Further development of BMW’s fully-variable valve control system valvetronic

Klaus, Benedikt; Drexler, Gottfried; Eder, Torsten; Eisenkoelbl, Markus; Luttermann, Christoph; Schleusener, Michael

doi:10.1007/bf03227780

Cited by 8 publications

(2 citation statements)

References 4 publications

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“…In 2001, BMW introduced the Valvetronic system, which allows for step-less adjustment of lift and valve opening time. The solution used by BMW has an additional electromechanically operated lever between the camshaft and the rocker arm which allows adjustment of the inlet valve lift [1]. A very similar solution was used by Nissan (system VVAL -Variable Valve Event and Lift) and Toyota (Valvematic system) in 2007 [18].…”

Section: Introductionvariable Valve Timing Systemsmentioning

confidence: 99%

Comparative analysis of theoretical cycles of independent valve control systems of the SI engine

Żmudka,

Postrzednik

2024

Combustion Engines

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The objects of the study were theoretical cycles of the load control systems and charge exchange process in the naturally aspirated SI engine, including: classic, quantitative throttling control (Seiliger-Sabathe open cycle); system with late inlet valve closing LIVC (the Atkinson-Miller open cycle); system with early inlet valve closing EIVC; system with early exhaust valve closing EEVC, enabling internal exhaust gas recirculation; system of fully independent valve control FIVC. The aim of using camless independent valve control algorithms is to eliminate the throttle as an control valve for load and filling control of the SI engine, while retaining quantitative load control. The aim of the research is to select the camless valve control algorithm most beneficial in terms of energy (the highest effective efficiency) and economy (the lowest fuel consumption).

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Section: Introductionvariable Valve Timing Systemsmentioning

confidence: 99%

Comparative analysis of theoretical cycles of independent valve control systems of the SI engine

Żmudka,

Postrzednik

2024

Combustion Engines

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“…Similarly, improvement to the pumping losses via EGR is also limited because the quantity of EGR that can be utilized before it impacts the combustion process is usually less than 20%. A variable valve lift (VVL) [3,4] device could change the effective cylinder volumes at a large scale; therefore, it can significantly reduce the pumping losses at a light load. However, the manufacturing cost and the difficulty in calibration, as well as the controlling of a VVL, would make it difficult to be widely applied.…”

Section: Introductionmentioning

confidence: 99%

Development and Validation of a Variable Displacement Variable Compression Ratio Miller Cycle Technology on an Automotive Gasoline Engine

et al. 2023

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At partial load, traditional automotive gasoline engines have high pumping losses due to the throttling of the intake charge for load control. Variable Valve Timing (VVT) and the introduction of externally cooled EGR could reduce the pumping losses but only with a very limited effect. On the other hand, in the medium to full load range, the engine cannot utilize a high compression ratio due to limitations in knocking. A variable displacement, variable compression ratio device which utilizes an asymmetric camshaft to realize the different closure times of the two intake valves is discussed in this paper. The large-scale change in the intake valve timing leads to the large-scale change in the effective cylinder volume at the intake valve closure, which realizes a variable cylinder volume and a variable effective compression ratio. The device is utilized to reduce the pumping losses and to increase the in-cylinder thermal efficiency at the same time. Engine dyno test results indicate that, in the low to medium load range, a later closure of the intake valve could reduce the effective cylinder volume, and the intake pressure could be significantly increased, and therefore pumping losses reduced. However, the reduced effective cylinder volume due to a later intake valve closure would lead to reduction in the effective compression ratio (ECR) and a drop in in-cylinder thermal efficiency. Therefore, there is a balance point between the pumping loss reduction and the drop in in-cylinder thermal efficiency. On the other side, in the medium to full load range, when avoiding knocking becomes the major controlling factor of the combustion phasing (degree of constant-volume combustion) and the effective expansion ratio (EER), too high of an effective compression ratio would lead to significant drop in the effective expansion ratio EER and also the in-cylinder thermal efficiency. Therefore, there exists a best compromise between the ECR and EER, and the best system would be one with a moderate ECR but an EER as high as possible. The quantitative equations which include both ECR and EER in the thermal efficiency calculations captured the above observations pretty well and can be utilized to optimize for the best compromise of IVC, EVO, ECR, EER and engine performances during the concept stage and/or the calibration stage of an engine.

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Control of Gasoline Engines

Isermann

2014

Engine Modeling and Control

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Further development of BMW’s fully-variable valve control system valvetronic

Cited by 8 publications

References 4 publications

Comparative analysis of theoretical cycles of independent valve control systems of the SI engine

Comparative analysis of theoretical cycles of independent valve control systems of the SI engine

Development and Validation of a Variable Displacement Variable Compression Ratio Miller Cycle Technology on an Automotive Gasoline Engine

Control of Gasoline Engines

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