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Ford introduced a new in-line 4-cylinder 2.3L DOHC 16-valve engine in its European D-class Scorpio vehicle. The engine is based on the proven 2.0L-DOHC engine with 8 or 16 valves. The new engine replaces the 2.0L DOHC 8-valve version. Primary focus of the development of this new 2.3L engine was on the noise and vibration improvement, both for the engine and for the vehicle interior noise. One measure to achieve this target was the application of balance shafts. In this paper, the development of the new engine will be described from the design stage to the production version. It will focus on the design of the balance shaft housing and all relevant engine NVH features. The various stages of the design and detailed optimization are explained. The NVH prediction by CAE methods is verified with experimental results. The influence of optimized components like the oil pan, front cover and the chain tensioner on the noise behavior will be discussed.

The distortion of the cylinder liners of internal combustion engines has a significant affect on engine operation. It can affect the lubrication oil consumption, the blow-by, the wear behaviour and due to the friction, the fuel consumption. In order to achieve future requirements regarding exhaust emissions and fuel consumption, the requirements for low cylinder distortion engine blocks will play a significant role. Hence, a new technique to determine liner distortion during fired engine operation was developed.

In order to evaluate the dynamic behavior of IC-engines simulation models are being applied at an ever increasing rate. The simulation models used of until now, were calculation models for an individual valve train. These models were not capable of analysing the interactions of bending and torsional vibrations between individual valve trains of a complete camshaft. For this reason a calculation model has been developed which comprises the entire valve train from the drive gear of the camshaft to the last valve. The camshaft is represented by a combined bending and torsional vibration model with elastic bearings. Combining this model with a camshaft-drive-system simulation model, it is possible to record interactions between the individual valve trains of a complete cylinder head. Bending and torsional effects in the camshaft and effects resulting from the chain or belt forces are taken into consideration.

Potential improvements in spark ignited engine performance gained through the application of ceramic valve train components were predicted using state-of-the-art valve train simulation and gas exchange computer programs. The use of ceramic valves, ceramic pushrods, and ceramic hydraulic tappet housings, in combination with modified valve spring and valve lift parameters, were analyzed for a 2.8L overhead valve V-6 engine. The results show that significant improvements in dynamic valve train behavior and engine performance are possible with the largest gains coming from the use of ceramic valves. Potential improvements in valve train dynamics include: a 20% increase in maximum engine speed; a 30% reduction in the maximum valve train forces; and a 30% reduction in valve train friction. These benefits can then be used to either improve fuel economy, high speed engine power or low speed torque by up to 5%.

Based on NVH tests conducted on a heavy-duty turbocharged DI diesel engine, noise relevant differences between steady-state and transient operating condition were investigated. A vehicle drive-by test simulating the effects of vehicle mass and inertia was performed, followed by transient NVH measurements in a semi-anechoic test cell. Steady-state noise was exceeded by 5 dBA during transient operation due to broadband increase of noise excitation combined with structure resonance amplification. Transient noise results mainly from “harsher” combustion as a consequence of enlarged ignition delay indicated by significant increase in maximum cylinder pressure gradient. Variation of geartrain excitation and combustion excitation revealed that geartrain noise is of minor importance in this context.

A combined finite element method (FEM), multibody system simulation (MSS), and hydrodynamic (HD) bearing simulation technique can be applied to solve for engine crankshaft and cylinder block dynamics. The cylinder block and crankshaft are implemented in the MSS program as flexible FEM structures. The main bearing oil film reaction is described in the MSS program by a pre-calculated reaction force database. The results are displacements and deformations of the crank train parts and the main bearing reaction forces. Verification of the tool was carried out by comparison of main bearing cap accelerations to measured data.

Customer requirements for quiet and more comfortable vehicles have steadily increased. Requirements for lightweight vehicle designs and the need for more fuel efficient engines are often contradictory to the customer expectations for NVH refinement. The driveline can be a significant source of NVH issues in the vehicle. The increasing complexity of modern driveline systems as well as the existence of several variants in the driveline architecture (front wheel, rear wheel and four-wheel/all-wheel drive, automatic-, manual-, automatic-shifted manual transmission, etc.) can make the driveline integration task very challenging. Due to the multitude of driveline components and potential driveline excitations sources, several driveline-related noise and vibration problems within different frequency ranges have to be understood and controlled to ensure a well refined vehicle.

