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This paper describes a method for optimization of engine settings in view of best total cost of operation fluids. Under specific legal NOX tailpipe emissions requirements the engine out NOX can be matched to the current achievable SCR NOX conversion efficiency. In view of a heavy duty long haul truck application various specific engine operation modes are defined. A heavy duty diesel engine was calibrated for all operation modes in an engine test cell. The characteristics of engine operation are demonstrated in different transient test cycles. Optimum engine operation mode (EOM) selection strategies between individual engine operation modes are discussed in view of legal test cycles and real world driving cycles which have been derived from on-road tests.

To avoid frequent regeneration intervals leading to expeditious ageing of the catalyst and substantial fuel penalty for the owner, it is always desired to estimate the soot coming from diesel exhaust emission, the soot accumulated and burnt in the Diesel Particulate Filter (DPF). Certain applications and vehicle duty cycles cannot make use of the differential pressure sensor for estimating the soot loading in the DPF because of the limitations of the sensor tolerance and measurement accuracy. The physical soot model is always active and hence a precise and more accurate model is preferred to calibrate & optimize the regeneration interval. This paper presents the approach to estimate the engine-out soot and the accumulated soot in the DPF using a graphical calculation tool (AVL Concerto CalcGraf™).

Fuel injection is a key process influencing the performance of Gasoline Direct Injection (GDI) Engines. Injecting fuel at elevated temperature can initiate flash boiling which can lead to faster breakup, reduced penetration, and increased spray-cone angle. Thus, it impacts engine efficiency in terms of combustion quality, CO2, NOx and soot emission levels. This research deals with modelling of flash boiling processes occurring in gasoline fuel injectors. The flashing mass transfer rate is modelled by the advanced Hertz-Knudsen model considering the deviation from the thermodynamic-equilibrium conditions. The effect of nucleation-site density and its variation with degree of superheat is studied. The model is validated against benchmark test cases and a substantiated comparison with experiment is achieved.

In relation to further tightening of the emissions legislation for on-road heavy duty Diesel engines, the future potential of cooled exhaust gas recirculation (EGR) as a result of developments in the cooling systems of such engines has been evaluated. Four basic engine concepts were investigated: an engine with SCR exhaust gas aftertreatment for control of the nitrogen oxides (NOx), an engine with cooled EGR and particulate (PM) filtration, an engine with low pressure EGR and PM filtration and an engine with two stage low temperature cooled EGR also with a particulate filter. A 10.5 litre engine was calibrated and tested under conditions representative for each concept, such that 1.7 g/kWh (1.3 g/bhp-hr) NOx could be achieved over the ESC and ETC. This corresponds to emissions 15% below the Euro 5 legislation level.

The world of automotive engineering shows a clear direction for upcoming development trends. Stringent fleet average fuel consumption targets and CO2 penalties as well as rising fuel prices and the consumer demand to lower operating costs increases the engineering efforts to optimize fuel economy. Passenger car engines have the benefit of higher degree of technology which can be utilized to reach the challenging targets. Variable valve timing, downsizing and turbo charging, direct gasoline injection, highly sophisticated operating strategies and even more electrification are already common technologies in the automotive industry but can not be directly carried over into a motorcycle application. The major differences like very small packaging space, higher rated speeds, higher power density in combination with lower production numbers and product costs do not allow implementation such high of degree of advanced technology into small-engine applications.

Trends towards lower vehicle fuel consumption and smaller environmental impact will increase the share of Diesel hybrids and Diesel Range Extended Vehicles (REV). Because of the Diesel engine presence and the ever tightening soot particle emissions, these vehicles will still require soot particle emissions control systems. Ceramic wall-flow monoliths are currently the key players in the Diesel Particulate Filter (DPF) market, offering certain advantages compared to other DPF technologies such as the metal based DPFs. The latter had, in the past, issues with respect to filtration efficiency, available filtration area and, sometimes, their manufacturing cost, the latter factor making them less attractive for most of the conventional Diesel engine powered vehicles. Nevertheless, metal substrate DPFs may find a better position in vehicles like Diesel hybrids and REVs in which high instant power consumption is readily offered enabling electrical filter regeneration.

The OBD II and EOBD legislation have significantly increased the number of system components that have to be monitored in order to avoid emissions degradation. Consequently, the algorithm design and the related calibration effort is becoming more and more challenging. Because of decreasing OBD thresholds, the monitoring strategy accuracy, which is tightly related with the components tolerances and the calibration quality, has to be improved. A model-based offline simulation of the monitoring strategies allows consideration of component and sensor tolerances as well as a first calibration optimization in the early development phase. AVL applied and improved a methodology that takes into account this information, which would require a big effort using testbed or vehicle measurements. In many cases a component influence analysis is possible before hardware is available for testbed measurements.

