An oil hydraulic flow divider is a broad term which can mean a number of things, all pertaining to a pressurized oil system. Such systems might be found in high-performance racing vehicles or airplane engines. Essentially, an oil hydraulic flow divider's job is to split a given amount of pressurized oil between multiple destinations; like multiple crank-cases for example. They can be as simple as a T-shaped pipe junction, but this is only effective in dividing the flow of oil equally between two destinations. When a specific ratio of oil is needed, a proportional valve or a proportional solenoid is used.
A proportional valve is an oil hydraulic flow divider with few working parts. They are used when the flow of oil is not accompanied by a change in electrical potential from an alternator or powertrain control module. Oil is pumped from a reservoir into two valves. Each valve contains an outlet which is held closed by a pressure-driven spring. These springs will not allow passage until the pressure within the valve exceeds a given threshold. This pressure is dependent upon the volume of each valve. One is larger than the other, always in a fixed ratio dependent upon the needs of the vehicle. The valve with the smaller volume will exceed the pressure threshold first, meaning more oil will pass through that valve than the other. This effectively divides the amount of oil passing into two separate destinations, but it's a fixed ratio which cannot be changed.
In computer controlled oil hydraulic flow dividers, a proportional solenoid is used. The exact ratio of oil needed at two separate destinations is determined, and divergent electrical signals of specific amperages are sent to two separate parts of the solenoid. The solenoid is comprised of an oil inlet, a fork leading into two pistons, and two metal springs set in housings which govern these pistons. The majority of the pressure being exerted by the oil is displaced by air pressure passing in from small inlets behind the pistons. When electrical signals are sent to the springs behind these pistons, they magnetize and coil in on themselves, but only to a degree determined by the strength of the electrical signals they receive. The pistons block off the incoming flow of air pressure as well as ease back enough to expose ports leading out of each side of the solenoid. The degree to which each of the pistons pulls back determines the exact ratio of oil flow to each destination.
