VESSEL

DESCRIPTION

Technological Area:

This invention relates to wax based actuator for cooling circulation systems of internal combustion engines which has fast response time by means of its vessel in which wax compound is filled in and which allows the wax compound to be filled in with thin wax thickness by means of its geometry which is different from cylindrical ones which is state of the art. Known Situation of the Art:

In internal combustion engines, it is important to keep the engine in designed temperature range with regards to combustion efficiency and progressing emission standards so cooling circulation systems have crucial importance.

Cooling circulation systems are mostly with liquid coolant in today's engine technology and thermostats are main temperature control devices of these systems. They are used to provide flow through required outputs (bypass circuit or radiator circuit) with required flow rates to keep the engine's temperature around designed value. To control this flow, different types of actuators such as wax based actuator, electrically heated wax based actuators or electromechanical actuators are used. In wax based actuators, a wax compound which is expandable by increasing temperature is filled inside a vessel and a cover, a piston and a diaphragm assembled together for sealing of wax. This assembly controls the coolant flow. In case temperature increases the wax compound inside the thermal actuator assembly starts to expand. This expansion causes a lift on the piston and the valves which is engaged to this piston. In case of temperature decreases this time wax compound starts to shrink and the valves and engaged piston moves back by means of the spring force. Thereby the valves and accordingly coolant flow are controlled.

Coolant circulating the engine and by-pass circuit doesn't cool the engine and temperature of the coolant starts to increase. This hot coolant causes expansion of the wax compound during the circulation until the radiator output is opened by actuator. Likewise, coolant circulating the engine and radiator circuit is cooled by radiator and temperature of the coolant starts to decrease and wax compound starts to shrink until the by-pass output is closed by the actuator. This opening period caused by expansion and closing period caused by shrinkage takes time called response time of system which has parameters and one of them is response time of wax compound. The increasing temperature of the coolant circulating the engine starts to heat the vessel and it is transferred to the wax compound inside of the vessel and the wax compound starts to heat gradually from outer side to inner side. All amount of the wax compound should be at the same temperature so that expansion and melting should be occurred regularly. Likewise decreasing temperature of the coolant circulating the engine starts to cool the vessel and it starts to cool the wax compound gradually from outer side to inner side. All amount of wax compound should be at the same temperature so that shrinkage and jelling should be occurred regularly. This heat transfer to set all amount of the wax compound takes some time which called response time of the wax compound which is critical for the response time of system.

The slower response time is the longer stabilization time for reaching targeted engine temperature which means inefficient fuel combustion and higher emission rates.

The main criteria effecting response time of wax compound is heat transfer coefficient of wax material. Thickness of wax directly effects on the response time which is necessary to reach a stabilized temperature of whole mass of wax placed in vessel.

Melt and expansion is proportional to heat that transferred to the wax compound. In wax based actuators, a wax compound is filled inside a cylindrical vessel which is called as pellet and it becomes a cylinder shape due to vessel geometry. Therefore the wax placed in center core of pellet will sense the temperature of environment with a long delayed time due to very low heat transfer coefficient of wax material and being far away from outer surface of pellet. Main portion of response time is consumed to achieve same temperature on the center of wax pellet placed in wax actuator.

To fasten the response time of this wax compound actuator with cylindrical vessel the ingredient of the compound might be changed. But it is not accurate enough to reach the desired response time and also changes the temperature that wax compound starts to expand or shrink.

Heating the wax compound by a forced convection is an option to eliminate the response time delays of wax compound while opening. For this electrically heated wax based actuator is implemented. An electrical resistance heater which is surrounded by the wax compound inside the vessel is used to heat the wax compound. A voltage is applied on this resistance, which heats the wax compound so that wax compound expands. In this way fastening the response time of wax compound while expanding might be possible yet it is not possible to fasten the response time while shrinking since cooling the wax compound for is occurred on its own environment without any intervention. Also applying continuous voltage causes over heating on wax compound which may causes loss of physical characteristics on wax compound or may cause harm on sealing components.

Using an electromechanical actuator might be another option to control the valve structure. Valves controlling the flows through by-pass and radiator outputs engaged directly to an electromechanical actuator. Electromechanical actuator is controlled directly by the ECU via an electronic control card independent of temperature. According to control signal from the ECU the valves are positioned to the desired position within seconds. In this way it might be possible to achieve very fast response time since electromotor drives the valve both opening and closing direction within a few seconds. This way it is possible to have a smart cooling circulation unit. Yet using an electromechanical actuator has some reliability concerns. For instance it should work under the hood not only in cold but also in extreme hot environment, it requires a robust electromechanical actuator which has wide operating temperature range, it needs an electronic controller which is able to communicate with ECU which should meet EMC/EMI requirements and it needs a robust body so as to activate the valves with limited electromechanical force. Herewith it is not easy to implement such kind of system: Electromotor may stall because of any jam on mechanism, controller may fail because of any overcurrent or over temperature and communication with ECU may fail so it is essential to have a fail-safe precaution which is a wax based actuator. Beside it is not an economic solution to use an electromechanical actuator and a control card instead of a wax based actuator.

