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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.

The aerodynamic wind tunnel at Volvo Cars, known as the PVT, was recently upgraded to a moving ground wind tunnel to improve simulation quality. The moving ground simulation system consists of a 5-belt rolling road system (a centre belt and four wheel drive units). Flow simulation has also been improved by a new boundary layer control (BLC) system with a basic suction scoop, large distributed suction areas and aft belt tangential blowing. In addition, the wind tunnel main fan motor has been up-graded from 2.3 MW to 5 MW to provide a wind speed of 250 km/h in the full test section. Previously, 250 km/h was achieved only by installing inserts to reduce the test section area. The present paper provides an outline of the design features, philosophy of the new systems, aerodynamic calibration and commissioning results.

The paper investigates the dynamics of the tire and brake during hard braking or wheel locking, from the view point of a brake manufacturer. A new test rig, named BRAD (BRembo Automotive Dynamometer) is presented which measures the forces acting both at the brake and at the tire-ground interface. Lateral forces are not measured. In the test rig, the ground is represented by a drum. The features of the test rig are presented. The measurement accuracy is declared. The first result is that, near wheel locking, a substantial part of the braking power is generated by the tire and not by the brake. The test rig quantifies such a partitioning of brake power, which is important for current and future electric motorsport activities. Some 30% of the braking power is due to tire during hard braking. The second result is that, due to such important braking power at the tire, the tire is heated up, which increases considerably the maximum friction.

Transient and steady-state kinetic data are herein presented to analyze the inhibiting effect of ammonia on the NH₃-SCR of NO at low temperatures over a Fe-zeolite commercial catalyst for vehicles. It is shown that in SCR converter models a rate expression accounting for NH₃ inhibition of the Standard SCR reaction is needed in order to predict the specific dynamics observed both in lab-scale and in engine test bench runs upon switching on and off the ammonia feed. Two redox, dual site kinetic models are developed which ascribe such inhibition to the spill-over of ammonia from its adsorption sites, associated with the zeolite, to the redox sites, associated with the Fe promoter. Better agreement both with lab-scale intrinsic kinetic runs and with engine test-bench data, particularly during transients associated with dosing of ammonia to the SCR catalyst, is obtained assuming slow migration of NH₃ between the two sites.

Post-injection strategies prove to be a valuable option for reducing soot emission, but experimental results often differ from publication to publication. These discrepancies are likely caused by the selected operating conditions and engine hardware in separate studies. Efforts to optimize not only engine-out soot, but simultaneously fuel economy and emissions of nitrogen oxides (NOx) complicate the understanding of post-injection effects even more. Still, the large amount of published work on the topic is gradually forming a consensus. In the current work, a Design-of-Experiments (DoE) procedure and regression analysis are used to investigate the influence of various operating conditions on post-injection scheduling and efficacy. The study targets emission reductions of soot and NOx, as well as fuel economy improvements. Experiments are conducted on a heavy-duty compression ignition engine at three load-speed combinations.

The purpose of the ELEVATE (European Low Emission V4 Automotive Two-stroke Engine) industrial research project is to develop a small, compact, light weight, high torque and highly efficient clean gasoline 2-stroke engine of 120 kW which could industrially replace the relatively big existing automotive spark ignition or diesel 4-stroke engine used in the top of the mid size or in the large size vehicles, including the minivan vehicles used for multi people and family transportation. This new gasoline direct injection engine concept is based on the combined implementation on a 4-stroke bottom end of several 2-stroke engine innovative technologies such as the IAPAC compressed air assisted direct fuel injection, the CAI (Controlled Auto-Ignition) combustion process, the D2SC (Dual Delivery Screw SuperCharger) for both low pressure engine scavenging and higher pressure IAPAC air assisted DI and the ETV (Exhaust charge Trapping Valve).

A test rig (named RuotaVia) is presented for the in-door testing of road vehicle suspension systems. It is basically a drum (ϕ 2.6 m) providing a running surface for testing the dynamic performance of a single tire or suspension system (corner). The suspension system is instrumented for the measurement of the forces and the moments acting at each joint connecting the suspension to the car body. A new 6 axis load cell was designed and manufactured for this purpose. The accelerations in various locations of the system (wheel carrier, suspension arms, …) and the wheel centre displacements in the longitudinal and vertical directions are monitored. The effect of the dynamic interaction between the test rig and the suspension system is discussed in the paper. The direct measurement of the forces and moments at the suspension-chassis joints is still an effective way for understanding the vibration and harshness (VH) suspension performances.

