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Lean-burn hydrogen internal combustion engines are a good option for future transportation solutions since they do not emit carbon-dioxide and unburned hydro-carbons, and the emissions of nitric-oxides (NOx) can be kept low. However, under lean-burn conditions the combustion duration increases, and the combustion stability decreases, leading to a reduced thermal efficiency. Turbulent jet ignition (TJI) can be used to extend the lean-burn limit, while decreasing the combustion duration and improving combustion stability. The objective of this paper is to investigate the feasibility of a passive pre-chamber TJI system on a heavy-duty hydrogen engine under lean-burn conditions using CFD modelling. The studied concept is mono-fuel, port-fuel injected, and spark ignited in the pre-chamber. The overall design of the pre-chamber is discussed and the effect of design parameters on the engine performance are studied.

A model-based control approach is proposed to give proper reference for the feed-forward combustion control of Partially Pre-mixed Combustion (PPC) engines. The current study presents a simplified first principal model, which has been developed to provide a base estimation of the ignition properties. This model is used to describe the behavior of a single-cylinder heavy-duty diesel engine fueled with a mix of bio-butanol and n-heptane (80vol% bio-butanol and 20 vol% n-heptane). The model has been validated at 8 bar gross Indicated Mean Effective Pressure (gIMEP) in PPC mode. Inlet temperature and pressure have been varied to test the model capabilities. First the experiments were conducted to generate reference points with BH80 under PPC conditions. And then CFD simulations were conducted to give initial parameter set up, e.g. fuel distribution, zone dividing, for the multi-zone model.

Green zones are challenging problems for the thermal management systems of hybrid vehicles. This is because within the green zone the engine is turned off, and the only way to keep the aftertreatment system warm is lost. This means that there is a risk of leaving the green zone with a cold and ineffective aftertreatment system, resulting in high emissions. A thermal management strategy that heats the aftertreatment system prior to turning off the engine, in an optimal way, to reduce the NOx emissions when the engine is restarted, is developed. The strategy is also used to evaluate under what conditions pre-heating is a suitable strategy, by evaluating the performance in simulations using a model of a heavy-duty diesel powertrain and scenario designed for this purpose.

Multiple injection strategies are commonly used in conventional Diesel engines due to the flexibility for optimizing heat-release timing with a consequent improvement in fuel economy and engine-out emissions. This is also desirable in low-temperature combustion (LTC) engines since it offers the potential to reduce unburned hydrocarbon and CO emissions. To better utilize these benefits and find optimal calibrations of split injection strategies, it is imperative that the fundamental processes of multiple injection combustion are understood and computational fluid dynamics models accurately describe the flow dynamics and combustion characteristics between different injection events. To this end, this work is dedicated to the identification of suitable methodologies to predict the multiple injection combustion process.

Rubber is a non-linear viscoelastic material which properties depend upon several factors. In a tire two of these factors, namely the temperature and excitation frequency, are significantly influenced by the vehicle operating conditions. In the past years, applied research studied how rubber viscoelastic characteristics affect structural and frictional tire properties. The present study focuses on how these effects interact with the vehicle handling response. Based on state of the art theory of friction, structural properties of rubber and on experimental evidence, the dependency of key tire parameters on temperature and rolling speed is established. These results are then used in combination with a single-track vehicle model to assess their impact on key vehicle parameters; as an example, the understeer coefficient, yaw resonance peak / damping and maximum acceleration are studied.

A contemporary approach for improving and developing the understanding of heavy-duty Diesel engine combustion processes is to use a concerted effort between experiments at well-characterized boundary conditions and detailed, high-fidelity models. In this paper, combustion processes of n-dodecane fuel sprays under heavy-duty Diesel engine conditions are investigated using this approach. Reacting fuel sprays are studied in a constant-volume pre-burn vessel at an ambient temperature of 900 K with three reference cases having specific combinations of injection pressure, ambient density and ambient oxygen concentration (80, 150 & 160 MPa - 22.8 & 40 kg/m3-15 & 20.5% O2). In addition to a free jet, two different walls were placed inside the combustion vessel to study flame-wall interaction.

The interactions between automatic controls, physics, and driver is an important step towards highly automated driving. This study investigates the dynamical interactions between human-selected driving modes, vehicle controller and physical plant parameters, to determine how to optimally adapt powertrain control to different human-like driving requirements. A cyber-physical system (CPS) based framework is proposed for co-design optimization of the physical plant parameters and controller variables for an electric powertrain, in view of vehicle’s dynamic performance, ride comfort, and energy efficiency under different driving modes. System structure, performance requirements and constraints, optimization goals and methodology are investigated. Intelligent powertrain control algorithms are synthesized for three driving modes, namely sport, eco, and normal modes, with appropriate protocol selections. The performance exploration methodology is presented.

