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The Controls and Software Engineering Team at BorgWarner Drivetrain Systems has successfully employed model-based software development for the past several years. Their drivetrain system control software, developed using MATLAB/Simulink/Stateflow, and autocoded using TargetLink, is on the road in many passenger vehicle applications. Using these tools, BorgWarner has realized the widely recognized benefits of model-based design; such as increased speed to market, improved quality, and reduced complexity. Validating algorithms early through simulation and rapid prototyping, then translating them to production software through automatic code generation has proven very successful for BorgWarner. When starting with model-based design, the BorgWarner team focused on developing the core application control algorithms in the modeling environment. Lower-level software such as I/O drivers, the task scheduler, and communication logic was still hand-coded.

A multivariable Linear Quadratic Gaussian (LQG) control algorithm is developed for engine idle speed control. Difficulties posed by inherent engine non-linearity, time varying engine events and delays are considered. A non-linear engine model used to design and test the control algorithm is described. Control engineers can use the engine model and control algorithm as a basis for further work in this area. A dynamic feedforward compensation which dramatically reduces disturbance deviations is also described. Finally, the effects of typical production air-to-fuel ratio control on the idle speed control system are evaluated.

The performance of fuels in the Jet Fuel Thermal Oxidation Tester (JFTOT) has been compared with that in a simulated engine oil cooler. In an attempt to improve the poor correlation found ‘between these tests, a carbon “burn-off method has been developed to quantify the extent of deposition in the JFTOT and has been used to examine the influence of JFTOT operating conditions on fuel performance. This has shown that the poor correlation between the tests may be due to the low fuel flow rate and the use of aluminium (rather than stainless steel) test specimens in the standard JFTOT.