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Zero-dimensional heat release rate models have the advantage of being both easy to handle and computationally efficient. In addition, they are capable of predicting the effects of important engine parameters on the combustion process. In this study, a zero-dimensional combustion model based on physical and chemical sub-models for local processes like injection, spray formation, ignition and combustion is presented. In terms of injection simulation, the presented model accounts for a phenomenological nozzle flow model considering the nozzle passage inlet configuration and an approach for modeling the characteristics of the Diesel spray and consequently the mixing process. A formulation for modeling the effects of intake swirl flow pattern, squish flow and injection characteristics on the in-cylinder turbulent kinetic energy is presented and compared with the CFD simulation results.

Introducing new exhaust-gas aftertreatment concepts at mass production level places exacting demands on the overall development process - from defining process engineering to developing and calibrating appropriate control-unit algorithms. Strategies for operating and controlling exhaust-gas aftertreatment components, such as oxidation and selective catalytic reduction catalysts (DOC and SCR), diesel particulate filters (DPF) and SCR on DPF systems (SCR/DPF), have a major influence on meeting statutory exhaust-emission standards. Therefore it is not only necessary to consider the physical behavior of individual components in the powertrain but also the way in which they interact as the basis for ensuring efficient operation of the overall system.

The purpose of this paper is to investigate a new, universally applicable technique to protect the filter from overheating that could overcome the need for trap bypassing; namely, the trap protection by limiting A/F ratio during regeneration. The technique is supported by control of A/F ratio, leading to an indirect control of exhaust oxygen content and consequently trap regeneration rate. Realisation of the above-mentioned, very simple idea, so as to work effectively in the multitude of possible trap failure scenarios occuring during vehicle driving, is shown to be a fairly complicated task. The new method of trap protection, now being at the stage of initial investigations, is expected to lead to a safe and reliable system with wide applicability, without the need to bypass the trap at any circumstances. As such, it will also be attractive for passenger car applications, supported by the recent advances in wide application of electronic fuel control.

The modeling of transient phenomena occurring inside an automotive 3-way catalytic converter poses a significant challenge to the emissions control engineer. Since the significant progress that has been observed with steady-state models cannot be directly exploited in this direction, it is necessary to develop a fully transient model and computer code incorporating dynamic behaviour of the three way catalytic converter in a relatively simple and effective way. The Laboratory of Applied Thermodynamics (LAT), Aristotle University Thessaloniki, is cooperating with the Engine Direction of FIAT Research Center, in the development of a computer code fulfilling these objectives, within the framework of an EEC Brite EuRam cost shared project. The CRF and LAT modeling approaches, along with the underlying philosophy and experimental work, are presented in this paper.

As the late combustion phase in SI engines is of high importance for a further reduction of fuel consumption and especially emissions, the impacts of unburnt mass, located in a small volume with a relatively large surface near the wall and in the top land volume, is of high relevance throughout the range of operation. To investigate and quantify the respective interactions, a state of the art Mercedes-Benz single cylinder research SI-engine was equipped with extensive measurement technology. To detect the axial and radial temperature distribution, several surface thermocouples were applied in two layers around the top land volume. As an additional reference, multiple surface thermocouples in the cylinder head complement the highly dynamic temperature measurements in the boundary zones of the combustion chamber.

This study examines the effects of neat soy-based biodiesel (B100) and its 50% v/v blend (B50) with low sulphur automotive diesel on vehicle PAH emissions. The measurements were conducted on a chassis dynamometer with constant volume sampling (CVS) according to the European regulated technique. The vehicle was a Euro 2 compliant diesel passenger car, equipped with a 1.9 litre common-rail turbocharged direct injection engine and an oxidation catalyst. Emissions of PAHs, nitro-PAHs and oxy-PAHs were measured over the urban phase (UDC) and the extra-urban phase (EUDC) of the type approval cycle (NEDC). In addition, for evaluating realistic driving performance the non-legislated Artemis driving cycles (Urban, Road and Motorway) were used. Overall, 12 PAHs, 4 nitro-PAHs, and 6 oxy-PAHs were determined. The results indicated that PAH emissions exhibited a reduction with biodiesel during all driving modes.

The oil supply of combustion engines today is typically realized by oil pumps with constant displacement. To secure the operational safety in hot idling these pumps are oversized, what causes low efficiency in most of operating speeds. IAV developed a vane-type oil pump, which allows to infinitely regulate the delivery rate. Because of no oil release over a pressure limiting valve the pump achieves a higher efficiency in a wide range of operation. The design of the theoretical delivery characteristic allows the calculated and particular increase of oil pressure to avoid critical operating conditions and to support hydraulically operated functions as variable camshaft timing.

