Internal combustion engine and straddle-type vehicle equipped with the engine

Patent metadata

Field	Value
Publication number	US-9464956-B2
Application number	US-201213552672-A
Country	US
Kind code	B2
Filing date	Jul 19, 2012
Priority date	Jul 20, 2011
Publication date	Oct 11, 2016
Grant date	Oct 11, 2016

Abstract

In a single-cylinder internal combustion engine fitted with a knock sensor, a temperature increase of the knock sensor is suppressed and prevented, and the reliability of the knock sensor is improved. The engine includes a crankcase, a cylinder block connected to the crankcase, a cylinder head connected to the cylinder block, a sensor mounting boss provided on the cylinder block, and a knock sensor mounted to the boss. Fins are provided on the cylinder block and the cylinder head. A heat insulation member is provided between the boss and the knock sensor.

First claim

What is claimed is:

1. A single-cylinder internal combustion engine for a vehicle, the single-cylinder internal combustion engine comprising:
a crankcase accommodating a crankshaft;
a cylinder block connected to the crankcase and including a cylinder provided therein;
a cylinder head connected to the cylinder block;
a sensor mounting boss provided on the crankcase, the cylinder block, or the cylinder head;
a sensor arranged to detect knocking of the single-cylinder internal combustion engine, the sensor being mounted to the sensor mounting boss;
a fin provided on at least a portion of the cylinder block and the cylinder head; and
a heat insulation member interposed between the sensor mounting boss and the sensor; wherein
the heat insulation member is made of a material having a lower thermal conductivity than that of the sensor mounting boss;
the sensor is arranged to detect vibrations;
the single-cylinder internal combustion engine further includes a bolt arranged to mount the sensor and the heat insulation member to the sensor mounting boss, a portion of the bolt being in contact with the sensor mounting boss and another portion of the bolt being in direct contact with the sensor;
each of the cylinder block and the cylinder head includes a top surface, a bottom surface, a left surface, and a right surface;
an intake pipe is connected to one of the to surface, the bottom surface, the left surface, and the right surface of the cylinder head, and an exhaust pipe is connected to an opposite surface to the surface to which the intake pipe is connected; and
the sensor mounting boss is provided on the surface of the cylinder head to which the intake pipe is connected or on a surface of the cylinder block that corresponds to the surface of the cylinder head to which the intake pipe is connected.

2. The single-cylinder internal combustion engine according to claim 1 , wherein:
the heat insulation member includes a through-hole provided therein;
the sensor includes an obverse surface, a reverse surface in contact with the heat insulation member, and a through-hole passing from the obverse surface to the reverse surface, and the sensor is arranged to detect vibrations; and
the single-cylinder internal combustion engine further comprises:
a bolt arranged to mount the sensor and the heat insulation member to the sensor mounting boss, the bolt including a shaft portion and a head, the shaft portion penetrating through the through-hole of the sensor and the through-hole of the heat insulation member and being inserted in the sensor mounting boss, and the head being in contact with the obverse surface of the sensor and having a larger diameter than that of the shaft portion.

3. The single-cylinder internal combustion engine according to claim 1 , wherein the sensor mounting boss is provided on the cylinder block.

4. The single-cylinder internal combustion engine according to claim 1 , wherein the sensor mounting boss is provided on the cylinder head.

5. The single-cylinder internal combustion engine according to claim 1 , wherein:
the sensor mounting boss is made of a metal; and
the heat insulation member is made of a resin.

6. The single-cylinder internal combustion engine according to claim 1 , wherein:
the sensor mounting boss is made of a metal; and
the heat insulation member is made of a ceramic.

7. The single-cylinder internal combustion engine according to claim 1 , wherein the sensor mounting boss is continuous with the fin.

8. The single-cylinder internal combustion engine according to claim 1 , further comprising an air guide member mounted to at least a portion of the crankcase, the cylinder block, or the cylinder head and arranged to guide air at least to the sensor mounting boss.

9. The single-cylinder internal combustion engine according to claim 8 , further comprising:
a fan disposed at a side of the crankcase and arranged to be driven by the crankshaft; wherein
the air guide member includes a shroud including a suction port provided at a position facing the fan.

10. The single-cylinder internal combustion engine according to claim 1 , wherein the heat insulation member is a separate part from the sensor, the cylinder block, and the cylinder head.

11. A straddle-type vehicle comprising:
a single-cylinder internal combustion engine according to claim 1 .

Assignees

• Nakajima Akitoshi
• Inomori Toshinori
• Yamaha Motor Co Ltd

Inventors

• Nakajima Akitoshi
• Inomori Toshinori

Classifications

• F01P1/06

  Arrangements for cooling other engine or machine parts · CPC title

• F02B75/16

  Engines characterised by number of cylinders, e.g. single-cylinder engines (F02B75/26 takes precedence) · CPC title

• F02B61/02

  for driving cycles · CPC title

• F02B77/085

  with sensors measuring combustion processes, e.g. knocking, pressure, ionization, combustion flame · CPC title

• G01L23/221 Primary

  for detecting or indicating knocks in internal combustion engines · CPC title