The iMT gearbox from Kia revolutionises models with 48-volt mild hybrid technology

The proliferation of models with 48-volt mild hybrid technology is prompting brands to take a serious interest in improving the performance of this type of system. Kia has taken a step forward and has just unveiled the iMT electronic gearbox, designed for its models with this type of hybridisation. It has been designed to achieve maximum fuel efficiency and reduce emissions of polluting gases.

The electronic clutch is integrated into the hybrid system itself and assists the engine at times when it is not necessary to keep the engine running, taking advantage of the car’s own momentum. The clutch coordinates with the car’s starter motor when the car is coasting in order to switch the engine off and disengage it before the Kia Stop & Start system kicks in.

When the car is coasting, it also allows the engine to be switched off for short periods of time, provided the speed does not exceed 125 km/h. To restart the engine, you only need to press the accelerator or the clutch slightly to change gear, and the engine comes back to life immediately. As a result, fuel savings of 3% are achieved under normal driving conditions.

How the Kia iMT gearbox works

The Kia iMT gearbox works as follows:

• When the driver leaves the gear engaged while coasting, the system gently slows the car down. This situation can occur when lifting off the accelerator while taking a corner, at a junction or due to traffic conditions.
• While the gear remains engaged, the iMT sends an electronic signal to the gearbox and to the starter-generator motor (MHSG), which switches the engine off and disengages it.
• With the engine off and disengaged, the car keeps moving but with less deceleration in order to make the most of its kinetic energy.
• If the driver wants more power and to gain speed, all they need to do is press the accelerator or the clutch so that the MHSG restarts the engine, either engaged in the selected gear or disengaged.
• The electrical energy from the MHSG and the 48-volt battery brings the engine and transmission up to the correct rotational speed, allowing them to operate without any perceptible interruption in traction.
• If the system detects that the speed has dropped below a certain level, it starts the engine and engages it, to prevent the loss of the power needed to maintain forward thrust.

This new gearbox has been developed by the Technical Centre of Hyundai Motor Europe in Offenbach, Germany, and, in addition to all these innovations, it works like a normal gearbox, so it poses no difficulty whatsoever for the driver.