Advanced Computational Fluid Dynamics (CFD) modeling of reacting sprays provides access to information not available even applying the most advanced experimental techniques. This is particularly evident if the combustion model handles detailed chemical kinetic models efficiently to describe the fuel auto-ignition and oxidation processes. Complex chemistry also provides the temporal evolution of key species closely related to emissions formation, such as polycyclic aromatic hydrocarbons (PAHs) that are well-known as soot precursors. In this framework, present investigation focuses on the analysis of the so-called Spray-A combustion characteristics using two different flamelet-based combustion models. Both Reynolds-Averaged Navier-Stokes (RANS) and Large-Eddy Simulation (LES) predictions are combined to study not only the averaged spray characteristics, but also the relevance of different realizations in this particular problem.

Partially premixed compression ignition combustion is one of the low temperature combustion techniques which is being actively investigated. This approach provides a significant reduction of both soot and NOx emissions. Comparing to the homogeneous charge compression ignition mode, PPCI combustion provides better control on ignition timing and noise reduction through air-fuel mixture stratification which lowers heat release rate compared to other advanced combustion modes. In this work, CFD simulations were conducted for a low and a high air-fuel mixture stratification cases on a light-duty optical engine operating in PPCI mode. Such conditions for PRF70 as fuel were experimentally achieved by injection timing and spray targeting at similar thermodynamic conditions.

The modeling of fuel sprays under well-characterized conditions relevant for heavy-duty Diesel engine applications, allows for detailed analyses of individual phenomena aimed at improving emission formation and fuel consumption. However, the complexity of a reacting fuel spray under heavy-duty conditions currently prohibits direct simulation. Using a systematic approach, we extrapolate available spray models to the desired conditions without inclusion of chemical reactions. For validation, experimental techniques are utilized to characterize inert sprays of n-dodecane in a high-pressure, high-temperature (900 K) constant volume vessel with full optical access. The liquid fuel spray is studied using high-speed diffused back-illumination for conditions with different densities (22.8 and 40 kg/m3) and injection pressures (150, 80 and 160 MPa), using a 0.205-mm orifice diameter nozzle.

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.

For natural gas (NG)-diesel RCCI, a multi-zonal, detailed chemistry modeling approach is presented. This dual fuel combustion process requires further understanding of the ignition and combustion processes to maximize thermal efficiency and minimize (partially) unburned fuel emissions. The introduction of two fuels with different physical and chemical properties makes the combustion process complicated and challenging to model. In this study, a multi-zone approach is applied to NG-diesel RCCI combustion in a heavy-duty engine. Auto-ignition chemistry is believed to be the key process in RCCI. Starting from a multi-zone model that can describe auto-ignition dominated processes, such as HCCI and PCCI, this model is adapted by including reaction mechanisms for natural gas and NOx and by improving the in-cylinder pressure prediction. The model is validated using NG-diesel RCCI measurements that are performed on a 6 cylinder heavy-duty engine.

Homogeneous Charge Compression Ignition (HCCI) combustion technology has demonstrated a profound potential to decrease both emissions and fuel consumption. In this way, the significance of the 2-stroke HCCI engine has been underestimated as it can provide more power stroke in comparison to a 4-stroke engine. Moreover, the mass of trapped residual gases is much larger in a 2-stroke engine, causing higher initial charge temperatures, which leads to easier auto-ignition. For controlling 2-stroke HCCI engines, it is vital to find optimized simulation approaches of HCCI combustion with a focus on ignition timing. In this study, a Computational Fluid Dynamic (CFD) model for a 2-stroke gasoline engine was developed coupled to a semi-detailed chemical mechanism of iso-octane to investigate the simulation capability of the considered chemical mechanism and the effects of different simulation parameters such as the turbulence model, grid density and time step size.

This paper discusses the development and subsequent validation process of generic multi-body models for commercial vehicle combinations. The model is intended for performance assessment and improving of current and future combinations for the European road network. A second goal is to employ the model for the development of driver support systems and active steering strategies for both low speed manoeuvrability and high speed stability. The model is developed in SimMechanics, which is part of the MATLAB/Simulink software. Due to its modularity, one can quickly modify the model to the desired configuration and dimensions; therefore various multi articulation vehicle models can be created. The paper further illustrates the simplified and generic modelling methods used to build particular components such as chassis, tyres or suspension in the multibody domain.

