scholarly journals Practical Aspects of Cylinder Deactivation and Reactivation

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2540
Author(s):  
Norbert Zsiga ◽  
Johannes Ritzmann ◽  
Patrik Soltic
Keyword(s):  
Internal Combustion Engines ◽  
Engine Speed ◽  
Initial Conditions ◽  
Torque Ripple ◽  
Combustion Engines ◽  
Mode Transition ◽  
Valve Timing ◽  
Effective Measure ◽  
Cylinder Deactivation ◽  
Exhaust Valves

Cylinder deactivation is an effective measure to reduce the fuel consumption of internal combustion engines. This paper deals with several practical aspects of switching from conventional operation to operation with deactivated cylinders, i.e., gas spring operation with closed intake and exhaust valves. The focus of this paper lies on one particular quantity-controlled stoichiometrically-operated engine where the load is controlled using the valve timing. Nevertheless, the main results are transferable to other engines and engine types, including quality-controlled engines. The first aspect of this paper is an analysis of the transition from fired to gas spring operation, and vice versa, as well as the gas spring operation itself. This is essential for mode changes, such as cylinder deactivation or skip-firing operation. Simulation results show that optimizing the valve timing in the last cycle before deactivating/first cycle after reactivating a cylinder, respectively, is advantageous. We further show that steady-state gas spring operation is reached after approximately 6 s regardless of the initial conditions and the engine speed. The second aspect of this paper experimentally verifies the advantage of optimized valve timings. Furthermore, we show measurements that demonstrate the occurrence of an unavoidable torque ripple, especially when the transition to and from the deactivated cylinder operation is performed too quickly. We also confirm with our experiments that a more gradual mode transition reduces the torque drop.

Variable Valve-Timing Unit Suitable for Internal Combustion Engines

1972 ◽  
Vol 186 (1) ◽  
pp. 301-306 ◽  
Author(s):  
G. E. Roe
Keyword(s):  
Internal Combustion Engines ◽  
Engine Speed ◽  
Valve Lift ◽  
Specific Power ◽  
Combustion Engines ◽  
Valve Timing ◽  
Specific Power Output ◽  
Torque Curve ◽  
Lift Curve ◽  
Variable Valve

As the specific power output of I.C. engines is increased, the range of engine speed over which useful torque is available is reduced. This ‘power band’ can be widened by having automatically varying valve timing, with the timing being a function of engine speed and/or load. A prototype cyclic phasing unit has been tested which successfully varies the timing of a poppet valve with opening, closing points, and the form of valve lift curve being readily varied independently. The unit is simple mechanically, but ideally one unit is needed for each valve, so principal application is likely to be on engines with a small number of cylinders. In addition to flattening the torque curve, such a unit is likely to give improved fuel consumption and lower exhaust emissions, particularly hydrocarbons.

scholarly journals Analysis of thermodynamic parameters in spark ignition VCR engine

2019 ◽  
Vol 294 ◽  
pp. 05001
Author(s):  
Patryk Urbański ◽  
Maciej Bajerlein ◽  
Jerzy Merkisz ◽  
Andrzej Ziółkowski ◽  
Dawid Gallas
Keyword(s):  
Thermodynamic Parameters ◽  
Motion Analysis ◽  
Internal Combustion Engines ◽  
Initial Conditions ◽  
Combustion Process ◽  
Internal Combustion ◽  
3D Models ◽  
Spark Ignition ◽  
Combustion Engines ◽  
Combustion Processes

3D models of Szymkowiak and conventional engines were created in the Solidworks program. During the motion analysis, the characteristics of the piston path were analyzed for the two considered engine units. The imported file with the generated piston routes was used in the AVL Fire program, which simulated combustion processes in the two engines with identical initial conditions. The configurations for two different compression ratios were taken into account. The basic thermodynamic parameters occurring during the combustion process in internal combustion engines were analyzed.

