Volvo Car Corporation

Volvo Personvagnar Ab

Peter M&ouml;ller

Jan M&uuml;ller

A diagnostic system in an engine management system is provided for generating a diagnostic trouble code (DTC) to indicate the operational status of a component or a sub-system. The diagnostic system includes a diagnostic function module (DF module) for each DTC or a group of related DTCs associated with a component or sub-system. The DF module includes means for executing an evaluation routine to evaluate a component/sub-system to which the DTC of the specific DF module relates, and a dynamic scheduler for determining which DF module may be allowed to execute an evaluation routine at a particular time. Each DF module includes means for producing a ranking value dependent on the operating status of the component or sub-system being evaluated, a ranking value being generated each time an evaluation routine is performed; means for processing and storing statistical results of the ranking values obtained over a number of evaluation routines; means for evaluating the statistical results to produce evaluated data in the form of either an evaluated no-fault signal or an evaluated fault signal, and means for establishing the priority of the associated evaluation routine, and means for transmitting the evaluated signals to the dynamic scheduler.

Diagnostic system in an engine management system

The invention relates to a method for the diagnosis of a sensor in connection with control of a combustion engine. The method includes feeding fuel under pressure (p) to the engine, detecting the pressure (p) by means of the sensor, and controlling the air/fuel mixture based on to the operating state of the engine. The invention involves an intentional modification of both the pressure (p) and injection time period (t ) during which fuel is fed to the engine. The modifications are selected in such a way that substantially no change in the fuel flow (F) to the engine is obtained. A check is performed to determine if the modifications of the pressure (p) and injection time period (t ) result in any unallowable deviation in the operating state of the engine. If so, an indication that the sensor is defective is provided. With the invention, an improved diagnosis method for checking the functioning of a fuel pressure sensor is provided.

Growing community of inventors

Mölndal, Sweden

Peter Möller

Growing community of inventors

Mölndal, Sweden

Peter M&ouml;ller

Peter Möller