SFS Suomen Standardit

 

This document specifies a test method for the quantitative determination of ignition and combustion delays of middle distillate fuels intended for use in compression ignition engines. The method utilizes a constant volume combustion chamber with direct fuel injection into heated, compressed synthetic air. A dynamic pressure wave is produced from the combustion of the product under test. An equation is given to calculate the derived cetane number (DCN) from the ignition and combustion delays determined from the dynamic pressure curve. This document is applicable to middle distillate fuels, fatty acid methyl esters (FAME) and blends of diesel fuels and FAME. The method is also applicable to middle distillate fuels of non-petroleum origin, oil-sands based fuels, blends of fuel containing biodiesel material, diesel fuel oils containing cetane number improver additives and low-sulphur diesel fuel oils. However, users applying this document especially to unconventional distillate fuels are warned that the relationship between derived cetane number and combustion behaviour in real engines is not yet fully understood. This document covers the ignition delay range from 2,6 ms to 3,9 ms and combustion delay from 3,78 ms to 6,56 ms (62,78 DCN to 39,44 DCN). NOTE The combustion analyser can measure shorter or longer ignition and combustion delays, but precision is not known. WARNING - The use of this document can involve hazardous materials, operations and equipment. This document does not purport to address all of the safety problems associated with its use. It is the responsibility of users of this document to take appropriate measures to ensure the safety and health of personnel prior to application of the document, and fulfil statutory and regulatory requirements for this purpose.

 

 

This part of ISO 7870 establishes a guide to the use and understanding of specialized control charts in situations where commonly used Shewhart control chart approach to the methods of statistical control of a process may either be not applicable or less efficient in detecting unnatural patterns of variation of the process. This part of ISO 7870 also provides guidance as to when control charts discussed in this document should be used, their control limits, advantages and limitations. Each control chart is illustrated with an example.