Model-based compressor surge avoidance algorithm for internal combustion engines utilizing cylinder deactivation during motoring conditions

2019 ◽  
pp. 146808741988347
Author(s):  
Alexander H Taylor ◽  
Troy E Odstrcil ◽  
Aswin K Ramesh ◽  
Gregory M Shaver ◽  
Edward Koeberlein ◽  
...  
Keyword(s):  
Internal Combustion Engines ◽  
Intake Manifold ◽  
Combustion Engines ◽  
Engine Exhaust ◽  
Engine Operation ◽  
Aftertreatment System ◽  
Cylinder Deactivation ◽  
Valve Motion ◽  
Compressor Surge ◽  
Intake Manifold Pressure

Cylinder deactivation is an efficient strategy for diesel engine exhaust aftertreatment thermal management. Temperatures in excess of 200 °C are necessary for peak NO x conversion efficiency of the aftertreatment system. However, during non-fired engine operation, known as motoring, conventional diesel engines pump low-temperature air through the aftertreatment system. One strategy to mitigate this is to deactivate valve motion during engine motoring. There is a specific condition where care must be taken to avoid compressor surge during the onset of valve deactivated motoring when following high load operation. This study proposes and validates an algorithm which (1) predicts the intake manifold pressure increase instigated while transitioning into cylinder deactivation during motoring, (2) estimates future mass air flow, and (3) avoids compressor surge by implementing staged cylinder deactivation during the onset of engine motoring operation.

scholarly journals Camshaftless Technology on Internal Engines

2020 ◽  
Vol 5 (2) ◽  
pp. 118-123
Author(s):  
Van Viet Pham
Keyword(s):  
Fuel Consumption ◽  
Internal Combustion Engines ◽  
Engine Performance ◽  
Control Valve ◽  
Internal Combustion ◽  
Exhaust Valve ◽  
Combustion Engines ◽  
Toothed Belt ◽  
Significant Performance ◽  
Exhaust Valves

Along with the development of internal combustion engines, camshafts have also been developed to optimize engine performance. In all types of internal combustion engines, the crankshaft is connected to the camshaft via a toothed belt, chain or pinion. When the crankshaft turns, the camshaft spins and opens and closes the intake and exhaust valve respectively. However, in this non-camshaft engine technology, each intake and exhaust valve will be integrated with an electronically controlled hydraulic pump unit. This system provides a unique ability to independently control intake and exhaust valves. For any engine load, load and discharge times can be programmed independently. The decision system is based on driving conditions, used to maximize performance or minimize fuel consumption and emissions. This allows a greater degree of control over the engine which in turn provides significant performance benefits. This article presents reviews of camshaftless technology developed by VALEO. It is a system that uses solenoid valves to open and close the valve. The solenoid valve will be mounted right on top of the valve inside the engine. The author can see that the technology using this electronic control valve will help reduce the fuel consumption of the engine.

Laminar Flame Characteristics of 2,5-Dimethylfuran (DMF) Biofuel: A Comparative Review with Ethanol and Gasoline

2021 ◽  
Vol 11 (1) ◽  
pp. 237-254
Author(s):  
Long Vuong Hoang ◽  
Danh Chan Nguyen ◽  
Thanh Hai Truong ◽  
Huu Cuong Le ◽  
Minh Nhat Nguyen
Keyword(s):  
Environmental Pollution ◽  
Internal Combustion Engines ◽  
Laminar Flame ◽  
Initial Conditions ◽  
Internal Combustion ◽  
Alternative Fuel ◽  
Early Years ◽  
Combustion Engines ◽  
Comparative Review ◽  
Potential Alternative

Since the early years of the 21st century, the whole world has faced two very urgent problems: the depletion of fossil energy sources and climate change due to environmental pollution. Among the solutions sought, 2,5-Dimethylfuran (DMF) emerged as a promising solution. DMF is a 2nd generation biofuel capable of mass production from biomass. There have been many studies confirming that DMF is a potential alternative fuel for traditional fuels (gasoline and diesel) in internal combustion engines, contributing to solving the problem of energy security and environmental pollution. However, in order to apply DMF in practice, more comprehensive studies are needed. Not out of the above trend, this paper analyzes and discusses in detail the characteristics of DMF's combustible laminar flame and its instability under different initial conditions. The evaluation results show that the flame characteristics of DMF are similar to those of gasoline, although the burning rate of DMF is much higher than that of gasoline. This shows that DMF can become a potential alternative fuel in internal combustion engines.

