Studies on measurement method of total friction loss of internal combustion engines

In the present study, a new test method is investigated to measure the total friction loss of engines over the entire ranges of speed and load. It is based on the idea that the friction loss close to the actual one of fired and braked engines can be measured by the run-out method because the temperature condition influencing the friction loss is nearly stable for the short test duration after the fuel cut. From the test results and the comparison with those measured by other conventional test methods, the following become evident. (1) The frictional mean effective pressure increases slightly as the revolution speed increases, but it decreases as either the load or the cooling water temperature increases. (2) The frictional mean effective pressure measured by the present method is smaller than that measured by the run-out method, the motoring method or Willans-line method, but it is larger than the one measured by the indicated pressure diagram method.