Powertrain Systems

The Delphi Pulse-width Modulated Actuator controls transmission fluid pressure, or flow, as a function of the voltage duty cycle that is applied to the actuator. The duty cycle of the actuator determines the average voltage level supplied to the coil, creating proportional pressure or flow. The Delphi Pulse-width Modulated Actuator has a three-port configuration (supply, control and exhaust) and can provide normally high or normally low control pressure relative to applied voltage.

 

Benefits

• Optimal magnetic design for cost, size, and mass savings
• Linear control pressure response and reduced hysteresis
• Insert-molded valve-seat design and hardened components enable reliable operation at more than 800 million cycles
• Pro-seal hydraulic design minimizes current requirement
• Contamination resistant design keeps fluid flow away from the magnetic moving components

Typical Applications

The Delphi Pulse-width Modulated Actuator is designed for various vehicle automatic transmission applications, including main-line pressure control, torque converter clutch, neutral idle, and direct clutch shifting.

The Delphi Pulse-width Modulated Actuator can also be adapted for flow and pressure control of hydraulic fluids in various non-automotive applications.

Control Pressure versus Duty Cycle

Normally Low Tranx PWM Solenoid 50 Psi, 50 Hz



Normally High Tranx PWM Solenoid 75 Psi, 60 Hz

These charts depict the controlled pressure versus the applied voltage duty cycle of Delphi Pulse-width Modulated Actuators for normally low and normally high control pressure applications.

Performance Advantages

Delphi Pulse-width Modulated Actuators are available in both normally high control pressure and normally low control pressure versions—both are used in automatic transmissions today. The actuators provide a smooth and linear transfer function between the applied duty cycle and the controlled pressure, and they offer a broad operating range for accurate pressure control. Part-to-part variation is minimized by a combination of robust engineering methodologies, precise components and in-process calibration.

Delphi's Pulse-width Modulated Actuators have a pro-seal design that minimizes the loading of the internal bias spring, leading to minimized current draw. The pro-seal design also allows the devices to meet higher cracking pressure requirements without the need for a large magnetic package. The hydraulic flow paths are also designed so that fluid flow is directed away from magnetic moving components to make the design robust to contaminated oil-related failures. Selection of appropriate materials and their treatment enables the valves to survive beyond 800 million cycles. Generally, the valves are designed to operate optimally at frequencies of 50-60 Hz. If required, it is possible, with minor modifications, to extend the frequency range for specific customer applications.

Delphi Pulse-width Modulated Actuators can be designed for stand alone or for module applications. Typically, stand alone applications require a standard connector for electrical interface. In module applications, the electrical interface can be to a lead frame.

The Delphi Advantage

Delphi has a long history of actuator design, development and manufacturing expertise and offers one of the widest portfolios of actuators for the automotive industry. Delphi is continually developing new and improved actuating technologies that help automotive manufacturers meet objectives for emissions control, fuel economy, and drivability. Delphi has the capability to provide a single actuating device or a multifunctional "smart" module to meet specific customer needs. Plus, Delphi offers a thorough understanding of automotive systems integration and has a global network of engineering and manufacturing resources to provide customers with localized program support.