CONTINUOUSLY VARIABLE TRANSMISSION (CVT)

A continuously variable transmission (CVT) is an automatic transmission that can change seamlessly through a continuous range of gear ratios. This contrasts with other transmissions that provide a limited number of gear ratios in fixed steps. CVT is not a recently developed mechanism. Daimler and Benz, aka Mercedes-Benz received a patent for it way back in 1886.

The CVT automatic transmission was developed by General Motors (GM) in the 1930s, but at that time the technology went on the shelf because the fluids and control devices needed to make it reliable weren’t available.

The 1961 DAF 600 (right) was the first car massproduced with a continuously variable transmission (CVT)the innovative DAF Variomatic system. The same system was carried over to the 750, the Daffodil, and its variants. No conventional gearboxes were offered on the cars - all these economy cars came with this Variomatic (CVT) transmission system as standard.

The DAF Variomatic employs centrifugal weights to control the drive ratio of the transmission and is enhanced by the engine manifold vacuum. The action of the bob weights and inlet vacuum combined to pull together the cheeks of two variablediameter driving pulleys, driven directly from the engine. These were connected, by rubber 'V' belts, to two similar driven pulleys, connected to the drive wheels. The cheeks of the driven pulleys were held together by spring tension, which was progressively overcome as the drive pulleys expanded and the tension of the belts increased.

Subaru takes credit for introducing the first continuously variable transmission to America with its 1989 Justy GL ECVT, a small hatchback. In the early 2000’s interest in the CVT picked up with GM launching its own production CVT in 2001 on its Saturn Vue SUV. Honda put CVTs on the option sheets of its Civic subcompact in 1996 and Insight hybrid in 2000.

Audi started offering CVTs in its A4 sedan in 2002.

The photograph above was in Beaded Wheels - Issue Number 143 as part of an article on the Waikato Branch 25th Anniversary written by Ian Howell.

There were 150 entries for that anniversary - a 50% increase over previous years, and the organisers welcomed a contingent from the Manawatu Branch, including vice Club Captain Maurice Holland.

ENGLAND’S BEST DEAD CAR COMPANIES

Alvis

A maker of ‘between-wars’, high quality sports cars in its heyday. Duller saloons followed, but the Graber styled TC and TF series of coupes and roadsters were a handsome swansong. Bought by Rover in 1965, car production ended two years later, Alvis becoming a military vehicles maker. It was swallowed up by BAE Systems in 2004.

Find the following hidden words in the grid below:

AERODROME AIRCRAFT ALBATROS AVIATOR

BRISTOL COCKPIT DENNIS ENGINE

FOKKER HUCKS HOOD JUNKERS

LEWIS LEYLAND MASTERTON MILITARY

MUSEUM NIEUPORT PROPELLER SOPWITH

SPANDAU TRIPLANE VICKERS VINTAGE

ZEPPELIN