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Use of fossil fuels in automotive sector is one of the primary causes of greenhouse emissions. The automotive engines need to perform at their best efficiency point to limit these emissions. Most of the quality indicators in this regard are based on near steady state global operational characteristics for engines without considering local performance. In the present study, extensive numerical simulations have been carried out covering a wide range of steady state and transient operating conditions to quantify interaction of turbocharger with engines through turbo lag phenomena which may cause increased emissions during the load change conditions. Furthermore possible innovations have been explored to minimize turbo lag phenomena. The paper aims to discuss these issues.

In this paper quality indicators have been developed to quantify the performance of turbocharged diesel engine under the transient event of rapid change in fueling rate which has been rarely investigated. The rate of fueling is changed from 40 mm3/injection to 52 mm3/injection at 1,000 rpm engine speed which corresponds to normal operating condition. To improve quality of transient response, torque assistance method and reduction of inertia of compressor wheel have been used. Parametric study has been undertaken to analyze the quality indicators such as outlet pressure of the compressor and the compressor speed. The turbo lag is quantified to obtain the close to optimal transient response of turbocharged diesel engine.

It has been shown that, with torque assist the transient response of the internal combustion engine is significantly improved. On the other hand, marginal improvement in transient response is observed by the reduction in inertia of the compressor wheel.

The findings indicate that turbo lag can be minimized by providing torque assistance by active and passive means.

The developed methods can be used in practice for efficient operation of vehicles.

The work carried out in the paper provides a way to minimize harmful emissions.

The quality indicators developed provide a quantitative measure of turbo lag phenomena and address the above mentioned problems.

TURBO‐CHARGING, of road vehicle engines, using exhaust gas‐flow to drive the turbine wheel, has been slow to catch on in this country. But it now gets a fillip from development work by Garrett Automotive Group, part of Allied Signal Inc.

This paper aims to propose positive and negative firm competitiveness effects of knowledge acquisition of pertinent, irrelevant and erroneous knowledge based on its distinctiveness, the source of knowledge and the presence of firm complements.

Aspects of knowledge acquisition from the innovation, knowledge and routines literatures are integrated to create propositions showing the effects of knowledge acquisition on firm competitiveness. Examples from different eras of the automobile industry are used to illustrate the propositions and demonstrate the enduring nature of these issues.

Various combinations of firm complements and knowledge type and criticality can cause significant competitive effects, such as parity, relative harm and opportunity capture, that managers should be cognizant of when planning knowledge acquisition.

Knowledge researchers should use a more integrative, holistic approach concerning firm resources to their empirical studies. This better allows for the competitive effects of interactions between new and existing firm resources to be captured.

The propositions emphasize the importance of increased managerial attention and understanding of potential problems of new knowledge acquisition. Moreover, managers should pay particular attention to their firm’s existing complements when assessing knowledge acquisition benefits.

The positive value of firm knowledge receives substantially more research attention than the potential negative effects. This paper identifies the competitiveness effects of acquiring pertinent, irrelevant or erroneous knowledge. Increased attention on the interaction of new knowledge and complements illustrates the positive and negative effects on firms.

The starting hesitation of a switched reluctance motor (SRM) is an issue which must be considered in the early motor design. It is mostly handled as a control concern. The starting procedure of a SRM using a single Hall-effect position sensor is analysed in this paper. This low cost position measurement solution requires a specific control strategy. That has been developed for a three-phase 6/4 SRM. The paper aims to discuss these issues.

The starting procedure begins with a rotor alignment step intending to bring the rotor to a known position. Afterward, only one phase is supplied on a periodic basis, to drive the rotor in the desired direction and accelerate up to a predefined speed threshold. Thus, the proposed procedure drastically simplifies the control strategy and permits a low cost sensor based control. 2D finite elements simulations are performed to analyse the starting performances in terms of response time and power efficiency. Both electrical and mechanical transients are considered in the simulation model thanks to simplifying assumption which consists in applying a time averaged voltages instead of instantaneous switching. Finally, the entire starting procedure with a one phase supply procedure is tested experimentally.

A starting procedure of a three-phase SRM is implemented. The control effectiveness is validated by complementary FE calculations and measurements.

The starting hesitation issue of a three-phase SRM is solved with an easy control strategy. During the acceleration phase, only one phase is self-controlled.

TO deliver a lecture in commemoration of the Wright Brothers before the Institute of Aeronautical Sciences is a great honour of which I am deeply aware: this honour one feels is due not solely to the technical situation but to somemore subtle link between the Institute and the Royal Aeronautical Society and our two countries.

In this two‐part paper, aeroelastic analysis of turbomachinery blade rows and phase‐lagged boundary conditions used for analysis are described. Part I of the paper describes a study of phase‐lagged boundary condition methods used for non‐zero interblade phase angle analysis. The merits of time‐shifted (direct‐store), Fourier decomposition and multiple passage methods are compared. These methods are implemented in a time marching Euler/Navier‐Stokes solver and are applied to a fan for subsonic and supersonic inflow and to a turbine geometry with supersonic exit flow. Results showed good comparisons with published results and measured data. The time‐shifted and Fourier decomposition methods compared favorably in computational costs with respect to multiple passage analysis despite a slower rate of convergence. The Fourier‐decomposition method was found to be better suited for workstation environment as it required significantly less storage, although at the expense of slightly higher computational cost. The time‐shifted method was found to be better suited for computers where fast input‐output devices are available.

Part II of the two‐part paper describes an aeroelastic analysis program and its application for stability computations of turbomachinery blade rows. Unsteady Euler or Navier‐Stokes equations are solved on dynamically deforming, body fitted, and grid to obtain the aeroelastic characteristics. Blade structural response is modeled using a modal representation of the blade and the work‐per‐cycle method is used to evaluate the stability characteristics. Non‐zero inter‐blade phase angle is modeled using phase‐lagged boundary conditions. Results are presented for a flat plate helical fan, a turbine cascade and a high‐speed fan, to highlight the aeroelastic analysis method, and its capability and accuracy. Obtained results showed good correlation with existing experimental, analytical and numerical results. Numerical analysis also showed that given the computational resources available currently, engineering solutions with good accuracy are possible using higher fidelity analyses.

The axial magnetic field occurs in the end-region of large turbo-generators is known to induce hot points or voltages between laminations, that may cause insulation breakdown and thus stator faults.

It is important to dispose of simple methods for estimating the axial flux rapidly with regard to the operating point of the machine.

The authors provide a practical model of the axial magnetic field based on a simplified vector diagram. The parameters required to build the vector composition of the flux densities are assessed with a limited number of finite element method simulations of the whole end-region of the machine. These simulations were validated by an experimental test on a real turbo-generator. Then the axial flux density was simply estimated for various operating points.

The originality of the paper concerns the practical model of the axial magnetic field based on a simplified vector diagram.

At the end of the second world war the electricity generating capacity of this country lagged seriously behind the consumer demand. In order to rectify this deficit two standard sizes of generating set were adopted. These were the 30 and 60 megawatts (MW) generators. Since then, to improve the Rankine cycle efficiency, set sizes have steadily increased and today 200‐MW sets are accepted practice and 550‐MW machines are being designed. The increase in turbo‐alternator size has had repercussions on condenser design, some aspects of which may increase the corrosion hazard. This has stimulated interest in the development of effective countermeasures, especially the application of cathodic protection.