Browse Publications Technical Papers 2001-01-0268
2001-03-05

Preparing for CARTRONIC - Interface and New Strategies for Torque Coordination and Conversion in a Spark Ignition Engine-Management System 2001-01-0268

A major trend in modern vehicle control is the increase of complexity and interaction of formerly autonomous systems. In order to manage the resulting network of more and more integrated (sub)systems Bosch has developed an open architecture called CARTRONIC for structuring the entire vehicle control system.
Structuring the system in functionally independent components improves modular software development and allows the integration of new elements such as integrated starter/generator and the implementation of advanced control concepts as drive train management. This approach leads to an open structure on a high level for the design of advanced vehicle control systems.
The paper describes the integration of the spark-ignition (SI) engine management system (EMS) into a CARTRONIC conform vehicle coordination requiring a new standard interface between the vehicle coordination and the EMS level.
The main variable in this interface is the torque demand, which must be realized by the engine within a specified time interval. A set of characteristics contains further information about the desired vehicle action e.g. predicted torque, driver's request and desired speed.
For the realization of an EMS compatible with the CARTRONIC interface the torque structure of the EMS must be modified. This means that torque demands independent of engine characteristics have to be processed on a vehicle coordination level while engine specific demands remain on the level of EMS coordination.
Separating the source of torque demands from the path of torque conversion opens ways to improve torque conversion strategies. A suitable approach for such strategy is the selection of the actuating path based upon the torque related time interval using a charge dynamics model.
The structure proposed in this paper defines the inter-face between vehicle coordination and a CARTRONIC compatible engine management system. Additionally, smart torque conversion strategies are introduced, which open up potential for improved driving comfort and further reductions in fuel consumption.

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