Computer Modelling of Temperature Distribution in Brake Drums for Fade Assessment

Simulation of the temperature distribution in a brake drum of a commercial truck is carried out using the finite element method. Verification of the predicted values is done using an inertia dynamometer with a data logging system. The effect of variable convective heat-transfer coefficient and the effect of contact area are also studied. From the investigation it is concluded that the present model can be used for the simulation of temperature distribution in rigid brake drums during a fade test.

Relating Vehicle Emission Regulations to Air Quality

The European regulations governing the emissions of gaseous pollutants from gasoline-engined motor vehicles is reviewed and discussed, including the so-called ‘Luxembourg Agreement’. The relationship between the regulation emission limits and those measured in practice from ‘as-received’ vehicles in use is also discussed. Having discussed the relationship between regulations and emissions, the further relationships between vehicle emissions and air quality are also discussed, giving particular attention to carbon monoxide, oxides of nitrogen and lead.

Performance Predictions for a Pneumatic Active Car Suspension System

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.

A Technique for the Accurate Measurement of Low Values of Rolling Resistance

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 Remodelling of Crewe Machine Shops: The Opus Programme

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.

Technical Considerations for Catalysts for the European Market

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.

Engine Friction—A Change in Emphasis

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.