The main oil pump in an automotive automatic transmission circulates oil when the engine is running. When the combustion engine in a hybrid vehicle is shut down, that responsibility falls to an auxiliary oil pump driven by an electric motor. Most auxiliary pumps are equipped with a sensor that monitors and regulates oil pressure. These pressure sensors fail frequently due to heat stress from transmission oil, which regularly reaches temperatures higher than 125° C (257° F).
Engineers at ebm-papst overcame this challenge by designing an auxiliary oil pump that does not use a pressure sensor. Model-Based Design with MATLAB® and Simulink® enabled them to develop and deploy a controller, build an automated system for engineering and end-of-line testing, and adapt to shifting customer requirements.
“Well into the project our customer’s requirements changed, and we had to significantly increase the accuracy of our pressure control,” says Jens Löffler, team leader for technology development at ebm-papst. “Model-Based Design made it possible to meet our customer’s changing requirements in a short time frame. In fact, without MATLAB and Simulink it would have been impossible to meet these new requirements in any time frame.”