Beside performance, handling and styling the sound characteristic of a motorcycle is a very important feature for the acceptance of the product by the customers and therefore the commercial success of a new product. Creating a special brand sound becomes more and more important to create a product that can be easily distinguished from competitor products and is therefore considered to be something special. On the other hand the legal limits in terms of pass - by noise allow for a very little margin for the creation of a special sound. During the product sound design phase the different perceptions of the rider wearing a helmet and pedestrians have to be considered. In passenger cars sound design has been known for a long time and the creation of a special sound for the driver inside the passenger compartment can be achieved with little influence on the exterior noise and therefore on the noise which is limited by legislation.

Worldwide OBD legislation has and will be tightened drastically. In the US, OBD II for PC and the introduction of HD OBD for HD vehicles in 2010 will be the next steps. Further challenges have come up with the introduction of active exhaust gas aftertreatment components to meet the lower future emission standards, especially with the implementation of combined DPF-De-NOx-systems for PC and HD engines. Following such an increase in complexity, more comprehensive algorithms and software have to be developed to cope with the legislative requirements for exhaust gas aftertreatment devices. The calibration has to assure the proper functionality of OBD under all driving situations and ambient conditions. The increased complexity can only be mastered when new and efficient tools and methodologies are applied for both algorithm design and calibration. Consequently, OBD requirements have to be taken into account right from the start of engine development.

The reduction of nitrous oxides in the exhaust gases of internal combustion engines using a urea water solution is gaining more and more importance. While maintaining the future exhaust gas emission regulations, like the Euro 6 for passenger cars and the Euro 5 for commercial vehicles, urea dosing allows the engine management to be modified to improve fuel economy as well. The system manufacturer Robert Bosch has started early to develop the necessary dosing systems for the urea water solution. More than 300.000 Units have been delivered in 2007 for heavy duty applications. Typical dosing quantities for those systems are in the range of 0.01 l/h for passenger car systems and up to 10 l/h for commercial vehicles. During the first years of development and application of urea dosing systems, instantaneous flow measuring devices were used, which were not operating fully satisfactory.

The introduction of more stringent standards for engine emissions requires continuous improvement of exhaust gas aftertreatment systems. Modern systems require a combined design and application of different aftertreatment devices. Computer simulation helps to investigate the complexity of different system layouts. This study presents an overall aftertreatment modeling framework comprising dedicated models for pipes, oxidation catalysts, wall flow particulate filters and selective catalytic converters. The model equations of all components are discussed. The individual behavior of all components is compared to experimental data. With these well calibrated models a simulation study on a DOC-DPF-SCR exhaust system is performed. The impact of pipe wall insulation on the overall NOx conversion performance is investigated during four different engine operating conditions taken from a heavy-duty drive cycle.

This paper describes the development and achievement of a target engine sound for a V6 SUV in consideration of the sound quality preferences of customers in the U.S. First, a simple definition for engine sound under acceleration was found using order arrangement, frequency balance, and linearity. These elements are the product of commonly used characteristics in conventional development and can be applied simply when setting component targets. The development focused on order arrangement as the most important of these elements, and sounds with and without integer orders were selected as target candidates. Next, subjective auditory evaluations were performed in the U.S. using digitally processed sounds and an evaluation panel comprising roughly 40 subjects. The target sound was determined after classifying the results of this evaluation using cluster analysis.

Gasoline direct injection and turbocharging enable the progress of clean and fuel efficient SI engines. Accessing potential efficiency benefits requires very high power density to be achieved across a broad rpm range. This imposes risks which in conventional engines are rarely met. However, at torque levels exceeding 25 bar BMEP, the thermal in-cylinder conditions together with chemical reactivity of any ignitable matter, require major efforts in combustion system development. The paper presents a methodology to identify and locate sporadic self ignition events and it demonstrates non contact surface temperature measurement techniques for in-cylinder and exhaust system components.

Design of cylinder heads involves complex constraints that must satisfy thermal, strength, performance, and manufacturing requirements which present a great challenge for successful development. During development of a new highly loaded cylinder head, CAE methods predicted unacceptable fatigue safety factors for the initial prototype design. Hydropulsator component testing was undertaken and the results were correlated with the analysis predictions using a statistical method to calculate failure probability. Shape optimization was undertaken to improve high cycle fatigue safety in vulnerable regions of the cylinder head water jacket for the subsequent design release. The optimization process provided more efficient design guidance than previously discovered through a traditional iterative approach. Follow-on investigations examined other shape optimization software for fatigue improvement in the cylinder head.

