Turbo-Discharging: Reducing CO2 Emissions from Current and Future Vehicles

Turbo-Discharging is a fundamentally new approach to using internal combustion (IC) engine air systems to improve fuel economy, reduce engine CO2 emissions and simultaneously increase engine torque. Using a novel divided exhaust flow arrangement, the blow-down flow and the associated energy usually lost as part of the exhaust flow is recovered by a turbine. During the main displacement flow the turbine is by-passed and the crankshaft does not have to do any work exhausting the burnt gases through the turbine. The result is the recovery of the blowdown energy without negatively impacting the engine crankshaft torque. This energy is then innovatively used to depressurise the exhaust system which generates extra crankshaft torque during the exhaust stroke giving a primary torque increase and CO2 emission reduction.Secondary benefits include increased energy availability from the blowdown pulse and potentially improved low speed torque (through increased pressure drop across the turbine). There will be less hot exhaust gas residuals within the cylinder which will extend the knock limit of turbocharged spark ignition engines allowing further downsizing than is currently possible.Importantly, the effect on the combustion system is negligible allowing the Turbo-Discharging approach to be used with all current and future IC engines without significant redesign. The impact on CO2 emissions could therefore be much larger than costly technologies offering larger CO2 reductions in only small niche markets.Turbo-Discharging requires the addition of a turbine and compressor (as used in a conventional turbocharging system) and does not require complexities such as wastegating or variable geometry turbines. The cost is therefore small, placing the technology in a very competitive position compared with many other CO2 reducing technologies. With engine manufacturers requiring combined technologies to meet future CO2 emission targets, this technology will be very attractive to industry. Initial contact with industrial has shown that experimental demonstration of this technology is needed before they will invest. This project will experimentally study, develop and demonstrate Turbo-Discharging as a feasible, cost effective and novel approach to reducing IC engine CO2 emissions, ultimately leading to industrial collaboration and implementation of Turbo-Discharging on-vehicle.

Turbo-Discharging has the potential for significant real world fuel economy and CO2 reductions in applications such as passenger cars, commercial transport vehicles, off-road vehicles and machines e.g. power generation. New technologies to reduce fuel consumption that are cost effective and allow product differentiation will have a very significant impact in these markets. Turbo-Discharging has the potential to increase engine torque as well as improve fuel economy under most engine conditions, which is very unusual for new engine technologies. It is also predicted to be a very cost-effective solution applicable to all IC engines. The benefit of such a technology that improves fuel consumption on a large proportion of the vehicle fleet is much greater than one offering larger fuel economy benefits only in small niche markets. In the current economic climate where multiple technologies are needed to meet CO2 targets this will be very attractive to industry. Additional benefits from this technology include lower emissions (e.g. particulate matter, NOx, CO and HC, which scale with fuel consumption) that may reduce demand on and associated cost of emission after-treatment systems. Future engine developments such as exhaust thermal energy recovery are directly synergous with this technology meaning that the cost-benefit will improve. This research will open a new product area for the automotive industry enabling new businesses to start. Such a fundamentally new way of applying turbocharger technology requires a shift in how to design, develop and apply the technology to engines. This will result in new skills and business opportunities. Aftermarket business will grow as the technology is suitable as an add-on to existing IC engines offering fuel economy, emissions and performance improvements. Individual businesses (in e.g. construction or transport logistics) will benefit from reduced operating costs and potentially tax benefits. Torque and power improvements will also improve market position for automotive manufacturers and heavy duty engine manufacturers. This directly contributes to the UK's efforts to reduce CO2 emissions from IC engines. The economic impact is, therefore, potentially very large. Since this technology is using existing hardware in a fundamentally new and innovative way, it can be rapidly developed. It is anticipated that a successful demonstration of this technology will be achieved within this project and will lead to a collaborative project with industry. This work is ideally suited to lead onto a future TSB supported project. In addition to the technological impact, this project will give applied turbo-machinery experience to the Research Associate and PhD student. This will support high quality training within the University and output highly trained researchers with experience ideally suited to the advanced automotive industry where downsizing of engines is becoming prevalent. This will lead to long term economic reward from this research. To realise these benefits it is important to prove the feasibility of the technology to industry and gain strong support from key industrial organisations. A thorough communications and engagement plan (see the Impact Plan) has been documented to maximise the exposure of this work and generate further industrial support. The PI has significant experience working directly with the IC engine industry with such notable companies as Jaguar, Caterpillar (inc. Perkins) and Lotus and his work has contributed to their current and future products. His time as a chairman of UnICEG (which is strongly attended by industry) makes him well known outside of his direct fields of research and has resulted in many contacts already in place to begin the engagement of industry.