Abstract: In a method for controlling the heat in an internal combustion engine for a vehicle with a coolant circuit and actuable devices for influencing the heat balance of the internal combustion engine, wherein a coolant temperature and further operating parameters of the internal combustion engine are recorded, the actuable devices are operated as a function of the coolant temperature and the further operating parameters of the internal combustion engine in such a manner that an output value for determining a control variable is provided by means of a basic characteristic diagram as a function of the rotational speed and the load on the internal combustion engine, and this control value is corrected by means of a controller as a function of the coolant temperature and/or the further operating parameters.

Abstract: In order to appropriately control the temperature state of multiple equipment having differing management temperatures, while preventing complication of the apparatus structure, a cooling apparatus for a hybrid vehicle is provided with a seventh flow path 30g which flows coolant which has flowed only through a main flow path 22a of a radiator 22 to a water jacket 25 via a first thermostat 23 which has an induction temperature set relatively high; an eighth flow path 30h which flows coolant which has flowed through the main flow path 22a and a sub flow path 22b of the radiator 22 to the water jacket 25 via a second thermostat 24 which has an induction temperature set relatively low, and also supplies the coolant to a PDU 14 and a downverter 15; and a bypass flow path 30j which connects a fifth flow path 30e which supplies coolant discharged from the water jacket 25 to the radiator 22, and a position of the eighth flow path 30h on a downstream side of the second thermostat 24.

Abstract: A thermal management system of an electrochemical engine comprises a radiator provided with a wicking mechanism, a coolant pump fluidly connected to the radiator, a water tank, and a water pump. The water tank is located in the void spaces around fuel storage tanks, and may be filled directly or with reclaimed water from a vapor by-product of the electrochemical engine. The water pump is operable to supply water from the water tank to the wicking mechanism during peak power and/or hot day conditions. Moisture in the vapor by-product may be condensed with the excess cooling capacity of the radiator under less severe cooling conditions. Under freezing conditions, exhaust or coolant from the electrochemical engine may be used to unfreeze water in the tank and wicking mechanism supply lines.

Abstract: A water cooling device of a vertical multi-cylinder engine includes a cylinder block (1) one side wall of which is provided with a side water passage (3) running along a longitudinal direction of the cylinder block (1). The cylinder block (1) has an interior area provided with a cylinder jacket (4). Cooling water from a radiator is introduced into the cylinder jacket (4) through the side water passage (3). The side water passage (3) has an outlet (5) toward a lower portion of the cylinder jacket (4).

Abstract: A method and an apparatus for regulating the operating temperature of an internal combustion engine, wherein a cooling fluid is transported in a circuit through the internal combustion engine by means of a cooling fluid pump driven by an electric motor. The electric motor can be operated with a power dissipation loss which is increased in comparison with its nominal operation and the waste heat produced in that situation is transmitted to the cooling fluid.

Abstract: The present invention relates to a coolant crossover member and intake manifold assembly adapted for use in a vehicle engine and method for producing the same. The crossover and manifold assembly includes crossover and a manifold. The crossover has a passage formed therein extending between a first end and a second end thereof. The manifold is joined to the first and second ends of the crossover. The manifold is provided with first and second openings which define first and second inner surfaces, respectively.

Abstract: Methods, systems and devices for identifying irrational results from an engine coolant temperature (ECT) sensor in a vehicle are described. The vehicle suitably includes a processor in communication with the ECT sensor and an intake air temperature (IAT) sensor. The method includes the steps of receiving an ECT reading from the ECT sensor and a IAT reading at the processor, evaluating a temperature difference between the ECT reading and the IAT reading to determine if irrationality is present, and providing a fault indication in response to the evaluating step. The evaluating step includes monitoring the IAT reading during operation of the vehicle to identify the presence of an engine block heater if the temperature difference exceeds a pre-determined threshold.

Abstract: A multi-port rotary valve used to distribute coolant to an engine cooling system comprises a valve body having a plurality of outlet ports for directing coolant flow to a radiator circuit, a heater circuit, and an auxiliary circuit. An internal gear driven rotary disc includes a gear driven mechanism located on an inner circumference of the rotary disc. The rotary disc includes two apertures positioned on a top surface of the rotary disc for regulating predetermined flow paths and flow rates to the plurality of ports. An inlet housing body which includes an inlet port mates with the valve body and encases the rotary disc. An actuator which is coupled to a drive gear mounted internal to the inlet housing body is responsive to a control signal for transmitting a torque to the internal drive gear for rotating the rotary disc to regulate coolant flow.

