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The development of modern combustion engines (spark ignition as well as compression ignition) for vehicles compliant with future oriented emission legislation (BS6, Euro VI, China 6) has introduced several technologies for improvement of both fuel efficiency as well as low emissions combustion strategies. Some of these technologies as there are high pressure multiple injection systems or sophisticated exhaust gas after treatment system imply substantial increase in test and calibration time as well as equipment cost. With the introduction of 48V systems for hybridization a cost- efficient enhancement and, partially, an even attractive alternative is now available. An overview will be given on current technologies as well as on implemented test procedures. The focus will be on solutions which have potential for the Indian market, i.e. solutions which can be implemented with moderate application effort for currently available compact and medium size cars.

With upcoming emission regulations particle emissions for GDI engines are challenging engine and injector developers. Despite the introduction of GPFs, engine-out emission should be optimized to avoid extra cost and exhaust backpressure. Engine tests with a state of the art Miller GDI engine showed up to 200% increased particle emissions over the test duration due to injector deposit related diffusion flames. No spray altering deposits have been found inside the injector nozzle. To optimize this tip sooting behavior a tool chain is presented which involves injector multiphase simulations, a spray simulation coupled with a wallfilm model and testing. First the flow inside the injector is analyzed based on a 3D-XRay model. The next step is a Lagrangian spray simulation coupled with a wallfilm module which is used to simulate the fuel impingement on the injector tip and counter-bores.

Due to the restricted capacity of today's battery systems and therefore limited operating range of electric vehicles (EV), several solutions for recharging the energy storage during driving already have been published and still are the subject of extensive development programs. One example is the Range Extender (RE), which is a combination of an internal combustion engine (ICE) with a generator unit, which serves the purpose of a power back-up in case of a battery with low state of charge (SOC), without any direct connection to the drivetrain. For this kind of RE-application, different boundary conditions are very important. Especially in EVs topics like packaging space and NVH behavior play a main role. To fulfill these important characteristics, AVL has developed a Wankel-RE unit in which the generator is driven directly from the eccentric shaft of the rotary-piston ICE.

Traditional power train development work is concentrated mainly on test bed and on chassis dyno. Though we can simulate a lot of real world conditions on testbed and chassis dyno today, on road application work willis gaining more attention. This means that strategies and tools for invehicle testing under real world conditions are becoming more important. Emission, performance, fuel economy, combustion noise and driving comfort are linked to combustion quality, i.e. quality of fuel mixture preparation and flame propagation. The known testing and research equipment is only partly or not at all applicable for in-vehicle development work. New tools for on the road testing are required. Following, a general view on in-vehicle power train testing will be given. Additionally, new ways to investigate cylinder and cycle specific soot formation in GDI engines with fiber optic tools will be presented.

Recently, a particle number (PN) limit was introduced in the European light-duty vehicles legislation. The legislation requires measurement of PN, and particulate mass (PM), from the full dilution tunnel with constant volume sampling (CVS). Furthermore, PN measurements will be introduced in the next stage of the European Heavy-Duty regulation. Heavy-duty engine certification can be done either from the CVS or from a partial flow dilution system (PFDS). For research and development purposes, though, measurements are often conducted from the raw exhaust, thereby avoiding the high installation costs of CVS and PFDS. Although for legislative measurements requirements exist regarding sampling and transport of the aerosol sample, such requirements do not necessarily apply for raw exhaust measurements. Thus, measurement differences are often observed depending on where in the experimental set up sampling occurs.

Importance of electric and hybrid vehicles steeply increased in the last few years. Especially topics like CO2 reduction and local zero emissions are forcing companies to focus on electrification. While main technical problems seem to be solvable from a technical point of view, commercial and security topics are gaining more importance. For full electric vehicles the driving range is limited by the capacity of available batteries. As those batteries are one of the most heavy and expensive parts of these vehicles, reduction of battery size is a big topic in vehicle development. To increase a vehicle's driving range without increasing battery size some range extending backup system has to be available. Such a Range Extender should be a small system combining combustion engine and electric generator to produce the required electricity for charging the batteries whenever required.

The exhaust blowdown pulse from each cylinder of a multi-cylinder engine propagates through the exhaust manifold and can affect the in-cylinder pressure of other cylinders which have open exhaust valves. Depending on the firing interval between cylinders connected to the same exhaust manifold, this blowdown interference can affect the exhaust stroke pumping work and the exhaust pressure during overlap, which in turn affects the residual fraction in those cylinders. These blowdown interference effects are much greater for a turbocharged engine than for one which is naturally aspirated because the volume of the exhaust manifolds is minimized to improve turbocharger transient response and because the turbines restrict the flow out of the manifolds. The uneven firing order (intervals of 90°-180°-270°-180°) on each bank of a 90° V8 engine causes the blowdown interference effects to vary dramatically between cylinders.

