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Technical Paper

Ways to Meet Future Emission Standards with Diesel Engine Powered Sport Utility Vehicles (SUV)

The paper reports on the outcome of a still on-going joint-research project with the objective of establishing a demonstrator high speed direct injection (HSDI) diesel engine in a Sport Utility Vehicle (SUV) which allows to exploit the effectiveness of new engine and aftertreatment technologies for reducing exhaust emissions to future levels of US/EPA Tier 2 and Euro 4. This objective should be accomplished in three major steps: (1) reduce NOx by advanced engine technologies (cooled EGR, flexible high pressure common rail fuel injection system, adapted combustion system), (2) reduce particulates by the Continuous Regeneration Trap (CRT), and (3) reduce NOx further by a DeNOx aftertreatment technology. The current paper presents engine and vehicle results on step (1) and (2), and gives an outlook to step (3).
Technical Paper

Virtual Optimization of Vehicle and Powertrain Parameters with Consideration of Human Factors

The rapidly growing complexity and the growing cross linking of powertrain components leads to longer development times, especially in the vehicle calibration process. The number of systems which need to be fitted to each other and the number of parameters to be calibrated in the particular systems are increasing tremendously. The extensive use of simulation promises to reduce the calibration effort by providing pre-optimized parameter sets. This paper describes a new simulation methodology by the interlinking of advanced vehicle simulation and evaluation tools, in particular the AVL-tools CRUISE, VSM and DRIVE. This methodology allows to semi automatically pre-optimize powertrain and vehicle parameters before hardware is involved. So far the pre-calibration of vehicle and powertrain parameters by simulation was not satisfying because of the missing of a reliable evaluation tool for the produced simulation results.
Technical Paper

Vehicle Driveability Assessment using Neural Networks for Development, Calibration and Quality Tests

Actual automotive themes in the beginning century are globalization and platform concepts. Platforms reduce manpower for basic power train development and enable a higher vehicle quality by sharing development cost to many models. New drive train generations with direct injected diesel and gasoline engines, variable valve train systems and hybrid drives require complex electronic control systems with many control parameters, which must be calibrated for each platform model to fulfill the targets for emissions, diagnostics and driveability. Calibration becomes a critical procedure in vehicle development. A negative effect of the platform is the reduced possibility to give a model or an OEM a brand specific driveability character, traditionally an important sales - promoting factor. The paper describes a tool for the objective real time assessment of vehicle driveability and vehicle character, using a new subjective - objective approach.
Technical Paper

Validation of Diesel Fuel Spray and Mixture Formation from Nozzle Internal Flow Calculation

A series calculation methodology from the injector nozzle internal flow to the in-cylinder fuel spray and mixture formation in a diesel engine was developed. The present method was applied to a valve covered orifice (VCO) nozzle with the recent common rail injector system. The nozzle internal flow calculation using an Eulerian three-fluid model and a cavitation model was performed. The needle valve movement during the injection period was taken into account in this calculation. Inside the nozzle hole, cavitation appears at the nozzle hole inlet edge, and the cavitation region separates into two regions due to a secondary flow in the cross section, and it is distributed to the nozzle exit. Unsteady change of the secondary flow caused by needle movement affects the cavitation distribution in the nozzle hole, and the spread angle of the velocity vector at the nozzle exit.
Technical Paper

VVT+Port Deactivation Application on a Small Displacement SI 4 Cylinder 16V Engine: An Effective Way to Reduce Vehicle Fuel Consumption

During recent years several VVT devices have been developed, in order to improve either peak power and low end torque, or part load fuel consumption of SI engines. This paper describes an experimental activity, concerning the integration of a continuously variable cam phaser (CVCP), together with an intake port deactivation device, on a small 4 cylinder 16V engine. The target was to achieve significantly lower fuel consumption under normal driving conditions, compared to a standard MPFI application. A single hydraulic cam phaser is used to shift both the intake and the exhaust cams to retarded positions, at constant overlap. Thus, high EGR rates in the combustion chamber and late intake valve closure (“reverse Miller cycle”) are combined, in order to reduce pumping losses at part load.
Technical Paper

V6-SUV Engine Sound Development

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.
Technical Paper

Using Simulation and Optimization Tools to Decide Engine Design Concepts

To meet the future demands on internal combustion engines regarding efficiency emissions and durability all design parameters must be optimized together. As a result of progress in material engineering fuel injection technology turbo charging technology exhaust gas after treatment there arise a multiplicity of possible parameters, such as: design parameters (compression ratio, dimensioning depending on peak firing pressure and mean effective pressure), injection system (rate shaping, split injection, injection pressure, hole diameter), air management (turbo charging with or without VTG, EGR rate) combustion optimization (timing, air access ratio). The interaction of all these parameters can not be over-looked without simulation and optimization tools. This is valid for the concept layout, the optimization and the application process later on.
Technical Paper

ULEV and Fuel Economy - A Contradiction?

