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The potential of the turbogenerator-based power-train for hybrid vehicles is described. Data from a small gas turbine, a prototype high-speed generator and an advanced lead-acid battery pack show that the ‘turboelectric’ concept is feasible and can provide a viable road transport solution which will comply with the stringent environmental legislation. The simulation results show improved overall vehicle efficiencies due to the implementation of regenerative braking capability. Most importantly the lean combustion of the gas-turbine engine with a suitable energy control strategy can provide lower emissions than ultra-low-emission vehicle (ULEV) limits, while an acceptable zero-emissions vehicle (ZEV) driving range can be achieved for city centres.

The project relates to the design and development of a prototype high-speed turbo-generator as the thermal engine in a series hybrid vehicle. The substantial benefit of the turbo-generator against a diesel generator lies in the very high power±weight, power±volume ratio and renders itself particularly attractive for use in hybrid vehicle applications. However, to achieve a 50 kW power output, the turbo-generator has to have an operating speed of 60 000 r=min and thus important mechanical problems have to be solved. The core of this study addresses the requirement for an adequate understanding of rotor-dynamic behaviour by combining the results from both analytical and practical techniques. The assessment of modal testing, finite element analysis and vibration±condition monitoring, their feedback within the design-make-andtest procedure and the practical compromises and design constraints are presented and a design methodology is formulated. It is concluded that, under certain conditions, the prototype generator can be directly coupled to a small gas turbine, can operate safely and can produce the required power output.

The recent increase in vessel shaftline bearing incidents indicates that a static shaft alignment design may not be suitable for all operational shaftline loading conditions. Hull deflections caused by vessel loading or propeller loads initiated by interaction with the wakefield have become important considerations in modern vessel design. Jack-up tests, typically used as a bearing load verification method, can only be accomplished under static shaft conditions and cannot verify the shaft dynamic behavior under running operational conditions. A newly developed sensor using strain gauge technology measures the bearing load and the shaft misalignment angle through the bearing housing's deformation-induced strain. It effectively converts the bearing housing into a weighing machine by mapping the bearing housing strain onto the bearing load. Unlike jack-up tests, this method allows for the continuous measurement of the bearing load and misalignment angle under all shaftline operational conditions. It is envisaged that this technologically simple system will allow for the earliest possible diagnosis of shaft alignment-related problems, such as bearing unloading, bearing overloading, or excessive shaft-bearing misalignment. This provides a much earlier warning indicator when compared with the bearing temperature alarm. The subject technology has been tested on intermediate bearings and is considered for future application into stern tube bearings. 1. Introduction In post-IMO's (International Maritime Organization) Energy Efficiency Design Index vessel designs, the propulsion shafting arrangements become increasingly sensitive to shaft alignment with lower tolerances and margins, increasing the risk of stern tube bearing failures (Leontopoulos 2016a). This change is due to the wider use of more efficient, larger diameter propellers with increased cantilevered load on the shafting system and shorter shaftlines as a result of maximizing cargo space and minimizing engine room length. Widespread application of the single stern tube bearing design (an arrangement without a forward stern tube bearing) has also highlighted a decreased tolerance to eccentric propeller thrust and propeller forces in general. Reduced tolerance to shaft alignment sighting errors, bearing offset inaccuracies and other shaft installation errors, also affects the integrity of the shafting system and can result in complete bearing wiping with the consequence of vessel propulsion immobilization. This undesirable consequence has increased, particularly during the years 2013–2017.

A fully functional prototype sensor has been developed to provide new insights into vessel shaftline dynamics that introduces real time data collection and performance evaluation. The Smart Bearing Sensor was recently tested onboard a large container vessel and was shown to work with promising results. The sensor is based on strain gauge technology and has been shown to enable continuous measurement of the bearing reaction load through the strain induced onto the bearing housing by the shaft. Given the capability of continuous monitoring and recording of the bearing reaction load and shaft misalignment angle, the prototype sensor removes the need for jack-up tests for re-alignment purposes. It is envisaged that this system will allow for the earliest possible diagnosis of shaft alignment-related problems, such as bearing unloading, bearing overloading or excessive shaft-bearing misalignment. The prototype sensor could be incorporated into a marine condition monitoring system that provides a more timely warning against bearing failures, particularly when compared to bearing temperature sensor indications.