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Characterization of a New Advanced Diesel Oxidation Catalyst with Low Temperature NOx Storage Capability for LD Diesel

2012-06-18
Currently, two consolidated aftertreatment technologies are available for the reduction of NOx emissions from diesel engines: Urea SCR (Selective Catalytic Reduction) systems and LNT (Lean NOx Trap) systems. Urea SCR technology, which has been widely used for many years at stationary sources, is becoming nowadays an attractive alternative also for light-duty diesel applications. However, SCR systems are much more effective in NOx reduction efficiency at high load operating conditions than light load condition, characterized by lower exhaust gas temperatures.
Technical Paper

Experimental Investigation on Three Different Ceramic Substrate Materials for a Diesel Particulate Filter

2013-09-08
2013-24-0160
Three different ceramic substrate materials (Silicon Carbide, Cordierite and Aluminum Titanate) for a Diesel Particulate Filter (DPF) for a European passenger car diesel engine have been experimentally investigated in this work. The filters were soot loaded under real world operating conditions on the road and then regenerated in two different ways that simulate the urban driving conditions, which are the most severe for DPF regeneration, since the low exhaust flow has a limited capability to absorb the heat generated by the soot combustion. The tests showed higher temperature peaks, at the same soot loading, for Cordierite and Aluminum Titanate compared to the Silicon Carbide, thus leading to a lower soot mass limit, which in turn required for these components a higher regeneration frequency with draw backs in terms of fuel consumption and lube oil dilution.
Technical Paper

Virtual Set-up of a Racing Engine for the Optimization of Lap Performance through a Comprehensive Engine-Vehicle-Driver Model

2011-09-11
2011-24-0141
In Motorsports the understanding of the real engine performance within a complete circuit lap is a crucial topic. On the basis of the telemetry data the engineers are able to monitor this performance and try to adapt the engine to the vehicle's and race track's characteristics and driver's needs. However, quite often the telemetry is the sole analysis instrument for the Engine-Vehicle-Driver (EVD) system and it has no prediction capability. The engine optimization for best lap-time or best fuel economy is therefore a topic which is not trivial to solve, without the aid of suitable, reliable and predictive engineering tools. A complete EVD model was therefore built in a GT-SUITE™ environment for a Motorsport racing car (STCC-VW-Scirocco) equipped with a Compressed Natural Gas (CNG) turbocharged S.I. engine and calibrated on the basis of telemetry and test bench data.
Journal Article

The Effects of Neat Biodiesel Usage on Performance and Exhaust Emissions from a Small Displacement Passenger Car Diesel Engine

2010-05-05
2010-01-1515
The effects of using neat FAME (Fatty Acid Methyl Ester) in a modern small displacement passenger car diesel engine have been evaluated in this paper. In particular the effects on engine performance at full load with standard (i.e., without any special tuning) ECU calibration were analyzed, highlighting some issues in the low end torque due to the lower exhaust gas temperatures at the turbine inlet, which caused a remarkable decrease of the available boost, with a substantial decrease of the engine torque output, far beyond the expected engine derating due to the lower LHV of the fuel. However, further tests carried out after ECU recalibration, showed that the same torque levels measured under diesel operation can be obtained with neat biodiesel too, thus highlighting the potential for maintaining the same level of performance.
Journal Article

Particle Number and Size Distribution from a Small Displacement Automotive Diesel Engine during DPF Regeneration

2010-05-05
2010-01-1552
The aim of this work is to analyze particle number and size distribution from a small displacement Euro 5 common rail automotive diesel engine, equipped with a close coupled aftertreatment system, featuring a DOC and a DPF integrated in a single canning. In particular the effects of different combustion processes on PM characteristics were investigated, by comparing measurements made both under normal operating condition and under DPF regeneration mode. Exhaust gas was sampled at engine outlet, at DOC outlet and at DPF outlet, in order to fully characterize PM emissions through the whole exhaust line. After a two stage dilution system, sampled gas was analyzed by means of a TSI 3080 SMPS, in the range from 6 to 240 nm. Particle number and size distribution were evaluated at part load operating conditions, representative of urban driving.
Technical Paper

Effects of Rapeseed and Jatropha Methyl Ester on Performance and Emissions of a Euro 5 Small Displacement Automotive Diesel Engine

