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Gear mesh transmission error is a phenomenon that can lead to the troublesome noise known as gear whine. It is therefore important to be able to predict transmission error so it can be minimised at the design stage. This paper presents various methods of predicting transmission error and the importance of considering the effects of other components in the gearbox. The difficulty in predicting planetary gear transmission error is then explained and a software package that can predict it described. A simple one-stage planetary example then shows typical planetary gear transmission error results.

As legislation demands continually lower emissions of regulated pollutants, i.e. hydrocarbons, NOx, CO and particulates, vehicle and engine manufacturers have turned to catalyst technology in an attempt to achieve the ever more stringent limits. This technology has now been extended to diesel powered vehicles and a number of manufacturers are fitting oxidation catalysts as standard. This work presents experimental data to show the effectiveness of oxidation catalyst technology in reducing exhaust HC emissions from a modern high speed diesel engine. It tested the ability of the catalyst to reduce HC emissions at a range of steady state speed and load combinations to assess the controlling factors in catalyst efficiency. The work found that exhaust gas temperature is the most significant controlling factor in determining catalyst efficiency. This is significant because at low speed and load the exhaust of a diesel engine is below the light off temperature of the catalyst.

Ever increasingly stringent emissions regulations throughout the world mean that manufacturers have to pay more attention to the emissions performance of both spark ignition and compression ignition engines. Electronic engine management systems allow close control engine operating parameters, providing a means for tuning engines for low emissions with minimal costs in terms of performance. The aim of this paper was to quantify the effect of two tune parameters, start of injection timing and EGR rate, on the exhaust emissions of a modern, electronically controlled high speed direct injection diesel engine. The paper will present emissions data taken from the engine running at two speeds and load combinations representative of typical engine operating conditions during the European emissions cycle. At each of these points the tune strategy was varied and the results observed.

We show that the space prohibitive laboratory adiabatic demagnetization refrigerator properties of high magnetic field and a <2K environment (provided by a bath of liquid He4) can be alleviated, without a significant decrease in operational efficiency, through the use of a 2 or 3 salt pill refrigerator rather then the classical single salt pill design. The additional salt pills providing intermediate cooling stages, enabling operation from a 4K environment which can be provided by a single mechanical cooler. For such ADRs the minimum magnetic field required is 2 and 1 Tesla for the 2 and 3 salt pill cases respectively. Such low magnetic fields allow the possible use of permanent and high temperature mechanically cooled superconducting magnets, avoiding the danger of quenching of the superconducting magnet. We conclude that such ADRs offer a long orbital life time, high efficiency means of sub Kelvin cooling.