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Part 3 : The Marine Engine Story "The Drive to Conserve Energy and Realize Ever-larger Ships"


History

Released in January 2011

Vessels have continued to become larger in step with growth in seaborne trade.
And as ships have increased, engine technology has improved by leaps and bounds.

Before WWⅡ

Completion of First steamship Hideyoshi Maru

In 1874, the world's first vessel equipped with a three cylinder compound steam engine was launched. Just four years later in 1878, the first vessel powered by this revolutionary engine, the Hideyoshi Maru, was launched in the U.K. The Hideyoshi Maru transported coal from Miike, Fukuoka Prefecture to Kuchinotsu, Nagasaki Prefecture.

Hideyoshi Maru

MOL's first diesel vessel

1924 brought the launch of the Ondo Maru, the first large diesel –powered merchant vessel to serve domestic routes in Japan, and the Akagisan Maru, Japan's first ocean-going diesel ship. The Montevideo Maru, launched in 1926, was the first ship powered by a made-in-Japan diesel engine.

Akagisan Maru

The four-cycle diesel engine was used as a main engine.

Montevideo Maru

The Montevideo Maru featured a high-output (7,000HP) two-cycle engine.

Exhaust Gas turbo charger

The engine underwent continual upgrades, and in 1931, the Nachisan Maru adopted the first four-cycle engine equipped with an exhaust gas turbo charger.

Nachisan Maru
Post WWⅡ:
The Era of Rapid Growth

Postwar technology revolution

The first noteworthy technology revolution after the war was the adoption of degraded marine heavy oil (C oil) as a fuel for diesel engines. This was impossible before that time because C oil is highly viscous and difficult to ignite. Ocean shipping companies and shipbuilders teamed up to overcome this problem and the Atlas Maru launched in 1951 and the Awajisan Maru delivered the following year were able to run on degraded marine heavy oil, significantly reducing ship operating costs.

Atlas Maru
Awajisan Maru

The next breakthrough was practical application of turbochargers on large two-cycle diesel engines. Four-cycle engines had used exhaust gas turbochargers since before the war, but it would be another 22 years until they were adapted to two-cycle engines, realizing improvements in output and fuel efficiency. The advent of the turbocharged two-cycle diesel engine came in 1953 when this power plant was installed as a replacement for the main engine in the Arimasan Maru at a Japanese shipbuilding company.

Arimasan Maru

engine showed dramatic results - a 35% increase in output and an 8% decrease in fuel consumption. Over a half-century later, most ocean-going vessels are powered by turbocharged two-cycle diesel engines.

Automation of engine room

Remote operation console on the bridge of the Kinkasan Maru

In 1955-64, MOL actively adopted new technologies to automate vessels and thus reduce labor costs. The Kinkasan Maru launched in 1961 was the world's first vessel with an automated engine room, allowing centralized monitoring and measurement of engine room machinery, and operation of the main engine from the bridge.

Kinkasan Maru

Larger hulls and more powerful engines

Over the years since 1965 vessel hulls became larger and designs more diverse to accommodate specialized cargoes. Developments included bulk carriers that featured innovative, specialized car carriers to handle Japan's booming exports of automobiles. This decade was a revolutionary period in terms of both quality and quantity.

It was the tanker that grew bigger the most dramatically and rapidly compared to other ships. In 1971, the tanker Mitsuminesan Maru was launched, displacing a massive 220,000 tons. It was powered by the world's largest diesel engine at that time (38,000 HP).

The iron ore carrier also grew to mammoth size to meet increased demand for iron ore. In 1972, the iron ore carrier Chidorisan Maru, weighing in at 160,000 tons, joined the fleet.

Mitsuminesan Maru
Chidorisan Maru

Energy- efficient technology

As larger vessels first came on the scene, energy conservation was not generally so such a major concern, but MOL has always focused on fuel efficiency in adopting new ships.

One energy efficient feature was a system to generate electricity utilizing the heat of the main engine's exhaust gas. This was first used on the Tokiwasan Maru launched in 1965, well ahead of other Japanese ocean shipping companies, and has been used on many of our newbuilding vessels ever since.

The concept of waste heat energy recovery system to generate electric power is at the heart of ISHIN-III. It is a simple device to use the heat of the exhaust gas to produce steam, which in turn drives a turbine that generates electricity.