2011-09-11
2011-24-0109
The effects of using neat and blended (30% vol.) biodiesel, obtained from Rapeseed Methyl Ester (RME) and Jatropha Methyl Ester (JME), in a Euro 5 small displacement passenger car diesel engine have been evaluated in this paper. The impact of biodiesel usage on engine performance at full load was analyzed for a specifically adjusted ECU calibration: the same torque levels measured under diesel operation could be obtained, with lower smoke levels, thus highlighting the potential for maintaining the same level of performance while achieving substantial emissions benefits. In addition, the effects of biodiesel blends on brake-specific fuel consumption and on engine-out exhaust emissions (CO₂, CO, HC, NOx and smoke) were also evaluated at 6 different part load operating conditions, representative of the New European Driving Cycle. Emissions were also measured at the DPF outlet, thus providing information about after-treatment devices efficiencies with biodiesel.
Technical Paper

Development of a Control Strategy for Complex Light-Duty Diesel-Hybrid Powertrains

2011-09-11
2011-24-0076
Hybrid Electric Vehicles (HEVs) represent a powerful technology to save fuel and reduce CO₂ emissions, through the synergic use of a conventional internal combustion engine and one or more electric machines. However their performance strongly depends on the control strategy that shares the power demand among the engine and the electric motors at each time instant, with the objective of minimizing a pre-defined cost function over an entire driving cycle, and satisfying, at the same time, any additional constraints. The aim of this work is therefore the definition of a methodology to develop, through numerical simulation, a sub-optimal hybrid powertrain controller: starting from the problem definition, the ideal performance for a case study hybrid architecture was analyzed through a global optimization algorithm in order to point out information which can be used to define new control laws.
Technical Paper

Effects of Different Geometries of the Cylinder Head on the Combustion Characteristics of a VVA Gasoline Engine

2013-09-08
2013-24-0057
Two different modifications of the baseline cylinder head configuration have been designed and experimentally tested on a MultiAir turbocharged gasoline engine, in order to address the issue of the poor in-cylinder turbulence levels which are typical of the Early-Intake-Valve-Closing (EIVC) strategies which are adopted in Variable Valve Actuation systems at part load to reduce pumping losses. The first layout promotes turbulence by increasing the tumble motion at low valve lifts, while the second one allows the addition of a swirl vortex to the main tumble structure. The aim for both designs was to achieve a proper flame propagation speed at both part and full load. The experimental activity was initially focused on the part load analysis under high dilution of the mixture with internal EGR, which can allow significant further reductions in terms of pumping losses but, on the other hand, tends to adversely affect combustion stability and to increase cycle-to-cycle variations.
Technical Paper

Assessment of the Predictive Capabilities of a Combustion Model for a Modern Common Rail Automotive Diesel Engine

2016-04-05
2016-01-0547
The predictive capabilities of an innovative multizone combustion model DIPulse, developed by Gamma Technologies, were assessed in this work for a last generation common rail automotive diesel engine. A detailed validation process, based on an extensive experimental data set, was carried out concerning the predicted heat release rate, the in-cylinder pressure trace, as well as NOx and soot emissions for several operating points including both part load and full load points. After a preliminary calibration of the model, the combustion model parameters were then optimized through a Latin Hypercube Design of Experiment (DoE), with the aim of minimizing the RMS error between the predicted and experimental burn rate of several engine operating points, thus achieving a satisfactory agreement between simulation and experimental engine combustion and emissions parameters.
Technical Paper

Numerical Simulation of the Warm-Up of a Passenger Car Diesel Engine Equipped with an Advanced Cooling System

2016-04-05
2016-01-0555
The target for future cooling systems is to control the fluid temperatures and flows through a demand oriented control of the engine cooling to minimize energy demand and to achieve comfort, emissions, or service life advantages. The scope of this work is to create a complete engine thermal model (including both cooling and lubrication circuits) able to reproduce engine warm up along the New European Driving Cycle in order to assess the impact of different thermal management concepts on fuel consumption. The engine cylinder structure was modeled through a finite element representation of cylinder liner, piston and head in order to simulate the cylinder heat exchange to coolant or oil flow circuits and to predict heat distribution during transient conditions. Heat exchanges with other components (EGR cooler, turbo cooler, oil cooler) were also taken into account.
Technical Paper

Assessment of the Predictive Capabilities of a Combustion Model for a Modern Downsized Turbocharged SI Engine

