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- Agrell, Fredrik, et al.
(författare)
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Control of HCCI During Engine Transients by aid of Variable Valve Timings Through the use of Model Based Non-Linear Compensation
- 2005
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Ingår i: SAE transactions. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0096-736X. ; 114:3, s. 296-310
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Tidskriftsartikel (refereegranskat)abstract
- One of the main challenges with the Homogeneous Charge Compression Ignition, HCCI, combustion system is to control the Start Of Combustion, SOC, for varying load and external conditions. A method to achieve this on a cycle-by-cycle basis is to vary the valve timing based on a feedback signal from the SOC of previous cycles. The control can be achieved with two basic valve-timing strategies named the Overlap- and the IVC-method. The Overlap-method works by trapping of residuals while the IVC-method affects the effective compression ratio. In an earlier paper it has been shown that if the two methods are incorporated into one controller, SOC can be controlled in a relatively large operating window although the transient performance was not sufficient. The reason is that the simple PI-controller cannot be made fast enough to cope with the transients without magnifying the cycle-to-cycle variations of the combustion into instability. In this work a model based control system that features a non-linear compensation, based on the inverse of the non-linear function from valve timings to ignition delay, is suggested and evaluated. The results show good transient performance. Control performance from engine tests is reported. A combined engine and control simulation system is used for the development of the control strategies. The simulations are accomplished with a commercial cycle simulation code linked with a commercial control simulation code. The simulations are iteratively verified against engine test data. Engine tests are conducted on a single cylinder engine equipped with a hydraulic valve system.
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| 5. |
- Agrell, Fredrik, et al.
(författare)
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Transient Control of HCCI Through Combined Intake and Exhaust Valve Actuation
- 2003
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Konferensbidrag (refereegranskat)abstract
- Homogeneous Charge Compression Ignition, HCCI, has the attractive feature of low particulate emission and low Nitrogen Oxides, NOx, emission combined with high efficiency. The principle is a combination of an Otto and a Diesel engine in that a premixed charge is ignited by the compression heat.
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