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The effects of fuel temperature on both the geometry and the droplet size and velocity of a GDI swirled injector spray were investigated by means of visualizations and PDA measurements. Isooctane was used as model fuel and was injected in a quiescent bomb at injection pressure of 7 MPa. Bomb pressure ranged from 40 kPa to 800 kPa with injector nozzle temperature ranging from 293 K to 393 K. A drastic change in spray geometry was observed when conditions above the vaporization curve were reached. The temperature increase has two macroscopic effects on the spray geometry: at the nozzle exit the liquid flash boiling strongly enlarges the spray angle, at a certain distance from the nozzle the air entrainment collapses the spray. Raising the fuel temperature up to flash boiling conditions causes a significant decrease of the average droplet size.

Charge-coolers have a significant effect on the performance of turbocharged internal combustion engines. For a comprehensive simulation of internal combustion engines fitted with such devices it is important to model the whole of the manifold system. A wave-action model of a charge-cooler boundary is proposed, together with a methodology for predicting the heat transfer coefficient of the device. This approach enables the instantaneous effectiveness of the charge-cooler to be predicted as a function of the mass flow rate through the device.

In the ANNIE project - Applications of Neural Networks to Integrated Ergonomics - BE96-3433, a tool for integrating ergonomics into the design process is developed. This paper presents some features in the current ANNIE as applied to the design of car interiors. A variant of the ERGOMan mannequin with vision is controlled by a hybrid system for neuro-fuzzy simulation. It is trained by using an Elite system for registration of movements. An example of a trajectory generated by the system is shown. A fuzzy model is used for comfort evaluation. An experiment was performed to test its feasibility and it showed very promising results.

This paper introduces and discusses a new 2D physical model which has been developed and validated in order to study and optimize the handling behavior of the tire. It can be divided into two parts, the structural model and the contact area model. The parameters, that are function of the vertical load, are identified or calculated by comparison with the results provided by 3D finite element models. The input data for the identification procedure consist of a set of frequency responses performed on the finite element model. A second set of simulations on the 3D model of the tread pattern gives the characteristics of the contact model. Once built the 2D model it is easy to carry out both steady state and transient analysis. The steady state analysis returns the cornering carpet, in terms of lateral force and self-aligning moment as function of the cornering angle. The transient analysis allows the evaluation of the relaxation length and dynamic characteristics.

A Consortium of steel producing organizations has been working to reduce the mass of automobiles. An initiative identified as ULSAS (UltraLight Steel Automotive Suspension) is in progress which considers automotive rear suspension systems. The programme has evaluated and established the current status of material and process technology utilization and its application to rear suspension systems. Extensive studies have generated over fifty five design ideas which provide an indication of the potential opportunities for performance improvement that could be realised through the focused application of steel technologies. Work is in progress developing these ideas and quantifying the performance improvements.

Dynamic tests have been performed on carbon fiber racing seats following the FIA regulations. The tests have shown, in rear impact tests, a relatively strong rebound leading to large forward bending of neck, and, in side impact tests, very large lateral displacement of the head, the latter protruding dangerously towards hard portions of the car structure. Stiffening the seat back by steel struts results in reducing strongly both the motion and the acceleration of the head. Simulations of the dynamics of the tests have been done with multi-body models, including the Hybrid III dummy and seat deflection, by means of the program VEDYAC. It has been found that computer simulation can predict very accurately the result of a test, provided the numerical models have been carefully calibrated to match the dummy tolerance bands. Once they have been calibrated and validated with a number of tests, the computer models can be very useful to extend the test results to different test conditions.

The air entrainment in a transient diesel spray was studied using laser Doppler anemometry to provide information on the effect of gas density and temperature. The spray was injected vertically into a confined quiescent atmosphere and the entrained mass flow rate was evaluated by measuring the air velocity component normal to a cylindrical geometric surface surrounding the spray, and extending to about 200 nozzle diameters (50 mm). The experimental results, relative to a density range from 0.84 to 7.02 kg/m3 and a temperature range from 293 to 473 K, indicate that the non dimensional entrainment rate, averaged in time over the main injection period, depends on the distance from the nozzle and both gas density and temperature. A first analysis, based on the available data, allowed to quantify the dependence and provided a correlation with such variables.

The pressures on the Automotive Industry from both future legislation and customer requirements mean that major changes in Powertrain and Vehicle Systems matching will be needed. This paper reviews some possible future technologies and describes the process by which the often mutually exclusive total vehicle performance objectives can best be satisfied. In conclusion the paper includes a brief case study showing a proposed solution to a set of possible future vehicle performance and fuel economy objectives. The process is based on empirical data, experience and w-here appropriate, analytical techniques.

