An account of the genesis of the Jaguar XK120 is given, and the engine and car are described in some detail.
This paper describes BREL's approach to cost effective small batch manufacture through the introduction of group technology machining cells, new computer systems for part programming and manufacturing control, and the standardization of tooling and raw material.
The changing technologies and skill requirements in the maintenance of traction, rolling stock and plant and machinery have demanded a reappraisal of the training requirements for mechanical and electrical engineering regional workshop staff. This has led to the development of a modular training programme, which includes segments of training appropriate to the work location and the potential of the individuals. An investigation of conventional training schemes within British Rail's Mechanical and Electrical Engineering Department was undertaken. The training procedures operating in other transport organizations were also analysed. All types of work progressed in mechanical and electrical engineering areas and depots have been considered, including coach body making, plumbing, welding, as well as fitting and electrical work. Proposals in respect of mechanical and electrical engineering depot strategy which incorporates the impact of design and development of new products have also been considered. Also included are the implications of the significant change in the maintenance policy introduced in April 1987 for all British Rail's traction and rolling stock, with its emphasis on component changing. The information gathered from these various sources has enabled key areas for training development to be identified and the future training strategy to be formulated.
The kinematic, primary and secondary handling regimes are analysed. The design factors contributing to the understeer gradient are reviewed and representative values for a modern car are presented. The effects of three types of differential are considered, as are tractive forces on free differentials, aerodynamic forces, the effect of load increments and the effects of turning radius. Secondary handling is investigated and the main contributing factors to the non-linearity of steer angle and attitude angle are quantfied.
Axle loads for laden road tankers depend upon the configuration of the liquid tank. The paper determines the location of the centre of gravity of a liquid load in a tilted cylindrical barrel tank with dished and flanged ends and shows how the centre of gravity varies with the amount of liquid carried. The calculation permits greater accuracy in the determination of axle loads.
A fundamental theory concerning the theoretical power-torque envelopes over the speed ratio range of a general variable ratio belt drive is presented, to the best of the author's knowledge, for the first time. This theory applies to both V and flat belt drives, and is independent of the detailed designs. The analysis is based on two limiting factors, namely the maximum tension and the tendency of the belt to slip bodily on one or both pulleys assuming that the centre distance and the belt length are constant. These above factors determine the power and torque envelopes. The most suitable envelopes for the design purpose of the variable ratio belt drive are those of compact size, maximum belt tension and relatively high transmitted power.
A mathematical model of a pneumatic active car suspension system in a single wheel station form excited by realistic road roughness input is set up. The active control is exerted through a d.c. motor-driven air-pump. The model is used to show that essentially all the advantages of active control, within the terms of reference, are obtained by employing the control only at low frequencies and having the suspension parameters adapt to the running conditions as they vary. Control laws are derived using limited state feedback, linear stochastic optimal control theory and power consumption, and space requirements are evaluated. System performance is shown to be good in comparison with other known arrangements and encouragement for further work to extend the results is given.
The durability of automotive catalysts for European applications were investigated as a function of higher temperatures encountered in autobahn driving over extended periods of time, potentially higher lead levels anticipated in the beginning in European unleaded fuels and occasional misfuelling with leaded fuels. Increasing residual lead levels from 3 mg Pb/L to 10 mg Pb/L in laboratory experiments at 1000°C peak temperature substantially decreased three-way catalyst (TWC) performance. Higher temperature ageing conditions from 730 to 1000°C resulted in 50 per cent loss of BET area and increased stoichiometric light-off temperatures. The paper also reviews briefly the role of noble metals, rare earth oxides and base metal oxides in the formulation of practical TWCs. The operation of a TWC and the effects of A/F modulation frequency and amplitude on its performance are also discussed. Important thermal and chemical modes of TWC deactivation are discussed with specific examples. The importance of matching the active metal component to the support material to achieve the desired metal-support interactions and how this understanding has led to the development of practical TWC with proper utilization of noble metals is emphasized. Finally, the lean-burn versus stoichiometric combustion approach as it relates to catalyst requirements is also discussed.
Following the completion of the new rail lines, now under construction between Hannover, Würzburg, Mannheim and Stuttgart, the German Federal Railway will introduce a new concept in high-speed passenger travel which heralds the use of the new high-speed trains called Intercity-Express. As a forerunner of this new generation of vehicles, the Intercity-Experimental train was first put into operation in 1985. It incorporates the results of a systematic study of wheel-on-rail research and will open up a new dimension in travel when Intercity-Express is in full operation. From test running, which on 17 November 1986 led to a new German speed record of 345 km/h, a new series of test results was obtained which is reported here. The production Intercity-Express trains are briefly described; these will come into fleet operation in 1991.
