The present invention relates to a method for increased exhaust gas temperature and emission reduction at partial loads in a diesel engine, wherein said engine comprises a cylinder with a reciprocating piston, a variable compression volume (VCR), and at least one exhaust valve and at least one inlet valve, the latter being equipped with variable valve timing (WT). According to the prevailing engine power requirement, an engine control system determines when to open and close said inlet valve, and the size of said compression volume in order to achieve a sufficiently elevated exhaust gas temperature so that correct exhaust gas purification can be achieved. The method is characterized in that the cylinder pressure during the expansion stroke is managed by the engine control system by means of the VCR and VVT functions, such that said pressure reaches atmospheric or sub atmospheric levels at or before bottom dead centre, at engine loads at or below 25% of the maximum engine load, whereby the inlet valve is opened to allow air to mix with the combustion gases. The invention also relates to a corresponding device and a diesel engine comprising said device.