In one instance, disclosed herein is a controller configured for operating an engine in an extra-stroke mode, the controller comprising: a processor; and a memory storing instructions that, when executed by the processor, cause the electronic control module to generate commands for operations including: transitioning operation of the engine from a four-stroke mode to the extra-stroke mode or from the extra-stroke mode to the four-stroke mode, wherein the four-stroke mode includes an intake stroke, a compression stroke, a power stroke, and an exhaust stroke, and wherein the extra-stroke mode includes at least six strokes of a piston disposed within a combustion chamber of an engine cylinder of the engine, during which an exhaust valve of the engine cylinder is opened only once, during or immediately preceding a final upward stroke of the at least six strokes.

A compression ignition engine, commercial vehicle comprising such an engine, and a method for improving starting behaviour of such an engine. The engine is operable in a normal mode or a cold start mode. In the normal mode, a fuel injection system is controlled to inject a main fuel injection in a single pulse. In the cold start mode, the main fuel injection is split into a first split main and a second split main. The fuel injection system is controlled to inject the first and second split main in two distinct pulses, wherein the first split main is injected at a delayed timing for initiating a diffusion combustion phase in the pressurized combustion chamber, and wherein the second split main is injected during the diffusion combustion phase into the already combusting air-fuel mix.