When looking at Sulzer engine’s specifications, there is always some ambiguity. MAN B&W is very clear with its specifications, however Sulzer never gave one. That doesn’t mean MAN B&W is better than Sulzer engines.
Sulzer AG, a Swiss company, started in 1834 by the Sulzer brothers.
Want to know who were Sulzer Brothers?
It’s Mr.Salomon Sulzer and Mr. Bernet who formed Sulzer Brothers Limited first in 1775 and then established as Sulzer Ltd. A known employee of Sulzer was Rudolf Diesel, who invented the Diesel Engine.
In 1990, Sulzer spun off the diesel engine division into a separate company named “New Sulzer Diesel” (NSD) and sold most of the shares. In 1997 NSD was absorbed by Wartsila, creating Wartsila NSD.
The Sulzer brand among seafarers particularly known in connection with the Sulzer RTA engines, the most reliable series of Sulzer engines that was first built in 1982.
Other engine types that are still in use, the RND, RND-M and the RL series. Wartsila Sulzer RTA96-C, the biggest engine in the world and the 14 cylinder RT-flex 96C delivers a total output of 108,920 hp at 102 rpm. The machine is over 23 meters long. Below table shows complete series of engines which Sulzer has developed over a century.
| Year | Type of Engine | Cylinder diameter in cm |
| 1908 – 1931 | S | 18 – 90 |
| 1908 – 1932 | Z (ZA, ZF, ZPF, ZT) | 52,60,65,68,72,76 |
| 1929 – 1937 | DZ (DZL, DZD) | 60,70,76 |
| 1929 – 1937 | SN | 48 |
| 1930 – 1946 | DS (DSD, DSDT, DSDG, MSD, KD) | 53,60,70,72,76 |
| 1932 – 1964 | SD (SDT, SPD, MS, KD, SDS, SDH, SF) | 36,40,48,49,56,58,60,65,68,72,76 |
| 1934 – 1954 | ZD (ZDA) | 58,76 |
| 1950 – 1963 | RS (RSD, RSG, RSAD) | 58,76 |
| 1950 – 1963 | SAD | 60,72 |
| 1956 – 1987 | RD (RD, RF) | 44,56,68,76,90 |
| 1967 – 1981 | RN (RND, RNF, RNMD) | 68,76,90,105 |
| 1976 – 1989 | RN M (RND M, RNF M) | 68,76,90 |
| 1977 – 1988 | RL (RLA, RLB) | 56,66,76,90 |
| 1982 – | RT (RTA,RTA M, RTA C, RTA U, RTA T) | 38,48,52,58,62,68,72,76,84,96 |
| 1998 | RT Flex | 48,50,58,60,68,82,84,96 |
The letter ‘R‘ in the engine designations goes back to the Sulzer RSD two-stroke low-speed engine types introduced in 1950. The letter ‘R‘ stood for ‘Revidierter’, so the RSD types were ‘revised’ versions of the SD engine types that had been developed since 1930. Built in two bore sizes, 58 and 76cm, the RSD engines were the first two-stroke low-speed engines designed and built by Sulzer that had fully welded structures (columns and bedplates). Turbocharged versions followed in 1956 with the RSAD engine types.
The letter ‘R‘ was then retained over the following years in the RD, RND, RND..M, RLA, RLB, RTA and RT-flex engine types. Yet after the RSD and RSAD designations, the letter lost any connotation of ‘revised’. It was simply kept as an easily-recognised identifier for Sulzer low-speed engines. When electronically-controlled common-rail systems were applied in 1998, the designation RTA was adapted to RT-flex to emphasise the key feature of flexibility given by the new technology.’
| Parameters | RD | RND | RTA | RT-FLEX |
| Turbocharger | Pulse (No auxiliary Blower) | Constant Pressure | Constant Pressure | Constant Pressure |
| Scavenging | Loop | Loop and Under piston space | Uni flow | Uni flow |
| Exhaust valve | Rotary flap valve | Exhaust ports | Hydraulic operated | Hydraulic operated |
| Stroke Bore Ratio | 1.7 | 1.7 | 3 to 4.2 | |
| Piston | Convex shape | Convex shape | Concave shape | Concave shape |
| Piston cooling | Water | Water | Oil | Oil |
| Fuel pump | Suction valve control, no spill valve | Suction valve and spill valve | Suction valve, spill valve and VIT | Common rail system (jerk type) |
| Drive | Chain | Gear | Gear | Gear |
| Cylinder Lubrication | Mechanical drive | Mechanical drive | Load dependent, Electric motor driven | |
| Cylinder quills | Quills at upper part | Quills only at upper part | Quills at two level | |
| Cross head bearing | Two piece type | Two piece type | Continues bottom half type | Continues bottom half type |
| Piston skirt | short | Long | Short | Short |
| SFOC | 208 g/bhp/hr | 203 – 208 | 115 | 118 |
| MEP | 8.6 | 10.6 – 12.3 | 17 | 19.5 |
| Peak Pressure | 76 bar | 84 – 94 bar | 140 bar | 150 bar |
| Power/ cycle | 1700 KW | 2100 – 2500 KW | 3700 KW | 2100 – 5720 KW |
| Piston Speed | 6.1 m/s | 6.3 | 8 | 8 – 8.5 |
Wartsila v/s MAN Marine Engines- Who’s is the best ?
