Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 2

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
EN
Jet Propellant-8 (JP-8) is used as a fuel for a standard Compression Ignition (CI) engine instead of diesel oil, especially in the military applications. The properties of a kerosene-type fuel, which is JP-8, encourage us to test different strategies of mixture creation and combustion, which could be more effective for this fuel than these elaborated for diesel oil. The experiment aimed to show whether it is possible to realise an effective Low Temperature Combustion (LTC) strategy in a CI engine with a low compression ratio for JP-8 fuel. The tests were focused on the combustion of a lean homogeneous JP-8/air mixture close to the knock limit. Additionally, the combustion process of the homogeneous mixtures diluted with EGR was examined. The AVL research engine with a common rail system and low compression ratio (CR = 12) was adapted for the tests. In order to create a homogeneous mixture early, multi injection of JP-8 under high pressure (90 MPa) was applied. The results of the HCCI operation were compared to the Partially Premixed Combustion (PPC) mode without EGR, tested on the same engine with a low CR. The experiment showed that it is possible to realise the LTC process for the HCCI engine fueled with JP-8, though the knock limited the engine load. The application of EGR allowed controlling the phase and rate of the heat release. The higher share of EGR made the HCCI engine cycles less repetitive. Generally, for the HCCI engine operation, the CO and total hydrocarbons (THC) emissions were on a high level. The PM emission was also relatively high, whereas NOx was maintained on a low level for all of the examined points.
EN
This paper investigated the impact of the exhaust gas recirculation on the concentration of selected harmful chemical compounds from the AVL 5402 research diesel engine powered with diesel fuel (DF) and compressed natural gas (CNG). The engine was operated in the dual fuel mode. It means that the engine was conventionally fuelled by regular diesel fuel and simultaneously by CNG dosed into the inlet pipe. The necessary tests were carried out for the mixtures containing 30, 50 and 70% of CNG (by energy content) in the total chemical energy delivered together with diesel fuel (DF) into the combustion chamber. The research was conducted for the stationary conditions of the engine operation at 1200 rpm and constant 1004 Joules of a fuel chemical energy delivered in each cycle into the combustion chamber. Under such conditions, the impact of the EGR rate changed in range of 0–50% on the emissions of selected unburned hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOx) as well as particulate matter (PM), was evaluated. The obtained results confirmed that the EGR system is effective in the reduction of the NOx formation for all tested fuel mixtures. Nevertheless, it was found that the addition of CNG combusted in the diesel engine generates more harmful pollutants in comparison with diesel fuel. However, in some cases the concentration of NOx as well as PM was comparable or lower. It suggests that the combustion of CNG in diesels allows achieving environmental benefits. In this case, further optimization of the engine fuel supply system is necessary.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.