Abstract: A DCT hydraulic power control system has a pump, a high pressure section for providing oil to actuators of the DCT, a low pressure section for providing oil to a lubrication and cooling system of the DCT, and a regulator for directing excess oil from the high pressure section to the lubrication and cooling section. A hydraulic control includes a first directional valve disposed in a main line of the low pressure section between the pump and the lubrication and cooling system, wherein the directional valve is controlled by an ON/OFF valve disposed between a check valve and the directional valve, wherein the check valve is disposed in a branch line of the low pressure section leading to the high pressure section, and wherein a second directional valve connects the second pressure outlet associated to the low pressure section with a suction side of the pump.

Abstract: A DCT hydraulic power control system has a pump, a high pressure section for providing oil to actuators of the DCT, a low pressure section for providing oil to a lubrication and cooling system of the DCT, and a regulator for directing excess oil from the high pressure section to the lubrication and cooling section. A hydraulic control includes a first directional valve disposed in a main line of the low pressure section between the pump and the lubrication and cooling system, wherein the directional valve is controlled by an ON/OFF valve disposed between a check valve and the directional valve, wherein the check valve is disposed in a branch line of the low pressure section leading to the high pressure section, and wherein a second directional valve connects the second pressure outlet associated to the low pressure section with a suction side of the pump.

Abstract: Apparatus and method for controlling current flow through a magnetic coil actuator of a solenoid valve. The current through the magnetic coil is measured by sensing the voltage drop across a precision resistor in series with the coil. The apparatus includes a power switch for alternately switching the coil on and off. A flyback diode is coupled in parallel with the coil for operation during coil shut-off. A first voltage sensor continuously measures the combined voltage drop across the coil and the power switch. A second sensor, coupled across the precision resistor, samples the current flowing through the coil. The samplings occur synchronously with coil turn-on, and are delayed by a predetermined time delay which is long enough to allow the current flowing through the coil to reach steady state before the current is sampled. Circuitry is provided for employing the sensed voltage signal and current samplings to produce a signal whose value is a function of the resistive component of coil impedance.

Abstract: An electronic control apparatus (13) switches several electrical load resistances (16), in particular the solenoid valves of a power shift gear, depending on the position of various information switches (19). The electronic control apparatus (13) has a plurality of load lines (17) each leading to a load resistance (16), and a central unit (15) having a plurality of electronic switches (1). Each of the load lines (17) can be connected via an electronic switch (1) to a supply voltage (14). The electronic switches (1) can each be switched by a logical signal and each has an output (5) for a logical status signal. The logical status signal indicates an open load resistance when the switch is open and a short-circuited load resistance when the switch is closed with an open, short-circuited switch (1), the status signal suggests an open load resistance. The electronic control apparatus (13) monitors the position of the information switches (19).