Fuel-unlimited compression ignition engine

Some embodiments described herein relate to a method of operating a compression ignition (CI) engine. The CI engine may include a combustion chamber. A method of operating a CI engine includes receiving an amount of intake charge in a combustion chamber, compressing the intake charge, injecting an amount of fuel into the combustion chamber, the fuel having a cetane number of less than about 40, and combusting substantially all of the amount of fuel. The delay between injecting the amount of fuel into the combustion chamber and the start of combustion is less than about 2 milliseconds. The CI engine includes at least a two-stroke engine, an opposed-piston engine, a two-stroke opposed-piston engine, a five-stroke engine, a six-stroke engine, a free-piston engine, a free-piston engine linear generator, a rotary engine, and/or a Wankel rotary engine. 本文描述的一些实施例涉及操作压燃(CI)发动机的方法。CI发动机可以包括燃烧室。操作CI发动机的方法包括：在燃烧室中接收一定量进气充量，压缩进气充量，将一定量燃料喷射到燃烧室中，燃料具有小于约40的十六烷值，并且燃烧基本上所有所述一定量燃料。将所述一定量燃料喷射到燃烧室中与燃烧开始之间的延迟小于约2毫秒。CI发动机至少包括二冲程