Wärtsilä 46F is the latest in the marine engine 46 series originally launched in 1987. The new features include common rail injection and integrated controls enabling to achieve high performance and low exhaust emissions, regardless of fuel quality. It is particularly suited to applications, which demand an optimum space layout, savings in operating and maintenance costs, environmental performance and fuel adaptability. The new engines initially cover the output range from 7500 to 11,250 kW at 600 rpm in 6-, 7-, 8- and 9-cylinder in-line configurations. The 1250 kW cylinder output results in a high power-to-weight ratio.

This higher output has been achieved by increasing engine speed instead of mean effective pressure, using the latest developments in turbocharger technology for efficiency and environmental optimisation. In full-load operation, early closure of the inlet valves makes it possible to use a low effective compression ratio, resulting in a work cycle characterized by low combustion air temperature, which keeps the rate of NOx formation low. The high output also contributes directly to operational and maintenance savings. According to Wärtsilä, many typical single main engine applications, such as general cargo vessels and container feeder vessels, could benefit from using the 46F main engine with one or two fewer cylinders compared to current ship designs (e.g. 7-cylinder compared to 9-cylinder main engine), yielding maintenance savings in the region of 20%.

The 46F engine has modular built-on systems and features such as lubricating oil module with oil cooler and filter, crankshaft driven lubricating oil pump and cooling water pumps, and thermostatic valves. Apart from minimizing installation cost, built-on modules contribute to the engine's compact design resulting in the same outer dimensions as previous 46 engines while offering considerably higher power output. According to the company, 46F are the first engines to have continuous temperature monitoring of the big end bearings as standard. This, in addition to main bearing temperature monitoring and exhaust gas temperature monitoring, provides a complete set of reliable real-time data to monitor the engine performance - a prerequisite for Condition Based Maintenance that is becoming the standard in maintenance practice today.