Bentley will cease production of its 12-cylinder gasoline engine in April 2024, by which time more than 100,000 examples of the iconic W12 will have been handcrafted in the company’s Dream Factory in Crewe, England.

The decision comes as part of Bentley’s acceleration towards a sustainable future through its Beyond100 strategy which will see the company’s entire model line fully electrified by the start of the next decade, reducing fleet average emissions to 0 g/km CO₂. This has already begun, with the introduction of the Bentayga and Flying Spur Hybrid models—demand for which is exceeding the company’s expectations.

When production of the W12 ceases next year, Bentley’s entire model line will be available with the option of a hybrid powertrain. Meanwhile, an engine first made available in the sector-defining Continental GT, which has been powering Bentley both metaphorically and literally for the last 20 years, will be consigned to history.

Development work has concluded recently on the most powerful version of the W12 ever created. The ultimate iteration of this engine—destined for just 18 examples of the Bentley Batur to be handcrafted by Mulliner—is now confirmed as developing 750 PS and 1,000 N·m of torque. The increased torque figure forms the typical Bentley ‘torque plateau’, running from 1,750 rpm to 5,000 rpm—with peak power at 5,500 rpm.

While all Baturs are sold, a limited number of the 659 PS version of the W12 engine offered in the Speed versions of Continental GT, Bentayga and Flying Spur as well as the Continental GT Mulliner and Flying Spur Mulliner can still be ordered. Demand for these final W12-powered Speed and Mulliner models is expected to be high.

Bentley’s aim is to retrain and redeploy all 30 of the skilled craftspeople that hand-assemble and test every W12 engine at Bentley’s carbon-neutral factory in Crewe. Meanwhile, the W12 engine production facility will make way for an expanded line for the completion of other Bentley engines used for the plug-in hybrid models.

Since the first introduction of the 6.0-liter, twin-turbocharged W12 in 2003, the engineering team in Crewe has continually improved the performance of the engine in terms of power, torque, emissions and refinement. Over the last 20 years, power has increased by 37% and torque by 54%, while emissions have been reduced by 25%.

Initially this was through evolution and optimization of the control systems, improvements in the oil and cooling designs, turbocharging technology and more effective injection and combustion processes.

For the launch of the Bentayga in 2015, the W12 was completely redesigned from the sump up, and it’s that version of the engine that remains in production today—featuring cylinder deactivation, direct and port injection, and twin-scroll turbos.

A thoroughly reworked engine included a crankcase 30% stronger than its predecessor, while the cylinder surfaces were coated to reduce friction and improve corrosion resistance. A low-alloy steel coating is applied to the bores using an Atmospheric Plasma Spray (APS) process.

Improvements were also made to the cooling system, with the engine featuring three separate coolant circuits. The first is designed to bring the cylinder heads up to optimum operating temperature as quickly as possible for best engine performance and low emissions. The second cools the engine block and oil system, while the third handles the thermal load of the turbochargers. Each system has a dedicated water pump, allowing optimized individual control.

The W12 combines high-pressure direct fuel injection (200 bar injection pressure) with low-pressure port injection (six bar). The combination of these two systems maximizes refinement, lowers particulate emissions and optimizes power and torque delivery.

Twin-scroll turbochargers minimize turbo response time and provide a more efficient exhaust package. The exhaust assemblies for the three front and three rear cylinders are separate from one another which then feed the twin-scroll impellers. The turbocharger housing is welded directly to the exhaust manifolds and feature integrated speed sensors, allowing the engine to monitor turbo performance for maximum efficiency.

Bentley’s Variable Displacement system shuts down half of the engine under defined conditions. Intake and exhaust valves, fuel injection and ignition are all shut down on defined cylinders, with the engine running as a six-cylinder for improved efficiency. The system will run in this mode in gears three to eight, below 3,000 rpm and up to 300 N·m torque output.

For the final and ultimate version of the W12, Mulliner’s engineering team has reworked the intake, exhaust and cooling systems to liberate more power and torque.

The turbocharger compressors are of a new design to improve efficiency, while the ducts that feed air to them are 33 per cent larger—at peak power, the new engine ingests more than a ton of air (1,050 kg) per hour. Larger charge-air coolers, with a depth increased by 10 mm and a new core geometry, reject 35% more heat from the pressurized intake air, reducing intake temperature to a greater extent meaning a denser charge for more power.

The new intake and turbocharging system is matched with a heavily revised engine calibration to liberate the extra torque available, and the complete engine system is then paired with a new transmission calibration to deploy the additional power and torque and enhance the driving experience.

The W12 engine facility will have delivered over 105,000 engines before reaching its 20^th anniversary this year.