In recent years the automotive industry has been forced to reduce the harmful and pollutant emissions emitted by direct-injected diesel engines. To accomplish this difficult task various solutions have been proposed. One of these proposed solutions is the usage of gaseous fuels in addition to the use of liquid diesel. These gaseous fuels have more gasoline-like properties, such as high octane numbers, and thereby are resistant against auto-ignition. Diesel on the other hand, has a high cetane number which makes it prone to auto-ignition. In this case the gaseous fuel is injected in the inlet manifold, and the diesel is direct injected in the cylinder at the end of the compression stroke. Thereby the diesel fuel spontaneously ignites and acts as an ignition source. The main goals for the use of a dual-fuel operation with diesel and gaseous fuels are the reduction of particulate matter (PM) and nitrogen oxides (NOx) emission.

Ammonia/urea-SCR is a mature technology, applied worldwide for the control of NOx emissions in combustion exhausts from thermal power plants, cogeneration units, incinerators and stationary diesel engines and more recently also from mobile sources. However a greater DeNOx activity at low temperatures is desired in order to meet more and more restrictive legislations. In this paper we report transient and steady state data collected over commercial Fe-ZSM-5 and V₂O₅-WO₃/TiO₂ catalysts showing high NOx reduction efficiencies in the 200 - 350°C T-range when NO and ammonia react with nitrates, e.g., in the form of an aqueous solution of ammonium nitrate. Under such conditions a new reaction occurs, the so-called "Enhanced SCR" reaction, 2 NH₃ + 2 NO + NH₄NO₃ → 3 N₂ + 5 H₂O.

This study investigated how the amount of dilution applied can be extended while maintaining normal engine operation in a GDI engine. Adding exhaust gases or air to a stoichiometric air/fuel mixture yields several advantages regarding fuel consumption and engine out emissions. The aim of this paper is to reduce fuel consumption by means of diluted combustion, an advanced ignition system and adjusted valve timing. Tests were performed on a Volvo four-cylinder engine equipped with a dual coil ignition system. This system made it possible to extend the ignition duration and current. Furthermore, a sweep was performed in valve timing and type of dilution, i.e., air or exhaust gases. While maintaining a CoV in IMEP < 5%, the DCI system was able to extend the maximum lambda value by 0.1 - 0.15. Minimizing valve overlap increased lambda by an additional 0.1.

The purpose of the European « SPACE LIGHT » (Whole SPACE combustion for LIGHT duty diesel vehicles) 3-year project launched in 2001 is to research and develop an innovative Homogeneous internal mixture Charged Compression Ignition (HCCI) for passenger cars diesel engine where the combustion process can take place simultaneously in the whole SPACE of the combustion chamber while providing almost no NOx and particulates emissions. This paper presents the whole project with the main R&D tasks necessary to comply with the industrial and technical objectives of the project. The research approach adopted is briefly described. It is then followed by a detailed description of the most recent progress achieved during the tasks recently undertaken. The methodology adopted starts from the research study of the in-cylinder combustion specifications necessary to achieve HCCI combustion from experimental single cylinder engines testing in premixed charged conditions.

Recently introduced sulfur caps on marine fuels in so-called sulfur emission control areas (SECAs) are forcing shipping companies to sail on more or less automotive grade diesel in lieu of the considerably less expensive, but sulfur-laden heavy fuel oil (HFO) to which they were accustomed. This development is an opportunity for a bio-based substitute, given that most biomass is sulfur free by default. Moreover, given that biomass is typically solid to start with, cracking it to an HFO grade, which is highly viscous in nature, will involve fewer and/or less harsh process steps than would be the case if an automotive grade fuel were to be targeted. In this study, a renewable low sulfur heavy fuel oil (LSHFO) has been produced by means of subcritical water assisted lignin depolymerization in the presence of a short length surfactant, ethylene glycol monobutyl ether (EGBE).

