Development of an Objective Methodology for Assessment of Commercial Vehicle Gearshift Quality

摘要

Rapid growth in the Indian economy has led to new market trends for commercial vehicles. Customers now expect high levels of comfort from all tactile points in a truck cabin; the gear lever knob is frequently used and its reactions greatly influence how a driver perceives Gear Shift Quality (GSQ) and thereby vehicle quality. The subjectivity of human perception is difficult to measure objectively; therefore this paper represents an objective methodology to correlate customer feedback of gearshift reactions. For the attribute evaluation of a set of intermediate commercial vehicles; detailed subjective appraisals were conducted by expert level assessors for GSQ sub-attributes, and a consecutive objective measurement was performed to investigate and substantiate these vehicle assessments. Dynamic and Static testing techniques were used to measure GSQ parameters like efforts during gear shift/select, feel of different phases of gear engagement/selection, gate definitions and lever travels; this helped in formulating objective metrics that can be used to create a definition of GSQ in a vehicle segment and an objective methodology to assess the same. The scope of this paper provides a comparative study of GSQ attributes in a set of intermediate commercial vehicles and explains how, the subjectivity of human perception with regard to gearshift comfort can be captured through objective testing methods and correlated.