Measuring Vehicle Driveability

Emission controls, both exhaust and evaporative, have made it much more difficult to achieve satisfactory driveability. Since driveability is becoming a more critical factor, objective rating techniques are desirable. A surgemeter has been developed for objectively measuring vehicle surge, one driveability factor. A comparison of surgemeter ratings with surge ratings of expert drivers indicate that the surgemeter objectively measures surge. In one investigation, the surgemeter indicated that vehicle surge increased as the amount of exhaust gas recirculation required for NO_x control increased. In another investigation, the surgemeter was used to compare surge in seven different vehicles as part of a more comprehensive vehicle driveability rating program.

Good, overall vehicle driveability implies that the driver is satisfied with the automobile's power train operation. Driveability measurements generally employ subjective “seat-of-the-pants” techniques, and jargon to describe performance. These techniques and jargon are described and defined in this paper.