Control method and apparatus for diagnosing vehicles

• US 6,085,132 A
• Filed: 11/06/1998
• Issued: 07/04/2000
• Est. Priority Date: 08/06/1992
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Miura, Kiyoshi, Kawano, Kazuya, Takaku, Yutaka, Ishii, Toshio, Mukaihira, Takashi
• Primary Examiner(s): LOUIS JACQUES, JACQUES H
• Application Number:
  US09/187,529
• Time in Patent Office: 606 Days
• Field of Search: 701/29, 701/31, 701/32, 701/33, 701/35, 701/101, 701/102, 701/104, 701/114, 701/115, 73/117.2, 73/117.3, 73/118.1, 73/116, 123/436, 123/479, 123/481, 123/480, 123/690, 364/131-138, 340/436, 340/438, 340/439
• US Class Current: 701/29
• CPC Class Codes: B60W 2050/021 Means for detecting failure or malfunction
• CPC Class Codes: F02D 2041/227 Limping Home, i.e. taking specific engine control measures at abnormal conditions
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02D 41/266 the computer being backed-up or assisted by another circuit, e.g. analogue

Abstract

A diagnostic and control system first checks the current operation status of the vehicle engine, when a malfunction or abnormal condition is detected by diagnostic sensors. A selection of optimum corrective measures is then made and carried out taking into account the safety of the vehicle, based on current operational status of the engine. For this purpose, a set of prioritized corrective measures is determined beforehand for each of the individual monitored items, according to detected changes in the engine operating status. The individual control measures are selected considering the safety of the vehicle, possible measures to correct the malfunction, assuring vehicle operability, and maintaining appropriate engine operating parameters such as exhaust gas mixture, fuel consumption and the like.

Claims

1. Method for controlling operation of a vehicle having a plurality of vehicle elements, said method comprising:

A. providing prioritized sets of corrective measures associated with predetermined malfunctions of the vehicle elements;

B. detecting sensor output signals indicative of operating parameters of the vehicle elements;

C. determining a malfunction of at least one of the vehicle elements, based on the sensor output signals;

D. dependent on the determined malfunction and detected operating parameters, selecting a corrective measure from among corrective measures contained in a highest priority set;

E. implementing the selected corrective measure, whereby operation of a malfunctioning element is influenced by outputting respective control signals, and then determining an effect of the selected corrective measure; and

F. dependent on the determined effect, possibly continuing performance of steps D. and E. with a next lower priority set of corrective measures.

2. Method of controlling operation of a vehicle system having an internal combustion engine and a plurality of subsystems, said method comprising:

providing a predetermined set of prioritized countermeasures for remedying predetermined malfunctions of each of said subsystems, and storing said prioritized countermeasure in a memory;

sensing operating parameters of each of said subsystems and providing output signals indicative thereof;

processing said output signals in a data processor to detect a malfunction of at least one of said subsystems;

selecting a sequence of prioritized countermeasures depending on the detected malfunction and on the sensed operating parameters;

performing a routine for sequentially implementing said prioritized countermeasures to modify operation of said system in response to control signals from said data processor;

testing said at least one of said subsystems by sensing operating parameters thereof in response to said control signals after implementation of a countermeasure, to determine an effect of said countermeasure; and

if said malfunction is corrected, terminating performance of said routine.

3. Method for controlling operation of a vehicle having a plurality of vehicle elements, said method comprising:

establishing respective sets of ordered corrective measures for correcting vehicle malfunctions;

detecting sensor output signals of the vehicle elements;

determining a malfunction of at least one of the vehicle elements based on said sensor output signals;

assigning priorities to said respective sets of ordered corrective measures, based on said determined malfunction;

selecting a first corrective measure from corrective measures contained in a highest priority set;

implementing said first corrective measure by outputting control signals to influence operation of a malfunctioning element;

determining an effect of said first corrective measure; and

if said malfunction is not corrected, successively implementing at least a second corrective measure, and determining an effect thereof, for correcting said malfunction.