State-of-the-art powertrain concepts with automatic transmission must comply with increasingly stringent legislation on emissions and fuel consumption while fulfilling or surpassing customers' expectations as to driveability. In this respect, automated manual transmissions (AMT) and automated shift transmissions (AST) must compete with conventional automatic transmissions (AT) and continuously variable transmissions (CVT). In order to exploit the theoretical advantages of ASTs and put them into practice, complex ECU functions are needed to coordinate engine and transmission. Adaptive control, sophisticated clutch management and an intelligent shifting strategy allow shifting quality and shifting points to be simultaneously optimized to the effect that performance and comfort are increased while fuel consumption is reduced.

Exhaust gas from diesel engines will be subjected to new and stringent emissions standards. To lower the emissions of carbon particulates (soot), a filtration system has to be fitted in the exhaust line. Diesel Particulate Filters (DPF) trap the soot, which then has to be removed by combustion. Soot doped with cerium-based additives leads to an enhancement of reactivity with O2. It is also well known that the presence of NO2 significantly accelerates the carbon oxidation rate. The CRTTM (Continuous Regeneration Trap) system is based on this property. More recently, the DPNR system (Diesel Particulate NOx Reduction system), which is a DPF impregnated with a NOx trap catalyst, was proposed. The aim of the present study was to investigate the effect of different catalytic materials on soot combustion. Two catalysts were tested: a commercial Oxygen Storage Catalyst (OSC) and a Lean NOx trap catalyst (laboratory made). Different types of soot, both with and without an additive were tested.

Even though the 3-way catalyst chemistry has been studied extensively in the literature, some performance aspects of practical relevance have not been fully explained. It is believed that the Oxygen Storage Capacity function of 3-way catalytic components dominates the behavior during stoichiometry transitions from lean to rich mode and vice versa whereas a number of mathematical models have been proposed to describe the dynamics of pollutant conversion. Previous studies have suggested a strong impact of Sulfur on the pollutant conversion after a lean to rich transition, which has not been adequately explained and modelled. Lean to rich transitions are highly relevant to catalyst ‘purging’ needed after exposure to high O2 levels (e.g. after fuel cut-offs). This work presents engine test measurements with an engine-aged catalyst that highlight the negative impact of Sulfur on pollutant conversion after a lean to rich transition.

Particulate filters are a widely used emission control device on heavy-duty diesel engines. The accumulation of particulate matter, mostly consisting of soot, inside the filter results in increased filter pressure-drop (backpressure). This increased backpressure has been used by the on-board control systems as trigger for regeneration procedures, which aim to actively oxidize the accumulated soot. However, it is known that passive soot oxidation during normal operation affects the correlation between backpressure and the deposited soot mass in filter. Therefore, the backpressure alone cannot be a reliable trigger for regeneration. In this work we highlight operating conditions with very poor correlation between backpressure and accumulated soot mass in filter and evaluate the possible root causes. Experiments with several heavy-duty diesel engines and particulate filters were conducted on engine test bench.

Air quality improvement, especially in urban areas, is one of the major concerns for the coming years. For this reason, car manufacturers, equipment manufacturers and refiners have explored development issues to comply with increasingly severe anti-pollution requirements. In such a context, the identification of the most promising improvement options is essential. A research program, carried out by IFP (Institut Français du Pétrole), and supported by the French Ministry of Industry, IFP, PSA-Peugeot-Citroën, Renault and RVI (Renault Véhicules Industriels), has been built to study this point. It is based on a three years program with different steps focused on new engine technologies which will be available in the next 20 years in order to answer to more and more severe pollutant and CO2 emission regulations. This program is divided into three main parts: the first one for Diesel car engines, the second for Diesel truck engines and the third for spark ignition engines.

Air quality improvement, especially in urban areas, is one of the major concerns for the coming years. For this reason, car manufacturers, equipment manufacturers and refiners have been exploring development avenues to comply with increasingly severe anti-pollution requirements. In such a context, the identification of the most promising improvement options is essential. A research program, carried out by IFP (Institut Français du Pétrole), and supported by FSH (Fonds de Soutien aux Hydrocarbures), IFP, PSA-Peugeot-Citroën, Renault and Renault VI (Véhicules Industriels), has been built to study this point. It is a four years programme with different steps which will focus on new engine technologies: some of them are going to be marketed very soon (gasoline direct injection car engine, and diesel common rail injection car and truck engines) to anticipate the Euro 3 (2000) and the Euro 4 (2005) emissions specifications. The original work reported here is part of this research.

