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Technical Paper

Thermodynamic Analysis and Benchmark of Various Gasoline Combustion Concepts

2006-04-03
2006-01-0231
Novel Combustion technologies and strategies show high potential in reducing the fuel consumption of gasoline spark ignition (SI) engines. In this paper, a comparison between various gasoline combustion concepts at two representative engine operating points is shown. Advantages of the combustion concepts are analyzed using thermodynamic split of losses method. In this paper, a tool for thermodynamic assessment (Split of Losses) of conventional and new operating strategies of SI engine and its derivatives is used. Technologies, like variable valve actuation and/or gasoline direct injection, allow new strategies to run the SI engine unthrottled with early inlet valve closing (SI-VVA) combined with high EGR, charge stratification (SI-STRAT) and controlled auto ignition (CAI), also known as gasoline homogeneous charge compression ignition (HCCI). These diverse combustion concepts show thermodynamic gains that stem from several, often different sources.
Technical Paper

The Robert Bosch In-Line Pump for Diesel Engines, Type MW, Design, Application and Further Development

1979-02-01
790901
The range of Robert Bosch in-line pumps is designed for engines with cylinder outputs of up to 200 kW. Within this family of pumps the MW pump is used in small IDI engines and medium-sized DI engines with cylinder outputs in the region of 30 kW. More stringent exhaust emission legislation and the need to ensure optimum fuel economy call for efficient fuel-injection systems for diesel engines. In both of its designs the new MW pump meets these more exacting requirements and forms the contribution of Robert Bosch GmbH toward developing advanced diesel engines.
Technical Paper

The Impact of a Combustion Chamber Optimization on the Mixture Formation and Combustion in a CNG-DI Engine in Stratified Operation

2017-03-28
2017-01-0779
A previous study by the authors has shown an efficiency benefit of up to Δηi = 10 % for stratified operation of a high pressure natural gas direct injection (DI) spark ignition (SI) engine compared to the homogeneous stoichiometric operation with port fuel injection (PFI). While best efficiencies appeared at extremely lean operation at λ = 3.2, minimum HC emissions were found at λ = 2. The increasing HC emissions and narrow ignition time frames in the extremely lean stratified operation have given the need for a detailed analysis. To further investigate the mixture formation and flame propagation und these conditions, an optically accessible single-cylinder engine was used. The mixture formation and the flame luminosity have been investigated in two perpendicular planes inside the combustion chamber.
Technical Paper

The Challenge of Precise Characterizing the Specific Large-Span Flows in Urea Dosing Systems for NOx Reduction

2008-04-14
2008-01-1028
The reduction of nitrous oxides in the exhaust gases of internal combustion engines using a urea water solution is gaining more and more importance. While maintaining the future exhaust gas emission regulations, like the Euro 6 for passenger cars and the Euro 5 for commercial vehicles, urea dosing allows the engine management to be modified to improve fuel economy as well. The system manufacturer Robert Bosch has started early to develop the necessary dosing systems for the urea water solution. More than 300.000 Units have been delivered in 2007 for heavy duty applications. Typical dosing quantities for those systems are in the range of 0.01 l/h for passenger car systems and up to 10 l/h for commercial vehicles. During the first years of development and application of urea dosing systems, instantaneous flow measuring devices were used, which were not operating fully satisfactory.
Technical Paper

Study on Boosted Direct Injection SI Combustion with Ethanol Blends and the Influence on the Ignition System

2011-10-04
2011-36-0196
The stricter worldwide emission legislation and growing demands for lower fuel consumption and CO2-emission require for significant efforts to improve combustion efficiency while satisfying the emission quality demands. Ethanol fuel combined with boosting on direct injection gasoline engines provides a particularly promising and, at the same time, a challenging approach. Brazil is one of the main Ethanol fuel markets with its E24 and E100 fuel availability, which covers a large volume of the national needs. Additionally, worldwide Ethanol availability is becoming more and more important, e.g., in North America and Europe. Considering the future flex-fuel engine market with growing potentials identified on downsized spark ignition engines, it becomes necessary to investigate the synergies and challenges of Ethanol boosted operation. Main topic of the present work focuses on the operation of Ethanol blends up to E100 at high loads up to 30 bar imep.
Journal Article

Start/Stop Strategies for Two-Wheelers in the Emerging Markets

2013-10-15
2013-32-9125
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].
Technical Paper

Spray Formation of High Pressure Swirl Gasoline Injectors Investigated by Two-Dimensional Mie and LIEF Techniques

