Engine Performance
Work Example 16

WorkKey Level: 6
NATEF Automotive Tasks: I.A.8, VIII.A.8

Problem:

A vehicle is getting 20 miles per gallon (mpg) with the engine operating at approximately 180°F. For each 10° increase in engine operating temperature above 160° the fuel economy will increase 2.5%. If the 180° thermostat is removed and replaced with a 200° thermostat, what will be the new mpg?

Solution:

Replacing the 180° thermostat with a 200° thermostat equals a 20° increase in operation temperature.

Therefore, 20 mpg × 2.5% (0.025) = 0.5 mpg, and
20 mpg + 0.5 mpg = 20.5 mpg