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The emission of particulate matter from future GDI engines has to be optimized, to comply with more stringent emission standards such as EU6. Therefore, the mechanisms responsible for the formation of particles have to be analyzed in detail. The understanding of the in-cylinder processes, necessary for this purpose, can only be achieved by a complementary use of optically accessible single-cylinder engines as well as the numerical simulation. This however leads to great demands on the 3D flow simulation. In this paper the complete CFD approach, incorporating a detailed description of the entire underlying model chain is shown. Particularly the wall surface temperature and the temperature drop due to the interaction with liquid fuel spray were identified as important parameters influencing the spray-wall interaction and thus also the particulate emissions. Nevertheless, in conventional CFD models, the spray cooling cannot be captured because of an assumed constant wall temperature.

Stricter emissions legislation and growing demands for lower fuel consumption require significant efforts to improve combustion efficiency while satisfying the emission quality demands. Controlled Homogeneous Charge Compression Ignition (HCCI) combined with boosted air systems on gasoline engines provides a particularly promising, yet challenging, approach. Naturally aspirated (NA) HCCI has already shown considerable potential in combustion efficiency gains. Nevertheless, since the volumetric efficiency is limited in the NA HCCI operation range due to the hot residuals required to ignite the mixture and slow down reaction kinetics, only part-load operation is feasible in this combustion mode. Considering the future gasoline engine market with growing potentials identified in downsized gasoline engines, it becomes necessary to investigate the synergies and challenges of controlled, boosted HCCI.

Due to the increasingly stricter emission legislation and growing demands for lower fuel consumption, there have been significant efforts to improve combustion efficiency while satisfying the emission requirements. Homogeneous Charge Compression Ignition (HCCI) combined with turbo/supercharging on gasoline engines provides a particularly promising and, at the same time, a challenging approach. Naturally aspirated (n.a.) HCCI has already shown a considerable potential of about 14% in the New European Driving Cycle (NEDC) compared with a conventional 4-cylinder 2.0 liter gasoline Port Fuel Injection (PFI) engine without any advanced valve-train technology. The HCCI n.a. operation range is air breathing limited due to the hot residuals required for the self-ignition and to slow down reaction kinetics, and therefore is limited to a part-load operation area.

Environmental consciousness and tightening emissions legislation push the market share of electronic fuel injection within a dynamically growing world wide small engines market. Similar to automotive engines during late 1980's, this opens up opportunities for original equipment manufacturers (OEM) and suppliers to jointly advance small engines performance in terms of fuel economy, emissions, and drivability. In this context, advanced combustion system analyses from automotive engine testing have been applied to a typical production motorcycle small engine. The 125cc 4-stroke, 2-valve, air-cooled, single-cylinder engine with closed-loop lambda-controlled electronic port fuel injection was investigated in original series configuration on an engine dynamometer. The test cycle fuel consumption simulation provides reasonable best case fuel economy estimates based on stationary map fuel consumption measurements.

In order to meet future requirements for emission reduction and fuel economy a variety of concepts are available for gasoline engines. In the recent past new pathways have been found using alternative fuels and fuel combinations to establish cost optimized solutions. The presented concept for a SI-engine consists of combined injection of gasoline and hydrogen. A hydrogen enriched gas mixture is being injected additionally to gasoline into the engine manifold. The gas composition represents the output of an onboard gasoline reformer. The simulations and measurements show substantial benefits to improve the combustion process resulting in reduced cold start and warm up emissions and optimized part load operation. The replacement of gasoline by hydrogen-rich gas during engine start leads to zero hydrocarbons in the exhaust gas.

The worldwide stricter emission legislation and growing demands for lower fuel consumption require for significant efforts to improve combustion efficiency while satisfying the emission quality demands. Homogeneous Charge Compression Ignition (HCCI) on gasoline engines provides a particularly promising and, at the same time, challenging approach, especially regarding the combustion mode switch between spark-ignited (SI) and gasoline HCCI mode and vice-versa. Naturally aspirated (n.a.) HCCI shows considerable potential, but the operation range is air breathing limited due to hot residuals required for auto-ignition and to slow down reaction kinetics. Therefore it is limited to part-load operation. Considering the future gasoline engine market with growing potentials identified on downsized gasoline engines, it is imperative to investigate the synergies and challenges of boosted HCCI.

