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

Abstract

Because fuel efficiency is significantly impacted by the timing of combustion in internal combustion engines, accurate control of combustion phasing is critical. In this paper, a nonlinear combustion phasing model is introduced and calibrated, and both a feedforward model-based control strategy and an adaptive model-based control strategy are investigated for combustion phasing control. The combustion phasing model combines a knock integral model, burn duration model and a Wiebe function to predict the combustion phasing of a diesel engine. This model is simplified to be more suitable for combustion phasing control and is calibrated and validated using simulations and experimental data that include conditions with high exhaust gas recirculation fractions and high boost levels. Based on this model, an adaptive nonlinear model-based controller is designed for closed-loop control, and a feedforward model-based controller is designed for open-loop control. These two control approaches were tested in simulations. The simulation results show that during transient changes the CA50 (the crank angle at which 50% of the mass of fuel has burned) can reach steady state in no more than 5 cycles and the steady state errors are less than ±0.1 crank angle degree (CAD) for adaptive control, and less than ±0.5 CAD for feedforward model-based control.

Design of Active Fault-Tolerant Control System for Air-Fuel Ratio control of Internal Combustion engine using nonlinear regression-based observer model

“…Where τ f is representing the fuel vapor process at some fixed amount of time indicated by ( s ), is representing the fuel flow injection [ kg / s ], the flow of fuel in the cylinders is given by the vapor fuel flow [ kg / s ], and the liquid mass fuel flow [ kg / s ], To produce a more comprehensive model, it is possible to add ϰ as a vector dependent on the throttle opening or engine r/min N e [ 37 ]. In our scenario, the second option is more practical.…”

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

“…This TPA model can predict CA50 in the simulation with a ±0.84 CAD uncertainty as compared to experimental results [38]. Additional details regarding the agreement between the GT-ISE simulation model and experimental results can be found in [22] and [38]. Prior work has shown that the cylinderto-cylinder variations observed on this engine and are mainly caused by uneven mixing between the EGR, the quantity of fresh air, and any port-injected fuel.…”

“…CA50 is predicted using a SOC and BD model. These models are discussed in more detail in Sui and Hall 23 but are discussed briefly here for completion.…”

“…The authors have previously combined a KIM with a Wiebe function to predict CA50 for diesel engines and shown that this method can predict CA50 within ±0.5 CAD [22]. While this strategy worked, it assumed that the EGR fraction and pressure and temperature at intake valve closing (IVC) were known.…”

“…The authors have previously combined a KIM with a Wiebe function to predict CA50 for diesel engines and shown that this method can predict CA50 within ±0.5 crank angle degree (CAD). 23 While this strategy worked, it assumed that the EGR fraction and pressure and temperature at intake valve closing (IVC) were known. However, such measurements are rarely made on production engines and in fact cylinder-to-cylinder variations on engines using high dilution and boost can be significant.…”