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On the basis of the large amount of know-how accumulated in the field of automotive ethanol SI-engine fuelling in Brazil, it seemed appropriate to continue and set a new milestone in the usage of ethanol fuel. The paper presents the preliminary study made to enable the transfer of the ethanol technology to a 5.9-liter 4-cylinder boxer aircraft engine. The study describes the steps made to define the optimal parameter configuration for the transfer of the fuel system packaging, the fuel injector layout, the engine control unit (ECU) and the legislative redundancy requirements for aviation applications. The paper illustrates the use of numerical simulation techniques and special visualization approaches necessary to understand the physical phenomena of mixture preparation (spray atomization and momentum). Two different layouts are presented and discussed and a certain number of experimental results obtained with the retained solution are presented and discussed.

The paper presents a description of the development phases of the new third generation of “green” fuel injectors. The development objective for the new PICO-ECOlogical injector was to define a layout, which enables an optimal parameter configuration for both the mixture preparation (high flexibility to adapt different atomizer plate structures) and the manufacturing processes. It is demonstrated in which way the use of high-level numerical simulation and visualization techniques have become an integrated part of the development process. A detailed description is given of the new layout with respect to earlier versions and the advantageous new features obtained are discussed. Test results obtained by the new 3rd-generation injector layout are presented. The impact of the improved dynamic response capability is explained and experimental data at both engine test rig and vehicle FTP-cycle conditions are reported and discussed.

The paper presents the basic scientific analytical approach to identify the main physical parameters, which enable an optimization of several layouts for an Ethanol Cold Start (ECS) device. The main optimization criteria for the system layout are a single mixture preparation system for both cold start and hot engine handling, a short energy release time, a short start time and a possible high-precision ethanol metering system capability after start. The paper describes 3 suggested solutions. Two of the solutions are prototyped and tested on several vehicles. The paper concludes with a series of experimental data obtained on different flex engines with the new ECS-system variants. The obtained test results show good pure ethanol cold start capability for temperatures above 263 K and an excellent system temperature control of the fuel in the fuel-rail and in the injectors, which prevents the occurrence of any cavitations phenomenon.

The paper presents the main reasons for the increasing market share of vehicles with the capacity to run on random bio fuel blends. It explains the reason for which a single fuel supply system is mandatory in modern flex vehicles, even for cold start by pure ethanol fuelling The paper continues with an analytic research for the most appropriate device location and a detailed description of 3 suggested device layouts. The paper concludes by a presentation of a series of data obtained by real-time vehicle experiments at low ambient temperature conditions.

The paper presents a short introduction on the evolution from the first generation of software based flex fuel sensor systems over the second system generation including new gasoline/ethanol optimized fuel injectors to the 3rd generation, which combines all available optimized mechanical components. It demonstrates that to meet the new emission regulations and On Board Diagnostic requirements a new highly flexible Electronic Control Unit (ECU) is needed. A detailed description of the new powerful, layered-structure ECU-family is given. The paper concludes with some illustrative experimental results obtained by combining the new ECU-family with engine-layout optimized mechanical components.

In the present paper the impact of three different geometrical layouts of the discharge nozzle of a high-pressure diesel injector designed is examined for a common rail second generation direct injection system. The paper presents a comparative study of the spray behavior of the three different nozzle layouts connected to a 150 MPa rail-pressure when mounted on a 1.6 liter European passenger car engine. To evaluate experimentally the differences in the fundamental physical spray parameters several specially developed optical visualization techniques are used, which enable phase-Doppler, Laser-sheet and high-speed recordings of dense high pressure sprays. The change in basic spray parameters (time-resolved droplet distribution and spray momentum) caused by the nozzle geometry variation is examined. The impact on the in-cylinder penetration and mixing characteristics is studied with a 3D-numerical simulation code NCF-3D.