Fuel prices skyrocketed during the first "Oil Shock" in 1973, and fuel costs began to represent a drastically higher percentage of ship operating expenses. One countermeasure was to replace vessels' main engines. The resulting 40% to 50% savings in fuel was enough of a benefit to justify even the high costs of replacing the main engine. MOL followed this logic in 1980, replacing the main engine on the containership Rhine Maru.

Tokiwasan Maru
Rhine Maru
After Oil Shock

The world's first ultra energy-efficient diesel engine

In 1982, the Harriet Maru, equipped with the world's first ultra energy-efficient diesel engine, joined the MOL fleet. The engine boasted a heat efficiency rating of 50%, marking an all-time high in fuel efficiency. Its main engine adopted the Advanced Turbo Generating System, a significant improvement over the one used on the Tokiwasan Maru, and a shaft-driven generator.

Harriet Maru

We have seen even more improvements in fuel-saving technology since then, and today's main engines use nearly 70% of the fuel's thermal energy, although 40% to 50% is actually transmitted to the propeller shafts.

1985 brought the launch of a vessel that built upon the Harriet Maru's technology with the addition of computer controls for the power generating system. The Atagosan Maru launched in 1989 adopted the Turbo Compound System on the low rpm/high fuel efficient main engine as we continued our quest for increased fuel efficiency.

Atagosan Maru

Three cylinder compound steam engine

Its principle of the three cylinder compound steam engine is to use steam to drive the pistons, creating a reciprocal motion, and then convert that into rotational motion. The origin of the reciprocating motion is the same as the steam engines that drove early locomotives.

Inverted vertical type engine (1850s)
Reciprocating engine in the Shuri Maru

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4-cycle engine

In a diesel engine, air is taken into the cylinder and compressed, the fuel is injected into the combustion chamber and ignited, causing it to expand, and then the exhaust is pushed out of the cylinder. This is called a cycle. Engines that complete this cycle in two crankshaft rotations are called four-cycle engines and those that complete it in one rotation are called two-cycle engines. Ignition occurs with every other rotation of a four-cycle engine and with every rotation of a two-cycle engine. So generally, two-cycle engines are used to maximize power output. The addition of a turbocharger allows for a large-output, high-efficiency main engine.

How a four-cycle engine works
How a two-cycle engine works

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Exhaust Gas turbo charger

Forcing dense, pre-compressed air into the cylinders increases horsepower and reduces specific fuel consumption. This is called "turbocharging."

Turbochargers use a turbine driven by the engine's exhaust gas - energy that would otherwise be wasted – to compress the intake air. The addition of a turbocharger to a modern diesel engine boosts power output by almost 50%, compared to the same engine without a turbocharger, so virtually all of today's engines are turbocharged.

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Replacement of engine

Fuel costs represent a growing share of vessel operating expenses. Even though engine replacement is expensive, a new main engine with higher thermal efficiency can be cost-effective due to the fuel savings. In the case of Arimasan Maru, replacing the four-cycle engine with a turbocharged two-cycle engine brought a huge improvement in fuel efficiency.

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Replacing of main engine

Fuel costs as a percentage of operating expenses increased markedly.
In the case of the Rhine Maru, the 40% savings in fuel offset even the high costs of replacing the main steam turbine with main diesel engine.

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Engine saving technology for engine plants

A broad range of technologies contribute to energy efficiency — higher efficiency diesel engines (increased maximum pressure in-cylinder, long strokes, improvement of turbochargers, derating, fuel atomizer for low load operaion, and so on), waste heat energy recovery systems (steam turbine power generator, use of cooling water, absorption refrigeration devices), shaft power generators, use of surplus electricity to,assist propulsion, improved efficiency of auxiliary machinery, and many more.

Considering that pre-war steam locomotive engines heat efficiency was less than 10%, the advancement of the energy conservation technology for vessel engines is nothing short of breathtaking.

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The quest for improved energy-efficient technology

In addition to energy-efficient technologies already in use, the future holds even greater promise as work continues on the main engine driven power generator (which can be used as a motor to use onboard surplus electricity to assist propulsion); power saving management (computer control to ensure the optimum division of load between the steam turbine power generation system and the main engine power generation system) and so on.

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