scholarly journals Development and Experimental Validation of an Adaptive, Piston-Damage-Based Combustion Control System for SI Engines: Part 2—Implementation of Adaptive Strategies

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5342
Author(s):  
Alessandro Brusa ◽  
Nicolò Cavina ◽  
Nahuel Rojo ◽  
Jacopo Mecagni ◽  
Enrico Corti ◽  
...  

This work focuses on the implementation of innovative adaptive strategies and a closed-loop chain in a piston-damage-based combustion controller. In the previous paper (Part 1), implemented models and the open loop algorithm are described and validated by reproducing some vehicle maneuvers at the engine test cell. Such controller is further improved by implementing self-learning algorithms based on the analytical formulations of knock and the combustion model, to update the fuel Research Octane Number (RON) and the relationship between the combustion phase and the spark timing in real-time. These strategies are based on the availability of an on-board indicating system for the estimation of both the knock intensity and the combustion phase index. The equations used to develop the adaptive strategies are described in detail. A closed-loop chain is then added, and the complete controller is finally implemented in a Rapid Control Prototyping (RCP) device. The controller is validated with specific tests defined to verify the robustness and the accuracy of the adaptive strategies. Results of the online validation process are presented in the last part of the paper and the accuracy of the complete controller is finally demonstrated. Indeed, error between the cyclic and the target combustion phase index is within the range ±0.5 Crank Angle degrees (°CA), while the error between the measured and the calculated maximum in-cylinder pressure is included in the range ±5 bar, even when fuel RON or spark advance map is changing.

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5367
Author(s):  
Alessandro Brusa ◽  
Nicolò Cavina ◽  
Nahuel Rojo ◽  
Jacopo Mecagni ◽  
Enrico Corti ◽  
...  

This work is focused on the development and validation of a spark advance controller, based on a piston “damage” model and a predictive knock model. The algorithm represents an integrated and innovative way to manage both the knock intensity and combustion phase. It is characterized by a model-based open-loop algorithm with the capability of calculating with high accuracy the spark timing that achieves the desired piston damage in a certain period, for knock-limited engine operating conditions. Otherwise, it targets the maximum efficiency combustion phase. Such controller is primarily thought to be utilized under conditions in which feedback is not needed. In this paper, the main models and the structure of the open-loop controller are described and validated. The controller is implemented in a rapid control prototyping device and validated reproducing real driving maneuvers at the engine test bench. Results of the online validation process are presented at the end of the paper.


Author(s):  
Pipitone Emiliano

In order to reduce fuel cost and CO2 emissions, modern spark ignition (SI) engines need to lower as much as possible fuel consumption. A crucial factor for efficiency improvement is represented by the combustion phase, which in an SI engine is controlled acting on the spark advance. This fundamental engine parameter is currently controlled in an open-loop by means of maps stored in the electronic control unit (ECU) memory: such kind of control, however, does not allow running the engine always at its best performance, since optimal combustion phase depends on many variables, like ambient conditions, fuel quality, engine aging, and wear, etc. A better choice would be represented by a closed-loop spark timing control, which may be pursued by means of combustion phase indicators, i.e., parameters mostly derived from in-cylinder pressure analysis that assume fixed reference values when the combustion phase is optimal. As documented in literature (Pestana, 1989, “Engine Control Methods Using Combustion Pressure Feedback,” SAE Paper No. 890758; BERU Pressure Sensor Glow Plug (PSG) for Diesel Engines, http://beru.federalmogul.com; Sensata CPOS SERIES—Cylinder Pressure Only Sensors, http://www.sensata.com/download/cpos.pdf; Malaczynski et al., 2013, “Ion-Sense-Based Real-Time Combustion Sensing for Closed-Loop Engine Control,” SAE Int. J. Eng., 6(1), pp. 267–277; Yoshihisa et al., 1988, “MBT Control Through Individual Cylinder Pressure Detection,” SAE Paper 881779; Powell, 1993, “Engine Control Using Cylinder Pressure: Past, Present, and Future,” J. Dyn. Syst., Meas. Control, 115, pp. 343–350; Muller et al., 2000, “Combustion Pressure Based Engine Management System,” SAE Paper 2000-01-0928; Yoon et al., 2000, “Closed-Loop Control of Spark Advance and Air-Fuel Ratio in SI Engines Using Cylinder Pressure,” SAE Paper 2000-01-0933; Eriksson, 1999, “Spark Advance Modeling and Control,” Dissertation N° 580, Linkoping Studies in Science and Technology, Linköping, Sweden; Samir et al., 2011, “Neural Networks and Fuzzy Logic-Based Spark Advance Control of SI Engines,” Expert Syst. Appl., 38, pp. 6916–6925; Cook et al., 1947, “Spark-Timing Control Based on Correlation of Maximum-Economy Spark Timing, Flame-Front Travel, and Cylinder Pressure Rise,” NACA Technical Note 1217; Bargende, 1995, “Most Optimal Location of 50% Mass Fraction Burned and Automatic Knock Detection,” MTZ, 10(56), pp. 632–638.), the use of combustion phase indicators allows the determination of the best spark advance, apart from any variable or boundary condition. The implementation of a feedback spark timing control, based on the use of these combustion phase indicators, would ensure the minimum fuel consumption in every possible condition. Despite the presence of many literature references on the use combustion phase indicators, there is no evidence of any experimental comparison on the performance obtainable, in terms of both control accuracy and transient response, by the use of such indicators in a spark timing feedback control. The author, hence, carried out a proper experimental campaign comparing the performances of a proportional-integral spark timing control based on the use of five different in-cylinder pressure derived indicators. The experiments were carried out on a bench test, equipped with a series production four cylinder spark ignition engine and an eddy current dynamometer, using two data acquisition (DAQ) systems for data acquisition and spark timing control. Pressure sampling was performed by means of a flush mounted piezoelectric pressure transducer with the resolution of one crank angle degree. The feedback control was compared to the conventional map based control in terms of response time, control stability, and control accuracy in three different kinds of tests: steady-state, step response, and transient operation. All the combustion phase indicators proved to be suitable for proportional-integral feedback spark advance control, allowing fast and reliable control even in transient operations.


