| 1. |
- Thor, Mikael, 1982, et al.
(författare)
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Closed-loop diesel engine combustion phasing control based on crankshaft torque measurements
- 2014
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Ingår i: Control Engineering Practice. - : Elsevier BV. - 0967-0661. ; 33, s. 115-124
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Tidskriftsartikel (refereegranskat)abstract
- Methods for closed-loop combustion phasing control in a diesel engine, based on measurements of crankshaft torque, are developed and evaluated. A model-based method for estimation of cylinder individual torque contributions from the crankshaft torque measurements is explained and a novel approach for identification of crankshaft dynamics is proposed. The use of the combustion net torque concept for combustion phasing estimation in the torque domain is also described. Two different control schemes, one for individual cylinder control and one for average cylinder control, are studied. The proposed methods are experimentally evaluated using a light-duty diesel engine equipped with a crankshaft integrated torque sensor. The results indicate that it is possible to estimate and control on a cylinder individual basis using the measurements from the crankshaft torque sensor. Combustion phasing is estimated with bias levels of less than 0.5 crank angle degrees (CAD) and cycle-to-cycle standard deviations of less than 0.7 CAD for all cylinders and the implemented combustion phasing controllers manage to accurately counteract disturbances in both fuel injection timing and EGR fraction.
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| 2. |
- Thor, Mikael, 1982, et al.
(författare)
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Estimation of Combustion Phasing Using the Combustion Net Torque Method
- 2011
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Ingår i: IFAC Proceedings Volumes (IFAC-PapersOnline). - 2405-8963. - 9783902661937 ; 18:PART 1, s. 11827-11832
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Konferensbidrag (refereegranskat)abstract
- A new and computationally efficient method, called the combustion net torque method, for estimating combustion phasing in an internal combustion engine using crankshaft torque data is presented. The work is motivated by the need of such an estimation method for real-time implementation of a torque based closed-loop combustion phasing control system. The ideal properties of the proposed method, based on torque calculated from cylinder pressure, are studied using simulations and experimental data from both a spark ignited and a compression ignited engine. A relation to 50% burned mass fraction, the most common measure of combustion phasing, is established and the robustness of the method is investigated. The results show that the ideal estimation accuracy of the proposed method is high, especially around the combustion phasing position where maximum engine efficiency is achieved. Also, the computational complexity of the combustion net torque method is significantly lower compared to other existing techniques for torque domain combustion phasing estimation.
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| 3. |
- Thor, Mikael, 1982, et al.
(författare)
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Parameterized Diesel Engine Combustion Modeling for Torque Based Combustion Property Estimation
- 2012
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Ingår i: SAE Technical Papers. - 400 Commonwealth Drive, Warrendale, PA, United States : SAE International. - 0148-7191 .- 2688-3627.
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Tidskriftsartikel (refereegranskat)abstract
- Combustion model structures based on Vibe functions are outlined and investigated in this work. The focus of the study is the use of such model structures for estimation of diesel combustion properties by reconstructing in-cylinder pressure from measurements of crankshaft torque. Investigated combustion properties include the start and phasing of the combustion as well as maximum values of the in-cylinder pressure and its derivative. The accuracy associated with the proposed estimation method is evaluated using ideal torque data, i.e. torque calculated from in-cylinder pressure, that is generated using both simulations and experiments. The results indicate that the uncertainty associated with the estimation of a selected combustion property tends to increase if that property is located close to TDC, where the signal-to-noise ratio is low for a torque signal. The results also show that the ideal torque based estimation of combustion phasing and maximum in-cylinder pressure generally is very accurate while the estimation of start of combustion and the maximum in-cylinder pressure derivative suffers more from disturbances and model imperfections.
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| 4. |
- Thor, Mikael, 1982, et al.
(författare)
-
Using combustion net torque for estimation of combustion properties from measurements of crankshaft torque
- 2014
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Ingår i: Control Engineering Practice. - : Elsevier BV. - 0967-0661. ; 26:1, s. 233-244
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Tidskriftsartikel (refereegranskat)abstract
- Two methods, both based on the concept of combustion net torque, for estimation of combustion properties using measurements of crankshaft torque data are investigated in this work. The first of the proposed methods estimates entire burned mass fraction traces from corresponding combustion net torque traces. This is done by solving a convex optimization problem that is based on a derived analytical relation between the two quantities. The other proposed estimation method estimates the well established combustion phasing measure referred to as 50% burned mass fraction directly from combustion net torque using a nonlinear black-box mapping. The methods are assessed using both simulations and experimental data gathered from a 5-cylinder light-duty diesel engine equipped with a crankshaft torque sensor and cylinder pressure sensors that are used for reference measurements. The results indicate that both methods work well but the method that estimates entire burned mass fraction traces is more sensitive to torque data quality. Based on the experimental crankshaft torque data, the direct combustion phasing estimation method delivers estimates with a bias of less than 1 CAD and a cycle-to-cycle standard deviation of less than 2.7 CAD for all cylinders.
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