1999-03-01
1999-01-0498
Two-dimensional Mie and LIEF techniques were applied to investigate the spray formation of a high pressure gasoline swirl injector in a constant volume chamber. The results obtained provide information on the propagation of liquid fuel and fuel vapor for different fuel pressures and ambient conditions. Spray parameters like tip penetration, cone angles and two new defined parameters describing the radial fuel distribution were used to quantify the fuel distributions measured. Simultaneous detection of liquid and vapor fuel was applied to study the influence of ambient temperature, injector temperature and ambient pressure on the evaporating spray.
Journal Article

Procedure for Determining the Allowable Particle Contamination for Diesel Fuel Injection Equipment (FIE)

2009-04-20
2009-01-0870
Increasing injection pressures together with Diesel fuel lubricated Common Rail pumps replacing oil lubricated systems demand a more sophisticated investigation of robustness and durability against particle contamination of fuel. The established way of requiring filtration efficiency levels per lab standard is not significant enough if we look at variable factors like vibration of the fuel filter and viscosity of the fuel. Because these and other factors tremendously influence filtration efficiency, future Diesel FIE cleanliness requirements will need to define an allowable contamination limit downstream of the filter. More precisely, this is not a scalar limit but a contamination collective that considers the varying vehicle filtration and operating environment. This paper describes a procedure for defining allowable contamination limits of the FIE components. The procedure includes sensitivity, robustness and “key life” tests.
Technical Paper

Preparing for CARTRONIC - Interface and New Strategies for Torque Coordination and Conversion in a Spark Ignition Engine-Management System

2001-03-05
2001-01-0268
A major trend in modern vehicle control is the increase of complexity and interaction of formerly autonomous systems. In order to manage the resulting network of more and more integrated (sub)systems Bosch has developed an open architecture called CARTRONIC for structuring the entire vehicle control system. Structuring the system in functionally independent components improves modular software development and allows the integration of new elements such as integrated starter/generator and the implementation of advanced control concepts as drive train management. This approach leads to an open structure on a high level for the design of advanced vehicle control systems. The paper describes the integration of the spark-ignition (SI) engine management system (EMS) into a CARTRONIC conform vehicle coordination requiring a new standard interface between the vehicle coordination and the EMS level.
Technical Paper

Predictive Multi-objective Operation Strategy Considering Battery Ageing for Hybrid Electric Vehicles

2018-04-03
2018-01-1011
Due to the more stringent CO2 targets for vehicles, electrification of powertrains and operation strategies for electrified powertrains have drawn more attention. This paper presents a predictive multi-objective operation strategy for hybrid electric vehicles (HEVs), which simultaneously minimises the fuel consumption and the cycle ageing of traction batteries. The advantages of this proposed strategy are increased performance by using predictive information and high robustness to inaccuracy of predictive information. In this work, the benefits of the developed operation strategies are demonstrated in a strong Hybrid Electric Vehicle (sHEV) with P2-configuration. For the cycle ageing of a lithium-ion battery, an empirical model is built up with Gaussian processes based on experimental data.
Journal Article

Online Engine Speed based Adaptation of Combustion Phasing and Air-Fuel Ratio

2014-11-11
2014-32-0076
Equipping low cost two-wheelers with engine management systems (EMS) enables not only a reduction of emissions but also an improvement in fuel consumption and system robustness. These benefits are accompanied by initially higher system costs compared to carburetor systems. Therefore, intelligent software solutions are developed by Bosch, which enable a reduction of the necessary sensors for a port fuel injection system (PFI) and furthermore provide new possibilities for combustion control. One example for these intelligent software solutions is a model based evaluation of the engine speed. By use of the information contained in the engine speed signal, characteristic features like air charge, indicated mean effective pressure (imep) and combustion phasing are derivable. The present paper illustrates how these features could be used to reduce the system costs and to improve fuel consumption and system robustness.
Technical Paper

Online Engine Speed Based Adaptation of Combustion Phasing and Air-Fuel Ratio: Evaluation of Feature Quality

2015-11-17
2015-32-0749
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.
Journal Article

Online Engine Speed Based Adaptation of Air Charge for Two- Wheelers

2013-10-15
2013-32-9037
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.
Technical Paper

Numerical and Experimental Studies on Mixture Formation with an Outward-Opening Nozzle in a SI Engine with CNG-DI