Design of cylinder heads involves complex constraints that must satisfy thermal, strength, performance, and manufacturing requirements which present a great challenge for successful development. During development of a new highly loaded cylinder head, CAE methods predicted unacceptable fatigue safety factors for the initial prototype design. Hydropulsator component testing was undertaken and the results were correlated with the analysis predictions using a statistical method to calculate failure probability. Shape optimization was undertaken to improve high cycle fatigue safety in vulnerable regions of the cylinder head water jacket for the subsequent design release. The optimization process provided more efficient design guidance than previously discovered through a traditional iterative approach. Follow-on investigations examined other shape optimization software for fatigue improvement in the cylinder head.

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.

The optimization of engine NVH is still an important aspect for vehicle interior and exterior noise radiation. To optimize the engine noise / vibration contribution to the vehicle, a complete understanding of the excitation mechanism, the vibration transfer in the engine structure and the radiation efficiency of the individual engine components is required. Concerning the excitation within the engine, a very efficient analysis methodology for the combustion- and mechanical excitation within gasoline and diesel engines has been developed. Out of this methodology a software tool has been designed for a fast, efficient and detailed evaluation of the combustion- and mechanical excitation content of total engine noise. Recently this software tool has been successfully applied in engine NVH optimization work for defining the best optimization strategies for engine NVH reduction and noise quality improvement especially with respect to combustion excitation.

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.

In recent years several new gasoline engine technologies were introduced in order to reduce fuel consumption. Controlled autoignition seems to be an alternative to stratified part load operation, which is handicapped due to it's lean aftertreatment system for world wide application. The principal advantages of controlled auto ignition combustion under steady state operation - combining fuel economy benefits similar to stratified charge systems with nearly negligible NOx and soot emissions - are already well known. With the newly developed AVL- CSI system (Compression and Spark Ignition), a precise combustion control is achieved even under transient operation. For compensation of production and operation tolerances a cost optimized cylinder individual control was developed. Completely new functionalities of the engine management system are applied. This lean GDI concept complies with future emission standards without DeNOx catalyst and can be applied worldwide.

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.

DiMethyl Ether (DME) has been shown to be a very attractive fuel for low emission direct injection compression ignition (DICI) engines. It combines the advantages of the high efficiencies of diesel cycle engines with soot free combustion. However, its greatest drawback is the need to develop new fuel injection and handling systems. Previous approaches have been common rail type injection systems which have shown great potential in reducing harmful exhaust emissions and achieving good engine performance and efficiency due to good control of both the fuel injection characteristics and temperature. The concept also has proven benefits with respect to convenient and safe fuel handling. The logical evolution of this concept simplifies the fuel system and avoids special components for DME handling such as high pressure rail pumps while retaining all the benefits of the common rail principle.

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.

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).

The principal engine used in passenger cars is, and in the foreseeable future will be, the SI Engine. This paper summarizes AVL's experience in developing SI Engines for these vehicles. Special attention is given to the new targets of SI Engine development and the resulting design strategies during the concept phase of new engine families. The new modular concept of engine families includes a broad range of different engine designs like three to five cylinder inline and six to ten cylinder V-block engines, direct injection or fully variable valve actuation. It is shown that the design of central engine components, for example, that of the cylinder head, can be adapted for the different SI valve-train concepts by simply switching specific modular components.

The subject of this paper is the discussion of a non-dimensional combustion model that relies on the concept of mixing controlled combustion (MCC Heat Release Rate) avoiding the detailed description of the individual mixture formation and fuel oxidation processes. For diffusion combustion in today's direct injection diesel engines it can be shown that the rate of heat release (ROHR) is controlled mainly by two items, i.e. the instantaneous fuel mass present in the cylinder charge and the local density of turbulent kinetic energy. Both items can be derived from the injection process, the instantaneous fuel mass being the difference of fuel injected minus fuel burnt and the turbulent kinetic energy being produced mainly by the momentum of the fuel sprays. Following this strategy, the injection process is now understood as the most important controlling factor for the heat release rate.

An optical sensor system provides access to standard SI engine combustion chambers via the cylinder head gasket. Flame radiation within the plane of the gasket is observed with optical fibers which are arranged to allow the tomographic reconstruction of flame distribution. The effect of convective in-cylinder air motion generated by variations of inlet ports and combustion chamber geometries on flame propagation is directly visible. A high degree of correlation between flame intensity distribution and NOx emission levels yields a useful assessment of combustion chamber configurations with minimum emission levels. The location of knock centers is identified.

In order to facilitate the analysis of SI engine combustion phenomena, we have developed a fiber optic system which allows the observation of combustion in essentially standard engines. Optical access to the combustion chamber is achieved with micro-optic elements and optical fibers in the cylinder head gasket. Each fiber views a narrow cone of the combustion chamber and transmits the light seen within this acceptance cone to the detector and recorder unit. A large number of such fiber optic detectors have been incorporated in a cylinder head gasket and this multichannel system was arranged in a geometric configuration which allowed the reconstruction of the spatial flame intensity distribution within the observed combustion chamber cross-section. The spatial information was gained from the line-of-sight intensity signals by means of a tomographic reconstruction technique.