Type Synthesis of Variable Compression Ratio Engine Mechanisms

Mo, Young Kwang; Shim, Jae Kyung; Kwak, Seung Woo; Jo, Min Seok; Park, Ho Sung

doi:10.3390/app10186574

“…In this context, Variable compression ratio engines (VCR) make a contribution, in which the very last function of the Top dead center TDC piston is adjusted to optimize the compression ratio to increase thermodynamic performance, particularly at part load, and finally reduce gasoline consumption and CO2 emissions. Several VCR configurations presently exist [1][2][3][4][5], such as the gear-based crank mechanism engine (GBCM) with variable compression ratio (VCR_MCE-5) [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Kinematics modeling of the gear-based crank mechanism engine regardless of the compressions ratio variations

Sakhraoui,

Saggar,

Ayari

et al. 2023

Preprint

0

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In this work, geometric and kinematic modeling of the gear-based crank mechanism engine (GBCM) was performed. To this aim, a mechanical approach based on projective computational methods and mechanism theory laws is applied, to which a parametric study has allowed a conclusion on the geometrical and kinematic behaviors of the moving links. The study concluded that the kinematic quantities at connecting rod head are one-half of those at the piston top head. The extrinsic behavior like the stroke of the connecting rod head is twice the crank radius and the piston kinematic are identical to the conventional engine with the same crankshaft ratio regardless of the compression ratio and any gear wheel radius. Hence, all the extrinsic kinematic properties of a classic crankshaft mechanism of the fixed compression ratio engine remain valid for a gear-based crank mechanism engine and can be used for dynamic calculation purposes.

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Kinematics modeling of the gear-based crank mechanism engine regardless of the compressions ratio variations

Sakhraoui,

Saggar,

Ayari

et al. 2024

Sci Rep

1

0

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In this work, geometric and kinematic modeling of the gear-based crank mechanism engine (GBCM) was performed. To this aim, a mechanical approach based on projective computational methods and mechanism theory laws is applied, to which a parametric study has allowed a conclusion on the geometrical and kinematic behaviors of the moving links. The study concluded that the kinematic quantities at connecting rod head are one-half of those at the piston top head. The extrinsic behavior like the stroke of the connecting rod head is twice the crank radius and the piston kinematic are identical to the conventional engine with the same crankshaft ratio regardless of the compression ratio and any gear wheel radius. Hence, all the extrinsic kinematic properties of a classic crankshaft mechanism of the fixed compression ratio engine remain valid for a gear-based crank mechanism engine and can be used for dynamic calculation purposes.

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Structural Synthesis of Articulated Manipulators with Non-Fractionated or Fractionated Kinematic Chains without Isomorphism

Park

¹

,

Shim

²

,

Kim

³

et al. 2021

Applied Sciences

0

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As the kinematic structure of an articulated manipulator affects the characteristics of its motion, rigidity, vibration, and force transmissibility, finding the most suitable kinematic structure for the desired task is important in the conceptual design phase. This paper proposes a systematic method for generating non-isomorphic graphs of articulated manipulators that consist of a fixed base, an end-effector, and a two-degree-of-freedom (DOF) intermediate kinematic chain connecting the two. Based on the analysis of the structural characteristics of articulated manipulators, the conditions that must be satisfied for manipulators to have a desired DOF is identified. Then, isomorphism-free graph generation methods are proposed based on the concepts of the symmetry of a graph, and the number of graphs generated are determined. As a result, 969 graphs of articulated manipulators that have two-DOF non-fractionated intermediate kinematic chains and 33,438 graphs with two-DOF fractionated intermediate kinematic chains are generated, including practical articulated manipulators widely used in industry.

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Type Synthesis of Variable Compression Ratio Engine Mechanisms

Cited by 4 publications

References 21 publications

Kinematics modeling of the gear-based crank mechanism engine regardless of the compressions ratio variations

Kinematics modeling of the gear-based crank mechanism engine regardless of the compressions ratio variations

Kinematics modeling of the gear-based crank mechanism engine regardless of the compressions ratio variations

Structural Synthesis of Articulated Manipulators with Non-Fractionated or Fractionated Kinematic Chains without Isomorphism

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