Characterization of the system behaviour of a variable compression ratio (VCR) connecting rod with eccentrically piston pin suspension and hydraulic moment support

Wittek, Karsten; Geiger, Frank; Vaz, Marilia Gabriela Justino

doi:10.1016/j.enconman.2020.112814

Cited by 8 publications

(6 citation statements)

References 13 publications

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“…Among which are improvements in combustion systems, engine tribology, electronic control, and detection algorithms [11][12][13][14]. Additionally, technologies such as exhaust gas recirculation [15], turbocharging [16], direct injection, HCCI (homogeneous charge compression ignition) engines [17], alternative biofuels [18], ratios of variable compression [19][20][21], and cylinder deactivation (CDA) [21]. The latter has received high interest in its application for gasoline engines.…”

Section: Introductionmentioning

confidence: 99%

Study of the Cylinder Deactivation on Tribological Parameters and Emissions in an Internal Combustion Engine

2022

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In the present investigation, a study is carried out using numerical simulation on the effects of cylinder deactivation on tribological parameters and emissions in an internal combustion engine. For the development of the research, a tribological model was used to predict the characteristics of the lubrication film, friction conditions, blow-by gas, and deformation of the piston rings. Additionally, the construction of a CFD model was carried out to describe the kinematic movement of the engine piston. The analysis of results allowed for the demonstration of the active cylinders presenting an increase of 21.53% and 7.65% in the pressure and temperature in the cylinder wall. Additionally, the active cylinders present a reduction of 11.33% in the minimum thickness of the lubrication film and an increase in the friction force due to asperities, which implies an increase of 33% in power losses due to friction. The implementation of technologies such as cylinder deactivation causes an increase in combustion gas leaks caused by the increase in pressure of the active cylinders. However, the use of this technology allows reducing 9.09%, 8.26%, and 7.41% in CO, HC, and NO emissions. Although the use of technologies such as cylinder deactivation allows significant fuel savings, it is necessary to consider the negative effects caused by this technology, such as the increase in combustion gas leaks and the increase in power loss by the greatest frictional forces.

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Section: Introductionmentioning

confidence: 99%

Study of the Cylinder Deactivation on Tribological Parameters and Emissions in an Internal Combustion Engine

2022

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“…Over the time, many reviews were authored on the subject of the VCR engine (e.g., 14,[17][18][19][20][21] ) Equally, many others were focused on presenting specific VCR concepts or prototypes. 13,15,[22][23][24][25] Out of them, very few focused on the dynamic response of the VCR engine, i.e., on the response time of the CR adjustment automatic system, even though this is paramount for the PC road mobility, which means anything but steady operation.…”

Section: Introductionmentioning

confidence: 99%

“…As stated in, 27 this solution is passive as no external energy is needed to adjust the CR; moreover, it is said that the transition duration is achieved in 0.2-0.6 s but no explanation whatsoever was given at that time to justify this response time range. However, in paper, 22 the subject is fully addressed via experimental means; thus, this paper is the only one found which treats extensively the subject of the response time of a VCR engine or as called by the authors, "the transition process duration. "…”

Section: Introductionmentioning

confidence: 99%

Investigation on the response time of a self-regulation variable compression ratio engine

Clenci

Hara

Stănescu

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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Today, the greenhouse gas (GHG) emissions (specifically, CO2) represent the greatest challenge of the internal combustion (IC) engine and consequently, now, more than ever, the passenger car industry is looking for technologies meant to address this issue. Since CO2 emission is related to the combustion process occurring inside the engine, its reduction is inherently connected to lowering the fuel consumption, meaning that the only way to reduce it in the IC engine is to increase its overall efficiency. One solution to do this over the whole operating area is to fit the engine with a variable compression ratio (VCR) system, which may be advantageously combined with other enhancing-efficiency technologies. However, to avoid knocking and pre-ignition, such an engine should feature an adequate response time during the transition from the maximum compression ratio to the minimum one. Consequently, this paper describes a theoretical investigation on the kinematics and dynamics of a hinged VCR engine’s upper block tilting motion, aiming to show that this engine, as an automatic system with self-regulation of compression ratio, can respond adequately when the operating conditions change fast. This is paramount for the passenger car road mobility, which means anything but steady operation.

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“…The authors present crank angle based measurement results of motored full engine operation for two engine speeds at n = 1000 and 3000 normalmin − 1 . The covered measurement range could be expanded by the investigations of Wittek et al 28 Test bench results of a fired three-cylinder inline full engine could be shown. With the implemented mechanical data transfer, the VCR conrod behavior could be analyzed for engine speeds up to n = 4000 normalmin − 1 and loads up to imep = 15 bar .…”

Section: Introductionmentioning

confidence: 99%

Experimental analysis of the system behavior of a two-stage variable compression ratio (VCR) system in fired SI-engine operation

Hammermueller

Orlowsky

Hanciogullari

et al. 2021

International Journal of Engine Research

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Especially for turbocharged SI engines, systems that allow to adapt the geometrical compression ratio offer advantages in terms of part load efficiency and maximum power output. In this study a conrod based two-stage VCR system with an eccentric piston pin bearing is investigated in fired engine operation by means of a specially designed measurement technique. For this purpose different sensor technologies were equipped to a VCR conrod and the oil supply system of a prototype crankshaft. The data transmission was realized by an optimized mechanical linkage system and a digital rotation telemetry system. The high-performance measurement technique presented in this paper enables a detailed analysis of the influencing parameters resulting from the fired engine operation, such as dynamic pressure stimulation in the crankshaft oil supply or the acceleration of the internal oil columns. The presented crank angle based measurement results of the system are obtained through fired testbench investigations on a three-cylinder full engine in the entire engine map, focusing on the speed range up to [Formula: see text] and loads up to [Formula: see text]. A detailed analysis of the conrod system behavior in high and low compression ratio is shown. A key finding is, that the so called “hydraulic pretension” of the support chamber is necessary to meet the requirements for a stiff force transmission in the low compression ratio stage. The in-depth investigation contributes to the build up of a comprehensive system understanding and represents a solid base to expand the development process of conrod based two-stage VCR systems.

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Characterization of the system behaviour of a variable compression ratio (VCR) connecting rod with eccentrically piston pin suspension and hydraulic moment support

Cited by 8 publications

References 13 publications

Study of the Cylinder Deactivation on Tribological Parameters and Emissions in an Internal Combustion Engine

Study of the Cylinder Deactivation on Tribological Parameters and Emissions in an Internal Combustion Engine

Investigation on the response time of a self-regulation variable compression ratio engine

Experimental analysis of the system behavior of a two-stage variable compression ratio (VCR) system in fired SI-engine operation

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