ADEX 2023 – STX Engine aims at Korean propulsion independence by 2025

Paolo Valpolini

With strict German export controls in the Middle East countries hampering export, South Korean STX Engine is working on developing engines for armoured vehicles that will be fully local, including raw materials and parts, in order to attain full propulsion independence, the first fully South Korean product being expected by 2025

With over 45 years experience in the propulsion world, STX Engine started producing under license then MTU engines, namely the MB871 for the K1 main battle tank, followed in the late 1990s by the MT881 for the K9 155 mm self-propelled howitzer.

According to the company over 2,000 MB871 were produced rated at 1,200 hp. At ADEX the company was exhibiting the prototype of the SMV 1360 uprated engine that is capable to provide 1,360 hp. Developed in 2020, it maintains 70% commonality with the previous model, the output power increase being mainly due to the adoption of a common rail direct injection system.

The SMV 1360 provides a maximum torque of 4,400 NM at 1,800 rpm, has a bore and stroke of 169 x 1699 mm, weighs 2,460 kg, its dimensions being 1,332×1,953×1,146 mm.

STX Engine aims at replacing all K1 engines, the new product being easily integrated in the tank as its physical dimensions being very similar. The over 10% increase in power will provide a growth potential allowing the South Korean Army to upgrade its ageing tanks of that type, within the proposed K1A2 Product Improvement Programme.

As for the MT881, the company produced some 2,000 1,000 hp engines for the national customer, to which we must add some 600 on the export market, thanks to the success obtained by the K9 in Norway, Finland and Estonia, as well as 300 more that are powering the Turkish Firtina SP howitzer.

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The K9 might well become the first South Korean combat vehicle to feature a 100% national power solution. As anticipated the aim is to become fully free from other nations export regulations, thus avoiding critical export barriers that limit the South Korean export aspirations.

Known as SMV 1000, the number indicating the output in horsepower, the new engine will ensure exactly the same performances of the current MT881, with the further advantage to have a slightly lower mass, 1,478 kg compared to the 1,552 of the current engine. The SMV 1000 provides a 3,030 NM torque at 2,000 rpm, has a bore and stroke of 144×140 mm, is fitted with a um line nozzle direct injection, its dimensions being 1,426×1,250×1,210 mm.

In 2023 the company finalised the prototype, the engine being currently undergoing endurance tests on STX Engine test benches. These will finish in November this year, while in early 2024 the SMV 1000 will be installed on a K9 and will undergo mobility trials. The company aims to make the new engine available by 2025, and beside the K9 it will also target the Redback infantry fighting vehicle, the infantry fighting vehicle developed by Hanwha Defense recently selected by Australia.

Two years later STX Engine aims at adding another South Korean power solution to its portfolio, the SMV MK multipurpose engine. The engine, which is still in the design phase, will be made available with three different outputs, 350 hp, 520 hp and 750 hp, with maximum torque of respectively 2,60 Nm, 2,080 Nm and 1,353 Nm. It will be fitted with a Common Rail direct injection system, the engines with the two higher ratings having a mass under 1,000 kg while the 350 hp one will have a mass under 871 kg. The 750 hp aims at the K21 infantry fighting vehicle, the 520 hp to the K30/K31 air defence vehicle, and the 350 hp to the K2900A1, all these in-service systems needing soon or late to be upgraded. The SMV MK should be ready by 2027.

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The next step, planned one year later, will be the add-on of the first hybrid propulsion system, the SMV Hybrid. This will be a parallel hybrid solution and it is being designed by a team that includes, beside STX Engine, Hanwha Aerospace and Hyundai Rotem. The system will be made of the hybrid motor generator, the integrated control unit, the high voltage battery pack, the super capacitor pack, the plug-in system, and the artificial intelligence-based condition-based monitoring system.

At ADEX EDR On-Line understood that the development of a further engine is planned, this being a 6-cylinder with a 450 hp output, which development has apparently not yet started.

Photos by P. Valpolini