单项选择题
Which of the following conditions could contribute to the cracking of a diesel engine cylinder head?（）
A.Leaking seal ring B.Insufficient heat transfer from the exhaust valves C.Block cooling water passages to the head D.Excessive scavenging air provided to the engine
单项选择题 The cetane rating of diesel fuel is an indication of the（）
单项选择题 The cetane number of a diesel fuel oil indicates its（）
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?（）
