Denso Corporation

Yoshitaka Uematsu

Hajime Nomura

Akihito Iwai

Tsutomu Hayashi

Kensuke Mizui

Toshiaki Iwashita

An element crack detecting apparatus for an oxygen sensor detects a sensor output voltage for an abnormality detection period after a fuel cut-off is started during operation of an engine. When the output voltage becomes negative, an abnormality counter is counted up. When the abnormality counter value reaches a determination value, it is determined that the element crack is present. The abnormality detection period is variably set in response to an engine rotational speed, an intake air quantity and the mixture state immediately before the fuel cut-off is effected. The determination value is variably set in response to the oxygen sensor temperature and the mixture state immediately before the fuel cut-off is effected. Further, the determination value is variably set in response to a magnitude of the negative voltage of the oxygen sensor.

Element crack detecting apparatus and method for oxygen sensor

A control apparatus for vehicles has a memory, which includes a plurality of correction information tables and a designation information table. The correction information tables stores a plurality of address data indicating types of correction calculations, and a plurality of correction terms to be calculated based on operating conditions in dependence on the types of correction calculations. The designation information table is for designates sequentially the plurality of correction information tables based on the types of correction calculations. A processing unit calculates sequentially a plurality of control values based on the address data and the correction terms with reference to the correction information tables designated by the designation information table, and calculating a final control value from the sequentially calculated control values.

Vehicle control apparatus for calculating control value with basic value and correction value

In a control apparatus and method for vehicles, control data such as engine air-fuel ratio correction values are learned and stored in a backup RAM to be used in engine control. Before the data are actually used in the engine control, not all the stored data are checked but only the data read out from the backup RAM to be used for control calculation are checked. Thus, all the memory data necessary are ensured to be checked in a short period of time, and improper control operation resulting from erroneous data can be obviated. Further, abnormality checking of all the stored data is executed at a specified timing separately. When the abnormality is found in any of the data, all the data in the backup RAM are initialized.

Memory check apparatus and method for checking data upon retrieval from memory

An engine control system checks for a misfire from a change in the rotation speed of an engine. A rotation interrupt routine is executed every 30&deg; angular rotation of an engine crankshaft to calculate and store only the rotation speed. In one of a plurality of time interrupt routines which are executed every predetermined respective time intervals, a change in the stored rotation speed is calculated to check for a misfire of the engine. The time interrupt routines have different execution priorities which are lower than that of the rotation interrupt routine. The time interrupt routine for checking the misfire has a non-highest execution priority among the time interrupt routines so that engine control processing such as fuel injection and ignition may be executed in another of the time interrupt routines having its execution priority lower than that of the time interrupt routine for checking the misfire.

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Anjo, Japan

Yoshitaka Uematsu