Modern engines are intended to work at high efficiency and at the same time have low emissions. Since modern engines operate with nearly stoichiometric air/fuel mixtures to reduce nitrogen oxides, one of the most critical emissions is carbon monoxide and its prediction is therefore essential for today's engine design. The concept of the presented model is to combine the two-zone thermodynamic model and CHEMKIN software to predict the carbon monoxide emissions from a gasoline direct injection engine with good computational efficiency and low calculation time. The model calculation was divided into two parts. The first part is the two-zone model which can also predict the CO concentration for the exhaust condition by using the chemical equilibrium concentration. The second part is the kinetic model, which uses input data from the two-zone model and starts the calculation shortly before the end of combustion.

Further tightened emission legislation and new engine technologies increase the requirements for the exhaust after-treatment system of modern diesel passenger cars. Especially the increasing raw emissions of HC and CO as well as the low temperature of the exhaust gas for a long period during cold start of the New European Driving Cycle (NEDC) require additional efforts in the design of the oxidation catalyst system [1]. A highly efficient micro catalyst, which is mounted in front of a turbocharger, can help to treat efficiently these high HC and CO emissions. Due to the higher temperature level in front of the turbine and the significantly increased mass and heat transfer by turbulent flow, efficiency especially during cold start is highly increased. However the packaging constraints are more critical in this area due to heat considerations and also to maintain engine performance.

Under the persistent pressure to further reduce fuel consumption worldwide, it is necessary to advance the processes that influence the efficiency of gasoline engines. In doing so, harnessing the entire potential of fully variable mechanical valve trains will involve targeting efforts on optimizing all design parameters. A new type of valve timing system is used to portray thermodynamic and mechanical as well as electronic aspects of developing fully variable mechanical valve timing and lift systems

A physico-chemical model of a Cu-zeolite SCR/DPF-system involving NH₃ storage and SCR reactions as well as soot oxidation reactions with NO₂ has been developed and validated based on fundamental experimental investigations on synthetic gas test bench. The goal of the work was the quantitative modeling of NOx and NH₃ tailpipe emissions in transient test cycles in order to use the model for concept design analysis and the development of control strategies. Another focus was put on the impact of soot on SCR/DPF systems. In temperature-programmed desorption experiments, soot-loaded SCR/DPF filters showed a higher NH₃ storage capacity compared to soot-free samples. The measured effect was small, but could affect the NH₃ slip in vehicle applications. A bimodal desorption characteristic was measured for different adsorption temperatures and heating rates.

Global warming is a climate phenomenon with world-wide ecological, economic and social impact which calls for strong measures in reducing automotive fuel consumption and thus CO2 emissions. In this regard, turbocharging and the associated designing of the air path of the engine are key technologies in elaborating more efficient and downsized engines. Engine performance simulation or development, parameterization and testing of model-based air path control strategies require adequate performance maps characterizing the working behavior of turbochargers. The working behavior is typically identified on test rig which is expensive in terms of costs and time required. Hence, the objective of the research project “virtual Exhaust Gas Turbocharger” (vEGTC) is an alternative approach which considers a physical modeled vEGTC to allow a founded prediction of efficiency, pressure rise as well as pressure losses of an arbitrary turbocharger with known geometry.

This paper investigates an optimal design of a diesel engine and after-treatment systems for a series hybrid electric forklift application. A holistic modeling approach is developed in GT-Suite® to establish a model-based hardware definition for a diesel engine and an after-treatment system to accurately predict engine performance and emissions. The used engine model is validated with the experimental data. The engine design parameters including compression ratio, boost level, air-fuel ratio (AFR), injection timing, and injection pressure are optimized at a single operating point for the series hybrid electric vehicle, together with the performance of the after-treatment components. The engine and after-treatment models are then coupled with a series hybrid electric powertrain to evaluate the performance of the forklift in the standard VDI 2198 drive cycle.

As the Diesel Particulate Filter (DPF) technology is nowadays established, research is currently focusing on meeting the emission and durability requirements by proper system design. This paper focuses on the optimum combination between the catalytic coating and substrate structural properties using experimental and simulation methodologies. The application of these methodologies will be illustrated for the case of SiC substrates coated with innovative sol-gel coatings. Coated samples are characterized versus their uncoated counterparts. Multi-dimensional DOC and DPF simulation models are used to study several effects parametrically and increase our understanding on the governing phenomena. The comparative analysis of DOC/DPF systems covers filtration – pressure drop characteristics, CO/HC/NO oxidation performance, effect of washcoat amount and catalyst dispersion on oxidation activity and finally passive regeneration performance.