ASAM ACI

The majority of ECUs in a vehicle undergo the calibration development step. The calibration of some vehicle components can be very complex and time consuming. This is particularly true for internal combustion engines. The role of an engine ECU is to continuously measure a large amount of engine data (requested load, speed, fuel and air temperature, etc.) and to calculate a set of optimal control output signals. The control strategies of the engine ECU have to meet contradicting optimization goals (high torque at low fuel consumption and emission, etc.) in a multitude of different environment and dynamic load conditions. Running the tests on an engine dynamometer to find the optimal calibration parameters, curves and maps is a function of many input parameters and conditions. This complex task can hardly be done manually anymore within acceptable time and cost limits. Consequently, test stands are increasingly equipped with systems that automate the calibration task.

ASAM ACI (Automatic Calibration Interface) defines an interface between test stand automation systems (TAS) and automated calibration systems (ACS). The interface consists of an object-oriented, client-server API, which offers four services that are requested by the ACS (the client) and carried out by the TAS (the server).

• Player service: controlling of test stand actuators for set-point adjustment
• Recorder service: recording of measurement values (mean or actual) from the test stand
• Watcher service: monitoring of out-of-bounds channel values
• Device service: further services such as ECU-specific and test stand-specific operations

The services allow the ACS to preset the unit-under-test, request specific measurement tasks and retrieve the measurement values from the TAS. Based on these services, an ACS can automatically run a set of predefined tests, modify tests based upon earlier test results and even modify ECU calibration parameters of the unit-under-test. Client and server may reside on different host systems and communicate via TCP/IP. ASAM ACI is suitable for both static and transient test executions. The interface is currently not suitable for supporting an ACS that has to respond under real-time conditions.

ASAM ACI was initially developed with engine calibration in mind. However, the standard has been successfully used in other test environments such as wind tunnels, electrical motor test stands and in-vehicle test systems.

Standard Authors

A&D Company Ltd., AVL LIST GmbH, BMW AG, D2T, Daimler AG, ETAS GmbH, FEV Automatisierungssysteme GmbH, Horiba GmbH, Kristl, Seibt & Co GmbH, M&K Mess- und Kommunikationstechnik GmbH, Renault S.A., Volkswagen AG.