PCT: Innovative hydraulic concept for cost-effective and energy-efficient transmission automation

LSP Innovative Automotive Systems (LSP) presents the Piston Pressure Control (PCT) actuator for double clutch transmissions. This hydraulic clutch and gear actuation works as precisely as electromagnetic actuators, but the system is considerably less expensive and more energy-efficient. Vehicles with hybrid drives can now feature fail-safe dynamic manual transmissions.

Unterföhring, March 2021 – Double clutch transmissions – also known as dual clutch transmissions (DCT) – enable fully automatic gear changes without load torque interruption and are used in high-performance vehicles and hybrids (HEV), for example. In conventional hydraulic actuators, the control elements are operated by expensive spool valves. As a response to that, LSP developed PCT, a more cost-effective and energy-saving solution that uses a piston actuator in conjunction with leak-free and lower-cost ball-seat valves to operate the hydraulic actuators. The technology allows you to easily add hydraulic actuators to gearboxes and it can also operate multiple actuators either sequentially or simultaneously. Clutching and shifting are as precise as with electromagnetic actuators, but the system is much more economical and actually saves energy because PCT only requires appreciable power when the gearbox is activated (power on demand). This innovative solution means it costs less and saves energy to automate gearboxes.

Implemented in series production

Thanks to its simple design and inexpensive standard components, PCT is ideally suited for series production. One major German automotive supplier already uses LSP’s innovative actuator technology for dual clutch transmissions that it produces in large numbers. The technology can also be found in vehicles from a Chinese manufacturer and at a renowned Japanese automaker. The companies have recognized the advantages and are gaining a technological edge by using PCT.

Patented innovation “Made in Germany”

The copyright for PCT is held by LSP and the PCT patent has already been filed. Two further patent grant decisions were made by the German Patent and Trademark Office on February 22, 2021. In addition, the underlying innovation is also based on patent DE102006038446B4, for which LSP also holds the rights of use.

Exploiting synergy effects

LSP Innovative Automotive Systems is a pioneer in the field of brake technology and develops BLDC electric motors. To regulate pressure in its brake-by-wire technology a piston-cylinder unit is controlled by a brushless motor. Back in 2006, LSP took this basic principle and applied it with PCT to operate transmissions. In both technologies, a piston-cylinder unit is used for the actuation. The piston can be used to set pressure in the working chamber whereby pressure is built up via the piston-cylinder unit and reduced either via the piston-cylinder unit or solenoid valves, i.e. ball-seat valves or proportional valves – a technical solution that is patent protected. It turns out that the advantages of on-demand pressure with low energy requirements, high-precision dynamic control and high fault tolerance are equally relevant for brake-by-wire as they are for actuating dual clutches.

Other areas of application for PCT

Fail-safe, power-on-demand hydraulics that enable high-precision force or torque control is always the technology of choice when PCT is operating multiple actuators. With that in mind, LSP envisions numerous applications for PCT technology in the future:

  • Interruption-free, load torque 2-speed transmissions for electric vehicles that have a wide range of torque requirements in a variety of mobility scenarios, e.g., load vehicles
  • Actuators for drive axles with hybrid drives, e.g. for actuating transmission locks, clutches, electrohydraulic steering systems, etc.
  • Reciprocating internal combustion engines will be operated with new fuels (hydrogen, synthetic fuels, etc.) in the future and will require gear shifting and double-clutch transmissions. The advantages of PCT technology can be incorporated into future developments in this area.
  • Applications in industry where several hydraulic actuators have to be operated simultaneously or sequentially
  • Automated manual transmissions (AMT), which are increasingly widespread in emerging markets
  • Dual-clutch manual transmissions for off-road or new types of vehicles

For more detailed information on PCT visit us here:

and have a look at this recently published ATZ article

Go back