A detailed study of a cylinder activation concept by efficiency loss analysis and 1D simulation
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ORIGINAL PAPER
A detailed study of a cylinder activation concept by efficiency loss analysis and 1D simulation Thomas Buitkamp1 · Michael Günthner1 · Florian Müller1 · Tim Beutler1 Received: 10 July 2020 / Accepted: 25 August 2020 © The Author(s) 2020
Abstract Cylinder deactivation is a well-known measure for reducing fuel consumption, especially when applied to gasoline engines. Mostly, such systems are designed to deactivate half of the number of cylinders of the engine. In this study, a new concept is investigated for deactivating only one out of four cylinders of a commercial vehicle diesel engine (“3/4-cylinder concept”). For this purpose, cylinders 2–4 of the engine are operated in “real” 3-cylinder mode, thus with the firing order and ignition distance of a regular 3-cylinder engine, while the first cylinder is only activated near full load, running in parallel to the fourth cylinder. This concept was integrated into a test engine and evaluated on an engine test bench. As the investigations revealed significant improvements for the low-to-medium load region as well as disadvantages for high load, an extensive numerical analysis was carried out based on the experimental results. This included both 1D simulation runs and a detailed cylinder-specific efficiency loss analysis. Based on the results of this analysis, further steps for optimizing the concept were derived and studied by numerical calculations. As a result, it can be concluded that the 3/4-cylinder concept may provide significant improvements of real-world fuel economy when integrated as a drive unit into a tractor. Keywords Cylinder deactivation · Efficiency loss analysis · 1D simulation · Engine operating point shift · Gas exchange Abbreviations 1D/3D One-/three-dimensional BDC Bottom dead center (of piston) (B)MEP (Brake) mean effective pressure BSFC Brake specific fuel consumption CA Degrees crank angle CAL Cylinder activation line CFD Computational fluid dynamics DOHC Double overhead camshaft ECU Engine control unit EVO Exhaust valve opening (timing) EGR Exhaust gas recirculation IVC Intake valve closing (timing) OHV Overhead valves TDC Top dead center (of piston) TPA Three-pressure analysis
* Florian Müller [email protected]‑kl.de 1
Lehrstuhl für Antriebe in der Fahrzeugtechnik (LAF), Fachbereich Maschinenbau und Verfahrenstechnik, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany
1 Introduction In recent years, a multitude of different concepts for realizing an engine operating point shift have been developed and implemented in series applications for both gasoline and diesel engines. In most cases, the objective is to use more efficient operating regions of the engine map and, therefore, improve fuel consumption [1]; in some cases, the focus is also on increasing the exhaust gas temperature to heat up or maintain the temperature of the exhaust aftertreatment system, especially for diesel engines [2, 3]. Besides classic “downsizing” or “downspeeding” approaches on the one hand and complex operati
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