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Technical Paper

Low Cost Battery Sensor Algorithm

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.
Technical Paper

Knock Control on Small Four-Two-Wheeler Engines

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.
Technical Paper

Ion Current Sensing for Spark Ignition Engines

This paper describes an ion current measurement system with a new, modified inductive ignition system and evaluates the detection quality for misfire and knock detection. The System uses an ignition circuit with adjustable spark duration limitation. The measurement circuit is located at the low tension side of the secondary ignition coil. Due to the fact that a lot of influencing factors on misfire detection have been investigated, the estimation of the signal-to-noise-ratio is possible as well as the detection of critical operation points. Results of a closed-loop knock control with ion current are presented and are compared with the structure borne noise method.
Journal Article

Investigation on the Transient Behavior of a High Compression Two-Wheeler Single Cylinder Engine Close to Idling

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.
Technical Paper

Investigation on Fluid Mechanics of the Regenerative Pump Used in Gasoline Injection Systems

In order to optimize the inner flow of the regenerative pump used in gasoline injection systems, we carry out experimental and numerical flow investigations. A qualitative analysis of spatial flow phenomena in selected regions of the pump is presented by employing the laser light sheet technique. Therefore, a tenfold enlarged water model is built up, where dynamic similarity with the original flow is achieved. The results of the flow analysis have led to improved geometries which are compared with the original design by measured pump characteristic curves. Furthermore, three-dimensional simulations of the fully developed turbulent flow using a finite-element method are presented. The flow with respect to the rotating impeller is calculated by solving the Reynolds equations in connection with the k-ε-turbulence model.
Technical Paper

Investigation into the Formation and Prevention of Internal Diesel Injector Deposits

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.
Technical Paper

Information Technology - A Challenge for Automotive Electronics

In the automotive industry, a steadily growing number of mono-functional electronic control units (ECUs) with increasing complexity on the one hand and restrictive requirements for power consumption and mounting space on the other hand are forcing changes in car electronics. This tendency is enforced by increasing requirements on security, comfort, fuel consumption and emission. In luxury cars, we are now at up to 80 more or less independent electronic units with low potential for synergies between functions (pan-functional services). The actual assembly of electronic units is certainly easily expandable, has very low error propagation but it also involves lots of logistic and bulky cabling with unwanted weight as well as extensive space and power consumption. If trends are properly interpreted, synergies between functions for more comfort, additional safety and security as well as minor air pollution are required in the future at least at unchanged costs in the vehicle's electronics.
Technical Paper

GDI: Interaction Between Mixture Preparation, Combustion System and Injector Performance

The development of future engine generations for Gasoline Direct Injection requires sophisticated combustion systems to reach reduced fuel consumption and future emission standards. The design process of these combustion systems has to be based on a fundamental knowledge of the interacting mixture preparation mechanisms. Beside the air motion inside the cylinder mixture preparation is mainly feeded by the fuel spray quality, injector performance respectively. The article therefore presents a fundamental analysis of the GDI mixture preparation and affords an insight into the injector development. Comprehensive experimental studies were performed in high pressure/temperature vessels using Phase Doppler Anemometry, Laser Induced Fluorescence and video techniques to define the significant fuel spray features for GDI. CFD-calculations were additionally applied to study the temporal behavior of the mixture preparation under injection parameter variation.
Technical Paper

Future Electrical Steering Systems: Realizations with Safety Requirements

Additional future requirements for automobiles such as improved vehicle dynamics control, enhanced comfort, increased safety and compact packaging are met by modern electrical steering systems. Based on these requirements the new functionality is realized by various additional electrical components for measuring, signal processing and actuator control. However, the reliability of these new systems has to meet the standard of today's automotive steering products. To achieve the demands of the respective components (e.g. sensors, bus systems, electronic control units, power units, actuators) the systems have to be fault-tolerant and/or fail-silent. The realization of the derived safety structures requires both expertise and experience in design and mass production of safety relevant electrical systems. Beside system safety and system availability the redundant electrical systems also have to meet economic and market requirements.
Journal Article

Fuel-Independent Particulate Emissions in an SIDI Engine

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.
Technical Paper

Fuel Injection Equipment for Heavy Duty Diesel Engines for U. S. 1991/1994 Emission Limits

The particulate emissions can be reduced by increasing injection pressure. The NOx-emission can be lowered to the required amount with a retarded injection-begin. These measures raise fuel consumption by approximately 8-10 %. To avoid blue smoke from the cold engine, it is advantageous that the fuel injection is advanced during the warm-up period. These statements apply for injection systems with unit injectors as well as for pump-line-nozzle-systems. In this paper, the pump-line-nozzle-system will be described. With this system, injection pressures of 1200 to 1400 bar at the injection nozzle are reached. The injection-begin can be changed with a control-sleeve in-line pump. The injection-begin and fuel quantity can be flexibly and accurately adjusted by means of an electronic governor.
Technical Paper

