Development of a Valve Timing Control System

Maekawa, Keiichi; Ohsawa, Namieki; Akasaka, Akio

doi:10.4271/890680

Cited by 37 publications

(5 citation statements)

References 4 publications

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“…Additional details about the combustion modelling are reported in De Bellis et al 24 The in-cylinder turbulence is described by a zerodimensional (0D) sub-model belonging to the K-k family. The governing equations for mean-flow kinetic energy, K = 1=2mU 2 f , and turbulent kinetic energy, k = 3=2mu 02 , are…”

Section: Engine and Model Descriptionmentioning

confidence: 99%

“…Among the various innovative solutions, turbocharging technique and completely flexible valve actuation systems are currently the most promising technologies for further improvements. Initially, valve actuation systems were only used to control the intake and/or exhaust valve phasing (valve variable timing (VVT)) [1][2][3] or to realize different cam profiles according to the engine speed. 4,5 Most recent systems are able to independently define valve opening, closing and maximum lift (variable valve actuation (VVA)).…”

Section: Introductionmentioning

confidence: 99%

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A numerical procedure for the calibration of a turbocharged spark-ignition variable valve actuation engine at part load

Bozza

Bellis

Teodosio

2016

International Journal of Engine Research

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Referring to spark-ignition engines, the downsizing, coupled to turbocharging and variable valve actuation systems are very common solutions to reduce the brake-specific fuel consumption at low-medium brake mean effective pressure. However, the adoption of such solutions increases the complexity of engine control and management because of the additional degrees of freedom, and hence results in a longer calibration time and higher experimental efforts. In this work, a twin-cylinder turbocharged variable valve actuation spark-ignition engine is numerically investigated by a one-dimensional model (GT-Power™). The considered engine is equipped with a fully flexible variable valve actuation system, realizing both a common full-lift strategy and a more advanced early intake valve closure strategy. Refined sub-models are used to describe turbulence and combustion processes. In the first stage, one-dimensional engine model is validated against the experimental data at full and part load. The validated model is then integrated in a multipurpose commercial optimizer (modeFRONTIER™) with the aim to identify the engine calibration that minimizes brake-specific fuel consumption at part load. In particular, the decision parameters of the optimization process are the early intake valve closure angle, the throttle valve opening, the turbocharger setting and the spark timing. Proper constraints are posed for intake pressure in order to limit the gas-dynamic noise radiated at the intake mouth. The adopted optimization approach shows the capability to reproduce with good accuracy the experimentally identified calibration. The latter corresponds to the numerically derived Pareto frontier in brake mean effective pressure–brake specific fuel consumption plane. The optimization also underlines the advantages of an engine calibration based on a combination of early intake valve closure strategy and intake throttling rather than a purely throttle-based calibration. The developed automatic procedure allows for a ‘virtual’ calibration of the considered engine on completely theoretical basis and proves to be very helpful in reducing the experimental costs and the engine time-to-market.

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Section: Engine and Model Descriptionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A numerical procedure for the calibration of a turbocharged spark-ignition variable valve actuation engine at part load

Bozza

Bellis

Teodosio

2016

International Journal of Engine Research

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“…In order to increase the performance of internal combustion engines, several investigations have been conducted. One of the most important of these investigations is the one that tries to optimize the amount of timing of intake and exhaust valves for all intervals of engine load and speed in SI engines (Maekawa et al, 1989;Asmus,1991;Nakayasu et al, 2001). Valve control is one of the most important parameters for optimizing efficiency and emissions, permitting internal combustion engines to conform to the advent of the more recent federal gas mileage and emission requirements with their emphasis on lower engine speed and low pollution emissions (sher et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Relative Change in SI Engine Power and Economy with Variable Valve Timing: Simulation and ANOVA Analysis

Yamin¹

2018

MAS

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In this research, a comparison between the performance of Ricardo E6/T variable compression ratio engine was conducted at constant and variable valve timing. This was done at three different speeds. The inlet and exhaust valves timing was varied and the performance was tested using specialized software. Results showed strong dependency of engine power and economy on valve timing and lift for all speeds. Further, higher lifts and durations are favorable for good power and the opposite are favorable for good economy. Valve overlap is affecting the engine power and economy in opposite direction as other factors.

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“…The valve actuation systems currently available in the market allow for the variation in the phasing (variable valve timing (VVT)) [2][3][4] or the lift (VVA) 5 as a function of the operating point. The aim of both these solutions is the adjustment of the load with reduced valve throttling.…”

Section: Introductionmentioning

confidence: 99%

Study of a new mechanical variable valve actuation system: Part II—estimation of the actual fuel consumption improvement through one-dimensional fluid dynamic analysis and valve train friction estimation

Gimelli

Muccillo

Pennacchia

2015

International Journal of Engine Research

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It is commonly recognized that one of the most effective ways to improve Brake-Specific Fuel Consumption (BSFC) in a spark-ignition engine at partial load is the adoption of VVA strategies, which largely affect the pumping work. Many different solutions have been proposed, characterized by different levels of complexity, effectiveness and costs. VVA systems currently available on the market allow for variable valve timing and/or lift (VVA). The design of a new mechanical VVA system has been discussed in Part I of this article. That study led to the development of a four-element VVA mechanism. Now, to estimate the potential advantages of the studied system on engine performances, one-dimensional thermo-fluid dynamic analyses were conducted, considering both full load and partial load operating conditions. For this reason, this article addresses the definition of the one-dimensional model of a 638-cm3 single-cylinder engine under development, which will be equipped with the four-element VVA system. The findings from the one-dimensional study will be discussed in detail. In particular, the parametric analyses, which concern the engine power at wide open throttle and the SFC at partial load, will be presented. These results, however, are only theoretical results because the one-dimensional simulation is not able to take into account the increased friction losses due to the complexity of the VVA system. Therefore, to correctly quantify the actual fuel consumption allowed by the studied system (net of the generally increased power dissipated by friction when compared to a conventional valve train), a specific methodology, discussed in Part I, has been adopted.

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Development of a Valve Timing Control System

Cited by 37 publications

References 4 publications

A numerical procedure for the calibration of a turbocharged spark-ignition variable valve actuation engine at part load

A numerical procedure for the calibration of a turbocharged spark-ignition variable valve actuation engine at part load

Relative Change in SI Engine Power and Economy with Variable Valve Timing: Simulation and ANOVA Analysis

Study of a new mechanical variable valve actuation system: Part II—estimation of the actual fuel consumption improvement through one-dimensional fluid dynamic analysis and valve train friction estimation

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