Ricardo technology improving cost, weight, fuel efficiency in transmissions

Ricardo, an independent engineering firm specializing in total vehicle fuel economy and efficiency, has unveiled a research prototype vehicle that demonstrates the company's patent-pending eAMT electromagnetic linear actuation technology. This technology offers a low cost route to robust and highly efficient Automated Manual Transmission (AMT) and dry Dual Clutch Transmission (DCT) vehicles capable of delivering increased fuel economy and lower emissions.

The development vehicle is based on an Opel Corsa 1.2L gasoline-engine vehicle with an automated manual transmission. The control and actuation system of the original Easytronic system has been replaced with Ricardo's electromagnetic linear actuator. This technology can be multiplexed to operate both the clutch control and gear selection functions, the company states. In the research prototype vehicle the eAMT system demonstrates:

• Two-pedal vehicle automation at low cost, due to a significantly
reduced parts count through the use of a single electromagnetic
actuator in place of separate clutch and gear actuator units
• Opportunities for reduced size and weight
• Controllable actuator force of up to 800N peak and 350N continuous
• A torque interrupt of as little as 0.35 seconds during shifts
• An advanced implementation of Ricardo AMT control software employing
clutch "kiss" point adaption techniques and DCT-like microslip control
of a single dry clutch.

The eAMT research vehicle provides an ideal environment for testing, evaluating and refining the actuator and control technology in real-world driving conditions. Although the vehicle was intended as a first step in proving the capability of this technology for an advanced dry clutch eDCT system, the company states the transmission architecture of the eAMT vehicle represents a potentially attractive, automated two-pedal solution for smaller (A/B class) vehicles in markets that are price and/or manufacturing-cost sensitive.

Efficient, low cost and fully scalable control
The patent-pending linear electromagnetic actuator and control technology demonstrated on the eAMT vehicle offers a highly practical and cost-effective solution for advanced transmission systems. This technology is fully controllable in terms of position, force and velocity, and is scalable from small passenger car applications to large commercial vehicles and off-highway equipment.

In the AMT configuration demonstrated in Ricardo's eAMT prototype, a single actuator performs the functions of two systems in the current production unit: clutch operation and gear selection. Clutch control is achieved without modification to the release bearing configuration. Plus, it is extremely fast-acting: in benchmark step-response tests carried out against a current production hydraulic valve-actuated system, the Ricardo system was shown to be more than eight times faster, according to the company.

Toward a more cost-effective and fuel-efficient DCT implementatio
Ultimately this research program will see implementation of the technology in an eDCT transmission for a European C/D segment vehicle. With further IPR developments planned for the cooling of dry clutch modules, the dry clutch eDCT system will aim to provide a high efficiency, zero torque interrupt transmission system that, based on the results of simulation and component testing, could bring a fuel economy improvement of about 5 percent compared to a hydraulically actuated wet clutch DCT, while also offering significantly lower manufacturing costs, according to the company.

Lee Sykes, Ricardo global product group director for driveline and transmission systems, says: "The advanced electromagnetic linear actuation technology in the eAMT vehicle shows huge potential for the practical implementation of next-generation transmissions in the commercial vehicle and off-highway sectors as well as automotive. This is just one of the positive results of our eAMT research which also includes the demonstration of next generation software control - 'the art of the possible' in terms of multiplexing. The eAMT and ongoing eDCT research projects show Ricardo's commitment to providing its clients with advanced technology and services that will be key enablers of the more fuel efficient and cost-optimized automated transmission products of the future, as demanded in the major global automotive markets of Europe, the Americas and Asia."

For more information, visit www.ricardo.com.