What is a Lambda Control System in Marine?
With new, stringent pollution control regulations in place, manufacturers must design marine engines that meet these standards and do not compromise normal operation. To achieve this, engines incorporate various automated systems that not only reduce pollution levels but also improve efficiency and reduce other operating costs.
A Lambda Control System is one such system that controls the fuel injection system of a marine engine in response to load changes.
USS Midway – Largest Museum Ship In United States
Purpose of Lambda Control Unit
The primary function of any engine is to provide enough power to support the load placed on it. Loads may increase or decrease during operation, and for this purpose, excess fuel may be added to maintain performance.
A Lambda Control Unit is used to control the injection of excess fuel into the combustion chamber of a marine engine when the engine load changes (i.e., when the load temporarily increases).
This is achieved by controlling the two main components responsible for combustion: fuel and air. The controller monitors the relationship between charge air pressure and the engine fuel ratio at this load.
Working principle
The working principle of the Lambda controller is shown in the following figure:
When the engine load increases suddenly and momentarily, the Lambda controller regulates the fuel flow through the injection pump via the adjustment rod. To do this, it activates (1), which in turn commands the switch (2) to contact the piston rod (3) and push it downwards, thus closing the circuit.
As a result, the solenoid valve (4) opens, triggering the injection system to accelerate the turbocharger and increase the charge air pressure. This pushes the piston (3) back into the Lambda cylinder (5). When the Lambda value or ratio is reached, the solenoid valve closes, deactivating the injection system.
If the system is left running for more than 10 seconds, the solenoid valve activates, triggering a system fault alarm.
Fuel consumption limitation during start-up
During start-up, the Lambda controller acts as a fuel consumption limiter.
This prevents excessive smoke and too fast throttle response during start-up.
Advantages
- Reduces excessive visible smoke emissions when the engine load increases suddenly.
- Improves overall engine efficiency.
- Reduces carbon deposits in the engine exhaust system (exhaust valves, exhaust pipes, exhaust inlets, etc.).
- Reduces maintenance costs by reducing dirt accumulation on parts.