The stronger the marine engine, the better is the ship’s propulsion power and speed. When it comes to selecting marine engines for ships, there are only a few countable names in the market, including MAN B&W and Wartsila.In this article we are going to compare the two most powerful marine engine brands in the maritime industry.As discussed in one of our previous articles, the Most Popular Marine Propulsion Engines , MAN Diesel Turbo (previously known as MAN B&W) and Wartsila (Previously known as SULZER) are the two front-runner giants for supplying propulsion solution to the shipping industry.Wartsila & MAN both are in fact two rivals who have the best products and R&D in the industry. In this article, we will compare the different propulsion technologies provided by these two companies and will list out which technology has got the edge over the other.Note: This comparison is derived and compiled after taking views from professional marine engineers who have worked on both of these engines. However, this is not a yardstick for selecting marine engines for a ship.
Wartsila v/s MAN Marine Engines
| Technology/ System | Wartsila SULZER | MAN Diesel Turbo | Who gets the EDGE? |
| Intelligent Engine | RT Flex- A complete electronically controlled engine with common rail system | ME Engine- Complete electronically controlled engine integrated with hydraulic control. | Wartsila- For installing an Intelligent engine technology in 2001. Prior to MAN (2003). |
| Fuel Injection System | Common rail Electronic control with Delta Injection System | Hydraulic actuated Electronic Control Injection system | Wartsila- For integrating Delta control with 3 injectors controlled independently for different load. |
| Exhaust Valve Control | Electronically controlled variable exhaust valve timing | Camshaft operated Exhaust valve for reliable operation | MAN- For integrating a smart mechanical exhaust valve operation in Intelligent engine for reliable operation. |
| Fuel Injectors | Conventional fuel injectors | Zero Sac Volume type fuel injectors with slide valve | MAN- Slide type fuel injector reduces after burning and hence NOx emission |
| Fuel Pump | Spill, suction valve controlled pump with VIT | Jerk type plunger barrel controlled pump with Super VIT | MAN- Super VIT with independent injection timing control w.r.t fuel index. |
| Starting Air system | Starting air valve opened by 30 bar air and a closing supply for positive shut along with spring.A relief valve in air manifold to avoid overpressure during starting airline explosion. | Starting air valve open by 30 bar air and shut by spring.Bursting disc provided to avoid overpressure during explosion | Wartsila- Additional safety provided in positive closing and relief valve for reliability during manoeuvring. |
| Piston and Rings | Convex shaped piston with Jet Shaker cooling.Chromium coated Piston ring. | OROS type Piston for better combustion area and reduction in piston temperature.Controlled Pressure Relief type top piston ring. | MAN-With OROS piston, the Maximum piston temperature reduces by 90°C.With CPR ring, better pressure distribution on liner and lower ring. |
| Cylinder Liner | Fine honed and bore cooled Liner with mid layer insulation. | Bore cooled liner. | Wartsila- Better cooling and insulation increases Cylinder liner Life |
| Main Bearing | White metal bearing lined on thin back. | Tri metal bearing with high load carrying capacity. | MAN-Tri metal bearing with long life and better embed ability. |
| Crosshead | 12-15 bar pressure from separate pump supplied to bigger size plain bearing. | Small size bearing with oil wedges to retain oil which is supplied by normal system pressure. | Wartsila-Elevated pressure ensures better lubrication at high load.A backup line is provided in case of failure of crosshead pump. |
| Cylinder Lubrication | Electronically controlled Pulse Lubrication System with metered quantity injection | Alpha Adaptive Cylinder Lubrication control system allowing blending of cylinder oil for different grade of sulphur in fuel | MAN- ACC with different inputs like sulphur content and load index provide better neutralizing features. |
| Drive | Gear driven with timing gear driving the camshaft | Chain driven with 2 chains driving a camshaft | MAN- Chain drives are cheaper, lighter and easier to maintain and duplication provides backup. |
| Turbocharging | Prefers Axial turbocharger with constant pulse system. | Variable Turbine Angle turbocharger provides better operation at all load range | MAN-VTA allows engine to run without auxiliary blower at low load operation. |
| Exhaust Valve | Conventional Valve seat with Nimonic and Stellite coating | W seat for better operation and increased time between overhaul.Dura spindle with better heat resistant property. | MAN- W seat allows cooling of exhaust valve during combustion stroke |
| Miscellaneous | Tribo pack allows increased time between overhaul of cylinder component up to 3 years.Electronic monitoring system for safe operation | Electronic monitoring system for safe operation. | Wartsila- With Tribo pack which is a package of design measures increases the TBO to 3 years. |
From the above comparison, it can be seen that MAN has
an edges over Wartsila by a thin margins.
However, with the world’s most powerful marine engine (Wärtsilä RT-flex96C) in its basket, Wartsila is one company that doesn’t have to prove anything.
