Interpretation ID: aiam0944
Engineering Representative
Nissan Motor Company
Ltd.
560 Sylvan Avenue
Englewood Cliffs
New Jersey 07632;
Dear Mr. Kato: This is in response to your letter of December 28, 1972, concerning th application of Standard 124, 'Accelerator Control Systems', to a particular Nissan design.; Prior to our receipt of your letter, Nissan representatives met wit representatives from our Office of Operating Systems. At this meeting, Nissan representatives explained their questions and left a carburetor with NHTSA staff engineers as an aid to understanding the matters in question. Your company's concern is with the failure of a spring, designated as spring C, which in the event of severance or disconnection, would allow the secondary throttle plate to stay open slightly and thereby increase normal idle speed by approximately 300 rpm. Since spring C only returns the secondary throttle plate to idle position, spring C could not be considered as a return energy source under S5.1 of the standard, and, the failure of Spring C would not fall under the same requirements as a failure of either A or B. Further, spring C is not a part of the 'driver-operated accelerator control system' but is part of the 'fuel metering device', and, as such, severance or disconnection of spring C would not fall within the purview of S5.2.; You also presented a drawing of an accelerator control system and aske which point of severance or disconnection along the system is appropriate when conducting tests for the standard. Since the standard requires that the return to idle time must be met when 'any one component of the accelerator control system disconnected or severed', you ask if this would apply to bolts holding together mounting brackets, or just those components which move in relation to foot-pedal actuation. The components intended to be tested under severance or disconnection in the standard are those which are strictly defined in S4.1 'Driver-operated accelerator control system'. Accordingly, those components which move in accomplishing the regulation of engine speed would be tested, while fixed parts such as brackets and bolts depicted by the drawing you submitted would not be tested.; The carburetor your representatives left with us is being returned t Nissan under Separate cover. Your letter and the attached photographs of the carburetor with labeled springs will be placed in Docket 69-20.; Sincerely, E.T. Driver, Director, Office of Operating Systems