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Wyszukujesz frazę "valve actuation" wg kryterium: Temat


Wyświetlanie 1-6 z 6
Tytuł:
Reduction of pressure rise rates in boosted HCCI engine using advanced valve actuation strategies
Autorzy:
Hunicz, J.
Rybak, A.
Gęca, M.
Powiązania:
https://bibliotekanauki.pl/articles/243727.pdf
Data publikacji:
2018
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
low temperature combustion
HCCI
valve actuation
combustion harshness
Opis:
Homogeneous Charge Compression Ignition (HCCI) is a promising low temperature combustion technology which offers high fuel efficiency and extremely low exhaust emissions. However, there are still some pending issues to be resolved before the technology will achieve mass production level. Namely, combustion controllability should be improved and HCCI operating range should be widen. The latter is constrained by excessive combustion rates under high loads. In this study, advanced variable valve actuation strategies were applied to control auto-ignition timings and combustion rates. The examinations were conducted using single-cylinder research engine fuelled with directly injected gasoline. The HCCI combustion was achieved using negative valve overlap technique. The engine was run under boosted conditions, in an operation regime where acceptable pressure rise rate (PRR) level is usually exceeded. Selected valve timing sweeps were carried out within a scope of the experiments to evaluate PRR reduction potential. The obtained results manifested superior combustion controllability. Late exhaust valve closing enabled reduction of the amount of internally re-circulated exhaust, which propagated to the main event combustion. From the intake side, two effects were observed, i.e. variability of the intake air aspiration and variability of the apparent compression ratio. Both phenomena were found to affect combustion timings and rates.
Źródło:
Journal of KONES; 2018, 25, 4; 369-376
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy aspects of the SI engine load adjustment by early closing of inlet or exhaust valve
Autorzy:
Żmudka, Z.
Postrzednik, S.
Przybyła, G.
Powiązania:
https://bibliotekanauki.pl/articles/246087.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
spark-ignition engine
engine load
variable valve actuation
early valve closing
open theoretical cycle
Opis:
The theoretical analysis of the SI engine load adjustment has been presented. The load especially in SI engine is highly dependent on the process of charge exchange. This process has significant impact on the effectiveness of an engine work because it is connected with the necessity of overcoming the flow resistance, then with the necessity of doing a work, so-called the charge exchange work. The flow resistance caused by throttling valve is especially high during part load operation. The open theoretical cycle has been assumed as a model of processes proceeding in the engine. Using fully variable inlet and exhaust valves timing the cycle can be realized e.g. according to two systems: system with early inlet valve closing (EIVC) and system with early exhaust valve closing (EEVC). Both systems have been analysed individually and comparatively with the open Seiliger-Sabathe cycle, which is theoretical cycle for the classical throttle governing of an engine load. Benefits resulting from application of the systems with independent inlet and exhaust valves control have been assessed on the basis of the selected parameters: a fuel dose, a cycle work, a charge exchange work and a cycle efficiency. The use of the analysed systems to governing of the SI engine load will enable to eliminate a throttling valve from inlet system and reduce the charge exchange work, especially within the range of part load operation. Decrease of the charge exchange work leads to increase of the internal and effective works, which results in increase of the effective efficiency of the spark ignition engine. Additionally, the EEVC enables realization of the internal EGR.
Źródło:
Journal of KONES; 2016, 23, 4; 583-590
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Late intake valve closing as a way of the throttleless control of SI engine load
Autorzy:
Żmudka, Z.
Postrzednik, S.
Przybyła, G.
Powiązania:
https://bibliotekanauki.pl/articles/247952.pdf
Data publikacji:
2012
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
spark-ignition engine
variable valve actuation
late intake valve closing
open Atkinson-Miller cycle
charge exchange process
cycle efficiency
Opis:
The paper tackles the problems connected with the charge exchange in internal combustion engines. The theoretical analysis of the charge exchange process in the SI engine has been presented. The realization of the charge exchange process is connected with the necessity of overcoming the flow resistances, then with the necessity of doing a work, so-called the charge exchange work. The flow resistance caused by throttling valve is especially high at the partial load running of an engine. A system with independent, late intake valve closing has been analysed. The use of the analysed system to governing of an engine load will enable to eliminate a throttling valve from inlet system and reduce the charge exchange work, especially within the range of partial load. The decrease of the charge exchange work leads to an increase of the internal and effective works, which results in an increase of the effective efficiency of the spark ignition engine. The open, theoretical Atkinson-Miller cycle has been assumed as a model of processes proceeding in the engine with variable intake valve actuation. The system has been analysed individually and comparatively with open Seiliger-Sabathe cycle, which is theoretical cycle for the classic throttle governing of engine load. Benefits resulting from application of the system with late intake valve closing have been assessed on the basis of the selected parameters: a fuel dose, a cycle work, relative charge exchange work and cycle efficiency.