To increase the efficiency of a Variable Geometry Turbine at low massflow rates the vaneless space of the vanes is reduced. It is researched if this modification can reduce turbo lag. A turbine with modified vane ring is installed in the exhaust of a naturally aspirated engine and wide open throttle accelerations are performed to test the turbine performance. The new (reduced vaneless space) vane configuration induced a lower exhaust backpressure which allowed the engine to accelerate faster. The acceleration from 1500 to 3000 RPM was an average of 8 % faster for the new vane configuration. This in turn increased the massflow rate through the turbine which caused the power available to the turbine to be similar in compared vane rings. The initial turbine speeds was lower for the new vane configuration but it quickly caught up with the conventional configuration because the turbine acceleration was higher. The turbine efficiency was higher for the new vane configuration in most cases.

Styrene, or ethylbenzene, is mainly used as a monomer for the production of polymers, most notably Styrofoam. In the synthetis of styrene, the feedstock of benzene and ethylene is converted into aromatic oxygenates such as benzaldehyde, 2-phenyl ethanol and acetophenone. Benzaldehyde and phenyl ethanol are low value side streams, while acetophenone is a high value intermediate product. The side streams are now principally rejected from the process and burnt for process heat. Previous in-house research has shown that such aromatic oxygenates are suitable as diesel fuel additives and can in some cases improve the soot-NOx trade-off. In this study acetophenone, benzaldehyde and 2-phenyl ethanol are each added to commercial EN590 diesel at a ratio of 1:9, with the goal to ascertain whether or not the lower value benzaldehyde and 2-phenyl ethanol can perform on par with the higher value acetophenone. These compounds are now used in pure form.

At Eindhoven University of Technology an active suspension system has been developed [1]. This system is superior to other active suspension in terms of bandwidth and power consumption. This active suspension system was tested on a quarter car setup and showed improvements of up to 48% in comfort [2]. In order to implement this suspension in a test vehicle with the same improvements, a non-linear full-car model is developed in this paper which is used to simulate and design various controllers. The non-linear model incorporates non-linear damping, bump stops, actuator saturation and actuator friction. To model the friction in the actuator a combination of Coulomb and viscous friction is used. To model the MacPherson suspension strut, two methods are described and compared. Also the implications of using acceleration sensors which are placed in line with the MacPherson strut are discussed.

The wide range of diesel engine operating conditions demand for a robust combustion model to account for inherent changes. In this work, the Flamelet Generate Manifold (FGM) approach is applied, in STAR-CD framework, to simulate the conventional injection- and early injection-timing (PCCI like) combustion regimes. Igniting Counter flow Diffusion Flamelets (ICDFs) and Homogeneous Reactors (HRs) are used to tabulate chemistry for conventional and PCCI combustion modes, respectively. The validation of the models with experimental data shows that the above consideration of chemistry tabulation results in accurate ignition delay predictions. The study reveals that a moderate amount of 5 different pressure levels is necessary to include in the FGM database to capture the ignition delay in both combustion regimes.

The Flamelet Generated Manifold (FGM) method is a promising technique in engine combustion modeling to include tabulated chemistry. Different methodologies can be used for the generation of the manifold. Two approaches, based on igniting counterflow diffusion flamelets (ICDF) and homogeneous reactors (HR) are implemented and compared with Engine Combustion Network (ECN) experimental database for the baseline n-heptane case. Before analyzing the combustion results, the spray model is optimized after performing a sensitivity study with respect to turbulence models, cell sizes and time steps. The standard High Reynolds (Re) k-ε model leads to the best match of all turbulence models with the experimental data. For the convergence of the mixture fraction field an appropriate cell size is found to be smaller than that for an adequate spray penetration length which appears to be less influenced by the cell size.

Increasing fuel prices keep bringing attention to alternative, cheaper fuels. Liquefied Petroleum Gas (LPG) has been well known for decades as an alternative fuel for spark ignition (SI) passenger cars. More recently, aftermarket LPG systems were also introduced to Heavy Duty transport vehicles. These (port fuel) systems either vaporize the liquid fuel and then mix it with intake air, or inject fuel into the engine's intake ports. While this concept offers significant fuel cost reductions, for aftermarket certification and large-scale OEM use some concerns are present. Unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions are known to be high because of premixed charge getting trapped into crevices and possibly being blown through during valve-overlap. Apart from the higher emission levels, this also limits fuel efficiency and therefore cost savings.