The CBR (Controlled Burn Rate) technology for MPFI engines is known to enable the reduction of throttle losses of gasoline engines by high EGR (Exhaust Gas Recirculation) rates due to the dilution tolerance of the swirl charge motion system using port deactivation. Now a new aspect of CBR is being developed: extremely low emissions during and after cold start. This paper is focused on the combustion stability and low emission aspects of CBR technology. It is shown how engine out emissions and catalyst light off behavior of an engine can be significantly improved using port deactivation. The very stable combustion directly after engine start, extremely retarded ignition timings in combination with lean engine operation and open valve injection with minimized wall wetting lead to very low HC emissions and very high exhaust gas temperatures.
Technical Paper

ULEV Potential of a DI/TCI Diesel Passenger Car Engine Operated on Dimethyl Ether

The paper describes a feasibility test program on a 2 liter, 4 cylinder DI/TCI passenger car engine operated on the new alternative fuel Dimethyl Ether (DME, CH3 - O - CH3) with the aim of demonstrating its potential of meeting ULEV emissions (0.2 g/mi NOx in the FTP 75 test cycle) when installed in a full size passenger car. Special attention is drawn to the fuel injection equipment (FIE) as well as combustion system requirements towards the reduction of NOx and combustion noise while keeping energetic fuel consumption at the level of the baseline DI/TCI diesel engine. FIE and combustion system parameters were optimized on the steady state dynamometer by variation of a number of parameters, such as rate of injection, number of nozzle holes, compression ratio, piston bowl shape and exhaust gas recirculation.
Technical Paper

Two-Cylinder Gasoline Engine Concept for Highly Integrated Range Extender and Hybrid Powertrain Applications

The demand for improved fuel economy and the request for Zero Emission within cities require complex powertrains with an increasing level of electrification already in a short-termed timeframe until 2025. According to general expectations the demand for Mild-Hybrid powertrains will increase significantly within a broad range of implementation through all vehicle classes as well as on electric vehicles with integrated Range Extender (RE) mainly for use in urban areas. Whereas Mild Hybrid Vehicles basically use downsized combustion engines at current technology level, vehicles with a high level of powertrain electrification allow significantly different internal combustion engine (ICE) concepts. At AVL, various engine concepts have been investigated and evaluated with respect to the key criteria for a Range Extender application. A Wankel rotary engine concept as well as an inline 2 cylinder gasoline engine turned out to be most promising.
Technical Paper

Turbocharging the DI Gasoline Engine

Regarding concepts for naturally aspirated engines, the high potential for fuel economy of Gasoline Direct Injection can only partially be utilized within the constraints of current or future emission legislation like EURO III / IV or LEV/ULEV. Instead of an expected improvement of 20 - 25 % currently only 10 - 15% can be obtained by the engine alone without vehicle optimizations considering all limitations of high volume production. A detailed analysis reveals concrete measures for further improvement. The application of DI gasoline technology clearly favors the combination with other fuel efficient technologies like downsizing by turbocharging and the application of a variable effective compression ratio by intake valve timing variation. Using the flexibility of direct gasoline injection some deficiencies of these technologies can be eliminated.
Technical Paper

Trends of Future Emission Legislation and its Measurement Requirements

People have been altering the atmosphere on a small scale ever since they learned to make fire. Today's air pollution can influence ecosystems and transform climate worldwide. Motorized transport has become essential, today about 1000 million vehicles are on the world's roads [1]. Vehicle registrations are still sharply upward, where the future growth is most rapid in Asia and Latin America. Over the past, global pollution concerns have increased and air quality targets have been established. Also the reduction of green house gases like CO2 (Kyoto protocol) is considered. Aligned with such air quality targets automotive emission limits have been implemented. The future emission limits will require advanced engine technologies, but will also require adjustments to the measurement technologies. Furthermore new trends in the emission legislation will increase test requirements to represent the real world conditions in a more realistic way.
Technical Paper

Tool Based Calibration with the OBDmanager

At the moment the documentation of failure inhibition matrices and the fault path management for different controller types and different vehicle projects are mainly maintained manually in individual Excel tables. This is not only time consuming but also gives a high potential for fault liability. In addition there is also no guarantee that the calibration of these failure inhibition matrices and its fault path really works. Conflicting aims between costs, time and fault liability require a new approach for the calibration, documentation and testing of failure inhibition matrices and the complete Diagnostic System Management (DSM) calibration. The standardization and harmonization of the Diagnostic System Management calibration for different calibration projects and derivates is the first step to reduce time and costs. Creating a master calibration for the conjoint fault paths and labels provides a significant reduction of efforts.
Journal Article

Three-Way Catalyst Light-off During the NEDC Test Cycle: Fully Coupled 0D/1D Simulation of Gasoline Combustion, Pollutant Formation and Aftertreatment Systems

