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A promising SCR-only solution is presented to meet post-2010 NOx emission targets for heavy duty applications. The proposed concept is based on an engine from a EURO IV SCR application, which is considered optimal with respect to fuel economy and costs. The addition of advanced SCR after treatment comprising a standard and a close-coupled SCR catalyst offers a feasible emission solution, especially suited for EURO VI. In this paper, results of a simulation study are presented. This study concentrates on optimizing SCR deNOx performance. Simulation results of cold start FTP and WHTC test cycles are presented to demonstrate the potential of the close-coupled SCR concept. Comparison with measured engine out emissions of an EGR engine shows that a close-coupled SCR catalyst potentially has NOx reduction performance as good as EGR. Practical issues regarding the use of an SCR catalyst in close-coupled position will be addressed, as well as engine and exhaust layout.

Heavy-duty diesel engines are used in different application areas, like long-haul, city distribution, dump truck and building and construction industry. For these wide variety of areas, the engine performance needs to comply with the real-world legislation limits and should simultaneously have a low fuel consumption and good drivability. Meeting these requirements takes substantial development and calibration effort, where an optimal fuel consumption for each application is not always met in practice. TNO's Integrated Emission Management (IEM) strategy, is able to deal with these variations in operating conditions, while meeting legislation limits and obtaining on-line cost optimization. Based on the actual state of the engine and aftertreatment, optimal air-path setpoints are computed, which balances EGR and SCR usage.

Cylinder pressure-based combustion control is widely introduced for passenger cars. Benefits include enhanced emission robustness to fuel quality variation, reduced fuel consumption due to more accurate (multi-pulse) fuel injection, and minimized after treatment size. In addition, it enables the introduction of advanced, high-efficient combustion concepts. The application in truck engines is foreseen, but challenges need to be overcome related to durability, increased system costs, and impact on the cylinder head. In this paper, a new single cylinder pressure sensor concept for heavy-duty Diesel engines is presented. Compared to previous studies, this work focuses on heavy-duty Diesel powertrains, which are characterized by a relatively flexible crank shaft in contrast to the existing passenger car applications.

Heavy-duty diesel engines are used in a wide range of applications. For varying operating environments, the engine and aftertreatment system must comply with the real-world emission legislation limits. Simultaneously, minimal fuel consumption and good drivability are crucial for economic competitiveness and usability. Meeting these requirements takes substantial development and calibration effort, and complying with regulations results in a trade-off between emissions and fuel consumption. TNO's Integrated Emission Management (IEM) strategy finds online, the cost-optimal point in this trade-off and is able to deal with variations in operating conditions, while complying with legislation limits. Based on the actual state of the engine and aftertreatment system, an optimal engine operating point is computed using a model-based optimal-control algorithm.

To meet future emission targets, it becomes increasingly important to optimize the synergy between engine and aftertreatment system. By using an integrated control approach minimal fluid (fuel and DEF) consumption is targeted within the constraints of emission legislation during real-world operation. In such concept, the on-line availability of engine-out NOx emission is crucial. Here, the use of a Virtual NOx sensor can be of great added-value. Virtual sensing enables more direct and robust emission control allowing, for example, engine-out NOx determination during conditions in which the hardware sensor is not available, such as cold start conditions. Furthermore, with use of the virtual sensor, the engine control strategy can be directly based on NOx emission data, resulting in reduced response time and improved transient emission control. This paper presents the development and on-line implementation of a Virtual NOx sensor, using in-cylinder pressure as main input.

This paper focusses on the application of bioalcohols (ethanol and butanol) derived from seaweed in Heavy-Duty (HD) Compression Ignition (CI) combustion engines. Seaweed-based fuels do not claim land and are not in competition with the food chain. Currently, the application of high octane bioalcohols is limited to Spark Ignition (SI) engines. The Reactivity Controlled Compression Ignition (RCCI) combustion concept allows the use of these low carbon fuels in CI engines which have higher efficiencies associated with them than SI engines. This contributes to the reduction of tailpipe CO2 emissions as required by (future) legislation and reducing fuel consumption, i.e. Total-Cost-of-Ownership (TCO). Furthermore, it opens the HD transport market for these low carbon bioalcohol fuels from a novel sustainable biomass source. In this paper, both the production of seaweed-based fuels and the application of these fuels in CI engines is discussed.

A new cost-based control strategy is presented that optimizes engine-aftertreatment performance under all operating conditions. This Integrated Emission Management strategy minimizes fuel consumption within the set emission limits by on-line adjustment of air management based on the actual state of the exhaust gas aftertreatment system. Following a model-based approach, Integrated Emission Management offers a framework for future control strategy development. This approach alleviates calibration complexity, since it allows to make optimal trade-offs in an operational cost sense. The potential of the presented cost-optimal control strategy is demonstrated for a modern heavy-duty Euro VI engine. The studied diesel engine is equipped with cooled EGR, Variable Geometry Turbocharger, and a DPF-SCR aftertreatment system.