2016-04-05
2016-01-0557
A 0D phenomenological turbulence model, based on the K-k and k- ɛ approaches, was coupled with a predictive turbulent combustion model using the commercial code GT-Suite, and its predictive capabilities were assessed for a downsized turbocharged SI engine. Differently from the 3D-CFD approach which is typically utilized to describe the evolution of the in-cylinder flow field, and which has very high computational requirements, the 0D phenomenological approach adopted in this work gives the opportunity to predict the evolution of the in-cylinder charge motion and the subsequent combustion process by means of a turbulent combustion model, with a significantly reduced computational effort, thus paving the way for the simulation of the whole engine operating map.
Journal Article

Experimental and Numerical Assessment of Multi-Event Injection Strategies in a Solenoid Common-Rail Injector

2017-09-04
2017-24-0012
Nowadays, injection rate shaping and multi-pilot events can help to improve fuel efficiency, combustion noise and pollutant emissions in diesel engine, providing high flexibility in the shape of the injection that allows combustion process control. Different strategies can be used in order to obtain the required flexibility in the rate, such as very close pilot injections with almost zero Dwell Time or boot shaped injections with optional pilot injections. Modern Common-Rail Fuel Injection Systems (FIS) should be able to provide these innovative patterns to control the combustion phases intensity for optimal tradeoff between fuel consumption and emission levels.
Journal Article

Numerical Investigation on the Effects of Different Thermal Insulation Strategies for a Passenger Car Diesel Engine

2017-09-04
2017-24-0021
One of the key technologies for the improvement of the diesel engine thermal efficiency is the reduction of the engine heat transfer through the thermal insulation of the combustion chamber. This paper presents a numerical investigation on the effects of the combustion chamber insulation on the heat transfer, thermal efficiency and exhaust temperatures of a 1.6 l passenger car, turbo-charged diesel engine. First, the complete insulation of the engine components, like pistons, liner, firedeck and valves, has been simulated. This analysis has showed that the piston is the component with the greatest potential for the in-cylinder heat transfer reduction and for Brake Specific Fuel Consumption (BSFC) reduction, followed by firedeck, liner and valves. Afterwards, the study has been focused on the impact of different piston Thermal Barrier Coatings (TBCs) on heat transfer, performance and wall temperatures.
Technical Paper

A Methodology to Mimic Cycle to Cycle Variations and to Predict Knock Occurrence through Numerical Simulation

2014-04-01
2014-01-1070
In this paper a novel approach to mimic through numerical simulation Cycle-to-Cycle Variations (CCV) of the combustion process of Spark Ignition (SI) engines is described. The proposed methodology allows to reproduce the variability in combustion which is responsible for knock occurrence and thus to replicate the stochastic behavior of this abnormal combustion phenomenon. On the basis of the analysis of a comprehensive database of experimental data collected on a typical European downsized and turbocharged SI engine, the proposed approach was demonstrated to be capable to replicate in the simulation process the same percentage of knocking cycles experimentally measured in light-knock conditions, after a proper calibration of the Kinetics-Fit (KF), a new phenomenological knock model which was recently developed by Gamma Technologies.
Technical Paper

The Effect of Unleaded Gasoline Formulation on Antiknock Performance

1994-10-01
941862
The knock behavior of two groups of unleaded gasolines, each of which includes three fuels with different chemical compositions but comparable standard octane numbers, has been analyzed using a mass-produced engine. The aim of the work was to point out possible inconsistencies between the standard octane numbers of the fuels and their knock behavior in mass-produced engines. The fuels of the first group had R.O.N.s and M.O.N.s very close to the minimum values required by European Community regulations (95 and 85, respectively), whereas the fuels of the second group had higher R.O.N.s and M.O.N.s (about 100 and 87.5, respectively). One of the tested fuels in the first group was a typical European unleaded gasoline, the other gasolines had higher olefin or aromatic contents. An increase of the aromatic content has not shown appreciable differences between the expected knock behavior of the fuel from its standard octane numbers, and its performance on the mass-produced engine.
Journal Article

Analysis of the Performance of a Turbocharged S.I. Engine under Transient Operating Conditions by Means of Fast Running Models

