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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.

A TGDI (turbocharged gasoline direct injection) engine is developed to realize both excellent fuel economy and high dynamic performance to guarantee fun-to-drive. In order to achieve this target, it is of great importance to develop a superior combustion system for the target engine. In this study, CFD simulation analysis, steady flow test and transparent engine test investigation are extensively conducted to ensure efficient and effective design. One dimensional thermodynamic simulation is firstly conducted to optimize controlling parameters for each representative engine operating condition, and the results serve as the input and boundary condition for the subsequent Three-dimensional CFD simulation. 3D CFD simulation is carried out to guide intake port design, which is then measured and verified on steady flow test bench.

In the Indian two-wheeler market, legislation and customers demand for a reduction of emissions and an increase of fuel efficiency. For two-wheelers with engine management systems, a cost-efficient approach for this trend exploits that the periodical fluctuation of the engine speed of single cylinder engines contains useful information about its operating conditions. The present article focuses on the quality of the estimation of combustion phasing and air-fuel ratio of a 125cc single cylinder motorcycle engine, obtained from the evaluation of these fluctuations. The robustness of an oxygen sensor-less port fuel injection system can be increased by using the estimated air-fuel ratio to adapt the parameters of the fuel injection algorithm.

In a study using a single-cylinder engine a significant potential in fuel efficiency and emission reduction was found for stratified operation of a high pressure natural gas direct injection (DI) spark ignition (SI) engine. The control of the mixture formation process appeared to be critical to ensure stable inflammation of the mixture. Therefore, optical investigations of the mixture formation were performed on a geometric equivalent, optically accessible single-cylinder engine to investigate the correlation of mixture formation and inflammability. The two optical measurement techniques infrared (IR) absorption and laser-induced fluorescence (LIF) were employed. Mid-wavelength IR absorption appeared to be qualified for a global visualization of natural gas injection; LIF allows to quantify the equivalence ratio inside a detection level. While LIF measurements require complex equipment, the IR setup consists merely of a black body heater and a mid-wavelength sensitive IR camera.

Best fuel efficiency is one of the core requirements for commercial vehicles in India. Consequently it is a central challenge for commercial vehicle OEMs to optimize the entire powertrain, hence match engine, transmission and rear axle specifications best to the defined application. The very specific real world driving conditions in India (e.g. traffic situations, road conditions, driver behavior, etc.) and the large number of possible commercial powertrain combinations request an efficient and effective development methodology. This paper presents a methodology and tool chain to specify and develop commercial powertrains in a most efficient and effective way. The methodology is based on the measurement of real world driving scenarios, identification of representative Real World Driving Profiles and vehicle system simulation which allows extended analysis of the road topography, the traffic situation as well as the driver behavior.

Regarding the strongly growing two-wheeler market fuel economy, price and emission legislations are in focus of current development work. Fuel economy as well as emissions can be improved by introduction of engine management systems (EMS). In order to provide the benefits of an EMS for low cost motorcycles, efforts are being made at BOSCH to reduce the costs of a port fuel injection (PFI) system. The present paper describes a method of how to reduce the number of sensors of a PFI system by the use of sophisticated software functions based on high-resolution engine speed evaluation. In order to improve the performance of a system working without a MAP-sensor (manifold air pressure sensor) an air charge feature (ACFn) based on engine speed is introduced. It is shown by an experiment that ACFn allows to detect and adapt changes in manifold air pressure. Cross-influences on ACFn are analyzed by simulations and engine test bench measurements.

Fuel economy of two-wheelers is an important factor influencing the purchasing psychology of the consumer within the emerging markets. Additionally, air pollution being a major environmental topic, there is a rising concern about vehicle emissions, especially in the big cities and their metropolitan areas. Potentially, the relatively expensive engine management systems are providing more features and value in comparison to the carburettor counterpart. The combustion system analysis is carried out on a 125 cm3 motorcycle engine and the subsequent numerical simulation comparing the carburettor and the Electronic (Port) Fuel Injection which provides a basis to establish the fuel consumption benefit for the electronic injection systems [1].

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.

Further fuel efficiency improvements are mandatory in order to achieve the CO2 emission limits envisaged in the future. Electrification of the powertrain is seen as one of the key technologies to achieve these future goals. However, electrification of the power train typically goes with a massive cost increase of the overall system itself which is especially crucial for cost sensitive markets like India. AVL's approach to cost reduction for comparable performance and fuel consumption target values is an integration of functions. This paper demonstrates that, through a deeper interaction of the single powertrain components, further fuel efficiency optimization may be gained. System optimization at a powertrain level enables the achievement of future powertrain targets with respect to fuel efficiency and performance with only minimal and reduced requirements at a component level (i.e. combustion engine, electric drive, transmission and battery).

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.

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.

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 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 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.

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.

The world of automotive engineering shows a clear direction for upcoming development trends. Stringent fleet average fuel consumption targets and CO2 penalties as well as rising fuel prices and the consumer demand to lower operating costs increases the engineering efforts to optimize fuel economy. Passenger car engines have the benefit of higher degree of technology which can be utilized to reach the challenging targets. Variable valve timing, downsizing and turbo charging, direct gasoline injection, highly sophisticated operating strategies and even more electrification are already common technologies in the automotive industry but can not be directly carried over into a motorcycle application. The major differences like very small packaging space, higher rated speeds, higher power density in combination with lower production numbers and product costs do not allow implementation such high of degree of advanced technology into small-engine applications.

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.

Alternative fuels, especially fuels based on biological matter, are gaining more and more attention. Not only as a pure substitute of oil but also in terms of a possibility for further reduction in emission and as an option to improve the global CO2 balance. For improving the engine performance (emissions, fuel consumption, torque and drivability) the adjustment of fuel injection, the fuel evaporation process and the combustion process itself is paramount. In order to exploit the full potential of alternative fuels excellent knowledge of the fuel properties, including the impact on ignition and flame propagation, is required. This needs suitable tools for analysis of the fuel injection and combustion process. These tools have to support the optimization of the combustion system and the dynamic engine calibration for lowest emissions and most efficient use of fuel. As the term “Alternative Fuels” covers a very wide area a brief overview on available fuel types will be made.

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.

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.