NVH refinement is an important aspect of the powertrain development process. Powertrain NVH refinement is influenced by overall sound levels as well as sound quality. The sound quality and hence the level of powertrain NVH refinement can be negatively affected by the presence of excessive impulsive noise. This paper describes a process used to develop an understanding of impulsive powertrain noise. The paper begins with an introductory discussion of various sources of impulsive noise in an automotive powertrain. Following this, the paper outlines a process for identifying the source of the impulsive powertrain noise using examples from case studies. The remainder of the paper focuses on certain examples of impulsive noise such as Diesel knocking noise, injector ticking, impulsive cranktrain noise, and gear rattle. For these examples, the development of key objective metrics, optimization measures, and improvement potential are examined.

This paper introduces different modeling approaches of crankshafts, compares the refinement levels and discusses the difference between the results of the crankshaft durability calculation methodologies. A V6 crankshaft is considered for the comparison of the refinement levels depending on the deviation between the signals such as main bearing forces and deflection angle. Although a good correlation is observed between the results in low speed range, the deviation is evident through the mid to high speed ranges. The deviation amplitude differs depending on the signal being observed and model being used. An inline 4 crankshaft is considered for the comparison of the durability results. The analysis results show that the durability potential is underestimated with a classical crankshaft calculation approach which leads to a limitation of maximum speed of 5500 rpm.

Blending gasoline with oxygenates like ethanol, MTBE or ETBE has a proven potential to increase the thermodynamic efficiency by enhancing knock resistance. The present research focuses on assessing the capability of a 2- and tert-butanol mixture as a possible alternative to state-of-the-art oxygenates. The butanol mixture was blended into a non-oxygenated reference gasoline with a research octane number (RON) of 97. The butanol blending ratios were 15% and 30% by mass. Both the thermodynamic potential and the impact on emissions were investigated. Tests are performed on a highly boosted single-cylinder gasoline engine with high load capability and a direct injecting fuel system using a solenoid-actuated multi-hole injector. The engine is equipped with both intake and exhaust cam phasers. The engine has been chosen for the fuel investigation, as it represents the SI technology with a strongly increasing market share.

This paper describes an alternative catalyst aging process using a hot gas test stand for thermal aging. The solution presented is characterized by a burner technology that is combined with a combustion enhancement, which allows stoichiometric and rich operating conditions to simulate engine exhaust gases. The resulting efficiency was increased and the operation limits were broadened, compared to combustion engines that are typically used for catalyst aging. The primary modification that enabled this achievement was the recirculation of exhaust gas downstream from catalyst back to the burner. The burner allows the running simplified dynamic durability cycles, which are the standard bench cycle that is defined by the legislation as alternative aging procedure and the fuel shut-off simulation cycle ZDAKW. The hot gas test stand approach has been compared to the conventional engine test bench method.

A comparison study on the commonly used solution schemes of one-dimensional gas flow in IC engine manifolds, i.e. the method of characteristics and the finite difference schemes, was conducted in this paper. The study was based on computer simulations of the flow in a typical pipe-volume configuration under both steady and unsteady boundary conditions. The simulation results indicate that all the solution schemes offered fairly good accuracy in parallel pipes under steady flow conditions. However, under unsteady flow conditions, especially in tapered pipes commonly used in IC engine manifolds, all the existing solution schemes encountered difficulties. These included such aspects as the mass and energy conservation, non-physical overshoot, solution stability and physical process distortion. The solution schemes were compared based on the case calculations and the related problems are specified.

A comparison of two different types of NOx reducing catalysts will be worked out. The potential of two De-NOx catalysts using engine out hydrocarbon emissions for NOx conversion will be shown by variation of different engine parameters. An analysis of the hydrocarbon species upstream and downstream catalyst will demonstrate, which components are responsible for the NOx reduction in the exhaust gas of a lean burn engine. By variation of different parameters during adsorbtion and regeneration phases of the adsorber catalyst the efficiency in NOx reduction will be optimized. An assessment of the suitability for lean burn engines will consider the emission reduction efficiency as well as the influence on engine fuel consumption.

