Traffic congestion is bad enough at the best of times, but doubly irksome without automatic transmission. The reason for this is the constant switching between clutch, gas pedal and brake. Bosch’s recently launched eClutch aims to alleviate this issue by allowing drivers using manual transmission to use first gear without utilising the clutch – particularly useful in stop-and-go traffic.
How it works
The electronically controlled clutch closes the gap between automatic and manual transmission, thus allowing the car driver to simply use the brake and gas pedal, just like in an automatic transmission, but without accidentally stalling the engine.
In addition, the eClutch makes the ‘coasting’ function possible as, independently of the driver, the clutch decouples the engine from the transmission if the driver is no longer accelerating. The engine will then stop. The result of this is a real fuel saving, claimed by Bosch to be around 10% on average.
In terms of price, the eClutch costs significantly less than a conventional automatic transmission, and is thus an attractive alternative in the compact car segment, where price competition is tough. Unlike a full-blownautomatic transmission, the e-Clutch automates the clutch only, not the transmission.
The clutch pedal transmits an electric signal to an actuator, which then decouples the clutch. The principle behind the start-stop coasting function is simple: the Bosch system detects the driver’s easing of pressure on the gas pedal, decouples the engine from the transmission, and thus prevents the engine from consuming fuel.
Drivers can already manually simulate this effect by disengaging the clutch on a downhill stretch. In the future, the system will automatically assume this function, while stopping the engine at the same time. This is technically sophisticated, but ultimately worthwhile.
Helping prevent jerky gear shifts
As well as the stop-and-go feature and the possibility of saving fuel, the eClutch offers a number of other functions. For example, it can be used to support gear shifts, making them smoother. A special sensor detects the start of a gear shift and adjusts engine speed to ensure a smooth, easy gear change.
And, if the powertrain is electrified, the electronically controlled clutch means that a combination of hybrid powertrain and manual transmission is now possible for the first time. Up to now, it has only been possible to combine a hybrid powertrain with an automatic transmission, since it is not possible to coordinate a combustion engine and an electrical powertrain using a merely manual transmission.
In this respect, the eClutch offers two advantages: manual transmission is still possible in hybrid vehicles, and the price of entry-level hybrids can be reduced, since a fully automatic transmission is no longer necessary.