The regulation of particle number (PN) has been introduced in the Euro 5/6 light-duty vehicle legislation, as a result of the light duty inter-laboratory exercise of the Particle Measurement Program (PMP). The heavy-duty inter-laboratory exercise investigates whether the same or a similar procedure can be applied to the heavy-duty regulation. In the heavy-duty exercise two "golden" PN systems sample simultaneously; the first from the full dilution tunnel and the second from the partial flow system. One of the targets of the exercise is to compare the PN results from the two systems. In this study we follow a different approach: We use a PMP compliant system at different positions (full flow, partial flow and tailpipe) and we compare its emissions with a "reference" system always sampling from the full flow dilution tunnel.

Future limits on emissions for both gasoline and Diesel engines require adequate and advanced systems for the after-treatment of the exhaust gas. Computer models as a complementary tool to experimental investigations are an indispensable part to design reliable after-treatment devices such as catalytic converters and Diesel particulate filters including their influence on the power-train. Therefore, the objective of this contribution is to present an integrated 1D to 3D simulation workflow of of catalytic converters and Diesel particulate filters. The novelty of this approach is that parameters or set of parameters, obtained by a fast and efficient 1D-gas exchange and cycle simulation code for power-trains (AVL (2002a)), are readily transferable onto a 3D general purpose simulation code (AVL (2002b)). Thus, detailed aspects such as spatial distribution of temperatures or heat losses are investigated with only a single effort to estimate parameters.

The incorporation of a detailed engine process calculation that takes into account thermal behavior of the engine and exhaust system is essential for a realistic simulation of transient vehicle operation. This is the only possible way to have a precise preliminary calculation of fuel consumption and emissions. Therefore, a comprehensive thermal network of the engine based on the lumped capacity method has been developed. The model allows the computation of component temperatures in steady state operation as well as in transient engine studies, e.g. investigations of engine warm-up. The model is integrated in a co-simulation environment consisting of a detailed vehicle and engine cycle simulation code. The paper describes the procedure of the co-simulation and presents several examples of warm-up simulations.

The present contribution gives an overview of the use of different simulation tools for the optimization of injection parameters of a diesel engine. With a one-dimensional tool, the behavior of the mechanics and fluid dynamics of the entire injection system is calculated. This simulation provides information on the dynamic needle lift, injection rates, pressures, etc. The flow within the injector is simulated using a three-dimensional CFD tool. By use of a two-phase model, it is possible to analyze the cavitating flow inside the injector and to calculate the effective nozzle hole area as well as the exit flow characteristics. Mixture formation, combustion and pollutant formation simulation is performed adopting three-dimensional CFD. In order to provide the initial and boundary conditions for the engine CFD simulation and to optimize the engine cycle performance a one-dimensional tool is adopted.

A broad variety of new technologies for improving fuel economy is currently under development or investigation. The general statement is that always a compromise between fuel economy benefit and engine oncost has to be found. This paper describes a new way for improving fuel economy based on existing technologies used in a refined way. It is shown that with very simple and robust measures on the intake and exhaust ports and on the valve train mechanism 2 valve and 4 valve engines can show a significant improvement in fuel consumption without having a great cost penalty for production. The basic system consists of a single cam phaser and a special port arrangement on a 2 valve engine with a single camshaft operated at stoichiometric air/fuel ratio utilizing internal EGR and a reverse “Miller-Cycle”. Variable charge motion is generated using a shared flow through the intake and the exhaust port by varying cam timing.

The objective of this study to introduce the newly developed Discrete Channel Method (DCM) as a fast and efficient method for the prediction of the 3d and transient behavior of honeycomb-type catalytic converters in automotive applications. The approach is based on the assumption that the regions between the channels are treated as a reactor with a homogeneously distributed heat source due to chemical conversion. Therefore, each radial direction can be described by a center, a boundary and only a few intermediate channels between them. The discrete channels are described by transient, 1d conservation equations that characterize the behavior of channels at different radial positions. The heat entering and leaving each discrete channel is evaluated by the gradients of the temperature field in conjunction with the heat conductivity of the substrate. The approach is validated by experimental data and serves as a module in the thermodynamic and engine analysis design tool BOOST.