Wednesday 23 August 2017

Volvo dumps manual gearboxes for I-Shift

Volvo Trucks will no longer offer manual gearboxes as an option on heavy trucks, as its I-Shift automated transmission has become almost universally accepted.

The company said that less than five per cent of customers now specified the synchromesh gearbox, and production of it will end this year.

Mercedes-Benz led the move to standardise on automated gearboxes for heavy trucks with EPS which became the standard transmission on SK trucks from 1988, but the German manufacturer still offers manual transmissions as an option on its Arocs construction vehicles to this day.

The incentive for introducing EPS (which initially stood for Electro-Pneumatic Gear-shifting System, but was soon rebranded to the altogether pacier Electronic Power Shift) was concern over the ability of the proprietary synchromesh transmissions of the day to withstand the recordbreaking 1,765 Nm of torque produced by the company’s then new 435 bhp OM 442 LA V8 engine, while retaining an acceptable lever shift action.

EPS trucks still retained the clutch pedal, which had to be fully depressed by the driver every time a gearshift was initiated. The gearchange decision was still in the hands of the driver, although the shift was made by an electro-pneumatic switch in the cab, rather than a lever, and the change itself was only put through if the truck’s on-board computer deemed that it was appropriate.

Subsequent developments in vehicle electronics allowed the introduction of ‘clutchless’ automated manual transmissions, with sophisticated software that allowed the truck itself to select the appropriate gear ratio for conditions. Better automated clutch and engine control allowed most manufacturers to delete the synchromesh pinions from their gearboxes, saving weight and cost.

Volvo Trucks introduced clutchless and synchromeshless I-Shift in 2001, and it immediately won widespread acceptance from drivers, even those who had hitherto preferred manual shift ‘boxes.

The same mechanicals are used in the Optidriver transmission offered by Volvo Group stablemate Renault Trucks, and Volvo Trucks further refined the offering in 2014, with the launch of a dual-clutch I-Shift, giving a virtually seamless flow of power, for trucks of up to 540 hp.

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