Saturday, 20 December 2014
Honda goes for 8-speed DCT
First application of an eight-speed double-clutch transmission (DCT) with a torque converter takes place when Honda introduces the Acura ILX production car in North America.
Honda has shown a conventional seven-speed DCT with a torque converter on its NSX sports car and Acura luxury saloon, however this will be the first taste the general public will have of the technology which will be teamed with a 2.4-litre engine of 201bhp and 180lbft torque.
DCTs have been on the receiving end of criticism from North American drivers more used to the supreme smoothness of torque converters linked to planetary automatic transmissions.
Honda’s move appears to be a bid to woo sceptical North American drivers by combining the smoothness on take-off of the torque converter with the responsiveness and potential fuel efficiency of the DCT.
The company claims that ‘off-the-line torque multiplication’ for smoother and more powerful launches from zero that other DCTs cannot match.
Volkswagen, however, is unfazed by this by demonstrating just how well the Group's engineers understand the mechanics of transmissions; it does so by moving a further step up the DCT ladder with the introduction of its DQ511 10-speed DCT which is based on VW's DQ500 seven-speed DCT or DSG – double-shift gearbox.
This new system gains three additional ratios by revising the torque path through the existing sets of gear trains. The transmissions dimensions and torque capacity of 550Nm remain unchanged and are likely to prove a huge bonus on the manufacturing lines.
The ‘finely graduated’ steps between ratios three and nine open the way for fuel efficiency gains, according to the company, leaving first and tenth ratios as a ‘crawler’ ratio and a super-long cruising ratio respectively.