Experimental measurements and numerical computations were made to characterize a spray generated by a high-pressure swirl injector. The Phase Doppler technique was applied to get information on droplet sizes (d10) and axial velocities at defined distances from the injector tip. Global spray visualization was also made. Computations were carried out using a modified version of KIVA 3V. In particular, the break-up length of the sheet and its dimension were computed from a semi-empirical correlation related to the wave instability theory suggested by Dombrowski, including the modifications introduced by Han and Reitz. Two different approaches were used to describe the initial spray conditions. According to the first, discrete particles with a characteristic size equal to the thickness of the sheet are injected. The second approach assumes, that the particles having a SMD computed by a semi-empirical correlation are injected according to a statistical distribution.

The recent innovations on automotive Diesel engines require significant research efforts. The new generation of fully electronically controlled injection systems have opened new ways to reduce emissions and improve the efficiency of the engine. The free mapping of injection law together with the enhanced injection pressures favor, in fact, the optimization of mixture formation. In this field, the 3D simulation is playing a substantial role to support the design of combustion chamber. This paper presents a computational model to simulate the multi-injection process, the mixture formation and the combustion of DI diesel engines with high-pressure injection systems. The main code is a modified version of the KIVA 3V and the modifications presented in this work are a high pressure break up model and a multi component evaporation model. The code has been validated through experimental data on a 4-cylinder, 1910 cc, DI turbocharged Diesel engine (Fiat 1.9 JTD).

The first part of the paper gives an overview of the results obtained with European GDI-powered vehicles launched on the market. Thereafter, a discussion of in-vehicle limitations due to the exhaust gas after-treatment system requirements is given. The paper continues with a description of the current development status of European lean stratified direct injection system layouts. A detailed presentation is made of the mixture preparation system key components, basic control algorithms and the necessary new high-level experimental and analytical development tools. Particularly the topic of the multi-purpose use of 3-D numerical simulation is addressed both in the development and the engine control strategy calibration phases. The development of a small 1.6 liter lean stratified engine project is taken as example to demonstrate the dual application capability of the 3D simulation tool.

In the present paper are examined the consequences of a substantial rise in the injection pressure for Gasoline Direct Injection (GDI) injector assemblies. The paper presents a comparative study of the spray behavior of two different injector nozzle layouts submitted to current 10 Mpa rail-pressure as well as to a 30 Mpa injection pressure. To evaluate the differences in the fundamental physical spray parameters are used several specially developed optical visualization techniques, which enable phase-Doppler, PIV, Laser-sheet and high-speed recordings of dense high pressure fuel sprays. A recently developed injector actuator and the necessary modifications to existing high-pressure pumps to reach a 30 MPa pressure level in the fuel system are presented. The change in basic spray parameters (time-resolved droplet distribution and spray momentum) caused by the rail-pressure rise is examined.

The paper presents a study of a key-element in the mixture preparation process. A typical common-rail (CR) high-pressure fuel injector was fitted with a prototype injector nozzle with atomizer bores of a particular conical layout. It is demonstrated within certain layout limits, that a considerable enhancement can be obtained for the secondary break-up of the hard-core fluid sprays produced by the nozzle. The impact on the combustion process is examined in terms of pressure and heat release as well as of the engine-out pollutant emission. The results are compared to those of an earlier developed CR high-pressure injector nozzle. The atomization behavior of the prototype nozzle is illustrated through experimental results in terms of engine-out emissions from a 1.3-liter turbo-charged passenger car diesel engine. The detailed spray behavior is visualized on a component test rig by use of specially developed optical visualization techniques.

The paper presents the background research on the physics of the droplet coalescence phenomena carried out by an interactive usage of high-level 3-D numerical simulation tools and high-level optical visualization and measurement techniques. The presentation continues with the description of a new injector atomizer plate layout, which enables a physical coalescence control of the droplet population within the entire fuel spray. Finally are presented examples of the impact on exhaust emissions of the introduction the new atomizer plate with coalescence control by engine test bed experiments (steady state low load conditions) and vehicle tests (first cold part of the FTP-cycle).