General Motors' 3.6L DOHC 4V V6 engine has been upgraded to provide substantial improvements in performance, fuel economy, and emissions for the 2008 model year Cadillac CTS and STS. The fundamental change was a switch from traditional manifold-port fuel injection (MPFI) to spark ignition direct injection (SIDI). Additional modifications include enhanced cylinder head and intake manifold air flow capacities, optimized camshaft profiles, and increased compression ratio. The SIDI fuel system presented the greatest opportunities for system development and optimization in order to maximize improvements in performance, fuel economy, and emissions. In particular, the injector flow rate, orifice geometry, and spray pattern were selected to provide the optimum balance of high power and torque, low fuel consumption, stable combustion, low smoke emissions, and robust tolerance to injector plugging.

This paper shows that the functional integration of Electronic Throttle Control (ETC) into the engine control strategy allows improvements of emissions and fuel economy without making compromises in respect of driveability. A cost effective way for realizing ETC is the integration of the control electronics into the engine control unit (ECU). The paper describes the consequences of such an integration for the ECU hardware and software. Special attention is given to the ETC related safety aspects. Another chapter discusses different technologies for the throttle actuator drive. This is followed by a brief description of a suitable control strategy for a throttle actuator. Finally the paper gives also an overview about current status and development trends of accelerator pedal sensors necessary for ETC.

The electrification of the powertrain, the diversity and the complexity of the more or less individual technical solutions which are preferred by different car manufacturers, create a steadily increasing challenge for the whole automotive industry. Missing standards and sales volumes still below the market expectations on the one hand, and the increasing interaction of the main powertrain domains (engine, transmission, e-drive) caused by upcoming cross domain functions on the other hand, lead to increasing development costs and non-optimal solutions concerning fuel economy improvement. Within the domain of engine management systems Bosch established in the mid-nineties the so called torque structure as the solution to a similar situation addressing the coordination of air management, fuel injection and ignition.

The heat transfer process in a reciprocating engine is dominated by forced convection, which is drastically affected by mean flow, turbulence, flame propagation and its impingement on the combustion chamber walls. All these effects contribute to a transient heat flux, resulting in a fast-changing temporal and spatial temperature distribution at the surface of the combustion chamber walls. To quantify these changes in combustion chamber surface temperature, surface temperature measurements on the piston of a single cylinder diesel engine were taken. Therefore, thirteen fast-response thermocouples were installed in the piston surface. A wireless microwave telemetry system was used for data transmission out of the moving piston. A wide range of parameter studies were performed to determine the varying influences on the surface temperature of the piston.

In order to comply with more and more stringent emission standards, like EU6 which will be mandatory starting in September 2014, GDI engines have to be further optimized particularly in regard of PN emissions. It is generally accepted that the deposition of liquid fuel wall films in the combustion chamber is a significant source of particulate formation in GDI engines. Particularly the wall surface temperature and the temperature drop due to the interaction with liquid fuel spray were identified as important parameters influencing the spray-wall interaction [1]. In order to quantify this temperature drop at combustion chamber surfaces, surface temperature measurements on the piston of a single-cylinder engine were conducted. Therefore, eight fast-response thermocouples were embedded 0.3 μm beneath the piston surface and the signals were transmitted from the moving piston to the data acquisition system via telemetry.

Based on the fuel consumption analysis methods published on last year's SETC [1], we compared fuel economies of a typical 125cc production motorcycle equipped with either electronic (port) fuel injection (EFI/PFI) engine management system (EMS) or constant vacuum carburetor (Carb). In addition to earlier discussed PFI results, stationary engine map measurements of fuel consumption on an engine dynamometer (dyno) were conducted for the Carb engine. The powerful development tool of fuel consumption test cycle simulation uses these stationary engine dyno results to calculate fuel consumption of real transient vehicle operation. Here it was employed to assess economy of both fuel system configurations under different driving conditions. Besides the Indian Driving Cycle (IDC) and the World Motorcycle Test Cycle (WMTC), we investigated real world drive patterns typical for emerging markets in terms of a Bangalore urban cycle and a Malaysian suburban cycle.

The fuel-independent particulate emissions of a direct injection gasoline engine were investigated. This was done by running the engine with reference gasoline at four different loads and then switching to hydrogen or methane port fuel operation and comparing the resulting particulate emissions and their size distribution. Differences in the combustion characteristics of hydrogen and gasoline were accounted for by diluting the inlet air with nitrogen and matching the pressure or heat release traces to those of gasoline operation. Methane operation is expected to generate particulate emissions lower by several orders of magnitude compared to gasoline and hydrogen does not contribute to carbon soot formation because of the lack of carbon atoms in the molecule. Thus, any remaining particulate emissions at hydrogen gas operation must arise from non fuel related sources, e.g. from lubrication oil, metal abrasion or inlet air.