The goal of this work was to investigate the possibilities of applying high EGR rates with low NOx and PM emission levels on a two-stage turbocharged 12 liter heavy duty diesel engine. The EGR is applied by using a long and short route EGR system. For the ESC operating points A25 and C100 EGR is applied, such that the NOx emission is 0.5 g/kWh. Lowest PM level and BSFC are achieved when long route EGR is applied in A25 and short route is applied in C100. Increasing the fuel line pressure is an effective way to reduce PM at high EGR rate engine running conditions. At a fuel line pressure of 2400 bar PM emission are 0.06 g/kWh for A25 and 0.54 g/kWh for C100. At C100 the PM reduction coincides with also a significant fuel consumption improvement. Retarding the injection timing at C100 can improve the PM emission further to a level of 0.13 g/kWh at the expense of an increase in BSFC.

To meet 2010 emission targets, optimal SCR system performance is required. In addition, attention has to be paid to in-use compliance requirements. Closed-loop control seems an attractive option to meet the formulated goals. This study deals with the potential and limitations of closed-loop SCR control. High NOx conversion in combination with acceptable NH3 slip can be realized with an open-loop control strategy. However, closed-loop control is needed to make the SCR system robust for urea dosage inaccuracy, catalyst ageing and NOx engine-out variations. Then, the system meets conformity of production and in-use compliance norms. To demonstrate the potential of closed-loop SCR control, a NOx sensor based control strategy with cross-sensitivity compensation is compared with an adaptive surface coverage/NH3 slip control strategy and an open-loop strategy. The adaptive surface coverage/NH3 slip control strategy shows best performance over simulated ESC and ETC cycles.

Reaching EUROVI Heavy Duty emission limits will result in more testing time for developing control and OBD algorithms than to reach EUROV emissions. It is likely that these algorithms have to be adapted for a WHTC (World Heavy Duty Transient Cycle) for EUROVI. This cycle when started cold can only be performed a limited times a day on the engine testbench, because of the cooling down time. The development time and cost increases to reach EUROVI emission levels. Accurate simulation tools can reduce the time and costs by reducing the amount of tests required on the testbench. In order to use simulation tools to develop pre calibrations, the models must be fitted and validated. This paper will focus on the fit process of an SCR (Selective Catalytic Reduction) model. A unique test procedure has been developed to characterize an SCR catalyst using an engine testbench in ±2 days. This data is used in an automatic SCR fit tool to obtain the model parameters in a few days.

This paper presents a cylinder pressure-based control (CPBC) system for conventional diesel combustion with high EGR levels. Besides the commonly applied heat release estimation, the CPBC system is extended with a new virtual NOx and PM sensor. Using available cylinder pressure information, these emissions are estimated using a physically based combustion model. This opens the route to advanced On-Board Diagnostics and to optimized fuel consumption and emissions during all operating conditions. The potential of closed-loop CA50 and IMEP control is demonstrated on a multi-cylinder heavy-duty EGR engine. For uncalibrated injectors and fuel variations, the combustion control system makes the engine performance robust for the applied variations and reduces the need for a time-consuming calibration process. Cylinder balancing is shown to enable auto-calibration of fuel injectors and to enhance fuel flexibility.

Two major trends can be identified for powertrain control in the next decade. The legislation will more and more focus on in-use emissions. Together with the global trend to reduce the CO₂ emissions, this will lead to an integral drive train approach. To develop and validate this integral drive train approach, the need for a new chapter in powertrain testing arises. The climatic-altitude chamber, suited for heavy vehicles, serves a wide variety of testing needs. Ambient temperature can be controlled between -45°C and +55°C and ambient pressure can be reduced up to a level found at an altitude to 4000 meters. The chamber's dynamometers enable transient testing of heavy-duty engines and vehicles and the chamber is equipped with a comprehensive array of emission measurement capabilities, working under extreme conditions.

In the past decade, SCR deNOx technology with urea injection has grown to maturity. European OEMs will apply SCR deNOx to meet future heavy-duty emissions legislation starting with EURO-4 (2005/2006). Numerous research programs in Europe and the US have shown a variety of system layouts and control strategies. The main differences are formed by: the engine-out NOx calibration the application of an NO to NO2 catalyst open-loop or closed-loop urea dosage control. This paper gives an overview of possible SCR system configurations that are required for different stages of future emission legislation. Engine-out NOx emission is strongly influenced by ambient conditions. Projections in this study show that a combination of cold climate and a wintergrade fuel is the most severe: it may lead to 30% lower engine-out NOx emission with respect to laboratory conditions.