In-cylinder pressure time history is usually measured in order to calculate both indicated mean effective pressure, as a global engine performance index, and the rate of heat release, as a quantitative information about combustion progress. Generally such information is readily provided by acquisition systems in terms of heat release rate, which is computed by means of simple inverse models based on first law of thermodynamics. Nevertheless attention must be paid to any measurement uncertainty connected to pressure cycle relief which directly results into inaccurate heat release analysis. As far as i.m.e.p. evaluation is concerned, a wrong adjustment of T.D.C. reference position, leading to incorrect pressure-crank angle phasing, had been recognized as the major error source.

In the future generation of low consumption SI-engine layouts, it has become necessary to reduce costs as well as the complexity level and, increase the system reliability by the latter. To avoid driving the GDI-system in the critical, very lean stratified operation mode without losing the fuel consumption benefit, a solution is suggested, which combines a fully variable valve control system with a low level, robust GDI combustion layout. The first part of the present paper presents the latest development in the field of high precision multi-hole GDI injector spray nozzles. The basic aspects of mixture preparation with multi-hole gasoline atomizers are highlighted and their spray behavior compared to that of the current swirl atomizer nozzle. The second part of the paper presents primary optimization of a largely homogeneous GDI combustion layout combined with a fully variable valve timing control system including complete cylinder de-activation.

The paper describes the application of laser sheet flow visualisation with numerical image analysis as a useful complementary tool to numerical simulation techniques for the optimisation of fluid dynamics within SI-engine in-take systems. The lay-out of the laser sheet visualisation system and the applied numerical image analysis are discussed in detail. Two applicative examples are given, one of smoke induced visualisation of the internal gas flow of an intake manifold, the other of natural visualisation of fuel injector wall film deposit in the intake runner. Finally is concluded that the addition of visualisation techniques to the development strategy allows a time gain, because it contributes to a rapid understanding of complex flow phenomena.

Pollutant emissions from D.I. Diesel engines strongly depend on injection system characteristics and mainly on injection pressure and timing. In the latest years some solutions have been proposed based on very high fuel pressure values (up to 150 MPa). Among them, the so called “Common rail” system configuration, being able to electronically control needle lift and injection pressure, seems to be particularly promising. Much experimental and theoretical work has been done to improve system performance for automotive applications. With the aim of investigating the influence of some details of geometrical configuration on the injector operating mode, a mathematical model able to describe the pressure-time history in any section of the delivery pipe and the fuel injection rate through the nozzle has been developed, based on a semi-implicit finite volumes approach. The computed results have been compared with experimental data provided by the Institut Français du Pétrole.

The paper gives a short introduction to the notion of flex fuel approach for diesel engines. The paper continues with a description of a basic study of the diesel combustion process to allow the design of a strategy for recognition of a random bio-diesel fraction, Bx, by a purely software-based sensing technique, which creates an image of the temporal combustion behavior and uses only sensors already in service for current CR-mixture preparation systems. The paper concludes presenting a series of experimental verification data obtained on a large-scale series produced 1.3 liter Turbo-charged CR-rail passenger car engine.

The present paper describes a study of the basic parameters, which govern particulate (soot) formation within the combustion chamber of a small displacement (1.3 liter) turbocharged European CR-diesel engine. The main tools used for the study are a real fired engine, a numerical virtual engine and a special high ambient pressure vessel for injector spray visualization. The paper describes an improved soot formation model implemented in the virtual engine setup. A comparison is presented between measured and computed combustion data at 8 different load points. The paper concludes with a discussion of the means, which can be used to minimize the particulate matter formation in the design phase of both the combustion layout and the fuel injector atomizer as well as in the design of the injection control strategies.

The paper presents the today’s power train systems, which largely reflect a one to one mapping of physical units into a dedicated electronic control system. A new approach is suggested for a breakdown strategy with an ECU centered structure linked to a surrounding harness of sensors and actuators. Like body electronics did first, automotive graded combination of semiconductor and packaging technologies are used to develop a network of mechatronic components. This allows an easy and effective separation between the SW development at the vehicle level and an off-line optimization and calibration of components. A development project is shown for a gasoline direct injected engine, where mechatronic components (e.g. cylinder, fuel pump and injectors, valve train) are networked and controlled by a master digital core, which is the application SW restricted area of the car manufacturer.