Abstract: A control device of an engine having cylinders which are divided into two cylinder groups. The first cylinder group is provided with a first throttle valve and a first recirculation valve. The second cylinder group is provided with a second throttle valve and a second recirculation valve. When shifting from full cylinder operation to partial cylinder operation where the second cylinder group is left idle, the sum of the load of both the cylinder groups is maintained as substantially the same load as the total load before shifting to the partial cylinder operation, the first throttle valve is gradually opened, and the second throttle valve is gradually closed.

Abstract: A control device for a variable displacement engine, coupled with an automatic transmission, for an automobile, wherein the control device controls cylinders depending on the driving condition. The control device changes working cylinders without changing the number of working cylinders during the shift operation of the automatic transmission by detecting that the automatic transmission is going to shift. When the control device changes working cylinders without changing the number of working cylinders, the control device controls cylinders so that cylinders which are non-working before the changing work after the changing, and controls cylinders so that a non-working cylinder is not followed by another non-working cylinder in the firing order of the case of all cylinders are working.