ACERT Technology: How Caterpillar Engines Meet Current and ...

We have defined our first and immediate goal in migrating of the ACERT ®
emission technology to the MaK engine as follows:
• Demonstrate NOx levels 30 % below the current IMO rules with advanced,
ACERT ® combustion technology without any external systems or complex
additions to the engine design but maintain the excellent fuel efficiency, a
distinguishing feature of the MaK engine.
• Achieve invisible smoke over the whole operation range, particularly important
for passenger ships and frequent operation in emission sensitive areas
such as coastal waters.
You will recognize that the key elements of medium-speed ACERT ® Technology
are very similar to their high-speed counterpart.
Superior integration continues to be the main differentiator. It combines key
technologies such as combustion, fuel injection, turbocharging, and valve control.
Our endeavor was, to quickly leverage the ACERT ® specific flexibility in the
rugged marine environment by using readily available, simple, proven and
reliable components. The enabler is called the Flex Cam Technology.
But let us highlight the key features in more detail:
1. The starting point: The combustion system benefits from the long-stroke
technology, the foundation for clean combustion and high fuel efficiency,
distinguishing feature of the MaK engine against the rest of the industry.
2. The variable injection intensity is key for good combustion and invisible
smoke at low load. It improves atomization and fuel distribution. The injection
characteristic is modified at low load by the simple and reliable eccentric
cam mechanism - the Flex Cam. As our engines are designed to burn
heavy fuels of lowest quality, we have decided to maintain - for the time being
- the robust mechanical injection, capable to deliver fuel at pressures
beyond 1600 bar. Hydraulically actuated fuel systems with equivalent capability
are under development and will be applied in a next step, as you
will hear later on.
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