Modeling and MPC control of Homogeneous Charge Compression
Ignition(HCCI) Engine Dynamics
Dr Johan Bengtsson (Lund Institute of Technology)
The Homogeneous Charge Compression Ignition (HCCI) combustion engine
principle lacks direct ignition timing control, instead the auto-ignition
depends on
the operating condition. Since auto-ignition of a homogeneous mixture is very
sensitive to operating conditions, fast combustion phasing control is
necessary for
reliable operation. In this talk, a six-cylinder heavy-duty HCCI engine was
controlled on a cycle-to-cycle basis in real time. Today there exists
several different means to control an HCCI engine, such as dual fuels,
variable valve actuation (VVA), inlet temperature and compression ratio.
As actuator for controlling the HCCI combustion, a VVA system was used. As
for control principle, Model Predictive Control (MPC) have several
desirable features and today MPC can be applied to relatively fast
systems, such as cycle-to-cycle VVA actuation.
For sensor feedback control of the HCCI engine, cylinder pressure was used.
To the purpose of control synthesis requiring dynamic models, system
identification provided models of the HCCI combustion, the models being
validated by stochastic model validation. With such models providing a
basis for model-based control, for example MPC control. Multi-Input
Multi-Output control using MPC controllers were performed, while
satisfying the constraints on cylinder pressure, both control of the
combustion phasing and control of load torque with simultaneous
minimization of the fuel consumption and emissions.