Motorcycles Technology

Mechanism and Evolution of Dual Clutch Transmission

Honda's DCT, the world's first DCT mounted on a motorcycle, has evolved to be closer to the rider's senses

Mechanism and Evolution of Dual Clutch Transmission

In 2010, Honda introduced the world's first dual clutch transmission (DCT)*1 in a motorcycle, and has continued to evolve the DCT ever since. 2012 saw the introduction of the DCT in the NC700 series and the CTX700, expanding the circle of users. In 2016, this technology was introduced to the CRF1000L Africa Twin to expand riders’ field of use. And in 2020, it evolved to become quieter and smoother, with control closer to the rider's senses.



1.What is the Dual Clutch Transmission?

A Dual Clutch Transmission is a transmission in which clutch and shift operations are automated, while maintaining the structure of manual transmission with its advantages such as direct-feel acceleration.
With no need to operate the clutch, the rider can concentrate on the throttle and brake operation while riding, and smooth acceleration and deceleration is possible with fewer interruptions of driving force during shifting that inevitably occur with normal manual transmissions due to their structure.
As a transmission with two clutches (dual clutch), one for the 1st, 3rd, 5th gear and starting, and the other for the 2nd, 4th, and 6th gear, Dual Clutch Transmission is the world's first*1 technology for motorcycles.
*1: As of June 2010 (based on Honda research)

There are two gear shifting modes: the AT mode, which automates shifting operation, and the MT mode, which allows the rider to select a gear of their choice at any time. In the AT mode, in addition to the regular D mode, the S mode can be selected for sportier riding. The gears can be shifted at any time with shift switching according to the riding conditions, and after shifting the gears, the machine automatically returns to the AT mode.

dct_e_switch
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Previous control flow

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Control flow of the 2020 CRF1100L Africa Twin

The CRF1100L Africa Twin is equipped with a 6-axis IMU (inertial sensor) that detects angular velocity and acceleration for pitch, roll, and yaw. The addition of cornering run detection control enables gear shifting closer to the rider’s senses, while enhancing launch control and gearshift control delivers a sense of security and directness.



2.The Inner Workings of the Dual Clutch Transmission

We would like to present here the clutch operation and gear shift operation performed automatically during acceleration and deceleration.



3.Mechanism for Automatic Gear Switching

In a normal manual transmission, the shift spindle is rotated by operating the shift pedal on the left foot, and the gears are slid through the shift drum and shift fork, but in a dual clutch transmission, the shift motor takes on this role. The shift spindle is operated by the shift motor in the same way when using the optional foot pedal setting.

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dct_e_mt

Manual Transmission

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Dual Clutch Transmission

For NC750S 〈DCT〉/ NC750X 〈DCT〉

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Shifting is possible by foot as well as by hand.

Dual Clutch Transmission Change Pedal Kit

For CRF1100L Africa Twin

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Shift operation is possible by left foot just like a normal manual transmission vehicle.

It can be used with the DCT shift switch on the handlebar.

Dual Clutch Transmission Shift Pedal



4.Efforts to Deliver to a Wider Audience

In order to deliver to as many people as possible the riding sensation of manual transmission that can be enjoyed without clutch and shift operations, we have optimized the structure according to the characteristics of the engine and model. For example, in the series where the same engine is mounted on the same frame in the three types, "NC750S", "NC750X" and "X-ADV", the layout of the clutch and crankshaft was reviewed to realize the floor-type step of the "X-ADV".

Dual Clutch Transmission-Installed Models

Gold_Wing

Gold Wing 〈DCT〉

Gold_Wing_Tour

Gold Wing Tour 〈DCT〉

CRF1100L_Africa_Twin

CRF1100L Africa Twin 〈DCT〉

CRF1100L_Africa_Twin_Adventure_Sports

CRF1100L Africa Twin Adventure Sports 〈DCT〉

Rebel_1100

Rebel 1100〈DCT〉  

NC750X

NC750X 〈DCT〉  

X-ADV

X-ADV

FORZA750

FORZA750



5.Developers’ thoughts

We believe that the ultimate goal of the DCT is to "create the pleasure of maneuvering”. Since the creation of the DCT in 2010, the development team members have continued to work on evolving it to realize the purpose.

