Marine Commercial - Information

Yanmar Develops the Fuel Efficient and Durable EY33 Series for Vessels

July 25, 2016
Yanmar Co., Ltd.

An EY33 series engine for vessels

Delivering fuel efficiency and durability, Yanmar Co., Ltd.’s flagship engines for vessels, the EY33 series, is presently under development. The manufacturing phase for the auxiliary engines has already commenced and the development phase for the propulsion engines is on its way towards completion.

Development for the EY series arose from Yanmar's concept of Life Cycle Value and harmony with nature, which commenced in 2000. The latest engines developed boast the highest output of the series, delivering an optimized combustion performance and an enhanced load range under actual conditions, resulting in a 5% improvement in fuel efficiency compared to units from the previous Yanmar engine series. To meet International Maritime Organization (IMO) emissions regulations, nitrogen oxides (NOx) and CO2 have been reduced.Additionally, key components have been made more durable to allow for an increase in maintenance cycles from the previous 8,000 - 12,000hr to 12,000 - 15,000hr. With the EY series, Yanmar is intensifying its efforts towards minimizing environmental impact and improving life cycle value for its customers.

1. Key Features

Fuel Efficiency

  • Leveraging advanced 3D simulations, combustion variables have been optimized
  • Equipped with a high-pressure Miller cycle system that employs both a Miller-type camshaft* and a supercharger* that allows for high-pressure ratios, this system delivers reductions in NOx and CO2 emissions, in addition to greater fuel efficiency

Durability Enhancements

  • Pistons are constructed of two segments, employing alloy steel for the upper segment that is in direct contact during the combustion process
  • The outer circumference of the piston ring contains a CPC coating, enhancing abrasion resistance and reducing seizures
  • Yanmar's innovative processing for the inner surface of the cylinder liner improves oil retention, thereby reducing friction
  • The exhaust valves employ a new alloy material that enhances abrasion resistance and durability

More Power

  • The piston stroke length for the auxiliary engines has been increased from 380mm on previous models to 440mm
  • The rated speed for the propulsion engines has been increased from 620min-1 on previous models to 750min-1
  • Structural analysis has been performed on each part, with construction of the main parts and key moving parts optimized

2. EY33 Series Specifications

Model 6EY33W 8EY33W 6EY33LW 8EY33LW
Application Propulsion engine Auxiliary engine
Rated power (kW) 3360 4500 3600 4800
Rated speed (min-1) 750 720/750
No. of cylinders 6 8 6 8
Bore x stroke (mm) 330 x 440
Mean effective pressure (MPa) 2.38 2.66/2.55
Fuel Heavy fuel oil for vessels, Low grade fuel oils for vessels

Note: Propulsion engine: The engine for propelling the vessel. Auxiliary engine: The engine for powering the generators for electricity on the vessel

  • ※1:A camshaft which has a design that allows for rapid closing of the intake valves
  • ※2:Due to the rapid closing of the intake valves, this device pushes highly pressurized air through the cylinders, thereby offsetting pressure reductions inside of them
  • ※2:A technology that applies aluminum to mitigate tiny cracks that arise in hard chrome plating

About Yanmar

With beginnings in Osaka, Japan in 1912, Yanmar was the first ever to succeed in making a compact diesel engine of a practical size in 1933. Moving on, with industrial diesel engines as the cornerstone of the enterprise, Yanmar has continued to expand its product range, services, and expertise to deliver total solutions as an industrial equipment manufacturer. As a provider of small and large-size engines, ag machines and facilities, construction equipment, energy systems, marine, machine tools, and components — Yanmar’s global business operations span seven domains.

On land, out at sea, and in the midst of the city, Yanmar’s Mission of “providing sustainable solutions focused on the challenges customers face, in food production and harnessing power, thereby enriching people’s lives for all our tomorrows,” stands testament to Yanmar’s determination in providing us with “a sustainable future.” For more information, visit Yanmar Co., Ltd. at its worldwide website at


Public Relations Group
Brand Communication Division, Yanmar

  • Note: Information contained in the news release is valid at the time of publication and may differ from the most recently available information.