Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
  • F01P7/00—Controlling of coolant flow
  • F01P7/14—Controlling of coolant flow the coolant being liquid
  • F01P7/16—Controlling of coolant flow the coolant being liquid by thermostatic control
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
  • G05D23/00—Control of temperature
  • G05D23/19—Control of temperature characterised by the use of electric means
  • G05D23/30—Automatic controllers with an auxiliary heating device affecting the sensing element, e.g. for anticipating change of temperature
  • G05D23/303—Automatic controllers with an auxiliary heating device affecting the sensing element, e.g. for anticipating change of temperature using a sensing element having a resistance varying with temperature, e.g. thermistor

Definitions

• This invention relates to a thermostat electrically heated and map controlled, which uses a PTC heating element placed in its piston, to keep temperature of coolant circulated inside cooling systems of internal combustion engines in a defined range, managing opening and closing moves of thermostatic valve.
• Wax type thermostats are most common solution on today's engines to keep the engine in proper temperature range. Their working method bases on an expandable wax compound by temperature increasing. This expansion cause opening of a valve for cold coolant by a mechanism, which varies according the thermostat design.
• thermostatic valve let the coolant flow towards to radiator and coolant consequently engine temperature drop to the designated design temperature range.
• thermostatic valve starts to move back closing position because of the wax compound shrinkage after a response time period.
• Thermostatic valve gets close position and stop the coolant circulation towards to radiator and coolant get start to warm up.
• engine temperature is lower than the proper engine running temperature, fuel combustion efficiency is lower, engine is forced to run lower temperature than it is designed.
• Stabilising and keeping coolant temperature in designed range may not be possible due to response time of wax compound, in some engine running conditions. In these cases, harmful gases emissions rates are increased due to insufficient combustion of fuel. Engine designers estimate these conditions.
• wax compound may heated by forced convection under control independent than coolant temperature to rule the opening and closing movement of thermostatic valve according engine behaves estimated by engine designers.
• electrical wire resistance heaters are used to heat wax compound. When a voltage is applied on electrical wire resistance, it heats wax compound by forced convection consequently wax compound expands. But continuously voltage application causes over heating (it may reach over 800°C) on wax compound. By the time, wax looses its physical characteristics and sealing components get harm due to over heating.
• wire resistance heaters are those; they are energised by a relay. In case of a relay fails, resistance heater carries on heating non-stop and causes harms on wax compound and sealing components due to over heating. Or their heating wire may get broken due to fatigue in case of over electrical load. This fail causes dysfunction.
• a PTC heating element is placed in to piston which totally covered with wax compound in the thermostat.
• PTC heating element should be placed close to end of piston, where is always in contact with wax compound while thermostat piston and valve lift actions (closing - opening)
• Benefits of replacing PTC heater elements inside piston are to reduce response time of PTC heater element surrounded by wax compound and to reduce energy looses which is caused by sealing elements on the conventional PTC applications. Besides, since it is inside piston application is simpler than the conventional PTC applications with sealing elements. It has also cost advantage according to the conventional applications.
• Engine electronic control unit decides to start coolant flow towards to radiator, it energises the PTC heating elements, relatively quicker than its conventional alternative structures it heats wax compound to open thermostatic valve and to orient the coolant flow towards to radiator. By this way coolant temperature is dropped down. Because of the self temperature limiting characteristic of the PTC heating elements, it is even energised continuously, it never rise a higher temperature than its regulated reference temperature. This characteristic ensures avoiding wax compound spoil and sealing elements harms. Above the reference temperature, the semi-conducted and ferro-electrical properties of the ceramic are utilised to produce arise in resistance of several orders of magnitude, and hence produce it is self-limiting properties. These self- limiting properties ensure its reliability on application.
• Switching temperature can be structured during its production. Its switching temperature can be adjustable during the production between 50°C - 250°C. For example a PTC heating element, which its switching temperature is 250°C, as much as it is energised, heats its environment till reaching 250°C. When it reaches this temperature its electrical resistance value increases dramatically and it loses its heating features even if it is still energised. When the environment temperature drops down below 250°C it restarts to heat environment. This characteristic of PTC heating element is called as Self Temperature Regulation and our invention utilises this characteristic.
• Figure 1 Cross-section view that shows assembling and operating of the invention.
• Wax vessel (1) is top open.
• Wax compound (2) is placed inside wax vessel (1).
• Shape of wax compound (2) matches the wax vessel (2) to place it inside. By this way, expansion and shrinkage of wax compound (2) by temperature change creates a linear movement on Piston (6) at axis of the wax vessel (1) up or down.
• Piston (6) is placed inside flute of the wax compound (2). Piston (6) converts expansion and shrinkage of the wax compound (6) to a linear movement. This movement opens or closes valve (9) to orient the coolant flow. Cover (5) closes and seals the open side of wax vessel (1) besides, keeps Piston (6) to ensure its axial linear movement. Sealing element 1 (3) is used to seal from outer environment, Sealing element 2 (4) is used to keep the wax compound (2) inside wax vessel (1). PTC heater element (8) is placed inside closed edge of Piston (6) to utilise the heat it produces efficiently and to ensure quick heat transfer on wax compound (2). Energy is supplied to PTC heating elements (8) via energy cables (7), which are jointed on piston by a socket.

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Automation & Control Theory (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Temperature-Responsive Valves (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=44227977

Family Applications (1)

Country Status (5)

Cited By (1)

Families Citing this family (6)

Citations (1)

Family Cites Families (6)

• 2010
  • 2010-10-22 WO PCT/TR2010/000211 patent/WO2012053995A1/en active Application Filing
  • 2010-10-22 CN CN2010800703882A patent/CN103228886A/zh active Pending
  • 2010-10-22 DE DE112010004686T patent/DE112010004686T5/de not_active Withdrawn
  • 2010-10-22 EP EP10787589.0A patent/EP2630351A1/en not_active Withdrawn
  • 2010-10-22 BR BR112013009766A patent/BR112013009766A2/pt not_active Application Discontinuation

Patent Citations (1)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events