A vehicle with a production 1.6 litre 4 valve per cylinder engine that achieved Tier 0 (US87) emission standards, has demonstrated Low Emission Vehicle (LEV) capability. Minimal base engine modifications, the applications of auxiliary air injection and exhaust gas re-circulation (EGR) extended the hardware platform. The systems ultimate potential was achieved by a system specific software and calibration approach.

Experience has shown that a vehicle equipped with Active suspension and rear wheel steering can be a very powerful tool for research into vehicle dynamics. Passive or “adaptiveu vehicle suspension systems can be emulated. This has considerable potential for shortening vehicle development times. Active systems provide the ability to separate dynamic modes from one another. This enables detailed examination of each effect without the cross coupling normally experienced with passive vehicles. The driver is an important part of the dynamic loop and ultimately it is he/she who must be able to control the vehicle with confidence, precision, and minimum fatigue. An Active vehicle is a powerful way to investigate the feedback and cues needed by the driver, and to produce objective requirements to achieve them. Thus armed, vehicle design, computer simulation and development functions can be more effective in getting better products more quickly to the market.

The influence of spray-wall interaction on air entrainment in an unsteady non-evaporating diesel spray was studied using laser Doppler anemometry. The spray was injected into confined quiescent air at ambient pressure and temperature and made to impact on a flat wall. The air velocity component normal to a cylindrical surface surrounding the spray was measured during the entire injection period, allowing to evaluate the time history of the entrained air mass flow rate. The influence of wall distance and spray impingement angle on air entrainment characteristics has been investigated and the results indicate that the presence of a wall increases the entrained mass flow rate in the region close to the surface, during the main injection period. Normal impingement appears to produce stronger effects than oblique incidence at 30 and 45 deg. A qualitative explanation of the results is also proposed, based on the drop-gas momentum exchange mechanism.

The use of a functional model in the development of vehicle ride and handling characteristics can provide significant information to the engineer to aid and shorten the development process. This approach forms part of the new vehicle development strategy currently being developed at Lotus Engineering. The paper presents a description of a functional model that has been developed and used in the evaluation of vehicle ride and handling characteristics. The basic construction of the model is described and output is validated against vehicle test data. A case study shows how the model can be used in conjunction with vehicle testing to identify particular vehicle performance characteristics and provide potential solutions. The functional model makes use of global vehicle characteristics such as compliance steer effects and bump steer characteristics, rather than modelling individual suspension components.

In order to reduce the development time involved in optimising the combustion system and valve timing of the internal combustion engine, an electro-hydraulic valve actuation system has been developed. The effects of various combustion strategies, including asymmetrical valve events, on emissions and efficiency, together with their sensitivity to EGR and AFR were investigated. In addition, the influence of the cylinder head design on in-cylinder charge motion and combustion was investigated by correlating airflow, tumble and swirl data to the heat release data obtained during dynamometer testing.

The design of recovery steam generators for incineration plants encounters certain specific problems, related to the nature of the exhausted gases, which, if not properly faced, can strongly condition the conduction of the whole system. Two problems, namely, demand for particular attention: the corrosion at high temperature and the formation of organochlorine compounds, in presence of ashes and/or deposits for definite temperature intervals. These phenomena can be controlled and minimized, whenever possible, by limiting to the greatest extent the regions where the temperatures of the metallic walls and of the ashes and/or deposits are within the critical interval.

Designers are under increasing pressure to provide powertrain systems which meet tougher market and legislative requirements for:- performance, emissions and economy reliability and durability noise and refinement To meet increasing competition, powertrain products need to be “fast to market and right first time”. This implies the evolution of existing technology, comprising multicylinder reciprocating engines and gear transmissions, drawing on a database of decades of powerplant design experience. It is with this background that CAE has proven engineering value supporting key areas of powertrain engineering to meet these technological challenges in a cost effective and timely manner. This paper follows the analytical engineering of a typical component, the exhaust system. Particular emphasis is given to the manifold and downpipe components which duct gas from the cylinder head to the catalyst.

High engine efficiency and low emissions on spark ignition engines can be achieved with a new camshaft profile switching device. This enables the use of two camshaft profiles for inlet and exhaust that can be switched independent of each other by any engine management input. This paper proposes the use of this device to give an excellent torque curve together with reduced emissions, by selecting from two discrete inlet and exhaust camshaft profiles and timings against engine parameters such as speed, load and temperature.

For 1989 introduction Lotus further developed its own 2.2 litre four-cylinder turbocharged engine to produce world-leading specific performance of 91 kw/litre (122 bhp/litre), for a production unit. This very high level of performance was achieved in compliance with current and proposed Federal and European emissions standards.