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Stochastic Set-Point Optimization for In-Cycle Closed-Loop Combustion Control Operation

Jorques Moreno, Carlos LU ; Stenlåås, Ola LU and Tunestål, Per LU (2021) SAE WCX Digital Summit In SAE Technical Paper
Abstract
The constrained indicated efficiency optimization of the set-point reference for in-cycle closed-loop combustion regulators is investigated in this article. Closed-loop combustion control is able to reduce the stochastic cyclic variations of the combustion by the adjustment of multiple-injections, a pilot and main injection in this work. The set-point is determined by the demand on engine load, burned pilot mass reference and combustion timing. Two strategies were investigated, the regulation of the start of combustion (SOC) and the center of combustion (CA50).
The novel approach taken in this investigation consists of including the effect of the controlled variables on the combustion dispersion, instead of using mean-value models, and... (More)
The constrained indicated efficiency optimization of the set-point reference for in-cycle closed-loop combustion regulators is investigated in this article. Closed-loop combustion control is able to reduce the stochastic cyclic variations of the combustion by the adjustment of multiple-injections, a pilot and main injection in this work. The set-point is determined by the demand on engine load, burned pilot mass reference and combustion timing. Two strategies were investigated, the regulation of the start of combustion (SOC) and the center of combustion (CA50).
The novel approach taken in this investigation consists of including the effect of the controlled variables on the combustion dispersion, instead of using mean-value models, and solve the stochastic optimization problem. A stochastic heat release model is developed for simulation and calibrated with extensive data from a Scania D13 six-cylinder engine. A Monte Carlo approach is taken for the simulations. The set-point optimization is based on the stochastic simulation of the heat release shape, including operational constraints on the maximum pressure, maximum pressure rise rate, maximum and minimum exhaust temperature.
By exploiting the reduction of the cyclic variations, the indicated efficiency can be increased by up to +1.8%unit at low loads and +0.6%unit at medium loads, compared to open-loop operation. The greatest advantage resulted by the regulation of CA50 under demanding maximum pressure rise rate constraints. By considering the risk of pilot misfire, the indicated efficiency can be increased additionally by +0.3%unit. The benefits of the in-cycle closed-loop combustion control reduces as the engine load increases, due to the lower sensitivity to combustion variations. Future work can use the same approach to include other constraints such as NOx, additional fuel injections and regulators. (Less)
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author
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organization
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type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
host publication
SAE Technical Paper
series title
SAE Technical Paper
issue
2021-01-0531
article number
2021-01-0531
pages
21 pages
publisher
Society of Automotive Engineers
conference name
SAE WCX Digital Summit
conference dates
2021-04-12 - 2021-04-15
ISSN
0148-7191
2688-3627
language
English
LU publication?
yes
id
8818edca-6f1b-4f8e-9d1c-69ef6ab23cc3
alternative location
https://www.sae.org/publications/technical-papers/content/2021-01-0531/
date added to LUP
2021-04-20 09:18:27
date last changed
2021-04-20 11:52:30
@inproceedings{8818edca-6f1b-4f8e-9d1c-69ef6ab23cc3,
  abstract     = {The constrained indicated efficiency optimization of the set-point reference for in-cycle closed-loop combustion regulators is investigated in this article. Closed-loop combustion control is able to reduce the stochastic cyclic variations of the combustion by the adjustment of multiple-injections, a pilot and main injection in this work. The set-point is determined by the demand on engine load, burned pilot mass reference and combustion timing. Two strategies were investigated, the regulation of the start of combustion (SOC) and the center of combustion (CA50).<br/>The novel approach taken in this investigation consists of including the effect of the controlled variables on the combustion dispersion, instead of using mean-value models, and solve the stochastic optimization problem. A stochastic heat release model is developed for simulation and calibrated with extensive data from a Scania D13 six-cylinder engine. A Monte Carlo approach is taken for the simulations. The set-point optimization is based on the stochastic simulation of the heat release shape, including operational constraints on the maximum pressure, maximum pressure rise rate, maximum and minimum exhaust temperature.<br/>By exploiting the reduction of the cyclic variations, the indicated efficiency can be increased by up to +1.8%unit at low loads and +0.6%unit at medium loads, compared to open-loop operation. The greatest advantage resulted by the regulation of CA50 under demanding maximum pressure rise rate constraints. By considering the risk of pilot misfire, the indicated efficiency can be increased additionally by +0.3%unit. The benefits of the in-cycle closed-loop combustion control reduces as the engine load increases, due to the lower sensitivity to combustion variations. Future work can use the same approach to include other constraints such as NOx, additional fuel injections and regulators.},
  author       = {Jorques Moreno, Carlos and Stenlåås, Ola and Tunestål, Per},
  booktitle    = {SAE Technical Paper},
  issn         = {0148-7191},
  language     = {eng},
  number       = {2021-01-0531},
  publisher    = {Society of Automotive Engineers},
  series       = {SAE Technical Paper},
  title        = {Stochastic Set-Point Optimization for In-Cycle Closed-Loop Combustion Control Operation},
  url          = {https://www.sae.org/publications/technical-papers/content/2021-01-0531/},
  year         = {2021},
}