In our invention, it is aimed to implement fast response time wax based actuators with different vessel designs which provide geometry for wax compound to be filled with thin wax thickness.

Description of Figures: Figure 1 3D view of one embodiment of thermal element with H-shaped vessel Figure 2 Cross-section view of one embodiment of thermal actuator with Pi- shaped vessel

Figure 3 3D view of one embodiment of thermal element with bean type vessel Figure 4 Cross-section view of one embodiment of thermal actuator with bean type vessel

Figure 5 3D view of one embodiment of thermal element with slot type vessel Figure 6 Cross-section view of one embodiment of thermal actuator with slot type vessel

Figure 7 3D view of one embodiment of thermal element with triangle type vessel

Figure 8 Cross-section view of one embodiment of thermal actuator with triangle type vessel

Figure 9 3D view of one embodiment of thermal element with stacked type vessel

Figure 10 Cross-section view of one embodiment of thermal actuator with stacked type vessel

Figure 11 3D view of one embodiment of thermal element with cross type vessel Figure 12 Cross-section view of one embodiment of thermal actuator with cross type vessel

Description of the References:

There are references on the figures below and here are descriptions of references:

1. Fast response time actuator

2. vessel

P. Piston

C. Cover

D. Diaphragm

E. Expansible material Description of Invention:

A fast response time actuator (1), which is a component of the coolant circulation system of internal combustion engine essentially comprises:

• At least an expansible material (E), which is in fact a semi-fluid thermal sensible compound,

• At least a piston (P) which provides pushing up by means of the lift force caused by the extension of expansible material (E)

• At least a diaphragm (D) which provides sealing for leak-proof expansible material (E) encapsulation and guides the movement of piston (P) by bending up and down

• At least a cover (C) which encages piston (P), diaphragm (D) and expansible material (E),

• At least a vessel (2) in which expansible material (E) filled inside and which has a narrowing geometry and/or a divisional structure to thin the thickness of expansible material and increase the contact surface to provide increasing amount of heat conduction in unit time.

In an embodiment of the invention, fast response time actuator (1) is implemented by an h- shaped vessel (2) in which expansible material (E), diaphragm (D) and piston (P) is.

In one preferred embodiment of the invention, expansible material is a wax compound. Wax compound with proper dosage is filled inside h-shaped vessel (2). Above this a diaphragm (D) is placed which encapsulates the wax compound inside of the h-shaped vessel (6) and which helps lifting the piston (P) by bending bidirectionally and also guiding the piston (P). There is a cover (C) which has hollowed frusto-conical geometry enveloping the h-shaped vessel (2) and encaging the expansible material (E) and diaphragm (D) inside this structure and guiding the piston (P). Encaging is provided by bending the end point of h-shaped vessel (2) inward.

The h-shaped vessel (2) has geometry which is like a rod has a floor like H letter. End point of the h-shaped vessel (2) has suitable geometry for guiding the cover (C). This vessel (2) geometry has large joint face with coolant liquid which allows more efficient heat transfer to wax compound also wax compound filled inside has a thin wax thickness by means of this geometry.

In another embodiment of the invention, fast response time actuator (1) is implemented by a bean type vessel (2) Bean type vessel (2) has a rod geometry which' s view from below is like a bean. End point of bean type vessel (2) has a suitable geometry to guide the cover (C). Inner geometry of bean type vessel (2) has a geometry which allows wax compound to fill in a thin wax thickness so that more efficient heat transfer is provided.

In one embodiment of the invention, fast response time wax based actuator (1) is implemented by a slot type vessel (2). Slot type vessel has flatted surfaces which has a shape like a tongue.

In another embodiment of the invention, fast response time actuator (1) is implemented by a triangle type vessel (2). Triangle type vessel (2) has geometry like three engaged rods each has 120° engaging angle like an equilateral triangle. End point of triangle type vessel (2) has a suitable geometry to guide the cover (C). Inner geometry of triangle type vessel (2) has a geometry which allows wax compound to fill in a thin wax thickness and wide outer surface for contacting with the coolant fluid so that more efficient heat transfer is provided.

In another embodiment of the invention, fast response time actuator (1) is implemented by a stacked type vessel (2). Stacked type vessel (2) has geometry like at least three adjacent engaged rods in a row like a stack. End point of the stacked type vessel (2) has a suitable geometry to guide the cover (C). Inner geometry of stacked type vessel (2) has a geometry which allows wax compound to fill inside with a thin wax thickness so that more efficient heat transfer is provided.

In another embodiment of the invention, fast response time actuator (1) is implemented by a cross type vessel (2). Cross-type vessel (2) has geometry like four engaged rods placed like a cross shape. End point of cross type vessel (2) has a suitable geometry to guide the cover (C). Inner geometry of cross type vessel (2) allows wax compound to fill inside with a thin wax thickness by means of its inner geometry and has a wide surface for contacting with the coolant fluid so that more efficient heat transfer is provided.

In another embodiment of the invention, vessel (2) is a regular or irregular polygon or has a wavy geometry.