Nissan Motor Company Limited

Hiroaki Hoshikawa

Tsuyoshi Higuchi

Kakuzou Kaneko

Hayato Hirayama

Kazuo Muraki

Yoshito Utsumi

Takayoshi Ichihara

Satoru Ookuma

Naoya Tainaka

Kazuki Arima

Tomohiro Kawata

Yukinaga Moriguchi

Provided is a spray coating that is disposed on an inner peripheral surface of a cylinder bore of a cylinder block made of aluminum or an aluminum alloy. The spray coating contains 0.005% to 0.14% by mass of carbon, 0.01% to 3.0% by mass of nickel 10% to 20.5% by mass of chromium, 0.05% to 1.5% by mass of silicon, and a balance containing iron and inevitable impurities. The spray coating has a composition that forms a martensite+ferrite (M+F) region in the Schaeffler diagram, and a composition in which a nickel equivalent (NiE) and a chromium equivalent (CrE) satisfy a relationship expressed by the following Formulae (1): NiE≤0.95 CrE−8.59, (2): NiE≤4.1, and (3): CrE≥10. The spray coating has a two-phase structure formed of a martensite phase and a ferrite phase.

Spray coating

A sliding mechanism of the present invention includes a cylinder bore having a thermally sprayed iron-based coating and includes a piston with a piston ring covered with a hard coating composed mainly of carbon. The thermally sprayed coating has diamond abrasive grains. An area ratio of the diamond abrasive grains to a surface of the thermally sprayed coating is 0.3 to 1.8%, which enables suppressing wear of the piston ring having the hard coating composed mainly of carbon.

Sliding mechanism

A control method and a control device are provided for an internal combustion engine structured to vary a mechanical compression ratio by varying a range of slide of a piston with respect to a cylinder bore, and structured to control a flow of cooling water in a water jacket formed around the cylinder bore, wherein variation of the mechanical compression ratio causes the piston to slide on a corroded portion formed in the cylinder bore. A control process includes: acquiring a temperature correlating with a cylinder bore wall temperature; and stopping the flow of cooling water in the water jacket, in response to a condition that the acquired temperature is lower than a preset temperature point.

Control method for internal combustion engine and control device for internal combustion engine

A control method and a control device are provided for an internal combustion engine structured to vary a mechanical compression ratio by varying a range of slide of a piston with respect to a cylinder bore. A control process includes: acquiring a temperature correlating with a cylinder bore wall temperature; fixing the mechanical compression ratio to a preset compression ratio point, in response to a condition that the acquired temperature is lower than a preset temperature point; and setting the preset temperature point higher than a point corresponding to a point of the cylinder bore wall temperature at which condensed water occurs in the cylinder bore.

A crankshaft bearing part () has a pair of main bearing metals (), and lubricating oil is guided from an oil gallery to an inner circumferential oil groove () through an in-block oil passage () and a first oil hole (). Some of the lubricating oil is supplied to a control shaft bearing part () via a second oil hole () and an in-cap oil passage (). Lubricating oil is guided from a third oil hole () in a pair of control shaft bearing metals () to an inner circumferential oil groove (). The oil groove () in the crankshaft bearing part () functions also as an oil passage for supplying lubricating oil to the control shaft bearing part (), thereby achieving a simple configuration.

Bearing structure for multi-link-type piston crank mechanism for internal combustion engines

A bearing structure has a crankshaft rotatably supported by a crankshaft bearing part, formed of a cylinder block of an internal combustion engine and a first bearing cap, through a bearing metal, a second shaft rotatably supported by a second shaft bearing part formed of the first bearing cap and a second bearing cap, wherein the bearing metal has a bearing metal planar portion for rotatably supporting the crankshaft with an entire inner peripheral surface of the bearing metal, the inner peripheral surface at which the bearing metal planar portion is formed, a bearing metal oil groove portion formed with an oil groove formed to extend circumferentially in an inner peripheral surface of the bearing metal, the inner peripheral surface at which the bearing metal oil groove portion is formed, a first oil hole opening at the oil groove, and a second oil hole opening at the oil groove.

Bearing structure

An internal combustion engine () is designed so that the center axis P of a cylinder () is offset relative to a main journal part () of a crankshaft (). A bearing cap () is designed so that the side toward the cylinder center axis from a main bearing part () is secured to a bulkhead () by two fastening bolts () while the side away from the cylinder center axis from the main bearing part is secured to the bulkhead by one fastening bolt () and that the bearing cap securing force on the side toward the cylinder center axis from the main bearing part () is greater than the bearing cap securing force on the side away from the cylinder center axis.

Supporting structure for internal combustion engine

A bearing cap () fastened to a bulkhead () of a cylinder block () by bolts to support a crankshaft. A pair of protruding parts () that enlarge a joint surface () between the bearing cap () and the bulkhead () in a transverse direction of the crankshaft are formed respectively in a pair of side surfaces (). A pair of reinforcing parts () are positioned between a top surface () and the pair of protruding parts (), protrude from the pair of side surfaces () in the transverse direction of the crankshaft, and have a protrusion length that is smaller than that of the pair of protruding parts (). The stress on the joint portion between the bearing cap () and the bulkhead () generated by the crankshaft during operation of the internal combustion engine is thereby reduced.

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Kanagawa, Japan

Hiroaki Hoshikawa