The DCT is an excellent system that frees the rider from clutch and shift operations, while still being able to transmit "direct drive power" unlike other ATs; it does not spoil the fun riding that is the essence of motorcycles.

If you actually ride it, you will immediately understand that it is not just a regular AT. It allows the rider to get the torque and acceleration they want, when they want it, and how they want it. What we want to provide with the DCT is a sense of oneness between the rider and the motorcycle.

2010: “Establishment of the world's first installation system”

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Mounted on the VFR1200F in 2010/VFR1200X in 2014

After announcing the development of our technology at the Milan Show 2008,  in 2010, the VFR1200F sports tourer became the first motorcycle in the world to be equipped with Dual Clutch Transmission. It is since this time that the idea of switching between AT and MT modes at the will of the rider, and temporarily allowing manual operation even when the AT mode is used has been adopted.

2012: “Expansion of Users”

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Mounted on the NC700 series in 2012, CTX700 series in 2013, NM4 in 2014, NC750 series in 2016 and X-ADV in 2017

In 2012, the Dual Clutch Transmission was introduced to the 700cc NC series to allow more riders to experience it. By utilizing the know-how and manufacturing infrastructure of four-wheelers, to which hydraulic clutch control was applied ahead of motorcycles, we have been able to offer a more compact and reasonable model by drastically reviewing the structure, including reducing the number of parts compared to the previous systems. As the NC series gained popularity, many derivative models were equipped with DCT, and as more and more riders experienced it, it has grown its way to being a widely recognized technology.

2016: “Expansion of the Field of Use”

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Mounted on the CRF1000L Africa Twin in 2016

With the Dual Clutch Transmission, we sought to expand not only the "users" but also the "field of use”-In the 2016 CRF1000L Africa Twin, we took on the challenge of applying the DCT to a new territory: off-roading. By reviewing the clutch control and gear shifting control, a new mode for dirt riding has been added, which has been well received as an "adventure model" as it can be ridden anywhere. For the Africa Twin, the DCT model was selected by almost half of the customers, proving that the DCT is capable of demonstrating its true value even in off-road conditions where riding requires concentration.

2018: “7 gears for freedom of choice in shifting”

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Mounted on the Gold Wing Tour in 2018 and Gold Wing in 2019

As the next step in our efforts to "expand" the range of users and scenes, we aimed to "deepen" the sense of fulfillment of maneuvering the vehicle by ensuring that the evolution of each model is optimized in terms of both software and hardware.

In the Gold Wing, the shifting feel has been improved by adopting a 7-gear transmission instead of 5-gear manual transmission, allowing the rider to enjoy the full power feel of the vehicle. With the adoption of a cross ratio on the low-speed side, the shock caused by shifting gears is reduced while the adoption of a wide ratio in 7th gear enables controlling of the engine speed rotation during high-speed cruising, greatly improving quietness. Furthermore, a superior shift feel has been achieved by adopting dampers in various parts to reduce transmission noise and operation noise while shifting. The adoption of a geared chain eliminates the need for an additional reversing shaft, which contributes to making the system lightweight and compact, coming along with a very low-speed forward and reverse function that allows for easy turning of the vehicle body while seated. In terms of advances in control technology, we have achieved both quicker and smooth-feel shifting through coordinated control with throttle-by-wire (TBW), which electronically controls the throttle valve opening.

2020: DCT Control that Paved its Way to be Closer to “the Rider’s Senses”

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Mounted on the CRF1100L Africa Twin and CRF1100L Africa Twin Adventure Sports in 2020

The CRF1100L Africa Twin uses a 6-axis IMU to detect the vehicle's bank angle, acceleration, and deceleration, and to select gears that match the riding conditions, such as cornering. This enables gear shifting closer to the rider’s senses. Together with the G-Switch, which switches the clutch response characteristics, the rider can enjoy a direct and exciting ride.

The DCT technology is highly compatible with other technologies, and will continue to evolve as sensing devices, ECUs, AI, etc., are enhanced. We will continue to promote technological development with the aim of “creating a higher level pleasure of maneuvering".