The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 07, 2000
Filed:
Oct. 15, 1998
Kazuhiko Hayashi, Aichi-gun, JP;
Satoru Matsumoto, Toyota, JP;
Toyota Jidosha Kabushiki Kaisha, Toyota, JP;
Abstract
An immobilizer ECU (20) compares an internally stored reference code with a key code transmitted from a key (10). An engine ECU (24) transmits a rolling code A when an engine speed reaches 500 rpm. The immobilizer ECU (20) transmits a rolling code B when the codes coincide with each other. The engine ECU (24) will stop an engine if it cannot receive the rolling code B within a prescribed period of time. Further, there is provided a counter CIMMOF which is incremented at the beginning of such a process. The counter CIMMOF is reset only when the process is normally completed. If an ignition is turned off prior to transmission and reception of the rolling codes, the counter CIMMOF will be counted up. According to a value of the counter CIMMOF, a period of waiting for the rolling code B is gradually shortened. Further, when the process is completed or a backup power supply to a backup memory (24d) is cut off, a time to transmit and receive the rolling codes is advanced. Thus, the situation where the engine will be able to start due to disconnection of a communication line or the like is prevented.