High Fuel Economy Enabled by the Split Engine

2005 ◽  
Author(s):  
Marc Ross ◽  
Alberto J. Lo´pez ◽  
Frank H. Walker
Keyword(s):  
Fuel Economy ◽  
Internal Combustion Engines ◽  
Relative Phase ◽  
Spark Ignition ◽  
Small Displacement ◽  
Combustion Engines ◽  
Cylinder Deactivation ◽  
Light Duty ◽  
Light Trucks ◽  
Light Duty Vehicles

Half the engine displacement of popular cars and light trucks would be adequate for most driving. The split engine (SE) is introduced here as a concept to improve the fuel economy of light-duty vehicles with large spark-ignition internal combustion engines. It operates with a small-displacement portion of the engine for typical driving and activates the secondary portion of the engine to assist with high-power driving. SE is different from cylinder deactivation; the two portions of the engine have independent crankshafts which connect through a one-way clutch, a mechanical diode with indexing features to achieve the correct relative phase of the engine sections. For illustration, 6- and 8-cylinder SE are proposed and simple versions are modeled analytically. The 6-cylinder SE consists of two inline 3-cylinder engines of equal or near-equal displacement. The 8-cylinder SE consists of two opposed horizontal 4-cylinder engines of the same displacement. SE and cylinder deactivation are also compared. Moments of inertia and the time to connect both engine sections smoothly are estimated. Fuel economy improvements with SE are estimated for the EPA urban and highway cycles.

An Integrated Model of Ring Pack Performance

1991 ◽  
Vol 113 (3) ◽  
pp. 382-389 ◽  
Author(s):  
R. Keribar ◽  
Z. Dursunkaya ◽  
M. F. Flemming
Keyword(s):  
Internal Combustion Engines ◽  
Piston Ring ◽  
Engine Speed ◽  
Integrated Model ◽  
Design Parameters ◽  
Combustion Engines ◽  
Predictive Tool ◽  
Engine Friction ◽  
Piston Ring Pack ◽  
Ring Pack

This paper describes an integrated model developed for the detailed characterization and simulation of piston ring pack behavior in internal combustion engines and the prediction of ring pack performance. The model includes comprehensive and coupled treatments of (1) ring-liner hydrodynamic and boundary lubrication and friction; (2) ring axial, radial, and (toroidal) twist dynamics; (3) inter-ring gas dynamics and blowby. The physics of each of these highly inter-related phenomena are represented by submodels, which are intimately coupled to form a design-oriented predictive tool aimed at the calculation of ring film thicknesses, ring motions, land pressures, engine friction, and blowby. The paper also describes the results of a series of analytical studies investigating effects of engine speed and load and ring pack design parameters, on ring motions, film thicknesses, and inter-ring pressures, as well as ring friction and blowby.

scholarly journals Miller Cycle Analysis Using EGM

2005 ◽  
Author(s):  
Bernardo Ribeiro ◽  
Jorge Martins
Keyword(s):  
Heat Transfer ◽  
Entropy Generation ◽  
Compression Ratio ◽  
Internal Combustion Engines ◽  
Combustion Engines ◽  
Miller Cycle ◽  
Valve Timing ◽  
Entropy Generation Minimization ◽  
Flow And Heat Transfer ◽  
Variable Valve

The Entropy Generation Minimization (EGM) method is based on the analysis by three sciences (thermodynamics, fluid flow and heat transfer) of the different processes that may occur in a system or in an equipment. Herein the EGM method is applied to internal combustion engines to determine the entropy generation caused by different processes. A model incorporating entropy generation calculations is used to assess various engines configurations. Otto cycle was tested and Variable Valve Timing (VVT) and Variable Compression Ratio (VCR) were applied so thermodynamic benefits could be tested and evaluated. With the referred model, the Miller cycle variables are analyzed in order to establish the best working conditions of an engine under a certain load. The intake and exhaust valve timing, combustion start, compression ratio adjustment and heat transfer are the variables for which a best working condition is determined based on the minimization of the entropy generation of the several engine processes.

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