Abstract: A control system for a fan of a cooling system of an internal combustion engine of a motor vehicle having a viscous coupling (fan clutch) driving the fan and a control unit (PID governor) to which the setpoint temperature and the measured actual temperature of the cooling system (coolant temperature) are fed. The control unit (PID governor) is connected downstream to a limiter, which holds the ratio of output speed to input speed below a specifiable limit (x % of input speed). An overheat protection logic disables the limiter when the actual coolant temperature exceeds a specifiable critical temperature that is higher than the setpoint temperature of the control unit (PID governor).

Abstract: A cooling apparatus for the external connecting ducts of engine oil includes a metal tubular body having excellent heat conductivity and a crankcase bored with two insert holes in the upper side and a detecting hole in the lower side. The metal tubular body has one end provided with an oil inlet assembled with the detecting hole of the crankcase and the other end provided with two oil outlets respectively assembled with the two insert holes of the crankcase. The metal tubular body has its intermediate curved part installed near one side of an engine fan, so that the metal tubular body together with the machine oil inside can be cooled by the forceful wind of the engine fan, able to lower the temperature of the machine oil in the crankcase. The cooling apparatus elevates lubricating effect to machine parts and prolongs service life of an engine.

Abstract: In a cooling system for a motor vehicle engine having indirect charge air cooling, including a general cooling circuit for cooling a power-generating unit which comprises a coolant pump and a main coolant cooler, and an additional cooling circuit which branches off at an output point from the general cooling circuit and returns to the latter at an in-coupling point between the main coolant cooler and the coolant pump and contains an additional coolant cooler, means are provided for sensing the coolant temperature in an area where the coolant of the general cooling circuit and of the additional cooling circuit are mixed and also means for controlling the coolant flow as a function of the sensed coolant temperature.

Abstract: Heat transfer in coolant circuits, as in an internal combustion engine for example, can be beneficially enhanced by maintaining the coolant in a nucleate boiling state, but undesirable transitions to a film boiling state are then possible. The disclosed coolant circuit has selected surface(s) that have a tendency to experience high heat flux in comparison to adjacent surfaces in the coolant circuit. These surfaces are provided with a surface configuration, such as a matrix of nucleation cavities, which has a tendency to inhibit a change in boiling state. The surface configuration can be provided on the parent coolant circuit surface or on a surface of an insert positioned in the coolant circuit. Thus, transitions to film boiling can be effectively avoided at locations in the coolant circuit that are susceptible to such transitions.

Abstract: A system for discriminating malfunction of a radiator of an internal combustion engine, in which conditions for execution of malfunction discrimination of the radiator are decided to be established, when a decline amount of outside air temperature is less than a threshold value, and the malfunction discrimination is conducted by comparing an estimated and detected coolant temperatures with predetermined values. In the system, making the decision that the conditions are not established is prevented, utilizing a parameter related to a quantity of intake air. With this, it becomes possible to inhibit decisions finding that the conditions are not established in certain cases in which such a decision would ordinarily be unreasonably made, such as when the internal combustion engine is started while still insufficiently soaked, etc.

Abstract: An air-cooled charge air cooler for vehicles with a coolant-filled pre-cooler oriented in an air collection tank of the charge air cooler. The pre-cooler is sized to contact a majority of the charge air entering the charge air cooler. The pre-cooler has flow paths carrying coolant between manifolds of the pre-cooler and the flow paths define channels therethrough to direct charge air through the pre-cooler and into a cooling grate of the charge cooler. The channels have a depth that allows for a corresponding adjustment in the length of the cooling grate of the charge air cooler while maintaining the overall space requirement for the charge air cooler in a vehicle and meeting the increasing performance requirements for such charge air coolers.

Abstract: A heat exchanger for a marine internal combustion engine is disposed between first and sides of a V-shaped engine configuration. A plurality of tubes and related structure are disposed within a cavity formed as an integral part of an air intake manifold of the engine. A first cooling fluid, such as ethylene glycol, is circulated in thermal communication with outer surfaces of the plurality of tubes within the heat exchanger and a second cooling fluid, such as lake or sea water, is circulated through the internal passages of the plurality of tubes. A conduit is provided within an end portion of the heat exchanger to remove heat from a lubricant, such as oil, of the internal combustion engine.