The introduction of more stringent standards for engine emissions requires a steady development of engine control strategies in combination with efforts to optimize in-cylinder combustion and exhaust gas aftertreatment. With the goal of optimizing the overall emission performance this study presents the comprehensive simulation approach of a virtual vehicle model. A well established 1D gas dynamics and engine simulation model is extended by four key features. These are models for combustion and pollutant production in the cylinder, a model for the conversion of pollutants in a catalyst and a model for the effect of manifold wall wetting and fuel evaporation. The general species transport feature is linking these model together as it allows to transport an arbitrary number of chemical species in the entire system. Finally this highly detailed engine model is integrated into a vehicle model.
Technical Paper

Thermal Mechanical Fatigue Simulation of Cast iron Cylinder Heads

The requirement for increased power and reduced emission and fuel consumption levels for diesel engines has created very stringent demands on the cylinder head design. In current engine development programs it is often observed that the limiting design factor is given by the thermal mechanical fatigue strength of the cylinder head. Design iterations resulting from durability testing are often necessary due to the lack of adequate simulation techniques for prediction thermal mechanical fatigue (TMF) failure. A complete lifetime simulation process is presented in this paper with emphasis on a newly developed material model for describing the constitutive behavior of cast iron (i.e. gray cast iron and compacted graphite iron) under thermal cycling. The material model formulation is based on a continuum-damage-mechanics (CDM) approach in order to account for the tension / compression anomaly of cast iron.
Technical Paper

The Single Cylinder OM441LA

This paper will describe the design criteria for a single cylinder version of the Daimler-Chrysler OM441LA engine, which is currently used in multicylinder form as a key test in the ACEA A4 and A5 Oil Sequences. A test procedure has been developed for the single cylinder which provides results correlating with its multicylinder counterpart. The historical development of the procedure, correlation data, and economic benefits of use will be presented.
Technical Paper

The Role of Fuel Cells in Commercial Vehicles

Fuel Cells (FC) are promising candidates to reduce energy consumption and, hence, to improve the global climate situation due to significant gains in the process efficiencies. Whereas the development of fuel cells for passenger car applications has intensified during the last years, commercial vehicle applications have not been in the focus of developers so far. A reason for that is the limited availability of fuels such as hydrogen. Commercial vehicles are in the most cases operated with diesel fuel. AVL has developed three fuel cell applications for commercial vehicles operated with diesel fuel.
Technical Paper

The Performance of a Heavy Duty Diesel Engine with a Production Feasible DME Injection System

Over the last few years there has been much interest in DiMethyl Ether (DME) as an alternative fuel for diesel cycle engines. It combines the advantages of a high cetane number with soot free combustion, which makes it eminently suitable for compression ignition engines. However, due to the fact that it is a gas under ambient conditions, it requires special fuel handling and a specially designed fuel injection system, which until recently, was not available. The use of the digital hydraulic operating system (DHOS), combined with a fuel handling system designed to cope with the properties of DME, enables the fuel to be safely and conveniently handled, In addition, the flexibility of the injection system enables injection pressures to be chosen according to the needs of the combustion.
Technical Paper

The Interaction Between Diesel Fuel Density and Electronic Engine Management Systems

The influence of fuel density on exhaust emissions from diesel engines has been investigated in a number of studies and these have generally concluded that particulate emissions rise with increasing density This paper reviews recent work in this area, including the European Programme on Emissions, Fuels and Engine Technologies (EPEFE) and reports on a complementary study conducted by CONCAWE, in cooperation with AVL List GmbH The project was carried out with a passenger car equipped with an advanced technology high speed direct injection turbocharged / intercooled diesel engine fitted with a complex engine management system which was referenced to a specific fuel density This production model featured electronic diesel control, closed loop exhaust gas recirculation and an exhaust oxidation catalyst Tests were carried out with two EPEFE fuels which excluded the influence of key fuel properties other than density (828 8 and 855 1 kg/m3) Engine operation was adjusted for changes in fuel density by resetting the electronic programmable, read-only memory to obtain the same energy output from the two test fuels In chassis dynamometer tests over the ECE15 + EUDC test cycle the major impact of fuel density on particulate emissions for advanced engine technology/engine management systems was established A large proportion of the density effect on particulate and NOx emissions was due to physical interaction between fuel density and the electronic engine management system Limited bench engine testing of the basic engine showed that nearly complete compensation of the density effect on smoke (particulate) emissions could be achieved when no advanced technology was applied
Technical Paper

The Influence of Inlet Port Design on the In-Cylinder Charge Mixing

A detailed investigation of the influence of intake port design on the in-cylinder flow structure during the intake and compression strokes, the mixing of the residual gas and a non-premixed intake charge, and the extent and pattern of charge inhomogenity near the time of combustion is described. The engine geometry is typical of the current lean-burn design and the study includes comparison of a helical (swirl) port and an idealized direct (no swirl) port designs. The results show marked dependence of the in-cylinder charge mixing characteristics on the intake port design. It is found that combinations of intake port design and manifold fuel injection timing produce favourably-stratified or irregularly-mixed charge distributions at the time of spark ignition. The consequences with respect to combustion characteristics are pointed out.