单项选择题
Which of the listed factors will indicate the most about the ability of a fuel to ignite in a diesel engine?（）
A.Viscosity B.Sulfur content C.Pour point D.Cetane number
单项选择题 Why will a turbocharger diesel engine produce black smoke if excessive additional load is applied too quickly?（）
单项选择题 Cold weather starting of a diesel engine is more difficult than warm weather starting due to（）
单项选择题 The ignition quality of diesel fuel is indicated by its（）
