Supporting structure for internal combustion engine

Patent metadata

Field	Value
Publication number	US-9670872-B2
Application number	US-201414783340-A
Country	US
Kind code	B2
Filing date	Apr 3, 2014
Priority date	Apr 11, 2013
Publication date	Jun 6, 2017
Grant date	Jun 6, 2017

Abstract

An internal combustion engine ( 1 ) is designed so that the center axis P of a cylinder ( 4 ) is offset relative to a main journal part ( 2 a ) of a crankshaft ( 2 ). A bearing cap ( 17 ) is designed so that the side toward the cylinder center axis from a main bearing part ( 18 ) is secured to a bulkhead ( 7 ) by two fastening bolts ( 24 a, 24 c ) while the side away from the cylinder center axis from the main bearing part is secured to the bulkhead by one fastening bolt ( 24 b ) and that the bearing cap securing force on the side toward the cylinder center axis from the main bearing part ( 18 ) is greater than the bearing cap securing force on the side away from the cylinder center axis.

First claim

The invention claimed is:

1. An internal combustion engine comprising a first bearing cap secured to a cylinder block by fastening bolts and a crankshaft rotatably supported by the first bearing cap and the cylinder block, the cylinder block having a cylinder center axis offset relative to a rotation center of the crankshaft,
wherein a product of a distance from a center axis of the fastening bolts to the rotation center of the crankshaft and an axial force of the fastening bolts is defined as a bearing cap securing force,
when viewed from an axial direction of the crankshaft, a bearing cap securing force on a side toward the cylinder center axis from the rotation center of the crankshaft is larger than a bearing cap securing force on a side away from the cylinder center axis or a side having no cylinder center axis,
the first bearing cap is secured by two fastening bolts on the side toward the cylinder center axis while being secured by one fastening bolt on the side away from the cylinder center axis,
the first bearing cap has a cylinder block-side contact surface brought into contact with the cylinder block, and a top end surface opposite to the contact surface,
the first bearing cap is partially cut out at a cylinder center axis-side end of the top end surface to have a cutout portion at which the first bearing cap is secured to the cylinder block by an outer fastening bolt of the two fastening bolts disposed on the side toward the cylinder center axis, the outer fastening bolt having a distance from the rotation center of the crankshaft larger than a distance of an inner fastening bolt of the two fastening bolts from the rotation center of the crankshaft, and
the outer fastening bolt of the two fastening bolts securing the first bearing cap on the side toward the cylinder center axis is smaller in length than the inner fastening bolt of the two fastening bolts.

2. An internal combustion engine as claimed in claim 1 , further comprising a second hearing cap secured to the first bearing cap,
wherein the fastening bolts securing the first bearing cap on the side toward the cylinder center axis includes: a first fastening bolt securing the first bearing cap to the cylinder block while securing the second bearing cap to the first bearing cap; and a second fastening bolt securing the first bearing cap to the cylinder block, and
the fastening bolt securing the first bearing cap on the side away from the cylinder center axis serves as a third fastening bolt securing the first bearing cap to the cylinder block while securing the second bearing cap to the first bearing cap.

3. An internal combustion engine as claimed in claim 1 , wherein all of the fastening bolts are secured with the same axial force.

4. An internal combustion engine as claimed in claim 1 , further comprising a multi-link type piston crank mechanism comprising: an upper link connected at its one end to a piston pin of a piston; a lower link connected to the upper link and a crankpin of the crankshaft; a control shaft extending generally parallel with the crankshaft; and a control link swingably connected at its one end to an eccentric shaft section disposed eccentric with respect to a rotation center of the control shaft while being connected at the other end to the lower link, thereby making the top dead center position of the piston adjustable according to a rotation position of the control shaft, wherein the control shaft is rotatably supported by the first bearing cap and a second bearing cap secured to the first bearing cap, and the fastening bolts securing the first bearing cap to the cylinder block include a fastening bolt securing the second bearing cap to the first bearing cap.

Assignees

• Nissan Motor

Inventors

• Hoshikawa Hiroaki

Classifications

• F16C2360/22

  Internal combustion engines · CPC title

• F16C9/02

  Crankshaft bearings · CPC title

• F02F2007/0041

  Fixing Bolts · CPC title

• F02F7/0053 Primary

  Crankshaft bearings fitted in the crankcase · CPC title

• F02F7/0019

  Cylinders and crankshaft not in one plane (deaxation) · CPC title