Four-cycle engine lubrication structure

Details Four-cycle engine lubrication structure Four-cycle engine lubrication structure

1999-09-09

2001-03-20

Kamen, Noah P. (Department: 3747)

Internal-combustion engines

Lubricators

Crankcase, pressure control

Reexamination Certificate

active

06202621

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an improvement to a four-cycle engine lubrication structure.
2. Description of Related Art
Four-cycle engine lubrication structures such as, for example, the “Four-cycle Engine Lubrication Apparatus” of Japanese Patent Publication No. Hei. 6-25527 are well known.
The above technology relates to a four-cycle engine lubrication apparatus capable of preventing drops in output accompanying engine oil agitation and capable of reliably providing oil to each of the necessary places within the engine even when the vehicle is at an incline. As shown in
FIG. 2
of the above publication, there is provided a crank chamber
12
, a transmission chamber
13
separated from the crank chamber
12
by a bulkhead
14
, a through hole
15
provided at the bulkhead
14
to allow the crank chamber
12
and the transmission chamber
13
to communicate, and a unidirectional valve
16
provided at the through hole
15
for allowing oil to flow only from the crank chamber
12
to the transmission chamber
13
.
In the above technology, when the pressure within the crank chamber
12
becomes high, the unidirectional valve
16
opens and oil within the crank chamber
12
flows through the through hole
15
to the transmission chamber
13
. However, oil is collected at a position higher than the through hole
15
within the transmission chamber and this may hinder opening of the valve
16
. Therefore, the oil does not move smoothly from the crank chamber
12
to the transmission chamber
13
.
There is also an problem in the above technology, since air becomes mixed with the oil within the crank chamber
12
. Therefore, when the oil flows into the transmission chamber
13
, air is mixed in with the oil within the transmission chamber
13
and the oil is oxidized, causing increased deterioration of the oil.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a four-cycle engine lubrication structure capable of smoothly discharging oil from the crank chamber and suppressing oil deterioration.
In order to achieve the aforementioned object, a first aspect of the present invention includes an oil sump for lubricating oil provided at a lower part of a crank chamber of a dry sump-type four-cycle engine, a reed valve provided at an outlet of the oil sump and opening when crank chamber pressure is high, and an oil passage extending at an incline upwards from the outlet of the oil sump, with an outlet of the oil passage being provided above an oil surface level of oil accumulated within the engine.
Since the oil passage outlet is provided higher than the surface level of oil that has accumulated within the engine, oil coming from the oil passage outlet is not discharged within the collected oil. Therefore, discharge of oil from the oil passage outlet can be carried out smoothly. Oil mixed with air within the crank chamber is not directly mixed with collected oil. Therefore, oil oxidation is prevented. Furthermore, the oil is substantially protected against deterioration because there is no direct contact between the oil and hot blow-by gas, etc.
According to a second aspect of the present invention, projections are formed on the crank chamber inner wall at the inlet of the oil sump in such a manner as to project along the outer periphery of the crankshaft weight in an opposite direction to the direction of rotation of the crankshaft weight. The projections come into contact with the outer periphery of the crankshaft weight. Therefore, oil on the crankshaft weight is removed by the projections, causing the oil to flow rapidly to the oil sump. Accordingly, discharge of oil from the crank chamber is made easier as a result.
According to a third aspect of the present invention, an oil chamber is provided for separating and recovering oil from oil mist discharged from the oil passage outlet.
Since oil is separated and recovered from the oil mist at the oil chamber, air bubbles are no longer mixed with the recovered oil. Therefore, oil deterioration is prevented and oil provided to each part of the engine can be effectively utilized. Furthermore, the oil passage outlet is protected and oil is more effectively discharged from the crank chamber.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.


REFERENCES:
patent: 5456230 (1995-10-01), VanRens et al.
patent: 5960764 (1999-10-01), Araki
patent: 5975042 (1999-11-01), Aizawa et al.
patent: 6-25527 (1994-04-01), None

Affiliated with

Also associated with

Rating

Four-cycle engine lubrication structure does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Four-cycle engine lubrication structure, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Four-cycle engine lubrication structure will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2457447