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Particle Reduced, Efficient Gasoline Engines

Periodic Reporting for period 2 - PaREGEn (Particle Reduced, Efficient Gasoline Engines)

Reporting period: 2018-04-01 to 2019-12-31

In the “Particle Reduced, Efficient Gasoline Engines” (PaREGEn) project, development of gasoline engines as used in mid to premium sized passenger cars is being made. With the electrification of smaller vehicles, suitable for zero emissions in urban environments, addressing mid to premium sized cars is especially important: the requirement for clean, efficient and economic engines for cars regularly used for inter-urban and regional transport becomes more urgent and more effective to address the challenges of air quality, decarbonisation and cost-effective mobility.
Through the use of state of the art development techniques, such as optical single cylinder engines, a range of modelling and simulation tools, and the application of novel engine componentry, the optimal trade-off between cleanliness and efficiency is being identified. Of special attention throughout this process is the contribution of such technologies to the reduction of particle emission numbers, including those small particles between 10 and 23nm in size.
The overall objective of the project is to demonstrate a new generation of gasoline direct injection engines achieving a ≥ 15% reduction in CO2 emissions through the optimal combination of advanced engine and robust catalyst plus filter (aftertreatment) technologies. Modelling and simulation software will be verified that can improve the design and the control capability of the resulting vehicles. These vehicles will comply with upcoming Euro 6 RDE limits with particle number emissions measured down to a 10nm size threshold.
Growing road traffic in Europe results in detrimental effects on the environment and public health. In particular, carbon dioxide (CO2) and noxious emissions may not be sufficiently reduced in real driving, whilst some technologies may have led to increases in the emissions of nanoparticles that are undetected currently. The challenge was to develop a new generation of engine technologies that is significantly more fuel efficient than the best 2015 equivalent, in order to help mitigate the climate change effects of road transport, and to demonstrate pollutant emissions levels compliant with the Euro 6 real driving emissions (RDE) limits plus particle number emissions measured down to 10nm size.

Globally, the gasoline engine will remain the dominant passenger car prime mover this decade. These vehicles show about 10% higher CO2 emissions for those with gasoline engines compared to diesel. Given this basis and projections that gasoline engines (including those in hybrid powertrains) remain dominant in light duty vehicles throughout this decade, then improvements in gasoline engines have a greater potential to lower the passenger car vehicle parc CO2 emissions than improvements in diesel engines. Further, in Europe those passenger car vehicles with the higher annual mileages are often those with higher CO2 emissions. The challenge for the industry is, therefore, to develop highly efficient engines and to improve exhaust gas aftertreatment systems, in order to meet EU legislation in real driving conditions. Simultaneously, the European automotive industry has to improve competitiveness in order to maintain substantial market volumes of high-quality cars.

In PaREGEn, further development of gasoline engines used in mid to premium sized passenger cars has been made. With the electrification of powertrains in smaller vehicles, suitable for zero emissions in urban environments, addressing mid to premium sized cars has been especially important: the requirement for ultra-low emission, efficient and economic engines (whether hybridised or not) for cars regularly used for inter-urban and regional transport becomes more urgent, especially in light of the recent falling market share of diesel engine vehicles, as well as more effective to address the societal challenges of air quality, energy efficiency (decarbonization) and cost-effective mobility. Furthermore, it should be remembered that, should drop-in low carbon or net-zero carbon fuels become available in the coming decade, then it is the type of passenger car vehicles being developed in PaREGEn, that could contribute most to the additional defossilisation realisable.

Through the use of state of the art development techniques, such as optical single cylinder engines, a range of modelling and simulation tools from 0D to 3D (for understanding of in-cylinder particle formation process) and the application of novel engine componentry (next generation fuel or water injection and ignition equipment, boosting systems and exhaust gas aftertreatment technology), the optimal trade-offs between ultra-low emissions and efficiency have being identified. Of special attention throughout this process was the contribution of such technologies to the reduction and control of particle numbers, including those particles between 10 and 23 nm in size. One of the most valuable contributions from this project has been that the new modelling and simulation tools benefit engine design, development and control in general, long after the project is completed.

This learning has been used for the generation of two demonstration vehicles. The approaches to achieving the efficiency targets are different in each, using different combustion system, injection (fuel and water), ignition and dilutent technologies, different engine air handling systems and different aftertreatment packages. As such, the progress within the project has given insight into the best way forward to meet the requirements for these gasoline engines in all vehicle classes during this new decade.
Over the next one-and-a-half years the component, engine and aftertreatment technologies, now specified in concept, are being evaluated on the engine test bed and, if effective, will be fitted into two demonstrator vehicles for independent evaluation. The simulation tools will be validated through further experiment and the learning transferred into the control systems of the future vehicles. The step thereafter is market introduction: it is the full intention that the innovative technologies developed will be applied by others in the industry to ensure the maximum impact from the project. A roadmap to implementation of the technologies has been devised and is supported by more detailed plans relating to how the supply industry, for either the hardware or the simulation tools and techniques, will feed into this implementation.
The project PaREGEn has committed to achieve a 15% CO2 reduction along with real driving emissions targets. If successful and adopted across all light vehicle classes, these short-term gasoline engine developments are projected to reduce the European vehicle parc CO2 emissions by about 2.0 Mtonnes CO2 in 2025 and up to 10 Mt CO2 together with a 10% reduction in particle numbers >10 nm in 2030. In addition to improving the European competitiveness, one of the most valuable contributions from this project will be that the new modelling and simulation tools to benefit engine design, development and control in general long after project's end.
Concept Fig 1