📂︎ Technology News | 🖳︎ Wayne Gorrett | 🖃︎ June 24, 2020
➤ New ‘clutch-by-wire’ technology for future KIA mild-hybrid models.
KIA Motors today reveals more details of its new intelligent Manual Transmission (iMT), designed for a range of the brand’s mild-hybrid electric vehicles (MHEVs).
KIA’s new iMT has been developed at the Hyundai Motor Europe Technical Centre in Offenbach, Germany. The ‘clutch-by-wire’ system is engineered to boost fuel efficiency and reduce CO2 emissions, while retaining the driver engagement of a conventional manual transmission.
Instead of a mechanical linkage, the iMT’s clutch operates purely electronically, and is integrated seamlessly with a 48V MHEV powertrain. The iMT works with the mild-hybrid starter generator (MHSG) to switch off the engine earlier than KIA’s Idle Stop & Go start-stop system when coasting to a halt. This improves overall fuel efficiency and can reduce CO2 emissions by around three per cent in real-world driving conditions.
The chosen gear remains engaged even with the engine off. The engine restarts in the same gear as soon as the driver presses either the brake or accelerator pedals thanks to the burst of power provided by the MHSG. The transmission restarts the engine in neutral (with an open clutch) if the driver pushes the clutch pedal to change gear, or if the vehicle speed is too low for the current engaged gear.
How it works – step-by-step
The driver leaves the car in-gear as it starts to coast, gently slowing the car down (e.g. for a corner, junction, or traffic).
While in-gear, the iMT sends an electronic signal to the gearbox and MHSG to seamlessly switch off the engine and open the clutch.
With the engine switched off, the car continues coasting, with the open clutch limiting deceleration and allowing the car to make the most of its kinetic energy.
As the driver pushes the accelerator to pick up speed, or engages the clutch to change gear, the MHSG restarts the engine in the driver’s selected gear, or in neutral (with an open clutch).
Electric power from the MHSG and 48V battery instantly brings the engine and transmission up to the correct speed.
If the car drops below a certain speed, the engine restarts with assistance from the MHEV system, and the clutch closes, to avoid labouring the engine in the engaged gear.