PATENT OF THE WEEK– METHOD FOR DETECTING AN IRREGULARITY IN VALVE-TIMING CHAGEOVER IN AN ENGINE

The METHOD FOR DETECTING AN IRREGULARITY IN VALVE-TIMING CHANGEOVER IN AN ENGINE was invented by Yasunari Seki (Tochigi), Yuzuru Koike (Tochigi), Takashi Sata (Tochigi) and Masatoshi Obata (Tochigi) on the 5^th of March 1991, bearing patent number US4996954A.

This invention relates to a control method for detecting an irregularity in the valve-timing changeover for internal combustion engines that have selectable modes of valve-timing operation.

The method compares the oil pressure in the supply passage to the valve timing changeover mechanism which should exist after the changeover caused by the latest instruction to determine an irregularity if the pressure is not equal. This can be achieved by detecting the downstream oil pressure of the changeover valve in the oil supplying passage, comparing the valve-timing changeover instruction given by the control means and detected oil pressure and determining through said comparison an irregularity in the operation of the changeover valve. The invention further proposes to perform a fail-safe operation in case of irregularity and/or activate an alarm system on detection of the valve-timings not corresponding to the instruction given.