Since the automobile emission requirements of both the United States and Japan became very stringent for the 1975 model year vehicles, very sophisticated emission control devices have been installed on the vehicles and further engine modifications have been performed.
In order that all of our production vehicles may satisfy the emission requirements and be free from possible defects such as catalytic converter damage, we have developed and put into actual use a system called ECAS which allows us to assure satisfactory basic emission performance levels at assembly lines. This system consists of the following four tests: Idle Test, Functional Test, Short Cycle Test and Steady State Inspection Test.
By using this system, all operations from vehicle setup, on a chassis dynamometer to statistical analysis of the data, measurement, judgement of the obtained data, type-out of the results, indication for action to be taken, data filing and statistical treatment of the data, are processed automatically and controlled by the computer. In the Short Cycle Test the up-stream emissions of the vehicle, tracing Toyota's unique short cyclic mode on a chassis dynamometer, are continuously measured.
Based on the emission levels during each mode and the total emission level obtained from the above test we can diagnose, not only the emission control systems of a vehicle and its engine conditions such as valve clearance maladjustment and carburetor defects, but also the emission characteristics of this vehicle when tested by the FTP.