1992 ◽  
Vol 114 (1) ◽  
pp. 74-81 ◽  
Author(s):  
J. Rastegar ◽  
Q. Tu

Closed-form Grashof-type movability conditions are derived for closed-loop RSSR mechanisms using a geometrical approximation technique. The conditions that ensure the presence of crank-rocker and drag-link type mechanisms are derived with and without force transmission limitations. The force transmission limitations may be specified as a function of the output link angle. The accuracy of the approximated conditions is analyzed. As an example, the conditions are used to synthesize a function generating mechanism with fully rotatable crank and with various force transmission requirements. The developed technique is general, and can be applied to other similar spatial mechanisms. The application of this approach to geometrical synthesis of open-loop chain manipulators is discussed.


2020 ◽  
Vol 26 ◽  
pp. 41
Author(s):  
Tianxiao Wang

This article is concerned with linear quadratic optimal control problems of mean-field stochastic differential equations (MF-SDE) with deterministic coefficients. To treat the time inconsistency of the optimal control problems, linear closed-loop equilibrium strategies are introduced and characterized by variational approach. Our developed methodology drops the delicate convergence procedures in Yong [Trans. Amer. Math. Soc. 369 (2017) 5467–5523]. When the MF-SDE reduces to SDE, our Riccati system coincides with the analogue in Yong [Trans. Amer. Math. Soc. 369 (2017) 5467–5523]. However, these two systems are in general different from each other due to the conditional mean-field terms in the MF-SDE. Eventually, the comparisons with pre-committed optimal strategies, open-loop equilibrium strategies are given in details.


2020 ◽  
pp. 99-107
Author(s):  
Erdal Sehirli

This paper presents the comparison of LED driver topologies that include SEPIC, CUK and FLYBACK DC-DC converters. Both topologies are designed for 8W power and operated in discontinuous conduction mode (DCM) with 88 kHz switching frequency. Furthermore, inductors of SEPIC and CUK converters are wounded as coupled. Applications are realized by using SG3524 integrated circuit for open loop and PIC16F877 microcontroller for closed loop. Besides, ACS712 current sensor used to limit maximum LED current for closed loop applications. Finally, SEPIC, CUK and FLYBACK DC-DC LED drivers are compared with respect to LED current, LED voltage, input voltage and current. Also, advantages and disadvantages of all topologies are concluded.


2021 ◽  
Vol 13 (15) ◽  
pp. 2868
Author(s):  
Yonglin Tian ◽  
Xiao Wang ◽  
Yu Shen ◽  
Zhongzheng Guo ◽  
Zilei Wang ◽  
...  

Three-dimensional information perception from point clouds is of vital importance for improving the ability of machines to understand the world, especially for autonomous driving and unmanned aerial vehicles. Data annotation for point clouds is one of the most challenging and costly tasks. In this paper, we propose a closed-loop and virtual–real interactive point cloud generation and model-upgrading framework called Parallel Point Clouds (PPCs). To our best knowledge, this is the first time that the training model has been changed from an open-loop to a closed-loop mechanism. The feedback from the evaluation results is used to update the training dataset, benefiting from the flexibility of artificial scenes. Under the framework, a point-based LiDAR simulation model is proposed, which greatly simplifies the scanning operation. Besides, a group-based placing method is put forward to integrate hybrid point clouds, via locating candidate positions for virtual objects in real scenes. Taking advantage of the CAD models and mobile LiDAR devices, two hybrid point cloud datasets, i.e., ShapeKITTI and MobilePointClouds, are built for 3D detection tasks. With almost zero labor cost on data annotation for newly added objects, the models (PointPillars) trained with ShapeKITTI and MobilePointClouds achieved 78.6% and 60.0% of the average precision of the model trained with real data on 3D detection, respectively.


2020 ◽  
Vol 11 (1) ◽  
pp. 177
Author(s):  
Pasi Fränti ◽  
Teemu Nenonen ◽  
Mingchuan Yuan

Travelling salesman problem (TSP) has been widely studied for the classical closed loop variant but less attention has been paid to the open loop variant. Open loop solution has property of being also a spanning tree, although not necessarily the minimum spanning tree (MST). In this paper, we present a simple branch elimination algorithm that removes the branches from MST by cutting one link and then reconnecting the resulting subtrees via selected leaf nodes. The number of iterations equals to the number of branches (b) in the MST. Typically, b << n where n is the number of nodes. With O-Mopsi and Dots datasets, the algorithm reaches gap of 1.69% and 0.61 %, respectively. The algorithm is suitable especially for educational purposes by showing the connection between MST and TSP, but it can also serve as a quick approximation for more complex metaheuristics whose efficiency relies on quality of the initial solution.


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