Masanori Hanaoka

New Method for Measurement of Engine Oil Consumption (S-Trace Method)

A new method, the sulfur trace method (S-trace method), for measurement of engine oil consumption was investigated. This method uses the sulfur, naturally contained in the engine oil, as an oil tracer. This S-trace method requires about 20 minutes of engine operating time, and has a detection capability of 1 gram per hour. The coefficient of variation is better than 10% at the oil consumption level of 20 grams per hour. Furthermore, with the application of the S-trace method, oil consumption of individual cylinders and oil consumption lost through either the valve guide assembly or the piston-cylinder assembly can be measured.

A New Platinum Tipped Spark Plug Extends the Lean Misfire Limit and Useful Life

Higher compression ratio and lower air-fuel ratio tend to raise the required break down voltage. Various types of electrode configurations were examined. It was found that a very thin platinum plate attached to each electrode was effective in reducing the electrode wear. This newly developed platinum tipped spark plug uses a small sized center electrode and an enlarged initial spark gap. The lean misfire limit and the torque fluctuation at partial load are improved with the platinum tipped spark plug. After a durability test, the break down voltage became lower due to the grained platinum surface. The spark gap was almost unchanged during an 80 thousand kilometer durability test run.