This paper reports on a study of the TNO venturi EGR system and the Johnson Matthey CRT particulates trap on a DAF 355 kW engine. The results obtained indicate that this EGR-CRT combination is an effective means to achieve EURO-4 emission level, while maintaining good fuel economy. EGR strategy, injection timing and air-fuel ratio were optimised in such a way that good regeneration conditions were obtained across most of the engine operating map. Also transient EGR control is optimised to combine low NOx emission during the ETC with good driveability and good engine out particulates emission. The size of the oxidation catalyst in the CRT was investigated. It appeared that the larger oxidation catalyst showed a better regeneration performance during a low temperature duty-cycle. Negative aspects of a larger oxidation catalyst are increased costs and increased NO2 emission (because of the catalyst ability to oxidise more NO into NO2).

Whiplash injuries due to rear-end car collisions is one of the most aggravating traffic safety problems with serious implications for the European society. Yearly more than a million European citizens suffer neck injuries from rear-end car collisions, implying tremendous societal costs. Therefore the European Community has sponsored the European Whiplash project. The objective of this paper is to present a general overview of this project. Accident studies show the relevance of rear-impact- related whiplash injuries and representative rear impact conditions in which whiplash is likely to occur. For the development of a Rear Impact Dummy (RID) typical human responses to rear impact are needed and were obtained with human volunteer and Post Mortem Human Subject tests at low speeds. Accident reconstructions were performed in order to derive injury thresholds for the dummy.

Up to now, reduction of fuel consumption of vehicles equipped with CVT transmission has not been exploited to its full potential due to the reduced driveability when driving the optimum efficiency engine operating points. An ISG system with torque boost capabilities can be used to restore this driveability. This paper discusses the goals, the CAE simulation tool, the methodology used in the preparative study for evaluation and dimensioning of a CVT-ISG concept, as well as the simulation results. The conclusions, generated from numerous simulations, provide vital information for the component selection, and for the development of the powertrain management system.

The application of SCR deNOx aftertreatment was studied on two about 12 liter class heavy-duty diesel engines within a consortium project. Basically, the system consists of a dosage system for aqueous urea injection and a vanadia based SCR catalyst, without an upstream or downstream oxidation catalyst. The urea injection system for a DAF and a Renault V.I. (Véhicules Industriels) diesel engine was calibrated on the engine test bench taking into account dynamic effects of the catalyst. For both engine applications NOx reduction was 81% to 84% over the ESC and 72% over the ETC. CO emission increased up to 27%. PM emission is reduced by 4 to 23% and HC emission is reduced by more than 80%. These results are achieved with standard diesel fuel with about 350 ppm sulfur. The test engines and SCR deNOx systems were built into a DAF FT95 truck and a Renault V.I. Magnum truck.

In a NOx adsorber programme the feasibility for applying this technology to heavy duty diesel engines was investigated. After modelling and simulations for realising best λ < 1 engine conditions a platform was build which was used to obtain good NOx adsorber regeneration settings in a number of steady state key points without violating pre-defined limits. With these results the NOx adsorber was evaluated and tested. Besides establishing NOx conversions and BSFC penalties the programme also looked at the adsorber capabilities of dealing with sulphur poisoning and how well the adsorber could be de-sulphurised. This programme showed clearly the stronger and weaker points in the NOx adsorber technology for heavy duty application. From NOx conversion - BSFC penalty trade off curves it became clear that at lower loads high conversions (> 90%) with small fuel penalties (< 2.5%) were possible. However at high load the conversions were reduced (< 70%) and the fuel penalties increased (> 6%).

Plasma-assisted PM removal is examined in a packed-bed plasma system. This study focuses on the effect of plasma power, space velocity and exhaust gas composition on PM filtration. Experiments are done on an engine dynamometer with a VW 1.2l TDI engine. During these experiments, the airflow is throttled so large smoke levels are realized. Then, absolute filtration effects can better be observed. For relatively small space velocities, 90% filtration efficiency based on smoke measurements is determined at an energy density of 25 J/l (i.e. plasma power per exhaust gas volume flow). In the studied operating point, the filtration efficiency is not further increased for larger energy densities. Based on these results, we conclude that the available plasma power has to be increased for full flow experiments. In cases without airflow throttling, the plasma has no effect on PM filtration. Application of a 10 kV bias to enhance electrostatic precipitation is also seen to be ineffective.

The next generation off-road vehicles will see additional exhaust gas aftertreatment systems, ranging from DOC-SCR only to full DOC-DPF-SCR-AMOX systems. This will increase system complexity and development effort significantly. Emission requirements and the high number of vehicle configurations within the off-road industry will require a new process for development and validation. The introduced model-based approach using physical models of aftertreatment can reduce development effort and cost, improve performance robustness and help to identify performance issues early in the development process. A method to investigate and optimize a large matrix of variations by simulation is introduced. This can lead to a significant reduction in the number of required calibrations and can assist in the development of design specifications for the aftertreatment system. A case study for SCR calibration successfully demonstrates the potential of model-based development.