"Honda's Dual Clutch Transmission
Honda has been seeking to make motorcycling simpler for a long time. It produced automatic versions of its 400 cc twin and 750 cc four cylinder road machines for a brief period in the late 1970s and I spent a week on the CB750A at that time and loved it. With an powerband restacked for low-range torque and two-speed Hondamatic gear-changing, it was simplicity personified – twist-and-go and enjoy the ride.
Even then, the trends Honda was watching in the United States car market suggested that motorcycles would one day be automatic, as automatic transmissions were taking over from stick-shifts in cars. Humans want simplicity it seems and by 1976 when Honda launched its automatic motorcycles, two thirds of new car sales were fitted with an automatic transmission.
The current percentage of new car sales in America with automatic transmissions is 92.5 percent. The staunchly traditional motorcycle marketplace did not however, feel the same way about the idea of an automatic motorcycle in the 1970s and the Honda CB750A only garnered a few thousand sales. It was shelved and it was another three decades before the Honda DN-01 emerged with another automatic. The DN-01's "Human Friendly Transmission" was a CVT, but regardless of what mechanisms it used to do its job, it was an automatic.
The Dual Clutch Transmission is different though. It uses two clutches: one for first, third and fifth gears, the other for second, fourth and sixth, with the mainshaft for both clutches concentric, and each independently controlled by its own electro-hydraulic circuit. When a gear change occurs, the system pre-selects the target gear using the clutch not currently in use. The first clutch is then electronically disengaged as, simultaneously, the second clutch engages.
Honda spent a lot of money and time developing its own DCT. It's the only motorcycle currently in production that uses a DCT, though quite a few manufacturers use dual clutch transmissions in their performance cars. Numerous models from Ferrari, Audi and Porsche, plus supercars such as the Bugatti Veyron, Lamborghini Huracan, McLaren MP4-12C, Mercedes SLS AMG, BMW M3, Nissan GT-R, Mitsubishi Lancer Evolution X use dual clutch transmissions and Lotus has just applied for a patent for a simplified DCT. With a list of DCT devotees of such quality, Honda's efforts in developing the only motorcycle DCT in existence seem more than justified. A DCT does it faster and more efficiently and smoother. Q.E.D.
Remarkably, the DCT fitted to the Vultus is already Honda's second generation motorcycle DCT, the first being fitted to the 2009 VFR1200F.
The Honda DCT offers three modes of gear changing - automatic twist-and-go in D and S mode...
The Honda DCT offers three modes of gear changing - automatic twist-and-go in D and S mode, plus a trigger-operated computer-game-style manual MT mode - similar to the paddle gear-changes on a Formula One car and quite different to the foot-pedal operated sequential gearbox of a traditional motorcycle. In MT mode, the gears are shifted manually using the left index finger to shift up and the thumb to shift down
Traditional motorcycle enthusiasts love to pedal a manual gearbox, loading up the gear shift lever and flicking the throttle off momentarily for a fast gear change under acceleration. The irony is that novices will be able to change gears faster and smoother on the NM4 because the co-ordination of swapping cogs efficiently is done with technology, not with human clumsiness. Put two riders of equal weight, reflexes and co-ordination on two otherwise identical bikes, one with a manual gearbox and one with DCT, and the rider of the DCT bike will be faster over a quarter mile. Similarly, when hurtling into a corner and downshifting under brakes, enthusiasts love the challenge of getting it right by blipping the throttle and matching the revs to avoid the rear wheel chirping, as there's nothing quite like mastering a big motorcycle to make you feel king of the universe. Beginners will be able to achieve the same feeling and results without the same degree of riding expertise on the NM4 – another reason enthusiasts will hate it.
The DCT delivers a quick, smooth, consistent, seamless gear change conducted by a computer that is better than any human can orchestrate with a clutch, throttle and shift-pedal ... every time, no brainpower required. As the transmission transfers drive from one gear to the next with infinitesimal interruption of the power to the rear wheel, there is no gear change shock, and pitching of the machine is minimized, making the change feel direct as well as smooth.
The NM4 does not have a clutch lever or shift pedal. The Honda DCT offers three modes of gear changing – automatic twist-and-go in D and S mode, plus a trigger-operated computer-game-style manual MT mode – similar to the paddle gear-changes on a Formula One car and quite different to the foot-pedal operated sequential gearbox of a traditional motorcycle.
In MT mode, the gears are shifted manually using the left index finger to shift up and the thumb to shift down. This can even be employed to use engine braking to stabilize the bike on the entry into a corner. As it has two clutches, the NM4's power is delivered to the rear wheel without a break, and downshifts are seamless.
The digital dash of the NM4 changes colour depending on the drive mode selected, with subt...
The digital dash of the NM4 changes colour depending on the drive mode selected, with subtle colour changes from Neutral (white) through D (blue) to S (pink), ultimately to MT (red). The rider can choose one colour from five other tonal ranges of each colour - 25 individual colours altogether.
Automatic D mode is ideal for city riding, and offers the best fuel economy. Automatic S mode is sportier and the ECU lets the engine rev higher before shifting up and shifts down sooner when decelerating for extra engine braking. In either D or S mode, the DCT offers manual intervention – the rider simply selects the required gear using the up and down shift triggers on the left handlebar. It's not immediate, but soon after you've told it you want to go up or down a gear, it will shift seamlessly into that gear. Thanks to engine mapping and a well-programmed ECU, the DCT is designed to seamlessly revert back to automatic mode when it decides the excitement is over, using a number of parameters (throttle opening, vehicle speed and gear position) to make that decision. If you're a purist or a control freak, the Vultus will piss you off big time.
Furthermore, in D mode, the DCT system detects variations in rider input typical to certain environments, from busy urban streets to mountain switchbacks, and adapts its gear change schedule accordingly to create an extra level of riding compatibility. Motorcycling newbies raised on game systems will love these adaptive features, traditionalists will not."
Read the full article here: http://www.gizmag.com/honda-vultus-nm4- ... 3-90798141" onclick="window.open(this.href);return false;
