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As the industry strives to achieve improved fuel economy, stop-start systems for internal combustion engines are receiving additional focus. Studies and system proposals have been made for various electrical configurations ranging from 12 volts to 42 volts and higher [1, 2, 3]. Both cranking motor and belt alternator starter configurations have been proposed, with some concerns regarding the customer acceptance of the cranking motor solution [1] which were subsequently addressed [3]. Typically, 14 Volt Belt Alternator Starter (BAS) applications are limited to 1.6 liter gasoline (0.4 liter per cylinder) and 1.4 liter diesel (0.35 liter per cylinder) engines due to BAS torque output constraints. Some previous work extended this range to 0.7 liter per cylinder by utilizing a boosted supply voltage and auxiliary energy storage device [1].

New particulate sensing technologies are currently being readied for production to meet the on-board diagnostic (OBD) regulations associated with diagnosing diesel particulate filter (DPF) efficiency. The threshold levels for diagnosis have been tightened starting in 2013, requiring a new approach beyond the current techniques which often rely on differential pressure sensing across the filter. A new sensor has been developed to directly detect the particles passing through the DPF and estimate the cumulative particle flow. Using this information, an estimate can be made of the filter's efficiency and an associated diagnosis of its ability to meet emissions requirements. In this paper we will discuss the sensor's operating principle, accuracy and repeatability.

The need for improved emissions control in lean exhaust to meet tightening, world-wide NOx emissions standards has led to the development of selective catalytic reduction of NOx with ammonia as a major technology for emissions control. Current systems are being designed to use a solution of urea (32.5 wt %) dissolved in water or Diesel Exhaust Fluid (DEF) as the ammonia source. While DEF or AdBlue® is widely used as a source of ammonia, it has a number of issues at low temperatures, including freezing below −12 °C, solid deposit formation in the exhaust, and difficulties in dosing at exhaust temperatures below 200 °C. Additionally creating a uniform ammonia concentration can be problematic, complicating exhaust packaging and usually requiring a discrete mixer.

This paper presents a monitoring, feedback and control system for SCR urea dosing utilizing an embedded model and NH3 sensing after the SCR for loop closing control. A one-dimensional SCR model was developed and embedded in a Simulink/Matlab environment. This embedded model is utilized for on-line, real time control of 32.5% aqueous urea dosing in the exhaust stream. Engine testing and simulation are used with the embedded SCR model and NH3 sensor closed loop feedback to demonstrate the advantages of this control approach for meeting both NOx emission requirements and NH3 slip targets. The paper explores these advantages under heavy duty FTP cycle conditions. The potential benefits include SCR size optimization and fuel consumption rate reduction under certain operating conditions.