Źródło:
Journal of KONES; 2012, 19, 1; 491-499
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charge exchange control in a SI engine by early exhaust valve closing
Autorzy:
Żmudka, Z.
Postrzednik, S.
Przybyła, G.
Powiązania:
https://bibliotekanauki.pl/articles/248009.pdf
Data publikacji:
2013
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
spark-ignition engine
variable valve actuation
early exhaust valve closing
open theoretical cycle
charge exchange process
exhaust gas recirculation (EGR)
Opis:
The paper tackles the problems connected with the charge exchange in internal combustion engines. The theoretical analysis of the charge exchange process in the SI engine has been presented. A system with independent, early exhaust valve closing has been analysed. The analysed system enables realization of an internal EGR and elimination of a throttling valve from an inlet system and reduce the charge exchange work, especially within the range of partial load. The decrease of the charge exchange work leads to an increase of the internal and effective works, which results in an increase of the effective efficiency of the spark ignition engine. The open, theoretical cycle has been assumed as a model of processes proceeding in an engine. The system has been analysed individually and comparatively with open Seiliger-Sabathe cycle. Benefits resulting from application of the system with early exhaust valve closing have been assessed on the basis of the selected parameters: a fuel dose, a cycle work, a relative charge exchange work and a cycle efficiency. The best results within decrease of fuel consumption and increase of cycle efficiency are obtained for low engine load. The main parameters characterizing the process of the internal exhaust gas recirculation were also determined. These are the ratio and the multiplicity of the exhaust gas recirculation.
Źródło:
Journal of KONES; 2013, 20, 1; 387-394
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Throttleless control of SI engine load by fully flexible inlet valve actuation system
Autorzy:
Żmudka, Z.
Postrzednik, S.
Przybyła, G.
Powiązania:
https://bibliotekanauki.pl/articles/133835.pdf
Data publikacji:
2016
Wydawca:
Polskie Towarzystwo Naukowe Silników Spalinowych
Tematy:
spark-ignition engine
variable valve actuation
early inlet valve closure
theoretical cycle
charge exchange process
cycle efficiency
silnik o zapłonie iskrowym
cykl teoretyczny
wydajność cyklu
Opis:
A system with independent, early inlet valve closure (EIVC) has been analysed. The open, theoretical cycle has been assumed as a model of processes proceeding in the engine with variable inlet valve actuation. The system has been analysed individually and comparatively with open Seiliger-Sabathe cycle which is theoretical cycle for the classic throttle governing of engine load. The influence of EIVC on fuel economy, cycle work, relative charge exchange work and cycle efficiency has been theoretically investigated. The use of the analysed system to governing of an engine load will enable to eliminate a throttling valve from inlet system and reduce the charge exchange work, especially within the range of partial load. The decrease of the charge exchange work leads to an increase of the internal and effective works, which results in an increase of the effective efficiency of the spark ignition engine.
Źródło:
Combustion Engines; 2016, 55, 1; 44-48
2300-9896
2658-1442
Pojawia się w:
Combustion Engines
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Piezoelectric valve for controlled pneumatic shock absorber
Autorzy:
Wiszowaty, R.
Biczyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/31343107.pdf
Data publikacji:
2013
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
valve
piezovalve
actuation
piezoelectric actuator
APA
mass flow rates
landing gear
zawór
aktywator piezoelektryczny
masowe natężenie przepływu
Opis:
The work presents the idea of a valve equipped with an amplified piezoelectric actuator (APA® - Cedrat Technologies), designed for the use in an adaptive pneumatic shock absorber, which is considered as a landing gear of a small aircraft or unmanned aerial system. The idea of adaptation to impact conditions is based on the controlling the fluid flow between two chambers of the absorber. In the considered method flow intensity through the valve determines the absorber reaction. Utilization of the piezoelectric active element (APA) allows for fast acting of the system. A prototype of the valve and the absorber were created. The tests of the mass flow rate were performed.
Źródło:
IPPT Reports on Fundamental Technological Research; 2013, 4; 43-47
2299-3657
Pojawia się w:
IPPT Reports on Fundamental Technological Research
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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