Abstract: A method for operating a cooling and heating circuit of a motor vehicle driven by an internal combustion engine, the method has the steps providing a first cooling medium path through a bypass conduit, providing a second cooling medium path through a main cooler of the internal combustion engine, providing a third cooling medium through a heating heat exchanger, providing a fourth cooling medium path through a heat accumulator, subdividing cooling medium flows through the paths by an electrically operated valves, providing the cooling medium flows by at least one pump, controlling the valves by a control unit in dependence on operational and environmental parameters as well as nominal values, arranging a third control valve which is controlled by the control unit in the fourth cooling medium path and closing the third control valve completely or partially when a reference temperature of a remaining cooling and heating circuit exceeds a nominal value provided in the control unit, and opening the third control

Abstract: In a heat storage tank, a discharge port of an introduction passage is covered by a cup-shaped collision member constructed by a shield portion and a guide cover. In addition, a mixture protection plate having plural through holes is disposed in a tank body between the collision member and an inner surface of the tank body. Therefore, a high-speed water stream, upwardly injected from the discharge port, collides with the shield portion, and turns its flow direction by an approximately right angle. Thereafter, the water stream is guided by the guide cover to a lower side of the mixture protection plate. Accordingly, it can prevent water stored in the tank body from being mixed even when the injection water stream has a high speed.

Abstract: In a cooling system for a water-cooled internal combustion engine and a control method applicable to the control system, a pump to circulate a coolant to the water-cooled engine and a heat exchanger is drivingly controlled in such a manner that, when a temperature of the coolant detected by a temperature detector indicates a value higher than a predetermined target temperature, a flow state of the coolant circulated within a plurality of tubes arranged within the heat exchanger falls within a predetermined range including at least one of a transition range between a laminar flow range and a turbulence flow range and a part of the turbulence flow range which is placed in vicinity to the transition range (corresponding to 1800 through 6000 in Reynolds number) and the coolant is circulated through the pump into the water-cooled engine and the heat exchanger by a predetermined flow quantity.

Abstract: An apparatus and method for controlling the temperature of a component of an internal combustion engine is provided. The apparatus may be used to cool the combustibles such as the fuel, gasoline, diesel or alcohol or the inhaled air that is mixed with the fuel before the air and fuel, charge, enters the combustion chamber of the engine. Moreover, the apparatus may be used to cool fluids of an engine or transmission.

Abstract: A method and an apparatus for regulating the operating temperature of an internal combustion engine, wherein a cooling fluid is transported in a circuit through the internal combustion engine by means of a cooling fluid pump driven by an electric motor. The electric motor can be operated with a power dissipation loss which is increased in comparison with its nominal operation and the waste heat produced in that situation is transmitted to the cooling fluid.

Abstract: An aqueous fluid composition having a C1-C2 carboxylic acid salt and a C3-C5 carboxylic acid salt is used as a heat transfer fluid that provides improved heat transfer properties and improved corrosion protection. Such properties are desired for fluids used as an antifreeze coolant in automotive engines. The addition of a C6-C2 carboxylic acid further improves corrosion protection. The addition of hydrocarbyl triazoles or thiazoles also further improves corrosion protection. One specific embodiment of the present invention includes a solution of potassium formate, sodium propanoate, and sodium heptanoate in a weight ratio of 20:20:5, respectively, where the pH of the solution is between 8 and 9.5.

Abstract: The power unit for a motorcycle comprising an engine unit having a casing in which a crankshaft and a countershaft are rotatably supported in parallel to each other, and a transmission unit having a casing in which a transmission input shaft and a transmission output shaft are rotatably supported in parallel to each other to define a dry belt drive-type transmission device. The transmission input shaft of the transmission unit is being connected to the countershaft of the engine unit so as to be rotatable together with the countershaft. A cooling fan chamber is provided at a joined portion of the casing of the engine unit to the casing of the transmission unit, said cooling fan chamber is communicated with an inside and outside of the casing of the transmission unit. A cooling fan is disposed in said cooling fan chamber so as to rotate together with the connecting portion of the countershaft and the transmission input shaft in a vicinity of said connection section.

Abstract: A closed loop cooling water system for an internal combustion engine includes a radiator, an inlet line connecting the radiator to the internal combustion engine, a cooling water pump disposed in the inlet line, the cooling water pump having a suction side, a compensating tank, a compressor connected to the compensating tank, and a connecting line connecting the compensating tank to the inlet line on the suction side of the cooling water pump. The compressor supplies compressed air to the compensating tank to set the pressure level in the compensating tank. The pressure level in the compensating tank affects the pressure level on the suction side of the cooling water pump during operation.

