Abstract
The diesel engine is a promising power plant because for its higher efficiency and lower CO_2 emission compared to the SI engine. WHTC is scheduled to be adopted for the HD diesel engine emissions certification test in 2016 in Japan, including 14% weighted cold-start condition. In addition, it is supposed that diesel fuel's cetane number will tend to be lower due to the future degradation of crude oil. Taking into account these situations, we conducted engine tests to investigate the effects of a low cetane number fuel and low temperature operating conditions on combustion and emissions in a HD diesel engine. The test results indicate that particularly at low load, a combination of the low cetane and low temperature operation tend to increase ignition delay, thereby reducing PM and increasing CO and fuel consumption without changing NO_x emission and that pilot injection is useful to reduce ignition delay and recover the deteriorated efficiency for the low cetane fuel.
