Internal-combustion engines – Lubricators – Crankcase – pressure control
Reexamination Certificate
1999-04-23
2001-07-17
Kwon, John (Department: 3747)
Internal-combustion engines
Lubricators
Crankcase, pressure control
C123S1960CP
Reexamination Certificate
active
06260533
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an oil passageway structure for an internal combustion engine and, more particularly, to an oil passageway structure for introducing oil to an oil control valve for actuating hydraulic equipment.
BACKGROUND OF THE INVENTION
Some internal combustion engines include a crankshaft rotatably supported on a cylinder block, a crank timing sprocket positioned on the crankshaft, and a camshaft rotatably carried on a cylinder head for opening and closing intake and exhaust valves, which cylinder head is disposed on the cylinder block. Also included is a cam sprocket positioned on the camshaft, a timing chain wrapped around the crank timing sprocket and the cam sprocket, an enclosing member extending over the cylinder block and the cylinder head so as to cover the timing chain to form a chain chamber, and an oil pump disposed on the crankshaft on the side of the cylinder block.
In recent years, in some internal combustion engines, a variable valve timing system is provided for varying the valve timing of intake and exhaust valves in order to enhance a variety of required functions.
As illustrated in
FIG. 11
, the variable valve timing system is provided with: an oil pump
204
and a crank shaft timing sprocket
206
, both disposed on a crankshaft
202
; intake and exhaust camshaft sprockets
212
,
214
disposed on intake and exhaust camshafts
208
,
210
, respectively; a timing chain
216
wound around the crankshaft timing sprocket
206
and the camshaft sprockets
212
,
214
; a hydraulic actuator
218
provided as hydraulic equipment at an end portion of the intake camshaft
208
; an oil control valve
220
positioned in a cylinder head (not shown) for actuating the hydraulic actuator
218
; and, control means such as an electronic control unit (ECU)
222
(shown schematically) for actuating the oil control valve
220
. The control means
222
communicates with a crank angle sensor
224
and a cam angle sensor
226
via electrical signals (shown in dotted lines in
FIG. 11
) to calculate optimum valve timing in accordance with a running state of an internal combustion engine (not shown). The control means
222
actuates (via an electrical signal) the oil control valve
220
so as to control hydraulic pressure on the hydraulic actuator
218
, thereby varying respective phases of the intake camshaft
208
and the crankshaft
202
.
As illustrated in
FIG. 12
, in order to introduce oil from the oil pump
204
on the cylinder block side to the oil control valve
220
on the cylinder head side, an oil pipe
228
is mounted in the following manner: a pipe connection member
230
at one end of the oil pipe
228
is mounted on a cylinder block
234
by means of a union bolt
232
; and a pipe connection member
236
at the other end of the oil pipe
228
is mounted on an intake camshaft cap
240
by means of an additional union bolt
238
. The intake camshaft cap
240
retains the intake camshaft
208
. The oil pipe
228
is exposed and laid outside the engine.
Examples of such an oil passageway structure are disclosed in, for example, published Japanese Utility Model Application Laid-Open No. 5-6112, Japanese Patent Application Laid-open No. 8-232625, Japanese Patent Application Laid-Open No. 8-28231, Japanese Patent Application Laid-Open No. 9-170415, and Japanese Utility Model Application Laid-Open No. 62-179314. According to Japanese Utility Model Application No. 5-6112, a chain cover, i.e., an enclosing member, is formed with an oil passage in an internal combustion engine which has the oil pump positioned at a lower portion of the cylinder block. According to Japanese Patent Application No. 8-232625, a plurality of linear communication pipes are connected to an oil gallery in a crank case. Pursuant to Japanese Patent Application No. 8-28231, a hydraulic control valve, i.e., an oil control valve, is provided in a dead space of the cylinder block. According to Japanese Patent Application No. 9-170415, the cylinder head is formed with the oil passage in an internal combustion engine having variable valve timing. Pursuant to Japanese Utility Model Application No. 62-179314, a lubricating oil pipe is laid or disposed in the crank case.
In the past, with the internal combustion engine having the variable valve timing system, an inconvenience occurs when an oil pipe is laid outside the engine. This oil pipe extends from a main gallery as an oil passageway system which leads to the oil control valve. The main gallery is formed in the cylinder block. The inconvenience is that, if oil seeps from the oil pipe, then the oil escapes to the outside environment because the oil pipe is laid outside of the engine. Further inconveniences arise when oil passages are formed in the cylinder block and the cylinder head by drilling holes therein for the sole purpose of passage of oil. More specifically, the necessity of such dedicated holes involves dedicated fabrication facilities as well as a dedicated cylinder block and a dedicated cylinder head. In addition, such dedicated holes result in a reduced amount of freedom in design. Further, since the cylinder block is fabricated by dedicated machines, fabrication lines must be modified when the quantity of dedicated holes is to be increased or changes to the holes are desired. As a result, plant investment is increased.
SUMMARY OF THE INVENTION
In order to minimize or obviate the above-mentioned inconveniences, the present invention provides an oil passageway structure for an internal combustion engine having a crankshaft rotatably supported on a cylinder block of the engine, a crankshaft timing sprocket positioned on the crankshaft, a camshaft rotatably carried on a cylinder head for opening and closing intake and exhaust valves, the cylinder head being disposed on the cylinder block, a camshaft sprocket positioned on the camshaft, a timing chain wound around the crankshaft timing sprocket and the camshaft sprocket, and an enclosing member extending over the cylinder block and the cylinder head so as to cover the timing chain to form a chain chamber. An oil pump is provided on the side of the cylinder block, and an oil control valve is disposed on the side of the cylinder head for actuating hydraulic equipment, whereby oil from the oil pump is introduced into the oil control valve. The oil passageway structure according to the invention includes an oil pipe extending between a passage extending on a downstream side of the oil pump and the oil control valve, the oil pipe being provided inside the chain chamber.
Pursuant to the present invention, the oil pipe located inside the chain chamber is provided between the passage extending on the downstream side of the oil pump and the oil control valve. Further, the oil pipe can be bent when desired. As a result, there is provided a greater degree of freedom in design. In addition, there is no need to change respective shapes of the cylinder block and the cylinder head. Consequently, fabrication facilities or fabrication lines need not be modified, with a noncomitant reduction in plant investment. Moreover, oil can be prevented from escaping outside the engine, even if oil leaks from locations where the oil pipe is mounted. Further, since the oil pipe is mounted unitarily on the enclosing member, then sub assembly is achievable, with a consequential improvement in efficiency of assembly.
REFERENCES:
patent: 4702204 (1987-10-01), Anno et al.
patent: 5094201 (1992-03-01), Bedi
patent: 5666915 (1997-09-01), Kawashima et al.
patent: 5950763 (1999-09-01), Ohta
patent: 6000373 (1999-12-01), Woodhouse
patent: 6016784 (2000-01-01), Tanaka
patent: 62-179314 (1987-11-01), None
patent: 5-6112 (1993-01-01), None
patent: 08028231 (1996-01-01), None
patent: 08232625 (1996-09-01), None
patent: 091704150 (1997-06-01), None
Flynn ,Thiel, Boutell & Tanis, P.C.
Kwon John
Suzuki Motor Corporation
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