The work was concerned with the design, analysis and basic demonstration of a novel hydraulically assisted fixed geometry turbocharger system intended to help overcome some of the transient issues associated with current automotive boosting technologies. The novel system was based upon use of relatively lightweight parts, where kinetic energy is recovered during vehicle braking, stored in a simple hydraulic accumulator and then used later on to rapidly accelerate the engine's turbocharger. The turbocharger is fitted with a replacement centre housing enclosing a small impulse turbine, rigidly mounted to the turbocharger shaft and powered by a jet of oil. The aim is one of helping the engine to accelerate the vehicle while operating in a region of much higher brake efficiency due to the reduction in exhaust backpressure when compared with competing variable geometry and/or compound boosting technologies. The specific tasks involved concept design and computational analysis, including specification of the turbine type and geometry together with the associated hydraulic parts. A production turbocharger was reverse engineered to confirm the feasibility of packaging the hydraulic turbine system into the centre housing of a typical fixed geometry design. Finally an experimental rig was designed and manufactured to allow basic demonstration of the system, with speeds of up to ~90000 rpm @ 200 bar pressure from the pump via the accumulator achieved in ~0.8 seconds and clear potential for further optimisation. This hydraulic boosting system is capable of attaining 70% efficiency (a product of 0.85 from the oil pump, 0.95 from the hydraulic accumulator and 0.88 of Pelton wheel). The system has higher power density at low cost compared to the main competitor ‘E Boosting - with efficiency in the region of 90%’. The cost of E boosting and need for 48 volt battery makes it less favourable compared to the hydraulic turbine system. The concept has been shown to offer significant potential to assist a turbocharger to spool up via a Novel Hydraulic Kinetic Energy Recovery System approach.

The growing market of mobile electronic devices, renewable off-grid energy sources and electric vehicles requires high-performance energy storage devices. Rechargeable batteries are usually the first choice due to their high energy density. However, supercapacitors have a higher power density and longer life-time compared to batteries. For some applications supercapacitors are more suitable than batteries. They can also be used to complement batteries in order to extend a battery's life-time. The use of supercapacitors is, however, still limited due to their high costs. Most commercially available supercapacitors contain expensive electrolytes and costly electrode materials. In this thesis I will present the concept of cost efficient, paper-based supercapacitors. The idea is to produce supercapacitors with low-cost, green materials and inexpensive production processes. We show that supercapacitor electrodes can be produced by coating graphite on paper. Roll-to-roll techniques known from the paper industry can be employed to facilitate an economic large-scale production. We investigated the influence of paper on the supercapacitor's performance and discussed its role as passive component. Furthermore, we used chemically reduced graphite oxide (CRGO) and a CRGO-gold nanoparticle composite to produce electrodes for supercapacitors. The highest specific capacitance was achieved with the CRGO-gold nanoparticle electrodes. However, materials produced by chemical synthesis and intercalation of nanoparticles are too costly for a large-scale production of inexpensive supercapacitor electrodes. Therefore, we introduced the idea of producing graphene and similar nano-sized materials in a high-pressure homogenizer. Layered materials like graphite can be exfoliated when subjected to high shear forces. In order to form mechanical stable electrodes, binders need to be added. Nanofibrillated cellulose (NFC) can be used as binder to improve the mechanical stability of the porous electrodes. Furthermore, NFC can be prepared in a high-pressure homogenizer and we aim to produce both NFC and graphene simultaneously to obtain a NFC-graphene composite. The addition of 10% NFC in ratio to the amount of graphite, increased the supercapacitor's capacitance, enhanced the dispersion stability of homogenized graphite and improved the mechanical stability of graphite electrodes in both dry and wet conditions. Scanning electron microscope images of the electrode's cross section revealed that NFC changed the internal structure of graphite electrodes depending on the type of graphite used. Thus, we discussed the influence of NFC and the electrode structure on the capacitance of supercapacitors.

Limitations in energy recovery technology require extended research for development of existing and alternative solutions. This thesis project has treated valuing pneumatic drivetrain independent energy recovery system as a potential solution. The prototype built during this project uses a piston compressor to transform kinetic energy into compressed air. The compressed air was then stored in two air tanks and transformed into kinetic energy with an air motor on demand. The prototype was built on a rig using a high power electrical engine to simulate energy input from the wheels during braking. The air motor was then used to rotate a Volvo S40 engine simulating energy output to the wheels. To further illustrate how the technology can be implemented in vehicles and to emphasize the variety of pneumatic energy recovery solutions a 3D CAD model was designed and other components was reflected. Such as using a screw compressor instead of piston and also using the compressor as a motor reducing the number of components optimizing the system. The system storing the kinetic energy does not mean that the vehicle can manage without an ordinary brake system. The regenerative braking effect rapidly reduces at lower speeds; therefore friction brake is still required in order to bring the vehicle to a complete halt.Analyses of strength of strained components acknowledge that limited energy recovery is possible without redimensioning the driveshaft´s. The limitation is regulated by the original dimension for engine load, with subject to the CV joint. Optimum positioning of the compressor due to the limited space in a modern vehicle is behind the gearbox in conjunction with the gearbox outgoing pinion for short energy transportation.Electrical energy recovery system is the solution with the highest potential on the market today but electrical vehicles covers just a fraction of the vehicle industry doe to technical and infrastructural limitations. Drivetrain independent pneumatic, hydraulic or mechanical energy recovery systems lay the foundation of a common ground for all vehicles and other waste energy machinery to use one energy recovery technology. The market research indicates that this type of technology is up-to-the-minute. / <p>Validerat; 20110106 (anonymous)</p>