FEM Approximation of Internal Combustion Chambers for Knock Investigations

The resonances of SI engine combustion chambers are slightly excited during normal combustion but strongly excited by knock. In order to avoid knocking combustions extensive knowledge about knock and its effects is necessary. In this paper the combustion chamber of a serial production engine is modeled by finite elements. Modal analyses are performed in order to gain information about the resonances, their frequencies, and their frequency and amplitude modulations. Simulation results are compared to measured data using a high-resolution time-frequency method. Furthermore, a connection between knock origin and the excitation of the resonances is postulated applying transient analyses.
Technical Paper

Experimental and Numerical Comparison of Fuel Economy for 125cc Motorcycles with Carburetor or Electronic Port Fuel Injection Based on Different Drive Cycles

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.
Technical Paper

Experimental Measurement Techniques to Optimize Design of Gasoline Injection Valves

In order to reduce the spark-ignition engine exhaust-gas emission and fuel consumption, it is essential that the required air/fuel ratio is maintained under all operating conditions. An important contribution to this claim is delivered by the injection valve by metering the fuel precisely and producing fine atomization. In this report experimental methods to get specific measuring information and methods for optimizing flow in injection valves are described. Original valves as well as large-scale models were used for the investigations concerning the steady and unsteady-flow characteristics, and were equipped with a number of different sensors. Holograms of the short-time recording of the spray cone are generated and used for the quantification of the atomization quality when injecting into atmospheric pressure and into vacuum, thus complying with the conditions encountered in the engine intake-manifold.
Technical Paper

Expansion Devices for R-744 MAC Units

In mobile R-744 A/C units mechanical expansion devices (e.g. orifice tubes) or electronic valves (e.g. PWM-valves) can be used. Besides the costs, aspects like coefficient of performance (COP), cooling capacity or control behavior - especially for extreme conditions - influence the choice of the valve type. This paper will present a comparison between an ideal electronic valve and a two stage mechanical orifice tube under full load and part load conditions. The influence of the expansion valve on COP and cooling capacity in different ambient conditions can be sufficiently described with steady-state simulations. The simulation tools used for this work are based on Modelica/Dymola. The simulation results show that for European climate conditions the use of two-stage orifices might increase fuel consumption.
Technical Paper

Evaluating Different Measures to Improve the Numerical Simulation of the Mixture Formation in a Spark-Ignition CNG-DI-Engine

Compressed Natural Gas (CNG) is a promising alternative fuel for internal combustion engines as its combustion is fuel-efficient and lean in carbon dioxide compared to gasoline. The high octane number of methane gives rise to significant increase of the thermodynamic efficiency due to higher possible compression ratios. In order to use this potential, new stratified mixture formation concepts for CNG are investigated by means of numerical fluid simulations. For decades RANS methods have been the industry standard to model three-dimensional flows. Indeed, there are well-known deficiencies of the widely used eddy viscosity turbulence models based on the applied Boussinesq hypothesis. Reynolds stress turbulence models as well as scale resolving simulation approaches can be appealing alternative choices since they offer higher accuracy. However, due to their large computing effort, they are still mostly impractical for the daily use in industrial product development processes.
Technical Paper

Engine-Independent Exhaust Gas Aftertreatment Using a Burner Heated Catalyst

Meeting current exhaust emission standards requires rapid catalyst light-off. Closed-coupled catalysts are commonly used to reduce light-off time by minimizing exhaust heat loss between the engine and catalyst. However, this exhaust gas system design leads to a coupling of catalyst heating and engine operation. An engine-independent exhaust gas aftertreatment can be realized by combining a burner heated catalyst system (BHC) with an underfloor catalyst located far away from the engine. This paper describes some basic characteristics of such a BHC system and the results of fitting this system into a Volkswagen Touareg where a single catalyst was located about 1.8 m downstream of the engine. Nevertheless, it was possible to reach about 50% of the current European emission standard EU 4 without additional fuel consumption caused by the BHC system.
Technical Paper

Engine Management Systems in Hybrid Technology

Increasingly stringent requirements regarding exhaust emission, fuel consumption, driveability and comfort have led to an accelerated introduction of electronically controlled systems, the complexity of which can best be handled by microcomputers, these being the basis of all modern electronic control units. These electronic control units are usually installed in the passenger compartment, due to the need for moderate conditions in respect of temperature, vibration, moisture and dust. However because of the increasing variety of systems the available space for the installation of these control boxes has become smaller and smaller whilst the complexity of the wire harness has led to increased costs and electromagnetic interference problems. As a result there is an increasing demand for electronic control units (ECU) which can be installed in the engine compartment.
Technical Paper

Energy Management - A Key Approach to Design The System Structure of Powertrain Control: Technology Leadership Brief

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.
Technical Paper

Electronic Throttle Control (ETC): A Cost Effective System for improved Emissions, Fuel Economy, and Driveability

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.