Advanced Fault Tolerant Air-Fuel Ratio Control of Internal Combustion Gas Engine for Sensor and Actuator Faults

The reliability of a process machine can be significantly enhanced by introducing a fault-tolerant control system in it. Hardware redundancy is an important aspect to enhance fault tolerance capability and is studied in this paper. A novel modified triple modular redundancy (MTMR) approach is proposed for the sensors to avoid a shutdown in the case of simultaneous faults in more than one sensor, and dual redundancy is proposed for the actuators to avoid a single point of failure due to the single actuator fault. The performance of the control system is verified by simulation in MATLAB Simulink environment. The proposed MTMR fulfills the gap in conventional TMR by maintaining stability even in the case of simultaneous faults in two channels. Cost and benefit analysis (CBA) is carried out to determine the financial feasibility of the implementation of the proposed system. The results of the CBA demonstrate that the proposed system is financially feasible due to the positive net present value and small breakeven period.