Variable input speed to water pump

Abstract

A variable ratio drive belt system is used to drive the water pump. The variable ratio drive belt system comprises a variable pitch water pump pulley, or driven pulley, a variable pitch crankshaft pulley, or driver pulley, and a drive belt that is coupled between a water pump and an engine crankshaft. By increasing and decreasing the size of the variable pitch water pump pulley and increasing the size of the variable pitch crankshaft pulley as a function of engine speed, the water pump speed can be increased at low engine speed to provide improved coolant flow and decreased at higher engine speeds to prevent pump cavitation.

Description

BACKGROUND OF INVENTION [0001] The invention relates generally to water pumps and more specifically to water pumps having a variable speed input. [0002] Water pumps are typically used on vehicles today to provide heat transfer means for an engine during operation. Water pumps are typically driven by the engine crankshaft at a fixed ratio. Thus, as the engine idle speed is reduced, as is the trend in vehicles today to reduce emissions, the water pump speed is correspondingly reduced. This reduction in water pump speed results in a reduction in the coolant flow through the cooling system which can result in poor heater output for the interior of the vehicle when needed in cold weather and also can result in poor coolant flow for engine cooling during hot weather. [0003] Increasing the water pump speed by increasing the drive ratio from the crankshaft will increase the coolant flow at engine idle speeds, but it may result in overspeeding the pump at higher engine speeds which may produ...

AI Technical Summary

Benefits of technology

[0007] The present invention provides a method and apparatus for providing good coolant flow at low engine idle speeds while avoiding pump cavitation at high engine speeds.

[0009] In one preferred embodiment of the present invention, a variable ratio drive belt system is used to drive the water pump. By increasing and decreasing the size of the variable pitch driver and driven members as a function of engine speed, the water pump speed can be increased at low engine speed to provide improved coolant flow and decreased at higher engine speeds to prevent pump cavitation.

Problems solved by technology

This reduction in water pump speed results in a reduction in the coolant flow through the cooling system which can result in poor heater output for the interior of the vehicle when needed in cold weather and also can result in poor coolant flow for engine cooling during hot weather.

Increasing the water pump speed by increasing the drive ratio from the crankshaft will increase the coolant flow at engine idle speeds, but it may result in overspeeding the pump at higher engine speeds which may produce pump cavitation and reduced water pump bearing life.

Pump cavitation can result in pump damage and a reduction in cooling system performance.

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