Model Predictive Control of a Diesel Engine with Turbo Compound and Exhaust After-Treatment Constraints

Abstract

In this work we consider air path control of a Volvo Heavy Duty 13L Diesel engine equipped with three air path actuators Exhaust Gas Recirculation Valve (EGV), Intake Throttle Valve (ITV), turbocharger Wastegate (WG), and a Turbo Compound (TC). The purpose of the TC device is to recover the waste heat energy to improve fuel efficiency. Thus, the motivation is to control the air path system and in particular the exhaust energy to achieve satisfaction of the Exhaust After-Treatment System (EATS) requirements and assess the fuel economy. For this purpose a commercially available industrial tool for Model Predictive Control (MPC) has been applied. The designed controller is integrated in a production Engine Electrical Control Unit (EECU) and tests are performed both in engine test bench and on-road. The results show that by coordination of the air path actuators utilizing advanced MPC framework it leads to improvements in the exhaust energy conversion which was measured by fuel reduction of 0.3% with maintained NOx levels in a World-Harmonized Transient Cycle (WHTC) compared to a Proportional Integral Derivative (PID) control scheme. The designed MPC controller reached mass production maturity level and had a similar margin to the EU6 emission regulation as the compared PID control scheme.