Mitsunobu Kajitani

MODELING AND DETERIORATION DIAGNOSIS OF CATALYST ON VEHICLE BY VARIABLE FORGETTING FACTOR-BASED ON-LINE IDENTIFICATION METHOD

Abstract The majority of the conventional system purifying exhaust gas is composed of a three-way catalyst and an electronic fuel injection. However, harmful pollutants are increasingly emitted when the catalyst becomes aged. Therefore, it is necessary to detect the deterioration of the catalyst by means of on board diagnosis. In this paper, we propose a diagnosis method of the aged catalyst using recursive system identification method with variable forgetting factor. We focus on the parameter of identified model which represents characteristics of the catalyst, and possibility to describe the diagnosis of the aged catalyst.

An engine control systems design for low emission vehicles by generalized predictive control based on identified model

Conservation of the environment has become critical to the automotive industry. Recently, requirements for on-board diagnostic and engine control systems have been strictly enforced. In the present paper, in order to meet the requirements for a low-emissions vehicle, a novel construction method of the air-fuel ratio (A/F) control system is proposed. The construction method of the system is divided into two steps. The first step is to design the A/F control system for the engine based on an open loop design. The second step is to design the A/F control system for the catalyst system. The design method is based on the generalized predictive control in order to satisfy the robustness to open loop control as well as model uncertainty. The effectiveness of the proposed A/F control system is verified through the experiments using full-scale products.