Most of you have heard of all of the mainstream gearbox types – the classic manual, the slushbox torque converter automatic, the automated manual with a computer controlled clutch, the dual clutch automated manual, and finally the continuously variable transmission. That’s not all there is to transmission technology though, as there are a few smaller engineering companies out there with some innovative ideas of their own.
More after the jump.
Antonov 6-speed by Antonov
The Antonov transmission was created back in 2003, and uses two three-speed planetary gear modules on parallel shafts for a total of 6 forward ratios. The system is modular and four, five, six or more speeds versions can be engineered to suit a particular cost and application requirement.
Infinitely Variable Transmission by Torotrak
The IVT changes ratios by adjusting where a set of rollers makes contact with two parallel bowl-like plates – one connects to the engine (input plate) while the other connects to the wheels (output plate).
If the rollers contact the input plate on its inner radius and the output plate on its outermost radius, it creates a low gear ratio suitable for standstill starts. As the rotors swivel towards the outside of the input plate and the inside of the output plate, slowly moves towards creating a high-gear ratio for cruising. A special traction fluid ensures the rollers grip the plates strongly.
The problem with CVT is that has an infinite number of ratios between the lowest gear and the highest gear, but the highest gear is often not as “overdrive” as we would like it to be, which means cruising speeds in the highest gear can result in a relatively higher engine RPM than say, an auto transmission with dual overdrives.
The IVT does not have this problem as it has very high overdrives – 120km/h at 1,000rpm was achieved. It also does not need a torque converter or CVT lock-up clutch to start from a standstill.
Zeroshift by Zeroshift Ltd, England
This particular technology is mechanically similiar to a manual transmission, however it doesn’t use a synchromesh. Instead, it’s aim is to change gears without interrupting torque to the driving wheels. It uses two “bullets” to engage and disengage gears. One is called the drive bullet and the other is called the overdrive bullet. When a gear is engaged, both bullets are holding the gear. When a gear change is requested, the overdrive bullet moves to engage the dog teeth on the next gear, while the drive bullet still holds the first gear thanks to a retention angle.
The problem with this system is during the instant transition between the two gears, the engine, flywheel, and clutch will be spinning at a higher speed than the drive shaft, resulting in a large amount of inertia that must be relieved abruptly. To get around this, the system also precisely coordinates clutch pressure to absorb the inertia differentials.
Zeroshift Ltd says cost-wise, Zeroshift is cheaper to manufacture than a CVT or dual clutch transmission.
Have a look at a video from Zeroshift after the jump, showing the differences between a car equipped with Zeroshift and the other without.
The video clips below were filmed during back to back testing between two identical vehicles. One with a standard manual synchromesh (yellow) and the other equipped with a Zeroshift transmission (green). Both start from a standstill and accelerate. Gear shifts occur simultaneously and are indicated with a count down.
Video: Zeroshift – Internal Comparison
Video: Zeroshift – External Comparison