Internal-combustion engines – Cooling – With liquid coolant circulating means
Reexamination Certificate
1999-11-29
2001-09-18
Kamen, Noah P. (Department: 3747)
Internal-combustion engines
Cooling
With liquid coolant circulating means
C123S041090
Reexamination Certificate
active
06289854
ABSTRACT:
TECHNICAL FIELD
The present invention refers to a circulation pump for pumping a cooling medium by means of a rotating impeller, for instance for cooling a vehicle's engine, which pump is a part of a cooling system including a feeder line from the engine to a radiator, a return line from the radiator to the pump and a control valve for shunting the outflow from the engine via a bypass line back to the pump with respect to the operation condition of the engine, whereby an inlet is directed towards the centre of the impeller and a spiral-shaped outlet extends from the outer edge of the impeller.
BACKGROUND OF THE INVENTION
In a conventional cooling system, for example in a vehicle, the cooling medium pump for cooling the engine is operated in such a way that the flow varies depending on the engine speed. The control valve is used to control the flow of the pump, either to the radiator or back to the pump depending on the temperature of the flow, which leaves the engine. The capacity of the flow in a conventional system is dimensioned to manage engine operation under full load conditions, such as driving in an upward slope with a full throttle. Normally, the bypass line is also dimensioned for approximately the same amount of flow, which flows through the radiator so that the thermostat control can be as efficient as possible.
Accordingly, the flow capacity is not optimized for normal operation conditions, which means that the pump operates with high effect independent of the operation conditions. Consequently, the operation of the cooling medium pump results in considerable power dissipation, which effects the engine efficiency.
It is desirable to reduce this power dissipation without influencing the construction in a negative way, for example, avoiding that it becomes more bulky or considerably expensive to produce.
The Technical Problem
The object of the present invention is to provide a circulation pump, which solves the above-mentioned problems.
The Solution
For this purpose, the invention features a bypass line connected to the pump in such a way that a flow through this line produces and/or increases a pre-rotation of inflow to the impeller, resulting in a reduction of the power required by the engine. By providing this bypass flow the efficiency of the pump increases as long as some part of the coolant passes through the bypass line.
According to an advantageous embodiment of the invention the bypass flow is conducted into the pump via a passage, which is substantially tangentially connected to a central pump inlet.
Preferably, the passage includes a curved outer wall surface with a cross section area that reduces monotonously in direction of the central pump inlet.
The passage can thereby extend helically around the central inlet.
Suitably the passage forms an area reduction, which allows the flow from the bypass line, essentially tangentially increase the flow speed in the direction of the inlet.
In an embodiment, at least one inlet is directed to the centre of the impeller and the bypass line extends at least partly spiral-wounded around the inlet and the bypass line branches.
In another suitable embodiment an inlet extends partly in the bypass line and is directed towards the centre of a device equipped with a blade which has an opening, which device essentially tangentially directs the flow from the bypass line towards the flow from the inlet through said opening and produces a pre-rotation. The device provided with the blade is arranged essentially in the flow from the bypass line immediately before the impeller.
In the preferred embodiments the pre-rotation is in the direction of the impeller's rotation.
The invention also refers to a cooling medium pump for pumping a cooling medium by means of a rotating impeller, for instance to cool a vehicle's engine, which pump is included in a cooling system including a feeder line from the engine to a radiator, a return line from the radiator to the pump and a valve for shunting the outflow from the engine via a bypass line back to the pump. The bypass line is connected to the pump in such way that a flow, essentially from this line, results in and/or increases a pre-rotation of inflow to the impeller, which pre-rotation results in a reduction of the power required by the engine. In the cooling medium pump, the flow depends on the operation conditions of the engine. Preferably the valve is thermostat-controlled.
According to a method of the invention, for optimizing the flow capacity in a circulation pump for pumping a cooling medium by means of a rotating impeller, for instance for cooling a vehicle's engine, which pump is part of a circulation system including a feeder line from the engine to a radiator, a return line from the radiator to the pump and a control valve for shunting the outflow from the engine via a bypass line back to the pump, depending on the operation condition of the engine, an inlet is directed towards the centre of the impeller and a helical outlet extends from the outer edge of the impeller, characterized by the bypass flow essentially from the bypass line encountering the central inlet flow from the inlet, essentially in such a way that a rotation of the inlet flow is produced and the bypass flow meets the inlet flow essentially tangentially.
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Andersson Arne
Etemad Sassan
Holmström Jan Christian
Burns Doane Swecker & Mathis L.L.P.
Huynh Hai
Kamen Noah P.
Volvo Lastvagnar AB
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