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Ricardo Introduces New Technology Enabling Low-cost Automated Manual and Dual Clutch Transmissions

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Ricardo’s eAMT transmission, with detail of the electromagnetic linear actuation technology. Click to enlarge.

Ricardo has unveiled a research prototype vehicle that demonstrates the company’s patent-pending electromagnetic linear actuation technology. This technology offers a low-cost route to robust and 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 a gasoline-fueled 1.2L Opel Corsa with AMT in which the control and actuation system of the original Easytronic system has been replaced with the electromagnetic linear actuator technology. The new technology is sufficiently versatile and controllable that it can be multiplexed in order to operate both the clutch control and gear selection functions. In the research prototype vehicle this eAMT system demonstrates:

  • Two-pedal vehicle automation at low cost, owing to a significantly reduced parts count through 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.

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The eAMT demonstrator vehicle.

The eAMT research vehicle provides an environment for the actuator and control technology to be tested, evaluated and refined in real-world driving conditions. While the vehicle was intended as a first step in proving the capability of this technology for an advanced, dry clutch eDCT system, the transmission architecture of the eAMT vehicle represents a potentially attractive automated two-pedal solution for smaller (A/B class) vehicles in price and/or manufacturing cost sensitive markets, according to Ricardo.

The linear electromagnetic actuator and control technology demonstrated on the eAMT vehicle is fully controllable in terms of position, force and velocity, and is scalable from small passenger car applications through to large commercial vehicles and off-highway equipment. In an AMT configuration such as that demonstrated in Ricardo’s eAMT prototype, a single actuator substitutes for the separate clutch operation and gear selection systems of the current production unit. Clutch control is achieved without modification to the release bearing arrangement. Moreover, 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 in excess of eight times faster.

Ultimately this research program will see the implementation of this same technology in an eDCT transmission for a European C/D segment vehicle. With further IPR (intellectual property rights) 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, aims to provide a fuel consumption saving of in the region of 5% in comparison with a hydraulically actuated wet clutch DCT, while also offering significantly lower manufacturing cost.

Comments

Raymond

I see this technology possibly becoming widely available for GM, since they are starting to show major interest in dual-clutch sequential manuals just like Ford with its Powershift technology.

I can see within a few years' time the new Chevrolet small car (which was previewed in the September 2008 issue of Motor Trend) using a six-speed DCT with the Ricardo actuator for smooth shifts and excellent fuel economy at highway speeds.

John Taylor

If Ricardo is smart, they will option the system to car manufacturers on a production basis without limiting their right to also sell the same clutch to other car manufacturers.

GM is in the habit of buying up options to use a new gas saving technology, then shelving it while keeping competitors from getting more efficient, and also bankrupting the inventor.

ToppaTom

This is cool, dual clutch/dual shaft transmissions are a fine evolutionary advance. But I wonder if the "torque interrupt of as little as 0.35 seconds" is correct.
If the electonic throttle does not reduce torque to about zero, for each shift, you're in for a shock. If the electonic throttle does, I don't want one.
Note to GM: Don't buy it.
I assume they mean the transition from gear to gear will be "as little as 0.35 seconds".

arnold

The whole point of dual clutch is constant mesh transmission so there is no 'shift' nvolved.
That leaves .35 for the whole operation.

ToppaTom

I guess they do mean the whole shift operation. In reality all normal manual transmissions are constant mesh (since the 1929 Cadillac synchromesh). A automatic transmission operates like a dual shaft or dual clutch transmission but softens the shifts with the fluid clutch (torque converter). I believe the dual clutch/shaft transmissions are not so much a "discovery", as made practical by throttle-by-wire and computer control. On a dual clutch transmission, if second is being engaged while first is being precisely released, all is well, but wear or erratic driver input might be a real problem without computer control to always keep the time, where 2 “gears” are engaged, very short.

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