Nonlinear Optimal Control of Internal Combustion Engine Test Benches
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Test benches are an important tool in industry. In the automotive industry test benches are common
in the development and parametrization of the internal combustion engine, of control units, of the
drive line up to the entire vehicle. The increased distribution of alternative fuel vehicles leads to a
further increased use of test benches.
The device under test must be operated at a test bench as it would be operated in a vehicle. In
a vehicle, the load to the internal combustion engine results from the environment such as the
slope of the road. The load has to be computed and enforced by one or more dynamometer/s at a
test bench. If the configuration of the test bench and the test bench controller allow an accurate
simultion of the load conditions, measurements in a vehicle can be replaced by measurements at a
test bench. The advantages of test benches are reduced costs and time spent as well as reproducible
The significance of experiments at a test bench is a direct consequence of the precision of the test
bench controller. The task of the test bench controller is to set the inputs to the test bench ?
the accelerator pedal position of the internal combustion engine and the manipulated variable/s of
the dynamometer ? such that the measured shaft torque tracks the desired shaft torque and the
measured engine speed tracks the desired engine speed while the tracking error remains within a
defined range. Either, an electric dynamometer, a hydrodynamic dynamometer or both dynamometers
serve as actuators to the test bench controller. Hydrodynamic dynamometers are an interesting
alternative to electric dynamometers as their performance is very high, the moment of inertia is
small and the costs are quite low.