Abstract: In a cooling system for a motor vehicle engine having indirect charge air cooling, including a general cooling circuit for cooling a power-generating unit which comprises a coolant pump and a main coolant cooler, and an additional cooling circuit which branches off at an output point from the general cooling circuit and returns to the latter at an in-coupling point between the main coolant cooler and the coolant pump and contains an additional coolant cooler, means are provided for sensing the coolant temperature in an area where the coolant of the general cooling circuit and of the additional cooling circuit are mixed and also means for controlling the coolant flow as a function of the sensed coolant temperature.

Abstract: A riding lawn mower includes a frame; ground engaging wheels mounted with said frame; at least one cutting deck mounted to the frame; an engine mounted to the frame and operatively connected to drive said ground engaging wheels and said at least one cutting deck, said engine has fluid to be cooled; and, a radiator system, the radiator system including: a housing, a radiator having first and second opposing sides, mounted in the housing and operatively connected with said engine to intake fluid at a first temperature from said engine and to output fluid back to said engine at a second temperature, a screen mounted in the housing and adjacent the first side of the radiator, a bi-directional fan mounted in the housing adjacent the second side of the radiator and operable to direct an air flow in a standard direction first through the screen and then through the radiator and operable as desired to direct an airflow in a discharge direction, opposite the standard direction, first through the radiator and then thro

Abstract: A system provides electrical power and compressed air includes a wheeled hand truck frame, an engine, a compressor, a generator, and a reservoir having several horizontally disposed cylindrical tanks in fluid communication and arranged in one or a few vertical planes. A portion of a lower-most tank of the reservoir is below the plane including the axle for the wheels; and the respective centers of gravity of the engine, the fuel tank, and the reservoir are arranged for relatively greater stability. A control system for the engine, generator, and compressor provides priority response to air demand and/or priority response to electrical power demand by reducing lower priority loads on the engine prior to increasing engine speed. A throttle controller moves the engine throttle from high speed to low speed in response to low demand for compressed air in combination with low demand for electrical power. The throttle controller includes a low demand valve and throttle positioning air cylinder.

Abstract: A cooling system for use in association with an engine encased within an engine compartment, having a remotely positioned cooling fan and radiator. The cooling system includes a containment member operably positioned within the engine compartment. The containment member includes an exposure opening which defines a cavity. The cooling system likewise includes a conduit associated with the containment member. The conduit includes a first end placed in fluid communication with the cavity and a second end extending outside of the engine compartment which is placed in fluid communication with the cooling fan. Circulation of the fan directs the passage of fluid from within the cavity and the conduit.

Abstract: A closed loop cooling water system for an internal combustion engine includes a radiator, an inlet line connecting the radiator to the internal combustion engine, a cooling water pump disposed in the inlet line, the cooling water pump having a suction side, a compensating tank, a compressor connected to the compensating tank, and a connecting line connecting the compensating tank to the inlet line on the suction side of the cooling water pump. The compressor supplies compressed air to the compensating tank to set the pressure level in the compensating tank. The pressure level in the compensating tank affects the pressure level on the suction side of the cooling water pump during operation.

Abstract: A portable, self-contained apparatus for cooling automotive engine fluid, e.g. engine coolant, includes quick couplers for connection to an automotive engine. The apparatus receives hot engine fluid from the engine, cools the engine fluid, and returns the cooled engine fluid to the engine. A fluid reservoir and one or more heat exchangers aid in the cooling process. Corresponding methods provide similar advantages.

Abstract: An engine working machine formed by storing a radiator and a cooling fan, for leading heat exchange air for the radiator, in a package together with an engine and a working machine. Wherein a storage space for the engine and working machine is separate from a ventilating port, which communicates with a space between the radiator and the cooling fan. The space is shielded by partitions from an air leading space to which air is led after being passed through the radiator by the cooling fan. A cooling air leading port for externally cooling the engine and the working machine is formed in a part of the package so that outside air led from the cooling air leading port passes the storing space and is exhausted from the ventilating port to the air leading space, to which air is led after having passed through the radiator.

Abstract: An exhaust gas re-circulation system provides for intake of exhaust gases from a first end 206 into one of a plurality of corrugated inner tubes 204 housed within an outer tube 200. Corrugations in said inner tube 204 provide for an increased surface area for heat exchange with a surrounding coolant medium and for decreased velocity of flow of exhaust gas increasing the density of charge of exhaust gas returned to a combustion chamber of an associated internal combustion engine by an inlet manifold where said exhaust gas re-circulation system connects to said inlet manifold at a second end 207. Said outer tube provides for inlet 203 and outlet 202 of coolant medium. Said outer tube further comprises corrugated portions to withstand vibration/expansion. Said inner and outer tubes are manufactured from thin wall metal tubes.

