Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Combustion Engines

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Comparative study of combustion and emissions of diesel engine fuelled with FAME and HVO

Hunicz Jacek, Krzaczek Paweł, Gęca Michał, Rybak Arkadiusz, Mikulski Maciej

Combustion Engines

2021

R. 60, nr 1

72--78

This study investigates combustion and emission characteristics of a contemporary single-cylinder compression ignition engine fuelled with diesel, fatty acid methyl esters (FAME) and hydrotreated vegetable oil (HVO). These two drop-in fuels have an increasing share in automotive supply chains, yet have substantially different physical and auto-ignition properties. HVO has a lower viscosity and higher cetane number, and FAME has contrary characteristics. These parameters heavily affect mixture formation and the following combustion process, causing that the engine preoptimized to one fuel option can provide deteriorated performance and excess emissions if another sustainable option is applied. To investigate the scale of this problem, injection pressure sweeps were performed around the stock, low NOx and low PM engine calibration utilizing split fuel injection. The results showed that FAME and HVO prefer lower injection pressures than diesel fuel, with the benefits of simultaneous reduction of all emission indicators compared to DF. Additionally, reduction of injection pressure from 80 MPa to 60 MPa for biodiesels at low engine load resulted in improved brake thermal efficiency by 1 percentage point, due to reduced parasitic losses in the common rail system.

Effects of combustion timing on pressure rise rates in a residual effected HCCI engine

Hunicz Jacek, Gęca Michał, Kordos Paweł, Rybak Arkadiusz

Combustion Engines

2019

R. 58, nr 3

46--50

Realization of a low temperature combustion concept in homogeneous charge compression ignition (HCCI) engines is a cutting-edge technology that offers clean combustion in parallel with high thermal efficiency. Low combustion temperature prevents from NOx formation whereas homogeneous mixture assures smokeless exhaust. However, achieving the production feasibility by HCCI technology is hampered by high pressure rise rates and the resulting combustion noise at a high load operation. This paper explores combustion timing parameters that are capable of maintaining permissible levels of pressure rise rates under a high load regime. On the basis of experimental data collected at a high load HCCI operation, pressure rise level was correlated with combustion duration. Furthermore, combustion duration has been found to scale with in-cylinder volume, for which 50% of mass fraction burned appeared. The results showed quantitatively limitations of engine load, pointing out on required combustion timings to achieve acceptable combustion harshness depending on engine load.