Oxygen enriched air (EA) is a well known industrial mixture in which the content of oxygen is higher respect the atmospheric one, in the range 22-35%. Oxygen EA can be obtained by desorption from water, taking advantage of the higher oxygen solubility in water compared to the nitrogen one, since the Henry constants of this two gases are different. The production of EA by this new approach was already studied by experimental runs and theoretical considerations. New results using salt water are reported. EA promoted combustion is considered as one of the most interesting technologies to improve the performance in diesel engines and to simultaneously control and reduce pollution. This paper explores, by means of 3-dimensional computational fluid dynamics simulations, the effects of EA on the performance and exhaust emissions of a high-speed direct-injection diesel engine.

N-butanol, as a biomass-based renewable fuel, has many superior fuel properties. It has a higher energy content and cetane number than its alcohol competitors, methanol and ethanol. Previous studies have proved that n-butanol has the capability to achieve lower emissions without sacrifice on thermal efficiency when blended with diesel. However, most studies on n-butanol are limited to low blending ratios, which restricts the improvement of emissions. In this paper, 80% by volume of n-butanol was blended with 20% by volume of n-heptane (namely BH80). The influences of various engine parameters (combustion phasing, EGR ratio, injection timing and intake pressure, respectively) on its combustion and emission characteristics are tested at different loads. The results showed that when BH80 uses more than 40% EGR, the emitted soot and nitrogen oxides (NOx) emissions are below the EURO VI legislation.

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.

It is well known that the addition of gaseous fuels to the intake manifold of diesel engines can have significant benefits in terms of both reducing emissions of hazardous gases and soot and improving fuel economy. Particularly, the addition of LPG has been investigated in numerous studies. Drawbacks, however, of such dual fuel strategies can be found in storage complexity and end-user inconvenience. It is for this reason that on-board refining of a single fuel (for example, diesel) could be an interesting alternative. A second-generation fuel reformer has been engineered and successfully tested. The reformer can work with both gaseous and liquid fuels and by means of partial oxidation of a rich fuel-air mix, converts these into syngas: a mixture of H₂ and CO. The process occurs as partial oxidation takes place in an adiabatic ceramic reaction chamber. High efficiency is ensured by the high temperature inside the chamber due to heat release.

Many studies have been carried out to optimize the aerodynamic performances of a single car or a single vehicle. In present days the traffic increases and sophisticated technologies are developing to guarantee the drivers safety, to minimize the fuel consumption and be more environmentally friendly. Within this research area a new technique that is being studied is Platooning: this means that different vehicles travel in a configuration that minimizes the aerodynamic drag and therefore the fuel consumption and the longitudinal space. In the present study platoons with different vehicles and configurations are taken into account, to analyze the influence of car shape and relative distance between the vehicles. The research has been carried out using CFD techniques to investigate the different flow fields around different platoons, while wind tunnel tests have been used to validate the results of the CFD simulations.

Selective Catalytic Reduction (SCR) systems are nowadays widely applied for the reduction of NOx emitted from Diesel engines. The typical process is based on the injection of aqueous urea in the exhaust gases before the SCR catalyst, which determines the production of the ammonia needed for the catalytic reduction of NOx. However, this technology is affected by two main limitations: a) the evaporation of the urea water solution (UWS) requires a sufficiently high temperature of the exhaust gases and b) the formation of solid deposits during the UWS evaporation is a frequent phenomenon which compromise the correct operation of the system. In this context, to overcome these issues, a technology based on the injection of gaseous ammonia has been recently proposed: in this case, ammonia is stored at the solid state in a cartridge containing a Strontium Chloride salt and it is desorbed by means of electrical heating.

In recent years, the increase of gasoline fuel injection pressure is a way to improve thermal efficiency and lower engine-out emissions in GDI homogenous combustion concept. The challenge of controlling particulate formation as well in mass and number concentrations imposed by emissions regulations can be pursued improving the mixture preparation process and avoiding mixture inhomogeneity with ultra-high injection pressure values up to 100 MPa. The increase of the fuel injection pressure in GDI homogeneous systems meets the demand for increased injector static flow, while simultaneously improves the spray atomization and mixing characteristics with consequent better combustion performance. Few studies quantify the effects of high injection pressure on transient gasoline spray evolution. The aim of this work was to simulate with OpenFOAM the spray morphology of a commercial gasoline injected in a constant volume vessel by a prototypal GDI injector.

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.