Abstract: An intake apparatus is provided for an engine of a vehicle. The intake apparatus can introduce fresh air under the vehicle's large running wind pressure. The intake apparatus also allows the opening area and profile of an air inlet to be selected freely. The intake apparatus includes a pair of intake ducts 13 for introducing the air into the engine and an air-introducing duct 15 connected to respective upstream ends of the intake ducts 13 to provide the air inlet 14. The air-introducing duct 15 is formed independently of a cowling 16 fitted to a front of the vehicle. The air-introducing duct 15 has its leading end 15a positioned ahead of a leading end 16a of the cowling 16.

Abstract: In an electric vehicle, the traction motor is driven from a battery by way of a controllable electric power switcher. In operation of the switcher, the power losses of the switches depends upon the power being handled; during acceleration the power is high, and at constant speed on level ground the power is small. Thus, the power “dissipated” by the switches varies with time. A cooler transfers heat from the switcher. During acceleration, the cooler may not be sufficient to limit the instantaneous switch temperature. A phase-change heat “sink” coupled to the switches absorbs heat from the switches during hard acceleration, and returns the heat to the cooler under more constant-speed conditions.

Abstract: A cooling system for a vehicle comprises: a radiator and a water pump. The water pump comprises: a housing that forms a main body of the water pump and is mounted on an engine cylinder block that is provided with a plurality of coolant passageways; a pulley that is transfers turning force from an engine crankshaft to the water pump; a first impeller that forces coolant to circulate through an engine; a pump shaft that is rotatably mounted to the housing, one end of which is fixedly connected to the pulley, the other end of which is fixedly connected to the first impeller; a second impeller that forces coolant to circulate the engine and the radiator; and a second impeller rotating means that selectively rotates the second impeller according to a coolant temperature.

Abstract: An integrated fluid recovery reservoir and thermostat assembly 12 for use within an engine cooling system 10. The integrated fluid recovery reservoir and thermostat assembly 12 includes a coolant reservoir housing 26 which is mounted directly to the engine 14 and which includes inlet ports 28, 30 for receiving coolant 38 from engine 14 and an outlet flow portion or module 46 which is fluidly coupled to the radiator 18. The assembly 10 further includes a flow control module and thermostat assembly 42 which is attached to the reservoir housing 26 and which selectively and fluidly communicates with the reservoir housing 26, with the coolant pump 20 and with the radiator 18. A thermostat valve 72 is attached to and/or within assembly 42 and cooperates with assembly 42 to selectively control the flow of the coolant 38 through the engine cooling system 10.

Abstract: A method of regulating heat in a internal combustion engine by measuring temperature at a plurality of points and providing changes in temperature for the cooling and providing changes in temperature for the cooling and/or heating medium. The regulation of the heat of the internal combustion engine results from detecting and monitoring changes in critical component temperatures and/or characteristic output values of the internal combustion engine. These critical component temperature changes per unit time and/or output characteristic value changes per unit time are used in the regulation of the heat of the internal combustion engine.

Abstract: An apparatus and method for cooling a work machine is disclosed. The apparatus has a fan element located inside an engine compartment of the work machine in a horizontal orientation. The fan element draws external air from above the work machine into the engine compartment. A deflector directs the air through a plurality of cooling cores which are radially spaced about the engine compartment and interspersed with a plurality of core spaces. The apparatus can be cleaned by spraying fluid from the outside through the plurality of cooling cores, causing any trapped debris to fall to the bottom of the engine compartment, where it can be removed through a cleanout.

Abstract: The present invention 10 discloses an emergency cooling and refilling system that can be adapted to fit any application involving a heat exchanger, such as an automobile radiator 32, transmission cooler 36, or air conditioner condenser coil 34 or residential and commercial central air condenser coils 64. The present invention 10 can be factory installed or retrofitted to existing units and is automatically activated when a thermocouple 20 detects a high temperature condition and activates a pump 24 that moves fluid 16 from an independent reservoir 22 to atomizers 28 facing the component to be cooled and sprayed thereupon. The atomized spray 30 takes on a spiraling nature due to the presence of a rotational nozzle 86 within the atomizer 28 that is acted upon by the passage of the pressurized fluid traveling through multiple diagonal channels 94 cut in the nozzle's head 78.

