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High efficient Particulate free Gasoline Engines

Periodic Reporting for period 1 - UPGRADE (High efficient Particulate free Gasoline Engines)

Reporting period: 2016-10-01 to 2018-03-31

The UPGRADE project addresses very precise and consistent objectives to support the transition to high efficiency, clean and affordable powertrain technology systems, based on Spark Ignited GDI (Gasoline Direct Injection) approach, suitable for future Light Duty applications.
The project also includes a deep analysis of the phenomenon of formation of the nanoparticles in relationship to the engine design and its operating conditions, through both experimental and numerical investigations. Thanks to these activities, understanding and prediction of soot formation mechanism for smaller particulates, between 10 and 23 nm, will be largely improved, allowing car manufacturers to understand technological levers that can be exploited to decrease particulate emissions and to develop the next generation of particulate free GDI engines. The main objectives are:
• Development of two advanced high efficient and clean engine platforms (TRL 7), one representative of the “small” size target (around 1.0 litre displacement) and the second of the “medium” size target (around 2.0 litre displacement), covering respectively A-B-C and D-E-F market segments.
• Analysis and development of the after-treatment technologies, focusing on new GPF technologies targeting PN filtration down to 10 nm diameter
• Provide demonstration of the call overall targets (15% improvement on CO2 emissions based on the WLTP cycle and compliancy with Euro 6 RDE standards) through the realization of two full demonstrator vehicles (TRL 7): one B-segment vehicle equipped with the small downsized stoichiometric engine and one F-segment vehicle equipped with the medium size lean-burn engine. The vehicle will be fully calibrated and assessed by independent testing, according to on road test procedures, using the available best representative PEMS (Portable Emission Measurement System) technology and considering also PN measurement below 23 nm diameter.
The following main results have been achieved in the first 18 months of the project:
• A new model able to predict soot distribution in size and to interact with detailed chemistry has been implemented in the 3D CFD code and tested on academic cases to ensure its consistency and stability.
• Understanding of the mechanisms of particles formation including the very small ones below 23 nm not yet regulated and highlight of the technological levers that will allow a reduction of these small particles emissions.
• Quantification of the engine out very small particulate emissions (10 to 23 nm) in a fully representative GDI combustion system.
• Determination of filtration efficiency and pressure drop behavior during different test procedures including WLTC, RDE warm and cold in dynamic and moderate driving style conditions
• Series of carefully designed clean and loaded pressure drop as well as filtration efficiency tests under both steady state and transient conditions, using advanced equipment for size resolved measurements to support the modeling process
• Identification of critical filter soot loading in terms of maximum regeneration temperature during passive filter regeneration to be considered for a reliable regeneration strategy
• Deeper analysis of back pressure behavior and filtration efficiency in direct relation to defined soot load levels of selected filter systems
• Evaluation and integration of an optimized ICE air intake circuit using advanced technologies such as low pressure EGR and electric super charger.
• Validation of a new camshaft profile focused on extreme late concept, for fuel consumption reduction and knocking mitigation.
• Development of advanced control strategies on a prototypal control unit to optimize the interaction among the new valve lift profile, the electric super charger, the belt starter generator, the active belt tensioner and the other engine auxiliaries.
• Development of a new front end accessory drive (FEAD) able to manage all the functions available thanks to the BSG, such as cranking, energy generation and recuperation on the belt side.
• A first demonstrator engine has been built and tested in lean conditions. Lean operation has been evaluated and shows a limit at a about 14 bar bmep, with a decrease towards higher engine speeds. The data have been analysed and evaluated and is used for the definition of the combustion system of the final demonstrator engine and gives further input to the Task “Lean Limit Extension”.
• The emission data have been used to define a first set of aftertreatment components, consisting of a three way catalyst, a coated particulate filter and an in production diesel SCR system with increased volume of about 7 liters, which will be evaluated in the next step and further optimised for the final demonstrator.
The new soot modeling capabilities offered by the new sectional soot model will allow car manufacturers to develop faster and better new GDI engines taking into account the production of very small particles, below 23 nm, as soon as the first design of the engine thanks to accurate soot emissions modeling. In parallel, understanding and prediction of soot formation mechanism for smaller particulates, between 10 and 23 nm, has been largely improved, allowing car manufacturers to understand technological levers that can be exploited to decrease particulate production in number and to develop the next generation of particulate free GDI engines.
The exhaust gas aftertreatment system, especially the gasoline particle filter, will be an essential part to achieve future requirements and to maximize emission control robustness in the field, in particular considering that a future particle size threshold of 10nm requires the development of solutions beyond today´s state of the art. The findings of the workpackage “Control and filtration of nanoparticles” will contribute towards a competitive future of the internal combustion engine and, with these results, will provide a solid basis for the development of an ultra clean vehicle as targeted in Upgrade.
Concerning the B-segment vehicle, the 3 cylinder engine concept developed in the project will strongly impact on the competitiveness of the future engine generation. This approach, conceived as “modular” ,will multiply the benefits demonstrated on the 3-cylinder engine version as, in most cases, technological approaches could be scaled-up to the same extent.
Concerning the F-segment vehicle, a demonstrator engine and vehicle will be built to demonstrate lean operation in both WLTC and Real driving, as well as necessary complementary technologies to cover the full engine operating range.
New engine technologies