“…Figure 12 shows a special application case for a DMF, a FFT versus time of torsional vibrations during a mode change in cylinder deactivation mode from two-cylinder mode in part load back into threecylinder operation for a state-of-the-art in-line three cylinder GTDI engine. 7 An increase of the 1 st and the 0.5 th engine order can be observed in Figure 12, as expected. This bears the risk of low-frequency vibrations, resulting in inacceptable vibrations in the vehicle.…”
Section: Countermeasures Based On Mechanical Principlessupporting
confidence: 79%
“…Figure 11.Signal flow of the individual parameters and their effect on the attributes.Figure 12.Torsional vibration signature of an i3-engine with and without cylinder deactivation. 7 …”
Section: Parametric Studymentioning
confidence: 99%
“…published in Stoffels, 5 Biermann, 6 and Küpper et al. 7 it was demonstrated that the level and characteristics of the vehicle’s interior noise is mainly governed by the torsional vibrations, in turn dominated by the chosen engine architecture and combustion characteristics of the ICE. 6,8–10 In combination with downsized powertrains, the main concerning NVH issues, such as shuffle, low-speed vibrations (also called lugging), and gear rattle 5,10,11 can be referred to torsional vibration problems.…”
The engine downsizing approach can be considered as state-of-the-art automotive propulsion system. However, future trends are also indicating a trend to a further reduction of the number of engine architectures, normally accompanied with a reduction of the number of cylinders in internal combustion engines, including prospective use of alternative fuels such as compressed natural gas or the downsized engine embedded in a powertrain with electrically driven propulsion systems. Hitherto, different simulation approaches are employed to evaluate the trade-off between noise, vibration and harshness, driveability, and fuel consumption. This paper presents the coupling of two simulation tools, each one an established tool in its discipline, namely a 1D-gas-dynamics tool for a downsized internal combustion engine including a dedicated boost-pressure control approach, and a multibody dynamics tool to simulate the powertrain and vehicle dynamics, using the functional mock-up interface. Using this approach as an industry first application, a significant reduction of development time while avoiding duplication of powertrain subsystem modeling, is achieved. This enables a transient simulation and supports a fast analysis of different powertrain architectures. It, furthermore, allows a detailed look at the impact of powertrain subsystems like the architecture of the internal combustion engine, flywheel, and driveline design on relevant vehicle attributes. Moreover, the transient simulation approach allows the investigation of lag effects caused by the air-path characteristics of the internal combustion engine, or transient effects brought up with the advent of hybrid powertrain architectures. The application case of this tool chain presented in this paper revealed that engine architecture reduction should be carried out carefully in order to not compromise driveability of the engine later on. This could bear the risk of sacrificing fuel economy due to a higher lugging limit, often linked to a reduced firing order of the engine, caused by a reduction of the number of cylinders. The paper finally discusses prospective solutions in terms of conventional mechanical solutions and added electrified propulsion including potential limitations to overcome this issue.
“…Figure 12 shows a special application case for a DMF, a FFT versus time of torsional vibrations during a mode change in cylinder deactivation mode from two-cylinder mode in part load back into threecylinder operation for a state-of-the-art in-line three cylinder GTDI engine. 7 An increase of the 1 st and the 0.5 th engine order can be observed in Figure 12, as expected. This bears the risk of low-frequency vibrations, resulting in inacceptable vibrations in the vehicle.…”
Section: Countermeasures Based On Mechanical Principlessupporting
confidence: 79%
“…Figure 11.Signal flow of the individual parameters and their effect on the attributes.Figure 12.Torsional vibration signature of an i3-engine with and without cylinder deactivation. 7 …”
Section: Parametric Studymentioning
confidence: 99%
“…published in Stoffels, 5 Biermann, 6 and Küpper et al. 7 it was demonstrated that the level and characteristics of the vehicle’s interior noise is mainly governed by the torsional vibrations, in turn dominated by the chosen engine architecture and combustion characteristics of the ICE. 6,8–10 In combination with downsized powertrains, the main concerning NVH issues, such as shuffle, low-speed vibrations (also called lugging), and gear rattle 5,10,11 can be referred to torsional vibration problems.…”
The engine downsizing approach can be considered as state-of-the-art automotive propulsion system. However, future trends are also indicating a trend to a further reduction of the number of engine architectures, normally accompanied with a reduction of the number of cylinders in internal combustion engines, including prospective use of alternative fuels such as compressed natural gas or the downsized engine embedded in a powertrain with electrically driven propulsion systems. Hitherto, different simulation approaches are employed to evaluate the trade-off between noise, vibration and harshness, driveability, and fuel consumption. This paper presents the coupling of two simulation tools, each one an established tool in its discipline, namely a 1D-gas-dynamics tool for a downsized internal combustion engine including a dedicated boost-pressure control approach, and a multibody dynamics tool to simulate the powertrain and vehicle dynamics, using the functional mock-up interface. Using this approach as an industry first application, a significant reduction of development time while avoiding duplication of powertrain subsystem modeling, is achieved. This enables a transient simulation and supports a fast analysis of different powertrain architectures. It, furthermore, allows a detailed look at the impact of powertrain subsystems like the architecture of the internal combustion engine, flywheel, and driveline design on relevant vehicle attributes. Moreover, the transient simulation approach allows the investigation of lag effects caused by the air-path characteristics of the internal combustion engine, or transient effects brought up with the advent of hybrid powertrain architectures. The application case of this tool chain presented in this paper revealed that engine architecture reduction should be carried out carefully in order to not compromise driveability of the engine later on. This could bear the risk of sacrificing fuel economy due to a higher lugging limit, often linked to a reduced firing order of the engine, caused by a reduction of the number of cylinders. The paper finally discusses prospective solutions in terms of conventional mechanical solutions and added electrified propulsion including potential limitations to overcome this issue.
“…These include rolling cylinder deactivation to reduce excitation and vibration damping features such as active engine mounts, dual-mass flywheels and pendulum absorbers. 20…”
The changes in thermal state, emissions and fuel economy of a 1.0-L, three-cylinder direct injection spark ignition engine when a cylinder is deactivated have been explored experimentally. Cylinder deactivation improved engine fuel economy by up to 15% at light engine loads by reducing pumping work, raising indicated thermal efficiency and raising combustion efficiency. Penalties included an increase in NOx emissions and small increases in rubbing friction and gas work losses of the deactivated cylinder. The cyclic pressure variation in the deactivated cylinder falls rapidly after deactivation through blow-by and heat transfer losses. After around seven cycles, the motoring loss is ~2 J/cycle. Engine structural temperatures settle within an 8- to 13-s interval after a switch between two- and three-cylinder operation. Engine heat rejection to coolant is reduced by ~13% by deactivating a cylinder, extending coolant warm-up time to thermostat-opening by 102 s.
“…Usually, exactly half of the number of cylinders are disabled in the deactivated mode [5][6][7]. More recently, however, there have been new concept proposals aiming at deactivating only one cylinder of a multi-cylinder engine [8][9][10]. Although the load increase is lower in these cases, this may still result in increased consumption benefits in real operating situations.…”
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.
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