Abstract: The invention provides a fuel injection apparatus in an internal combustion engine for an outboard machine which improves a pump performance of the high pressure fuel pump and accurately and stably supplies a fuel from a fuel injection valve. There is provided an injection fuel flow passage system in which a fuel within a vapor separator V is sucked and discharged by a high pressure fuel pump, a high pressure fuel discharged from the high pressure fuel pump is supplied to a fuel distribution pipe provided with a fuel injection valve and a return fuel of a pressure regulator connected to the fuel distribution pipe is returned into the vapor separator via a return fuel passage. A heat exchanger is arranged in the injection fuel flow passage system, and a cooling water branched from a discharge passage of a cooling water pump for cooling an engine is supplied to the heat exchanger via a cooling water introduction passage and is discharged toward the outside via a cooling water discharge passage.

Abstract: A coolant overflow bottle is interposed between the centrifugal fan and the radiator for guiding air expelled by the fan toward the radiator. The bottle includes a top, a bottom, a pair of nested curved sidewalls, and a rear wall. The side walls are joined at a leading edge, and join the top and bottom. The rear wall is joined to the side walls at a trailing edge, and joins the top and bottom. The bottle wails define an exterior shape for guiding air.

Abstract: An arrangement for filtering coolants used in internal combustion engines utilizes a panel filter disposed between a radiator core and an outlet header tank so as to trap particulates entrained in the coolant prior to returning the coolant to the engine. The panel filter has a pleated filter media surrounded by a gasket, which gasket seals between the outlet end of the radiator core and the outlet header tank.

Abstract: A system for detecting malfunction of a radiator, more precisely a thermostat (shut-off valve) in the engine cooling system. In the system, an estimated coolant temperature CTW is calculated from the temperature condition and operating condition at engine starting. When the estimated coolant temperature CTW has reached a judge malfunction value CTWJUD but the detected coolant temperature TW has not reached a judge normal value TWJUD, the thermostat 64 is discriminated to have malfunctioned, thereby enabling to detect malfunction of the radiator with high accuracy and high response.

Abstract: The apparatus is an enclosed engine generator assembly with air intake and air discharge openings into the enclosure in which the engine is installed and the radiator for engine cooling moved from the conventional vertical position in front of the engine to a horizontal orientation above the generator. The arrangement permits an assembly with a shorter overall length, but no significant increase in the height, and thereby facilitates installation aboard vehicles.

Abstract: An internal combustion engine cam drive arrangement and coolant manifold. The engine comprises an engine body that is formed with an coolant opening that is circumscribed by a flexible transmitter that drives cam shafts from the engine crankshaft. A coolant manifold communicates with this opening and overlies in part the flexible transmitter. At least a major part of the remaining portion of the flexible transmitter is covered by a timing cover. The timing cover and the coolant manifold each may be removed from the engine body independently of the other.

Abstract: An engine cooling apparatus suitable for use in a vehicle shortens engine warm-up time without decreasing the heat-radiation capacity of a radiator. A shroud is disposed between a radiator and a water-cooled engine. A first air passage for blowing air toward the engine and its auxiliaries is formed in the upper side of the shroud, and a second air passage for discharging air having passed through the radiator to outside the engine compartment is formed in the lower side of the shroud. Accordingly, air is prevented from directly striking the engine and from passing around to the upstream side of the radiator through gaps between the walls of the engine compartment and the radiator. Thus the engine warm-up time is shortened without reducing the heat-radiation capacity of the radiator.

Abstract: Disclosed is a motor-operated flow control valve for internal combustion engines which has a longer useful life and does not cause a drop of torque generated by a motor at the start-up. A rotor shaft (9) is reciprocated with rotating motion of a motor (32), whereupon a valve head (2a) is moved to open and close an orifice for control of a flow rate. Specific frequency of a rotor unit (33) of the motor (32) is set to be higher than the secondary vibration frequency of rotation of a 4-cycle internal combustion engine. The rotor unit (33) comprises an integral magnet (25), a single ball bearing (27) and a resin-made magnet holder (26) for supporting these two members, the magnet, the ball bearing and the magnet holder being formed into an integral structure. The rotor unit is supported such that an outer race (27c) of the ball bearing (27) is held at its one end against an inner peripheral wall of a housing resin (14) and a preload is applied to the other end of the outer race (27c).