Due to the principle of direct injection, which is applied in modern homogeneously operated gasoline engines, there are various operation points with significant particulate emissions. The spray droplets contact the piston surface during the warm-up and early injections, in particular. The fuel wall films and the resulting delayed evaporation of the liquid fuel is one of the main sources of soot particles. It is therefore necessary to carry out investigations into the formation of wall film. The influence of the spray impact angle is of special interest, as this is a major difference between engines with side-mounted injectors and centrally positioned injectors. This paper describes an infrared thermography-based method, which we used to carry out a systematic study of fuel deposits on the walls of the combustion chamber. The boundary conditions of the test section were close to those of real GDI engines operated with homogeneous charge.

1 High precision high pressure diesel common rail fuel injection systems play a key role in emission control, fuel consumption and driving performance. Deposits have been observed on internal injector components, for example in the armature assembly, in the slots of the piston and on the nozzle needle. The brownish to colourless deposits can adversely impact driveability and result in non-compliance with the Euro 4 or Euro 5 emission limits. The deposits have been extensively studied to understand their composition and their formation mechanism. Due to the location of these deposits, the influence of combustion gas can be completely ruled out. In fact, their formation can be explained by interactions of certain diesel fuel additives, including di- and mono-fatty acids. This paper describes the methodology used and the data generated that support the proposed mechanisms. Moreover, approaches to avoid such interactions are discussed.

The introduction of stricter emission legislation and the demand of increased power for small two-wheelers lead to an increase of technical requirements. Especially the introduction of liquid-cooling over air-cooling allows the introduction of higher compression ratios, which improves power output as well as thermodynamic efficiencies and thereby fuel consumption. But an increase in compression ratio also introduces further challenges during transient behavior especially close to idling. In order to keep the two-wheeler specific responsiveness of the vehicle, the overall rotational inertia of the engine must be kept low. But the combination of low inertia and high compression ratio can lead to a stalling of the engine if the throttle is opened and closed very quickly in idle operation. The fast opening and closing of the throttle is called a throttle blip.

The introduction of new emission legislation and the demand of increased power for small two-wheelers lead to an increase of technical requirements. Especially for single cylinder engines with high compression ratio the transient behavior close to idling is challenging. The demand for two-wheeler specific responsiveness of the vehicle requires low overall rotational inertia as well as small intake manifold volumes. The combination with high compression ratio can lead to a stalling of the engine if the throttle opens and closes very quickly in idle operation. The fast opening and closing of the throttle is called a throttle blip. Fast, in this context, means that the blipping event can occur in one to two working cycles. Previous work was focused on the development of a procedure to apply reproducible blipping events to a vehicle in order to derive a deeper physical understanding of the stalling events.

Today, knock control is part of standard automotive engine management systems. The structure-borne noise of the knock sensor signal is evaluated in the electronic control unit (ECU). In case of knocking combustions the ignition angle is first retarded and then subsequently advanced again. The small-sized combustion chamber of small two-wheeler engines, uncritical compression ratios and strong enrichment decrease the knock tendency. Nevertheless, knock control can effectuate higher performance, lower fuel consumption, compliance with lower legally demanded emission limits, and the possibility of using different fuel qualities. The Knock-Intensity-Detector 2 (KID2) and the Bosch knock control tool chain, based on many years of experience gained on automotive engines, provides an efficient calibration method that can also be used for two-wheeler engines. The raw signal of the structure-borne noise is used for signal analysis and simulation of different filter settings.

Large Eddy Simulations (LES) and tracer-based Laser-Induced Fluorescence (LIF) measurements were performed to study the dynamics of fuel wall-films on the piston top of an optically accessible, four-valve pent-roof GDI research engine for a total of eight operating conditions. Starting from a reference point, the systematic variations include changes in engine speed (600; 1,200 and 2,000 RPM) and load (1000 and 500 mbar intake pressure); concerning the fuel path the Start Of Injection (SOI=360°, 390° and 420° CA after gas exchange TDC) as well as the injection pressure (10, 20 and 35 MPa) were varied. For each condition, 40 experimental images were acquired phase-locked at 10° CA intervals after SOI, showing the wall-film dynamics in terms of spatial extent, thickness and temperature.

With the development of start stop technology to improve fuel economy and to reduce carbon dioxide (CO2) emissions, the information of State of Charge (SOC) of the battery is highly desirable. Recent days the battery sensors are used in mid-segment and luxury automobiles that monitors the current, voltage and temperature of the battery and calculates the charge model and sends the information via CAN or LIN. These dedicated sensors are intended to perform various functions other than basic start stop. Hence these sensors are proven to be expensive for emerging market, which is intended to perform only basic start stop as the market is looking for a low cost solution. Bosch- India has developed and implemented a novel idea of bringing a low cost and reliable battery charge detection algorithm that can be realized within the Electronic Control Unit (ECU) without a dedicated sensor.