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Most automatic transmissions are controlled in compliance with a predetermined program. Transient control during gear shift is also carried out according to a predetermined process. In this method a lot of labor is required to tune data tables. So we developed a tuning free system by feedback control using torque estimation technology and the experimental result is reported. Torque fluctuation during shift is detected and fed back to compare the torque reference, which is generated from the estimated torque itself. The engine torque is decreased by means of retarding the ignition spark advance, according to the comparison deviation. As a consequence of the feedback, the transient torque control is carried out without any tuning trouble, and better than usual torque fluctuation is obtained.

Mixture formation and the ignition process in 4 cycle 4 cylinder spark ignition engines were investigated, using an optical combustion sensor that combines fiber optics with a conventional spark plug. The sensor consists of a 1-mm diameter quartz glass optical fiber cable inserted through the center of a spark plug. The tip of the fiber is machined into a convex shape to provide a 120-degree view of the combustion chamber interior. Light emitted by the spark discharge between spark electrodes and the combustion flames in the cylinder is transmitted by the optical cable to an opto-electric transducer. As a result, the ignition and combustion process which depends on the mixture formation can be easily monitored without installing transparent pistons and cylinders. This sensor can give more accurate information on mixture formation in the cylinders.