;
• an electrical control connected to said first valve and to said mass air flow sensor, said electrical control having first logic means for actuating said fist valve to produce a step change in said mass air flow rate through said calibrated mass air flow manifold and said sensor manifold, from said first air flow rate to said second air flow rate, second logic means for energizing said mass air flow sensor to generate a sensor signal having a value corresponding to the mass air flow rate through said sensor manifold and memory means for recording a time required for said sensor signal to change from an initial value to a new stable new value in response to said step change in said mass air flow rate.

A response time test apparatus for a mass air flow sensor mounted on a sensor manifold, said sensor manifold having an air input end and an air output end, said test apparatus comprising:

• an air flow manifold having one end connectable to a vacuum source and an opposite end;
• means for connecting said opposite end of said air flow manifold to said air output end of said sensor manifold;
• a first sonic nozzle disposed in said air flow manifold for controlling the mass air flow through said sensor manifold to have a first determinable value;
• a first valve connected to said air flow for controlling the air flow through said air flow manifold;
• and
• an electronic control for providing electrical power energizing said mass air flow sensor to generate an output signal having a value corresponding to the mass air flow rate through said sensor manifold, means for activating said first valve to an open state permitting an air flow through said sonic nozzle, said air flow causing a determinable step change in the mass air flow sensor through said sensor manifold, means responsive to activating said first valve to determine the response time of said output signal of said mass air flow sensor to said determinable step change in said mass air flow rate in said sensor manifold and comparator means for comparing the response time of said mass air flow sensor with a reference response time to generate a fail signal when the response time of said mass air sensor is greater than said reference response time.