2013-04-08
2013-01-1115
The aim of this work is the assessment of the predictive capabilities of fast running models, obtained through an appropriate reduction and simplification process from detailed 1D fluid-dynamic models, for a turbocharged s.i. engine under highly transient operating conditions. Simulations results have been compared with experimental data for different types of models, ranging from fully detailed 1D fluid-dynamic models to map-based models, quantifying the degradation of the model accuracy and the reduction in the computational time for different kinds of driving cycles, from moderately transient such as the NEDC to highly dynamic such as the US06.
Technical Paper

Injection Strategies Tuning for the Use of Bio-Derived Fuels in a Common Rail HSDI Diesel Engine

2003-03-03
2003-01-0768
The potentialities in terms of engine performance and emissions reduction of pure biodiesel were examined on a Common Rail HSDI Diesel engine, trying to define a proper tuning of the injection strategies to bio-fuel characteristics. An experimental investigation was therefore carried out on a typical European passenger car Diesel engine, fuelled with a soybean oil derived biodiesel. A standard European diesel fuel was also used as a reference. In particular, the effects of an equal relative air/fuel ratio at full load condition were analysed; further, a sensitivity study on the outcome of the pilot injection timing and duration at part load on engine emissions was performed. Potentialities in recovering the performance gap between fossil fuel and biodiesel and in reducing NOx specific emissions, affecting only to a limited extent the biodiesel emission benefit in terms of CO, HC and FSN, were highlighted.
Technical Paper

Common Rail HSDI Diesel Engine Combustion and Emissions with Fossil / Bio-Derived Fuel Blends

2002-03-04
2002-01-0865
In order to evaluate the potentialities of bioderived diesel fuels, the effect of fueling a 1.9 l displacement HSDI automotive Diesel engine with biodiesel and fossil/biodiesel blend on its emission and combustion characteristics has been investigated. The fuels tested were a typical European diesel, a 50% biodiesel blend in the reference diesel, and a 100% biodiesel, obtained by mixing rape seed methyl ester (RME) and recycled cooking oil (CME). Steady state tests were performed at two different engine speeds (2500 and 4000 rpm), and for a wide range of loads, in order to evaluate the behavior of the fuels under a large number of operating conditions. Engine performance and exhaust emissions were analyzed, along with the combustion process in terms of heat release analysis. Experimental evidences showed appreciably lower CO and HC specific emissions and a substantial increase in NOx levels. A significant reduction of smoke emissions was also obtained.
Technical Paper

Calculating Heavy-Duty Truck Energy and Fuel Consumption Using Correlation Formulas Derived From VECTO Simulations

2019-04-02
2019-01-1278
The Vehicle Energy Consumption calculation Tool (VECTO) is used in Europe for calculating standardised energy consumption and CO2 emissions from Heavy-Duty Trucks (HDTs) for certification purposes. The tool requires detailed vehicle technical specifications and a series of component efficiency maps, which are difficult to retrieve for those that are outside of the manufacturing industry. In the context of quantifying HDT CO2 emissions, the Joint Research Centre (JRC) of the European Commission received VECTO simulation data of the 2016 vehicle fleet from the vehicle manufacturers. In previous work, this simulation data has been normalised to compensate for differences and issues in the quality of the input data used to run the simulations. This work, which is a continuation of the previous exercise, focuses on the deeper meaning of the data received to understand the factors contributing to energy and fuel consumption.
Journal Article

Computational Analysis of Internal and External EGR Strategies Combined with Miller Cycle Concept for a Two Stage Turbocharged Medium Speed Marine Diesel Engine

2011-04-12
2011-01-1142
In this work different internal and external EGR strategies, combined with extreme Miller cycles, were analyzed by means of a one-dimensional CFD simulation code for a Wärtsilä 6-cylinder, 4-strokes, medium-speed marine diesel engine, to evaluate their potential in order to reach the IMO Tier 3 NOx emissions target. By means of extreme Miller cycles, with Early Intake Valve Closures (up to 100 crank angle degrees before BDC), a shorter compression stroke and lower charge temperatures inside the cylinder can be achieved and thanks to the cooler combustion process, the NOx-specific emissions can be effectively reduced. EIVC strategies can also be combined with reductions of the scavenging period (valve overlap) to increase the amount of exhaust gases in the combustion chamber. However, the remarkably high boost pressure levels needed for such extreme Miller cycles, require mandatorily the use of two-stage turbocharging systems.
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