Abstract
The global automotive industry faces a major challenge to reduce the CO2 emissions of vehicles. In this regard, Diesel engine technology must continue to improve and meet the challenge. This paper will describe research to assess the potential of integrating state of the art combustion and aftertreatment technologies while attaining Euro 6 emissions levels. The paper presents the test results of a research vehicle equipped with advanced Exhaust Gas Re-circulation, series sequential turbo-charging, closed loop combustion control, Diesel Particulate Filter and Lean NOx Trap aftertreatment. The approach and capability of the individual technologies is discussed in conjunction with the integration challenges. The optimisation approach is described and the benefits of closed loop combustion control to accelerate the calibration process are shown. Furthermore, the paper discusses the conflicts between combustion and aftertreatment technologies in relation to exhaust temperature. Despite this challenge, the benefits of optimising combustion technology for low CO2 and utilising Lean NOx Trap aftertreatment for NOx control are quantified. The paper concludes that the strategy is most applicable to demanding Sports Utility Vehicles (SUV) and Light Duty Truck applications with high inertia and rolling resistance in combination with engine downsizing and downspeeding. To illustrate this point the optimised E6 emissions results for a 2150 kg SUV with automatic transmission are shown.
KEYWORDS: Diesel engine, combustion and NOx aftertreatment