WinGD confirms 30% methane reduction potential in VCR-equipped X-DF engines

Swiss marine power company WinGD has validated the performance of its viable compression ratio (VCR) technology in recent shop tests, confirming that new X-DF engines fitted with VCR can achieve methane reductions comparable to high-pressure dual-fuel systems.

As informed, the VCR shop tests were wrapped up at Japan-based Mitsui E&S DU’s (MESDU) facilities, where the first X-DF2.0 engines equipped with variable compression ratio technology are being constructed for a 95,000 dwt bulk carrier and a 7,000 CEU car carrier to be owned by Japanese shipping giant Nippon Yusen Kabushiki Kaisha (NYK Line).

According to WinGD, the six-cylinder 62-bore engine achieved approximately 30% fewer methane emissions than the same engine without VCR, taking total slip to roughly 0.83% of gas consumption.

Alongside lowering methane slip, the technology reportedly slashed fuel consumption by up to 5.8% in gas mode and 6.9% in diesel mode.

Representatives from the Winterthur-headquartered marine technology developer have highlighted that this accounts for less than half the European Union (EU) as well as provisional International Maritime Organization (IMO) default slip attributed to low-pressure, low-speed dual-fuel engines in maritime guidelines.

Moreover, it was disclosed that the reduction is anticipated to be even higher for engines with a larger bore.

This is understood to be particularly significant as both EU and IMO regulations are expected to include mechanisms to update default methane slip factors and allow shipping companies to supply their actual methane slip measurements, i.e. ship operators could cut carbon costs based on any methane slip improvement.

“Over the past decade we’ve worked to ensure that the unmatched reliability and low capital expenditure of X-DF engines are supported by the lowest possible overall GHG emissions. The fuel consumption and methane slip reductions achieved by VCR bring us to that point,” Peter Krähenbühl, Vice President Product Centre, WinGD, commented.

“Low GHG emissions will be fundamental for shipowners as carbon pricing measures take effect, which is why we have already seen strong uptake, with well over 100 new X-DF engines ordered with VCR so far,” he added.

Developed in June 2023 together with MESDU, the variable compression ratio technology adjusts the cylinder compression ratio based on factors like engine load, type of fuel and ambient conditions. The solution is said to be applicable to all X-DF engines.

WinGD spotlighted that a retrofit package has already been developed, too, and installed on a pilot case vessel, which has seen “positive results” so far.

The inaugural field test of the VCR technology was performed in August 2024 on a vessel operated by French shipping titan CMA CGM. The initiative came after a series of factory trials that allegedly showed efficiency gains with both diesel fuel and liquefied natural gas (LNG).

WinGD’s X-DF engines are said to have shown ‘considerable’ fuel consumption savings and emission reductions owing to their ‘low nitrogen oxide (NOx) design’ and the use of emission control strategies, as required in the recent updates to IMO’s NOx technical code.

The company’s X-DF-A ammonia-powered engine—for which WinGD unveiled an option to run on liquefied petroleum gas (LPG) in October 2024— showed “stellar” performance indicators during an early testing phase, as revealed in January 2025.

The single-cylinder testing is expected to enable a “rapid” validation of the ammonia combustion system under engine conditions while optimizing emissions and performance, the company shared.

On the other hand, in late February 2025, WinGD announced that its first methanol-fueled engine was all but ready for delivery upon passing factory and type approval tests. As explained, the ten-cylinder, 92‑bore X-DF-M engine, described as “the biggest” methanol-fueled engine built to date, was introduced in a ceremony held at engine builder CMD in Shanghai, China.