[2024 Green Mobility] Small but Strong Korea GM's 'Rightsizing Engine'

Mobility R&D Award Investigation
High Power and Fuel Efficiency Achieved in Small Displacement Engines

On the 25th, Korea GM received the Mobility R&D Award at the 2023 Korea Green Mobility Awards for developing engine lightweighting technology that improved fuel efficiency and driving performance.

Since last year, Korea GM has applied the 'Light-Sizing Engine' to the Chevrolet Trax crossover vehicle. The Light-Sizing Engine technology provides high output and fuel efficiency despite a small displacement. It is described as a more advanced technology than the downsizing engine, which simply reduces displacement and adds a turbocharger. By setting an appropriate engine displacement and electrifying components powered by the engine, as well as the turbocharger, it achieved a balance between performance and efficiency.

The E-Turbo engine of the Trax crossover equipped with this technology uses an aluminum block to reduce weight. It adopts a 3-cylinder engine that reduces the number of moving parts compared to an inline 4-cylinder engine. This significantly reduces engine friction loss and weight, delivering performance comparable to an inline 4-cylinder engine while improving fuel efficiency.

Additionally, based on the technology of GM Korea R&D Corporation, it applied an optimized combustion chamber design, a 350-bar ultra-high-pressure fuel injection system, injector injection optimization, and an Integrated Exhaust Manifold (IEM). For the first time in GM, it also equipped an oil-in-belt and crank offset.

To compensate for noise and vibration, which are weaknesses of the 3-cylinder engine, a 'balance shaft' was applied to control engine vibration itself. Along with this, the stiffness design of the driving components, including the crankshaft, was optimized, and a PT bending brace minimized vibrations generated by the engine and transmission combination.

With this technology, the Trax crossover reduced vibration and noise in the 1.2-liter (ℓ) low-displacement 3-cylinder engine while securing power performance of 139 horsepower and maximum torque of 22.4 kg.m, comparable to a 2.0ℓ naturally aspirated engine. As a result, since sales began in overseas markets in February last year, more than 20,000 units have been sold monthly since August of the same year. In the domestic market, it has maintained the No. 1 sales position in the crossover vehicle segment and ranked within the top 3 in the small sport utility vehicle (SUV) segment based on cumulative sales since April last year.