Safe operation of dual-fuel engines using constrained stochastic control

Abstract

Premixed combustion strategies have the potential to achieve high thermal efficiency and to lower the engine-out emissions such as NOx. However, the combustion is initiated at several kernels which create high pressure gradients inside the cylinder. Similarly to knock in spark ignition engines, these gradients might be responsible of important pressure oscillations with a harmful potential for the engine. This work aims to analyze the in-cylinder pressure oscillations in a dual-fuel combustion engine and to determine the feedback variables, control actuators, and control approach for a safe engine operation. Three combustion modes were examined: fully, highly, and partially premixed, and three indexes were analyzed to characterize the safe operation of the engine: the maximum pressure rise rate, the ringing intensity, and the maximum amplitude of pressure oscillations (MAPO). Results show that operation constraints exclusively based on indicators such as the pressure rise rate are not sufficient for a proper limitation of the in-cylinder pressure oscillations. This paper explores the use of a knock-like controller for maintaining the resonance index magnitude under a predefined limit where the gasoline fraction and the main injection timing were selected as control variables. The proposed strategy shows the ability to maintain the percentage of cycles exceeding the specified limit at a desired threshold at each combustion mode in all the cylinders.

Optimization of PID control parameters for marine dual-fuel engine using improved particle swarm algorithm

“…Air–fuel ratio control and mode switching of dual-fuel engines involve multiple subsystems, including fuel supply systems, ignition systems, and control logic, necessitating sophisticated control algorithms and reliable hardware to ensure the coordinated operation and reliability of these subsystems 13 . To enhance engine performance, numerous studies have delved into engine control methodologies.…”

An analysis of the resonance attenuation in a combustion chamber

“…8 In recent years, resonance excitation has been widely used for knock characterization 9 and to develop real time knock detection algorithms 10,11 and controllers. 10,12 In addition, resonance has been studied in 13 , where the resonance excitation intensity was controlled in a premixed dual-fuel engine. Moreover, resonance frequency has been recently used to estimate the trapped mass 14,15 by using signal analysis techniques.…”

Mapping the combustion modes of a dual-fuel compression ignition engine

“…Light-duty land vehicle engines typically use gasoline/ethanol as the LRF, 7–9 while marine engines typically usually use methane/natural gas, 10,11 and heavy-duty land vehicle engines have been used to study both of these primary fuel types, gasoline/ethanol, 12,13 and methane/natural gas. 14–18 These are general only general trends; a wide variety of novel LRF’s have been studied in a wide variety of engine types, such as a gaseous dimethyl ether (DME)/propane mixture in a light-duty engine. 19…”

“…Light-duty land vehicle engines typically use gasoline/ethanol as the LRF, [7][8][9] while marine engines typically usually use methane/natural gas, 10,11 and heavy-duty land vehicle engines have been used to study both of these primary fuel types, gasoline/ethanol, 12,13 and methane/natural gas. [14][15][16][17][18] These are general only general trends; a wide variety of novel LRF's have been studied in a wide variety of engine types, such as a gaseous dimethyl ether (DME)/propane mixture in a light-duty engine. 19 In addition to ITE and NO x /soot benefits, recent topics of RCCI research in just this journal include compositional effects of premixed LRF, 14 its effects on diesel spray ignition 10 and cyclic variability, 15 and the ability to operate these engines with constrained stochastic control 16 and sensor-based health management.…”

“…[14][15][16][17][18] These are general only general trends; a wide variety of novel LRF's have been studied in a wide variety of engine types, such as a gaseous dimethyl ether (DME)/propane mixture in a light-duty engine. 19 In addition to ITE and NO x /soot benefits, recent topics of RCCI research in just this journal include compositional effects of premixed LRF, 14 its effects on diesel spray ignition 10 and cyclic variability, 15 and the ability to operate these engines with constrained stochastic control 16 and sensor-based health management. 11 This paper intends to build on the existing state of the art by bridging the advanced mode of RCCI to the conventional mode of CDC via the intermediate mode of PDFC in an optimized multi-mode strategy.…”