Thermostat device

Details Thermostat device Thermostat device

2002-03-15

2003-07-15

Tapolcai, William E. (Department: 3744)

Automatic temperature and humidity regulation

Cooling radiator

Bypass

C236S06800R

Reexamination Certificate

active

06592046

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a thermostat device for cooling internal combustion engines, and particularly to a thermostat device having a small hydraulic resistance in comparison to conventional thermostats, and capable of immediately warming the cooling water for controlling the activation of the valve element regardless of the cooling water temperature at the time of starting the engine and seeking improved fuel consumption of the engine thereby.
2. Description of the Related Art
A thermostat device disposed in the cooling system of an internal combustion engine and the like comprises a sensor case having a thermally expanding body built therein which expands/contracts by sensing the temperature change in the cooling water filled in the circulation flow channel of the cooling system, conducts the opening/closing of the valve element pursuant to the volume change concurrent with the expansion/contraction of such thermally expanding body, and functions to retain the cooling water at a prescribed temperature.
FIG. 7
shows an example of a conventional thermostat device, and this thermostat device
1
A comprises a thermostat activation unit
30
, which is the actuator of the valve element, inside the valve housings
31
,
32
structured of two members. This thermostat activation unit
30
is fixed to the valve housing
32
, activates the first valve element
33
and the second valve element
35
(bypass valve) with an activation piston
9
built in the thermostat activation unit
30
, and controls the main flow channel
34
and the bypass flow channel
36
.
The housing
37
of the thermostat activation unit
30
is retained with a holder
39
, and this holder
39
encircles, in a cap shape, the end opposite to the side in which the aforementioned activation piston is protruding in the housing
37
. The cap-shaped holder
39
is supported with the valve housing
32
.
A pot-shaped center area is provided at the cross section of the first valve
33
, and the thermostat activation unit
30
is disposed at the center thereof. This center area blocks the main flow channel
34
together with the holder
39
with the first valve element
33
being in a closed position.
A bolt
38
is provided on the axial extension of the activation piston (not shown) of the thermostat activation unit
30
, and the second valve element
35
(bypass valve) is mounted on this bolt
38
with a slide guide, thereby enabling the opening/closing of the bypass flow channel
36
. The second valve element
35
(bypass valve) is energized with a spring member
41
. The first valve element
33
is energized with a spring member
40
, and this spring member is supported with the valve housing
31
.
The thermostat device
1
A structured as described above is disposed so as to allow the cooling water from the engine to circulate from the bypass flow channel
36
to the engine upon inflowing from a sleeve
42
, or to circulate to the radiator via a sleeve
43
.
The cooling water inflowing from the bypass
36
is returned directly to the engine since the cooling water is of a low temperature prior to the air becoming warm at the time of starting the engine.
When the cooling water reaches a prescribed temperature after the warm air operation, the wax inside the housing
37
expands pursuant to this temperature and extends the activation piston (not shown) of the thermostat activation unit
30
. Pursuant to this extension of the activation piston, the first valve element
33
resists the energization of the spring member
40
, comes down, and releases the main flow channel from the blocked state into an open state, and the second valve element
35
(bypass valve) blocks the bypass flow channel
36
. Thus, the cooling water inflowing from the sleeve
42
flows into the radiator via the sleeve
43
.
Furthermore, in order to forcibly expand the wax inside the housing
37
, this structure provides a heating unit
44
to the housing
37
, and protrudes this heating unit
44
from the valve housing
32
for connection with a superheating element
45
.
Incidentally, with this type of conventional thermostat device
1
A, since the housing
37
, which is the temperature sensor of the cooling water, is disposed inside the cooling water flow channel, the hydraulic resistance of the cooling water inflowing from the sleeve
42
becomes large, and it is thereby difficult to miniaturize the water pump for forcibly circulating the cooling water.
Moreover, there are cases where a hunting phenomenon would arise when the cooling water from the engine and the cooling water from the radiator are mixed in the vicinity of the housing
37
during the warm air operation at the time of starting the engine. When this type of phenomenon arises, the cooling water temperature inflowing to the engine becomes unstable, and it is difficult to improve the fuel consumption and to seek the immediate warming of the cooling water. As a preventive measure, it is necessary to add a twist to the structure of the valve housing
32
in order to mix the cooling water immediately before the housing
37
, which is the temperature sensor, or to mount a current plate such as a so-called interruption plate.
In addition, when this thermostat device
1
A is disposed as an entrance control unit, it may sense the cooling water inflowing from the engine, and there were cases of malfunctions such as overshoots and so forth.
Thus, the thermostat device according to the present invention was devised in view of the foregoing problems, and an object thereof is to provide a thermostat device capable of immediately warming the cooling water even at the time of starting the engine and improving the fuel consumption, and wherein the cooling water has a small hydraulic resistance.
SUMMARY OF THE INVENTION
The thermostat device of the present invention has a structure wherein, inside the housing of a bottom bypass-type thermostat device comprising a main valve element on the main body and a bypass valve element on the bottom side, the main valve element and bypass valve element are supported by a main shaft supported at the piston tip of a thermoelement, the temperature sensor of the thermoelement is disposed such that it does not directly contact the cooling water from the radiator outlet and senses the temperature by contacting a portion of the cooling water from the engine outlet, the temperature sensor is equipped with a heating element, and the opening/closing of the main valve element and bypass element pursuant to the cooling water temperature as well as the control of the opening/closing of the valve element pursuant to the application of said heating element are freely conducted thereby.
According to this type of structure, it is possible to prevent the hunting phenomenon caused by the cooling water from the engine during the warm air operation at the time of starting the engine, and to improve the fuel consumption as well as to seek the immediate warming of the cooling water. Thus, it is not necessary to improve the structure of the valve housing or to mount a current plate in order to mix the cooling water immediately before the housing, which is the temperature sensor.
Furthermore, formed on the housing are a first inflow sleeve to which a part of the cooling water from the engine outlet inflows, a second inflow sleeve to which the cooling water from the radiator inflows, a sub flow channel for outflowing a part of the cooling water from the first inflow sleeve to the cooling water main flow channel or bypass flow channel inside the engine, and a main flow channel for outflowing the cooling water from the radiator to the cooling water main flow channel inside the engine.
By forming the respective flow channels inside the housing as above, the internal structure of the thermostat may be simplified, and resin materials such as heat-resistant plastic may be manufactured integrally with the housing itself. This will allow the thermostat device to be compatible with units.
Moreover, the main valve is disposed

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