Fuzzy Logic Control of Diesel Combustion Phasing Using Ion Current Signal

Abstract

Diesel engines have to meet stringent emissions standards without penalties in performance and fuel economy. This necessitated the use of elaborate after treatment devices to reduce the tail pipe emissions. In order to decrease the demand on the after treatment devices, there is a need to reduce the emissions in the formation stage during combustion. This requires a precise control of the phasing of the combustion process. Currently, diesel engines are controlled by pre-set open loop schedules that require extensive, time consuming and costly laboratory tests and calibration tasks to meet the production target goals which are stricter than the emission standards. Such goals are set as a safe guard against the deterioration during engine life cycle. This paper presents an incremental fuzzy logic controller that adjusts the combustion phasing as per desired targets to meet production goals over the engine life period. An ion current/ glow plug sensor and its circuit are used to produce a signal indicative of different combustion parameters. Signal conditioning and filtering are applied to improve the quality of ion current. The algorithm developed in this paper optimizes the ion current feed back to increase its reliability for stable engine control while maintaining fast controller response, and high accuracy. Experiments are carried out on a four cylinder, turbo-charged, 4.5L heavy duty diesel engine equipped with a common rail injection system and an open ECU. The response of the controller is evaluated from experimental data obtained by running the engine under different steady, and transient operating conditions. The results demonstrate the ability of the closed-loop control system in achieving the desired combustion phasing.

Combustion phasing modeling and control for compression ignition engines with high dilution and boost levels

“…In addition to modeling diesel engine combustion phasing, there are also many studies that focus on the control of combustion phasing for diesel engines. 17,24–28 Model-based control of combustion phasing was studied in Hillion et al; 17 however, the CA50 reached steady state after more than 20 cycles when the operation condition changed in this study. Willems et al 24 and Yu et al 25 employed proportional–integral (PI) and proportional–integral–derivative (PID) feedback controllers to control the CA50 and indicated mean effective pressure (IMEP) with in-cylinder pressure sensors.…”

“…Willems et al 24 and Yu et al 25 employed proportional–integral (PI) and proportional–integral–derivative (PID) feedback controllers to control the CA50 and indicated mean effective pressure (IMEP) with in-cylinder pressure sensors. Meanwhile, PI feedback control based on the CA50 estimated by crankshaft torque measurements was used in Thor et al 26 and a fuzzy logic controller was used with an ion current signal to control the location of peak premixed combustion (LPPC), which was studied in Badawy et al 27 While these control approaches worked well, most commercial diesel engines do not have the in-cylinder pressure sensors, crankshaft torque sensors or ion current sensors required for these feedback control techniques. As such, these feedback strategies are still hard to apply in production engines.…”

Cylinder-specific model-based control of combustion phasing for multiple-cylinder diesel engines operating with high dilution and boost levels

“…Feedback control of CA50 and indicated mean effective pressure (IMEP) has also been examined in Willems et al 27 and Yu et al, 28 but required in-cylinder pressure sensors. Similarly, control of CA50 using feedback from crankshaft torque measurements 29 and control of the location of peak premixed combustion (LPPC) from an ion current signal 30 have also been shown to perform well. However, such sensors are not standard on production engines so the application of these methods may be limited and feedforward control techniques may be more useful.…”

Analysis of the ion current in misfiring and firing cycles during the cold starting of a compression ignition engine

“…biodiesel, hydrotreated vegetable oil, etc., which have significantly distinct physical, and chemical properties). 38,39 All the ion current studies mentioned so far were performed under warmed-up conditions. Only a couple of studies were found on the ion current measured during cold-starting of CI engines.…”

“…biodiesel, hydrotreated vegetable oil, etc., which have significantly distinct physical, and chemical properties). 38,39…”