| 1. |
- Liao, Hsien-Hsin, et al.
(författare)
-
Control of recompression HCCI with a three region switching controller
- 2013
-
Ingår i: Control Engineering Practice. - : Elsevier BV. - 0967-0661. ; 21:2, s. 135-145
-
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.
|
|
| 2. |
- Ravi, Nikhil, et al.
(författare)
-
Model predictive control of HCCI using variable valve actuation and fuel injection
- 2012
-
Ingår i: Control Engineering Practice. - : Elsevier BV. - 0967-0661. ; 20:4, s. 421-430
-
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.
|
|