2016-04-05
2016-01-0801
CNG direct injection is a promising technology to promote the acceptance of natural gas engines. Among the beneficial properties of CNG, like reduced pollutants and CO2 emissions, the direct injection contributes to a higher volumetric efficiency and thus to a better driveability, one of the most limiting drawbacks of today’s CNG vehicles. But such a combustion concept increases the demands on the injection system and mixture formation. Among other things it requires a much higher flow rate at low injection pressure. This can be only provided by an outward-opening nozzle due to its large cross-section. Nevertheless its hollow cone jet with a specific propagation behavior leads to an adverse fuel-air distribution especially at higher loads under scavenging conditions. This paper covers numerical and experimental analysis of CNG direct injection to understand its mixture formation.
Technical Paper

New Electronic Systems Worldwide - The Supplier's View

1986-11-01
861972
Despite the tough environmental conditions facing electronic systems in commercial vehicles, electronics is gaining ground also in these applications. In the drive sector it improves the operation of the main and auxiliary drives, upgrades fuel efficiency and reduces emission pollutant levels. It enhances safety by preventing wheel spinning in braking and acceleration. Electronic displays reduce the number of single indications otherwise needed, thus making for more clarity in information for the driver and facilitating the driver's task. Self-diagnosing and integrated emergency operation (“limp home”) capabilities are to ensure availability, a factor of special importance in commercial vehicles. A data interface standardized as widely as possible would allow add-on systems to be coupled easily and flexibly.
Technical Paper

New Approaches to Electronic Throttle Control

1991-02-01
910085
An electronic control of throttle angle is required for safety systems like traction control (ASR) and for advanced engine management systems with regard to further improvements of driving comfort and fuel economy. For applications, in which only ASR is required, two versions of a new traction control actuator (TCA) have been developed. Their function is based on controlling the effective length of the bowden cable between the accelerator pedal and the throttle. Besides retaining the mechanical linkage to the throttle, the concept has no need for a pedal position sensor, which is necessary for a drive-by-wire system. Design and performance of both actuators are described and their individual advantages are compared. Moreover, the communication of the system with ASR and its behaviour with regard to vehicle dynamics are illustrated.
Technical Paper

Model Based Top Down Process for Automotive E/E-Architecture Development

2008-04-14
2008-01-0284
Model based architecture methods for designing and optimizing electrical and electronic systems of vehicles are becoming more and more popular. However, there is still no standard on the models which are vital for design and description of architectures. Most methods and tools begin with a functional abstraction. The functional elements are mapped to electronic control units [ECU] which are connected through bus systems and supplied with electrical power via clamps. An open, unanswered question is the determination of specific control unit numbers and location in a vehicle platform. To do so, a new model layer is proposed: the “technological model” with so called “technological building blocks”. It sits in-between the “functional model” and the “communication model” and describes the necessary constraints for designing the optimum number and position for electronic control units.
Technical Paper

Mixture Formation in a CNG-DI Engine in Stratified Operation

2015-09-06
2015-24-2474
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.
Technical Paper

Methods for the Efficient Development and Optimization of Automotive Electrical Systems

1997-02-24
970301
In the last years, the requirements for electrical energy systems in motor vehicles have increased considerably. In the past, many studies were focused on single components of the electrical system. However, to shorten the development process, reduce costs, improve reliability and also to optimize the fuel consumption due to the electrical system, the electrical system must be regarded as a whole. The Robert Bosch GmbH has developed a simulation environment, which is intended to improve the development process of new vehicle electrical systems by means of computer simulation. On the basis of a freely selectable driving cycle and various driver models, it is possible to simulate the behavior of electrical energy supply structures. The model of the electrical system is coupled to a dynamic model of the drivetrain. The characteristics of this drivetrain can also be modified and various vehicle models can be selected for simulation.
Technical Paper

Methods and Analysis of Fuel Injection, Mixture Preparation and Charge Stratification in Different Direct Injected SI Engines

2001-03-05
2001-01-0970
Direct gasoline injection is one major approach in reducing fuel consumption to fulfill the stages of CO2 reduction commitments in Europe from today until 2008. One effort is to unthrottle the gasoline engine during idle and partial load utilizing charge stratification. This may be realized by using different combustion concepts. This paper shows the analysis of mixture preparation for three different types of direct injected gasoline engines. Each engine was driven with two injectors which have two different atomization concepts. The engine types draw a clear dividing line between their combustion concepts. The injectors were analyzed in a pressure chamber, in an optical engine, and in an actual 1-cylinder engine. The formation of wall-film in wall-guided combustion systems will be discussed. Several important injector and engine parameters for fuel direct injection are pointed out.
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