IP 541: Determination of ignition and combustion characteristics of residual fuels — Constant volume combustion chamber method

Overview:

Scope

This standard specifies a procedure for the quantitative determination of ignition and combustion characteristics of residual fuels for use in compression ignition engines.

Ignition Delay (ID) 2,7 - 7,6 ms, Main Combustion Delay (MCD) 3,1 - 9,7 ms, Position of Maximum ROHR (PMR) 3,1 - 11,8 ms, End of Main Combustion (EMC) 9,6 - 18,9 ms, End of Combustion (EC) 15,3 - 28,6 ms, Pre Combustion Period (PCP) 0,28 - 2,06 ms, Main Combustion Period (MCP) 3,9 - 9,3 ms, After Burning Period (ABP) 5,3 - 9,7 ms, maximum Rate Of Heat Release (maxROHR) 0,11 - 0,48 MPa/ms, Accumulated Rate of heat release (AR) 7,2 - 8,3 and the facultative determination of Net Heat of Combustion (NHC) 47,0 - 56,5 MJ/kg at 25 °C.

This standard is applicable to residual fuels of petroleum origin with viscosities up to 2 000 mm²/s @ 50 °C. However, precision has only been determined for residual fuels with viscosities in the range 25 to 800 mm²/s @ 50 °C. It is specifically applicable, but not limited, to products typical of Specifications ISO 8217 and CIMAC Recommendation Number 21.

The ignition and combustion relationship as determined by this method and real engine performance has not yet been established.

NOTE 1 - For an estimation of Cetane Number (ECN) see annex F.