NYK will install Variable Compression Ratio (VCR) systems on dual-fuel two-stroke LNG-powered car carriers to be built by Shin Kurushima Dockyard. The first vessel is scheduled to be delivered in 2026. NYK earlier announced it would install the VCR systems on two LNG-fueled coal carriers. (Earlier post.)

Cross section view of the VCR system. Source: WinGD.

The VCR system can adjust the compression ratio in the engine combustion chamber to an optimal balance according to engine power and LNG fuel properties. This will improve fuel efficiency during operation by about 3% in LNG gas mode and about 6% in diesel oil mode. The system is also expected to play an important role in reducing GHG emissions from existing ships and improving engine efficiency when decarbonized fuels are introduced.

WinGD introduced the VCR technology in June after more than a decade of co-development with Mitsui E&S Diesel United (MESDU). Compression ratio is altered by changing the piston position to adjust combustion chamber volume. The simple mechanical configuration has no impact on engine footprint or installation requirements. VCR can also be adjusted for part load operation, meaning that relatively larger savings can be achieved at the low speeds.

The simple hydraulic solution mounted on the piston crosshead represents a breakthrough in two-stroke engine design as the first concept enabling compression ratio to be adjusted, delivering significant greenhouse gas emissions reductions in both diesel and gas modes.

VCR technology is currently available as an option for WinGD 62- and 72-bore X‑DF engines and has no impact on engine footprint and installation requirements.

Separately, WinGD concluded an agreement with MESDU that will see WinGD engines being built at its main Tamano works for the first time. The agreement adds considerable engine building capacity and enables WinGD to meet growing demand in a leading shipbuilding market with a reputation for delivering sophisticated, high-quality vessels.

WinGD engines have previously been built only at the company’s Aioi Factory, which was acquired from IHI Group when the Diesel United business was sold to MITSUI E&S earlier this year. The new agreement, which complements an earlier cooperation agreement signed with Diesel United in 2015, means that WinGD engines can now be built at both the Aioi and Tamano Factory.

As well as WinGD’s existing diesel-fueled X‑Engines and LNG dual‑fuel X‑DF engines, the additional building capacity at the Tamano Factory will also be dedicated to X‑DF‑A ammonia‑fuelled and X‑DF‑M methanol‑fuelled engines, which will be available for delivery from Q1 2025.