IEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING
IEEJ Trans 2017; 12(S1): S117–S124
Published online in Wiley Online Library (wileyonlinelibrary.com). DOI:10.1002/tee.22444
Paper
ADRC-Based Transient Air/Fuel Ratio Control with Time-Varying Transport
Delay Consideration for Gasoline Engines
Zhijing Wang, Non-member
Xiaohong Jiao
a
, Non-member
This paper presents a fuel injection controller based on the modified active disturbance rejection control (ADRC) algorithm to
maintain the air/fuel ratio (AFR) at the stoichiometric value in the presence of a transport time delay. The factors affecting the
dynamics of the AFR include the variations of the intake manifold pressure, engine speed, and load torque, as well as uncertain
parameters existing in the fuel film evaporation and the oxygen sensor aging, which are viewed as the ’total disturbance’ to the
AFR system and estimated by the extended state observer (ESO). Thus, based on the Lyapunov–Krasovskii functional stability
theory, the ADRC fuel injection controller is designed with the gain matrices of the controller and observer and solved by
employing linear matrix inequalities. Considering the time-varying transport delay, a time delay block is added to the ESO. By
synchronizing the input signals of the ESO, the performance in terms of the timely compensation for the disturbance is improved.
The effectiveness of the proposed control strategy is validated through simulation of a V6 spark ignition engine model developed
by the Society of Instrument and Control Engineers (SICE) Research Committee on Advanced Powertrain Control Theory.
© 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Keywords: spark ignition engine; air/fuel ratio; active disturbance rejection control; time-varying delay; linear matrix inequality
Received 19 May 2016; Revised 19 November 2016
1. Introduction
In consideration of energy saving and environmental protection,
maintaining the air/fuel ratio (AFR) at the stoichiometric value
seems more and more important because of the great influence
AFR has on the conversion efficiency of the three-way catalyst
and fuel economy of a spark ignition (SI) engine. The main
challenges in the precise control of the AFR, especially during the
transient operations of the engine, involve the transport time delay
in the AFR system, which varies with the switching of engine
operations, variations of the intake manifold pressure, engine
speed, and load torque, as well as plant uncertainties due to the
wall-wetting phenomenon and aging of the universal exhaust gas
oxygen (UEGO) sensor.
In view of the impact of the transport time delay on the
dynamics of the AFR, several studies have been made. For
example, in [1] the internal model control and its application
to the AFR control system are presented. This method handles
the time delay in the AFR system under the condition that the
structure of the plant is already known in the absence of any
disturbance to the system. The Smith predictor shown in [2,3]
is widely used for time delay, which can remove the time delay
from the main loop. But the predictor is available only when
the parameters in the model match those in the plant, and the
performance may decrease when modeling errors exist. Moreover,
other challenges in maintaining the AFR at the stoichiometric
value involve the complications in the model construction of the
engine and some physicochemical processes such as the air intake
[4], fuel delivery, and the combustion. Thus, many algorithms
have been proposed to get an appropriate solution, such as the
neural network control algorithm applied in [5–7], which can
identify the engine model for controlling the AFR. However, this
a
Correspondence to: Xiaohong Jiao. E-mail: jiaoxh@ysu.edu.cn
School of Electrical Engineering, Yanshan University, Hebei 066004,
China
method definitely requires much training in practice. For reducing
the canister purge disturbance, [8] has derived a sliding-mode
controller. In [9], to reduce the influence of the uncertainties caused
by the wall-wetting phenomenon and the variations of the intake
manifold and engine speed, an extended state observer (ESO)
was constructed. But the time-varying transport delay in the AFR
system, which leads to the deviation of the fuel command, is
ignored. As for the parameter uncertainties in the AFR control
plant, the adaptive control algorithm is widely employed, typical
examples being given in [10–13]. On the basis of the mean value
engine model, adaptive fuel injection controllers are derived in
[10,11] to remove the influence of the uncertain parts caused by
the fuel film evaporation and the system description. Adaptive
update laws are derived on the Lyapunov design for the uncertain
parameters [12,13]. In [14], to deal with the biofuel parameters,
the adaptive algorithm is applied to estimate the biofuel content for
internal combustion engines. Taking the time-varying parameters
into consideration, [15] applies the switching linear parameter
varying (LPV) controller to the AFR control system for managing
the dynamics of the fuel path.
In this paper, a modified active disturbance rejection control
(ADRC) algorithm for the accurate regulation of the AFR is
derived, which can deal with the transport time delay generated
from the fuel injection to the AFR measurement and tries to
diminish the influence caused by the change of the engine
operation and the uncertain parameters in the AFR system. An ESO
is designed to estimate the ’total disturbance’ that is associated
with the unmeasurable air mass flow rate into the cylinder, the
uncertainties in the fuel film evaporation process, and the change
of the engine torque for the port-injected SI engine. The modified
part for the transport delay makes the control signal and the
system output to synchronize and removes the time delay from
the ESO, thus improving the performance of the estimations. The
gain matrices of the ADRC controller and the ESO can be solved
by linear matrix inequalities (LMIs), which ensures the stability of
the augmented error system.
© 2017 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.