Designed for the economical & reliable propulsion of small and medium-sized vessels
The Wärtsilä X35 engine provides excellent power and speed reliability for a wide variety of ship types, such as handysize bulk carriers and product tankers, general cargo vessels, reefers, feeder container ships, and small LPG carriers.
Available in 5-cylinder up to 8-cylinder configuration, the Wärtsilä X35 low-speed engine covers a power range from 3,475 to 6,960 kW at 142 to 167 rpm.
The Wärtsilä X35 is fully compliant with IMO Tier II requirements. It can also be equipped with a SCR catalyst to meet IMO Tier III NOx emission levels, and a scrubber to reduce SOx emissions to 0.1% – even with high sulphur fuels.
The introduction of the EEDI index also puts an emphasis on CO2 emissions and total vessel efficiency. The internal engine efficiency of Wärtsilä X35, and the possibility to apply various Power Take Off (PTO) arrangements for onboard electricity production, make it easy for shipyards to meet these new requirements.
The main targets when designing the Wärtsilä X35 was the powering of vessels with shallow draught requirements, compact engine dimensions and simple engine operation.
|Wärtsilä X35||IMO Tier II|
|Cylinder bore||350 mm||Fuel specification:|
|Piston stroke||1550 mm||Fuel oil||700 cSt/50oC|
|Speed||142-167 rpm||ISO-F 8217:2005,|
|Mean effective pressure at R1||21.0 bar||category ISO-RMK700|
|Piston speed||8.6 m/s|
|Rated power, principal dimensions and weights|
|Cyl.||Output in kW at||Lenght A
|167 rpm||142 rpm|
|5||4 350||3 475||3 700||3 475||4 434||74|
|6||5 220||4 170||4 440||4 170||5 046||84|
|7||6 090||4 865||5 180||4 865||5 658||95|
|8||6 960||5 560||5 920||5 560||6 270||105|
|2 264||830||5 556||1 220||6 850||1 326|
* Standard piston dismantling height, can be reduced with tilted piston withdrawal.
|Brake specific fuel consumption (BSFC) in g/kWh|
|Part load, % of R1||85||70||85||70||60|
Dimensions and weights
- All dimensions are in millimetres and are not binding.
- The engine weight is net in metric tonnes (t), without oil and water, and is not binding
- All brake specific fuel consumptions (BSFC) are quoted for fuel of lower calorific value 42.7 MJ/kg, and for ISO standard reference conditions(ISO 15550 and 3046).
- All given BSFC figures for Wärtsilä engines are given with a tolerance of +5% across 40–100% of engine load.
For engines Wärtsilä X62/72/92 & RT-flex82T-B, RT-flex58T-D ER-3, stepwise tolerances are now introduced for the brake specific fuel consumption (BSFC):
- 5% tolerance for 100% to 85% engine load
- 6% tolerance for 84% to 65% engine load
- 7% tolerance for 64% to 25% engine load
Standard Tuning, Delta Tuning, Low Load Tuning are available for the electronically-controlled common- rail engines providing optimum fuel consumption and flexibility for different engine loads.Delta Tuning focuses on reducing fuel consumption in the operating range below 90% engine load. Low Load Tuning reduces fuel consumption below 75% engine load.
Rating points for Wärtsilä low-speed engines
The engine layout fields for Wärtsilä low-speed engines are defined by the power/ speed rating points R1, R2, R3 and R4 (see diagram). In certain engines, the layout field is extended to the points R1+ and R2+. R1, or R1+ instead if applicable, is the nominal maximum continuous rating (MCR). Any power and speed within the respective engine layout field may be selected as the Contract-MCR (CMCR) point for an engine.
ISO standard reference conditions
- Total barometric pressure at R1: 1.0 bar
- Suction air temperature: 25 °C
- Relative humidity: 30%
- Scavenge air cooling water temperature: 29 °C
All Wärtsilä low-speed engines are fully compliant with IMO Tier II NOX limits specified in Annex VI of the MARPOL 73/78. They can also be equipped with a SCR catalyst to meet IMO Tier III NOX emission levels and a scrubber to reduce SOX emissions to 0.1% – even with high sulphur fuels.
The Pulse Lubricating System with electronic control of lubrication timing has been further developed. It is available for all Wärtsilä Generation X, Wärtsilä RT-flex and for selected Wärtsilä RTA engines. The guide feed rate for new engines equipped with Pulse Jet cylinder lubrication system is 0.6g/kWh. Engines with different Lubricating Systems might require a higher feed rate. This allows important savings in engine operating costs.
Wärtsilä common-rail system
With the common-rail system, fuel oil, servo oil and control oil are delivered at regulated pressures to rail pipes arranged along the side of the cylinders. Electronic control units then regulate delivery from these rail pipes for fuel injection and exhaust valve operation.
In this way, the Wärtsilä low-speed engines have complete flexibility in fuel injection timing, rate, pressure and volume, as well as in exhaust valve operation. This provides engine operational benefits that cannot be obtained with mechanically-controlled systems.
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