Combustion noise plays a considerable role in the acoustic tuning of gasoline and diesel engines. Even though noise levels of modern diesel engines reach extremely low values, they are still higher than those of conventional gasoline engines. On the other hand, new combustion procedures designed to improve fuel consumption lead to elevated combustion noise excitations as in case of today's direct injecting gasoline engines whose vibration excitation and airborne noise emissions are slightly increased during stratified operation. The partly conflicting development goals resulting from this can only be realized by integrating the NVH specialists' expertise into every development step from concept to SOP.

The reduction of the fuel consumption and the emissions are the two main goals for the development of current and future engines. Both consumption and emissions are highly influenced by the fluid and the material temperatures of the engine. This offers potential especially at low engine speeds and engine loads to reduce the cooling power and increase the material temperatures to a tribologic and thermodynamic optimized level. The cooling system which is able to control the cooling power and the material temperatures, the required control devices and the control strategy are designated as intelligent heat management. The definition of the requirements for the control devices and the definition of the control strategies requires detailed knowledge about the thermal engine behavior.

Fuel additives can contribute to maintaining the performance of diesel engines in a variety of ways. This holds true for current and future engine technology. Fouling of indirect injection engines (IDI) has been studied at length. Fouling of direct injection engines (Dl) is less known and less well understood. Problems associated with Dl fouling and a proposed mechanism for it are discussed. Additive effectiveness in preventing injector fouling is confirmed. Injector hole corrosion/erosion, as experienced in the Cummins N14 engine, can be avoided by the appropriate additive chemistry. Particulate traps can also benefit from ashless additive technology aimed at increasing the time between regeneration steps, hence improving effective trap life.

It is important to develop powertrain NVH characteristics with the goal of ultimately influencing/improving the in-vehicle NVH behavior since this is what matters to the end customer. One development tool called dB(VINS) based on a process called Vehicle Interior Noise Simulation (VINS) is used for determining interior vehicle noise based on powertrain level measurements (mount vibration and radiated noise) in combination with standardized vehicle transfer functions. Although this method is not intended to replace a complete transfer path analysis and does not take any vehicle specific sensitivity into account, it allows for powertrain-induced interior vehicle noise assessments without having an actual test vehicle available. Such a technique allows for vehicle centric powertrain NVH development right from an early vehicle development stage.

The reduction of particulate emissions from diesel engines is one of the most challenging problems associated with exhaust pollution control, second only to the control of NOx from any “lean burn” application. Particulate emissions can be controlled by adjustments to the combustion parameters of a diesel engine but these measures normally result in increased emissions of oxides of nitrogen. Diesel particulate filters (DPFs) hold out the prospect of substantially reducing regulated particulate emissions and the task of actually removing the particles from the exhaust gas has been solved by the development of effective filtration materials. The question of the reliable regeneration of these filters in situ, however, remains a difficult hurdle. Many of the solutions proposed to date suffer from high engineering complexity and/or high energy demand. In addition some have special disadvantages under certain operating conditions.

An improved plasma reactor has been designed, built and evaluated. It is characterized by a reduced power per area ratio, relative to previous designs, and includes several improvements to run the whole system safely in a car. The new reactor design includes a concentric inner high voltage electrode, a grounded outer electrode, a shielded high-voltage and high temperature resistant electrical connection. A generator controller has been developed for better control of operating conditions as required during the engine cold start phase. The new generator/reactor system was installed in the exhaust pipe of a gasoline direct injection engine. HC emissions could be reduced up to 30 % in the first 40 seconds of a cold start test. In addition to HC treatment the dielectric barrier discharge has also been investigated as a method for regenerating a diesel particulate trap.

Dielectric barrier discharges offer the advantage to excite molecules to reaction processes on a low temperature level in an O2 containing exhaust gas of gasoline or diesel engines. With the aim of a flexible coaxial reactor and a compact and efficient generator the influence of geometric and electric parameters on the reduction of exhaust gas components was determined. Geometric parameters studied were gap width, length, contour of the reactor. Electric parameters were: voltage curve, voltage height, frequency and electric power. Using the advantage of low temperature reactions it was possible to reduce the HC emission of a gasoline engine by about 35% within an electric power of 1000 W.