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Automotive & Transportation

Design and simulate vehicle dynamics, powertrain controllers, chassis and safety systems, and more with System Modeler. Combine with Mathematica for control system design and optimization.

Engine Throttle Control

A basic automotive control problem is to maintain a desired engine speed despite the torque disturbances due to power steering, air conditioning or engagements of automatic transmission. The main actuation scheme is by controlling the amount of air supplied to the engine via a throttle bypass valve. This example models a closed-loop throttle control that is synchronized to the crankshaft angle of an internal combustion engine.

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The Model

The engine speed is regulated with a throttle actuator. The speed controller is synchronized with the engine crankshaft angle. The sampling is done by the rotationalClock, which is an event-based clock that is triggered every 180° rotation of the crankshaft angle.

Sampled data engine controller that is synchronized with the crankshaft angle.


As the controller execution is synchronized with the engine crankshaft angle, it reduces the influence of load torque fluctuation. In the following plot, the engine speed stabilizes quickly to its stable speed despite the load torque fluctuation.


Analyze a nonperiodic synchronous system.

Simulation results.

Explore the Modelica_Synchronous Library to know more about sampled data systems.