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| 2. |
- Liao, Hsien-Hsin, et al.
(författare)
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Control of recompression HCCI with a three region switching controller
- 2013
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Ingår i: Control Engineering Practice. - : Elsevier BV. - 0967-0661. ; 21:2, s. 135-145
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Tidskriftsartikel (refereegranskat)abstract
- Homogeneous charge compression ignition (HCCI) presents new challenges in combustion phasing control due to the lack of direct ignition trigger. In addition, recompression HCCI possesses cycle-to-cycle coupling through trapping a large portion of the exhaust gas in the cylinder. This paper examines the change in the cycle-to-cycle coupling around different operating points in recompression HCCI and show that there are three qualitative types of temperature dynamics: smooth decaying when combustion phasing is early, oscillatory when phasing is late, and strongly converging with moderate combustion phasing. As a result, a three region switching linear model that combines three linearized models can capture the qualitative change in system characteristics. Based on this model, a three region switching controller is designed and shown in experiments that it can track a wide range of desired combustion phasing and improve the variance of combustion phasing over open-loop operations. In the last part of this paper, two semi-definite programming (SDP) formulations are presented to prove the stability of the switching control/model framework. (C) 2012 Elsevier Ltd. All rights reserved.
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| 3. |
- Liao, Hsien-Hsin, et al.
(författare)
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Controlling Combustion Phasing of Recompression HCCI with a Switching Controller
- 2010
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Konferensbidrag (refereegranskat)abstract
- Homogeneous charge compression ignition (HCCI) is more efficient and produces significantly less NOx emissions compared to spark ignitions. Using an exhaust recompression strategy to achieve HCCI, however, produces cycle-to-cycle coupling which makes the problem of controlling combustion phasing more difficult. In the past, a linear feedback controller designed with a single linearized model is effective in controlling combustion phasing around an operating point. However, HCCI dynamics can change dramatically around different operating points such that a single linearization is insufficient to approximate the entire operating range. Further investigation shows that the operating range can be roughly divided into three regions where a linear model can capture the qualitative system behavior in each of the regions. As a result, a three zone switching linear model approximates recompression HCCI dynamics far better than a single linearization. This new model structure also suggests that two of the three regions need completely opposite control actions. Therefore, the approach of using a static feedback control based on a single linearziation cannot be appropriate over the entire operating range. We propose a switching controller based on the switching linear model and achieve very good performance in controlling HCCI combustion phasing throughout the entire operating region. Lastly, a semi-definite programming (SDP) formulation of finding a Lyapunov function for the switching linear model is presented in order to guarantee stability of the switching control scheme.
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| 4. |
- Ravi, Nikhil, et al.
(författare)
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Model predictive control of HCCI using variable valve actuation and fuel injection
- 2012
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Ingår i: Control Engineering Practice. - : Elsevier BV. - 0967-0661. ; 20:4, s. 421-430
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Tidskriftsartikel (refereegranskat)abstract
- Control of work output and combustion phasing on a Homogeneous Charge Compression Ignition (HCCI) engine is essential to realize the benefits of superior efficiency and emissions. This paper presents a model predictive control approach for cycle-by-cycle control of HCCI while respecting constraints on actuators that might exist on a production implementation. The strategy is based on a physical model developed in previous work and uses valve actuation and split fuel injection to achieve the control objectives. In addition, it considers constraints on air–fuel ratio, ensuring that the system stays away from very lean or rich regions. Simulation and experimental results show that the controller works well over a range of conditions, and demonstrate the potential of this approach as a practical cycle-by-cycle control strategy for HCCI.
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| 5. |
- Widd, Anders, et al.
(författare)
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Control of Exhaust Recompression HCCI using Hybrid Model Predictive Control
- 2011
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Ingår i: Proc. 2011 American Control Conference (ACC2011). ; , s. 420-425
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Konferensbidrag (refereegranskat)abstract
- Homogeneous Charge Compression Ignition (HCCI) holds promise for reduced emissions and increased efficiency compared to conventional internal combustion engines. As HCCI lacks direct actuation over the combustion phasing, much work has been devoted to designing controllers capable of set-point tracking and disturbance rejection. This paper presents results on model predictive control (MPC) of the combustion phasing in an HCCI engine based on a hybrid model formulation composed of several linearizations of a physics-based nonlinear model. The explicit representation of the MPC was implemented experimentally and the performance during set point changes was compared to that of a switched state feedback controller. The hybrid MPC produced smoother transients without overshoot when the set point change traversed several linearizations.
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| 6. |
- Widd, Anders, et al.
(författare)
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Hybrid Model Predictive Control of Exhaust Recompression HCCI
- 2014
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Ingår i: Asian Journal of Control. - : Wiley. - 1934-6093 .- 1561-8625. ; 16:2, s. 370-381
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Tidskriftsartikel (refereegranskat)abstract
- Homogeneous charge compression ignition (HCCI) holds promise for reduced emissions and increased efficiency compared to conventional internal combustion engines. As HCCI lacks direct actuation over the combustion phasing, much work has been devoted to designing controllers capable of set-point tracking and disturbance rejection. This paper presents results on model predictive control (MPC) of the combustion phasing in an HCCI engine based on a hybrid model formulation composed of several linearizations of a physics-based nonlinear model. The explicit representation of the MPC was implemented experimentally and the performance during set point changes was compared to that of a switched state feedback controller. The hybrid MPC produced smoother transients without overshoot when the set point change traversed several linearizations.
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