The influence of fuel enrichment levels on the transient response of a single-point injected engine is reported. The measurements were made on a 1600 cc, four-cylinder engine driving an eddy current brake and linked to a set of inertia flywheels. Throttle ramps of 0.3, 1 and 2 second duration were used and the response of the engine was determined from in-cylinder pressure measurements and, in terms of torque, from the acceleration of the flywheels. The influence of parameters such as manfold temperature and size on the optimum enrichment pattern was then investigated. Measured data are compared with corresponding predictions from a simple model of fuel and air behaviour in the intake system. The results show that for the limited range of conditions explored, the model appears to give a reasonable approximation to the measured values.
The movement of pedestrians after frontal impact with vehicles and the inter-relationship between pedestrian throw distance and the pre-impact velocity of the vehicle is of interest in accident reconstruction. This paper derives a single-segment rigid-body model for the primary and secondary impacts between the pedestrian and the vehicle. Published data on staged collisions involving horizontal flight are used to derive pedestrian-ground friction coefficients and show that the friction coefficient decreases with increasing speed. The analysis shows that for horizontal flight the throw distances of adults and children are similar. For impacts with cars the model for primary and secondary impact yields calculated throw distances that closely match published results for staged collisions between cars and dummies and cadavers.
This paper describes the results of an investigation into the effects of the characteristics of the suspension system, initial track tension, vehicle weight and location of the centre of gravity on the tractive performance of tracked vehicles over unprepared terrain. The investigation was carried out using a newly developed computer simulation model NTVPM-86. The results show that the suspension characteristics, initial track tension and vehicle weight have noticeable effects on the mobility of tracked vehicles over marginal terrain, while the location of the centre of gravity, within the normal range, has a less significant influence on the tractive performance. It is demonstrated that the simulation model NTVPM-86 can play a significant role in the optimization of tracked vehicle design or in the evaluation of vehicle candidates for a given mission and environment.
The paper introduces the maintenance schedule as an integral part of the controls for planned maintenance and reviews the historical development of locomotive maintenance schedules and specifications within British Railways (BR). The events which led to the publication of maintenance schedules for locomotives and rolling stock in a variety of formats and content are explained, culminating in the 1985 decision to produce all such future documents to one standard, taking account of simplification of use at BR depots, the new maintenance policy and the benefits of computerization. The purpose of the maintenance schedule and its supporting documents is redefined in relation to the new maintenance strategy of BR and a new rationale introduced. The standard format is confirmed and the mechanisms for ensuring its maintenance explained. Future requirements associated with development of standard job descriptions, decoupling component overhauls from body overhauls assisted by a computerized maintenance schedule and the changes in overhaul specification promoted by BR's developing contract overhaul policy are described in detail.
This paper outlines the development of transmissions for commercial vehicles from 1895 to the present day. The contribution of transmission engineers to the automotive industry in the United Kingdom, Europe and the United States is reviewed, and some individual transmission systems are described in detail. The author predicts possible future trends in commercial vehicle engineering.
Twenty-two, 3 M W freight locomotives are being supplied to New Zealand Railways Corporation as part of the 25 kV electrification project of the North Island Main Trunk route. The mountainous terrain of this route favours a Bo-Bo-Bo configuration with its good curving performance. Separately excited d.c. traction motors fed from microprocessor-controlled thyristor bridges enable 1000 tonne trains to be started on a I in 50 gradient. The provision of a regenerative brake offers significant energy cost savings.
This paper reviews the evaluation of experimental methods for determining friction in engines. The latest techniques permit the investigator to examine changes of tribological behaviour in the engine. The use of these newer methods to improve conventional engines by design changes and to facilitate the introduction of novel materials is discussed.
This paper describes a method of measuring rolling resistance for vehicles with relatively high mass and low rolling resistance. The technique, in which the deceleration of a test vehicle is measured, overcomes some of the problems of other methods and allows a wide variety of surfaces to be used. Computerization is used for automatic timing and data processing. The implications of surface flatness and instrumental accuracy are discussed and the analysis of an experimental investigation shows that accuracies to within 3 per cent are possible.
The basic principles of stepper motors are explained. Under certain circumstances it is shown that a stepper motor may be a better option than a servo motor. The three most common types of stepper motor are described and their important characteristics are illustrated and explained. Finally, the principles of stepper motor drives and the various types available are analysed.
This paper presents some of the general practical problems involved in the design of a high-reduction compound planetary gear drive and examines such a drive for high speed ratio, power circulation and efficiency. The performance of the drive with respect to efficiency of 50–60 per cent has been obtained under various running conditions such as speed, load and temperature. An attempt was also made to balance internal forces in order to increase efficiency. At first sight, the number of factors involved appears to make it impossible for a general analysis of the problem to be made, but broad conclusions have been drawn.
The air-quality situation in Europe in relation to automobile exhaust emissions is described. In addition the European exhaust emission legislation and the consequences to engine concepts are discussed.
