A control device of a gasoline direct-injection engine is provided. The control device includes an engine body, an injector, and a controller. Within a high load operating range, the controller causes the injector to perform a pre-injection and a post injection. In the pre-injection, the fuel is injected to cause a fuel concentration within an in-cylinder radially peripheral section to be higher than a fuel concentration within an in-cylinder radially central section at a timing for the fuel to ignite. In the post injection, the fuel is injected to cause the fuel concentration within the radially central section to be higher than the fuel concentration within the radially peripheral section at a timing for the fuel to ignite. The timing for the fuel injected in the post injection to ignite is after an oxidative reaction of the fuel injected in the pre-injection occurs and after a compression top dead center.

A method for improving combustion in a combustion chamber of an internal combustion engine, a heat retaining element, and an internal combustion engine are provided. The internal combustion engine includes a main combustion chamber arranged between a head and a reciprocating piston, and a heat retaining element provided between the head and the main combustion chamber. The heat retaining element is a self-supporting structure coupled to the head that is configured to reduce heat transfer from the main combustion chamber into the engine head. The heat retaining element includes a head-facing portion substantially corresponding in shape to a portion of the head facing the main combustion chamber. The heat retaining element is provided such that a gap is provided between the head-facing portion of the heat retaining element and the portion of the head facing the main combustion chamber.

An internal combustion engine has a uniblock that defines a blind cylinder bore that terminates within the uniblock. A piston is inserted into the cylinder bore from a bottom end of the cylinder bore. Parallel first and second vertical planes extend along first and second lateral sides of the cylinder bore. A cylinder zone being defined between the first and second vertical planes. A crosshead is coupled to the piston. A first crankshaft has a first crankshaft axis that extends parallel to the first vertical plane and that is positioned outside of the cylinder zone. A second crankshaft has a second crankshaft axis that extends parallel to the second vertical plane and that is positioned outside of the cylinder zone. The first crankshaft is coupled to the crosshead with a first connecting rod and the second crankshaft is coupled to the crosshead with a second connecting rod.