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REal World Advanced Technologies foR Diesel Engines

Periodic Reporting for period 2 - REWARD (REal World Advanced Technologies foR Diesel Engines)

Reporting period: 2016-11-01 to 2018-04-30

The REWARD objective was to develop the knowhow, intellectual property rights and technical capabilities to adequately and cost-effectively produce cleaner, highly efficient Diesel powertrains and aftertreatment technologies for future cleaner passenger cars that go beyond EU6 RDE.
Conclusion of the Action: The emissions target (half of EU6 in RDE and WLTC) was reached. The major challenge was to keep both NOx and CO2 below the target in the WLTC. The CO2-emissions were compared to MY 2015 and MY 2018 reference vehicle configurations as no MY 2013 versions of these types are existing. This allowed an even clearer assessment of the new technologies. The target of 5% CO2-improvement under real driving conditions was achieved. Friction reduction with new coatings and lubricants was demonstrated on test rigs (TRL 5). Projections to WLTC showed 1% fuel consumption improvement with ultra-low viscosity hydrocarbon based lubricants and 2% improvement with a novel polyalkylene glycol based lubricant.
The 2-stroke Diesel engine architecture was developed on a single cylinder research engine (TRL 5). Projections to vehicle drives showed that the REWARD NOx targets were reached. However, the fuel consumption target was not achieved.
Overview of the results and their exploitation and dissemination: Architecture of the Diesel 2-stroke engine was developed in order to provide the best BSFC and the best scavenge with intensive OD, 1D and 3D calculations. Insights were obtained on how to break the trade-off between swirl targets and scavenge efficiency, as well as insights into the key parameters for the intake ports design. Engine combustion and emissions were developed on single cylinder research engine. In comparison with a state of the art 4-stroke engine the same level of pollutants was achieved. However, effective fuel consumption resulted in higher figures. A projection of fuel consumption from single-cylinder to twin-cylinder and three-cylinder engine showed for WLTC: 9% higher FC (compared to state of the art 4-stroke engines) with 2-cylinder variant engine in Renault CLIO and 17% higher FC (compared to state of the art 4-stroke engines) with 3-cylinder variant engine in Renault SCENIC.
A new low NOx combustion concept was developed for a 1.6L diesel engine and calibrated and tested in a B/C class passenger car (Renault Kadjar). A new aftertreatment system was laid out. The REWARD emission targets (half of Euro 6) were reached in RDE (on-road) tests with a conformity factor below 1. The CO2-target (5% improvement versus identical vehicle with baseline reference engine) under real driving conditions was also met. In WLTC the targets (emissions and fuel consumption) could not be reached. However, the NOx target (half of Euro 6) was reached with an fuel consumption improvement of 3% instead of the target 5%. The target TRL7 was achieved.
The work on Future 4-stroke D/E class Diesel engine included the approach to reduce the fuel consumption by extreme downsizing and rising the specific engine power to >100kW/l for a E class vehicle (Volvo XC60). This concept enabled friction reduction and more favourable operating conditions related to fuel consumption. The target power level required a high charge air flow with minimum pressure drop. This drove a novel quiescent combustion concept normally only seen in heavy duty engines. The aftertreatment system is a new LNT-SCRF/SCR-u/f SCR concept. The emission calibration had a strong focus on temperature management procedures for catalyst heating with low fuel consumption penalty. With this development approach the REWARD emission targets (half of Euro 6) was reached in RDE (on-road) tests. The CO2-target (5% improvement versus identical vehicle with baseline reference engine) under real driving conditions was also met. The target TRL7 was reached. The new quiescent combustion concept will be pursued in future developments.The final tests were supervised by an independent testing institute.
Exploitable results from the development of aftertreatment systems are new catalyst formulations and technologies for SCR and SCRF. Basic investigations and improved simulation models have been made for predicting the chemical reaction kinetics of the catalysts. This know-how will be exploited by providing consulting and engineering services. Related to the aftertreatment system development work are also engine measures for providing optimum catalyst temperatures which will be invested in new engine and vehicle developments. OEMs and engine engineering providers developed new combustion concepts and specific features for efficiency improvements. The low swirl and quiescent combustion concepts, which have been developed up to TRL 7, will be pursued by the OEMs and at least aspects thereof will be applied in serial production. The reduced engine-out NOx affects the aftertreatment system in terms of size, flow resistance and cost. The challenging development of very complex tasks such as the layout of the combustion concepts and the prototype calibration of demonstrator vehicles also stimulated the development of new methodical approaches. These include the combination of complex layout procedures with experimental and statistical approaches and also systematic procedures for calibration. Such topics have been published and are further applied in development projects. Measures for friction reduction are continuous issues for mechanical engine development. They primarily focus on complex interactions from materials, surface coatings, lubricants, thermal measures. Usually, individual approaches for friction reduction do not lead to big improvement steps but the interaction of various measures provide innovative and enduring solutions which are exploitable in large scale.
Socio-economic impact and the wider societal implications of REWARD: REWARD emphasized product developments close to production. Various topics were therefore developed, e.g. engine combustion concepts and aftertreatment system, and they were assessed in demonstrator vehicles. The new approaches had then to be integrated into existing hardware and software architectures meaning that the new hardware required new functionalities and a work-intensive recalibration of the total system architectures. This was carried out to the quality level which enabled the demonstration of the project targets in the realistic environment of on-road drives with vehicles. However, the quality level of serial production was not targeted and reached. These complex methodical tasks further require close cooperation between OEMs, universities, suppliers and engineering companies. Furthermore, the developments of REWARD contribute to initiatives of individual transport and its impact on environment, economy and society. In this context, e.g. recently published statistical data evidence the importance of diversity: In Germany, the Diesel share of new passenger cars diminished from 46% in 2016 to below 33% in 2018 (source AID). Only because of this the fleet CO2 emissions of new cars increased by 1,5 percentage points (source: Kraftfahr-Bundesamt, 04-2018). This simple example shows that Diesel engines claim their place for the achievement of the European climate goals due to their high efficiency. Ultra-low emissions are the obligatory side condition. Both were in the focus of REWARD.