Mercedes-Benz OM 601 / OM 602 / OM 603 diesel engine

Mercedes Benz
OM 601, OM 602, OM 603
Manufacturer:	Mercedes Benz
Production period:	1983-2001
Style:	Line four-cylinder OM 601  -line five-cylinder OM 602  -line six-cylinder OM 603
Engines:	2.0 liters (1997 cc)  2.2 liters (2197 cc)  2.3 liters (2299 cc)  2.5 liters (2497 cc)  2.9 liters (2874 cc)  3.0 liters (2996 cc)  3, 5 liters (3449 cc)
Previous model:	OM 615 (4-cylinder)  OM 616 (4-cylinder)  OM 617 (5-cylinder)
Successor:	OM 604 (4-cylinder)  OM 605 (5-cylinder)  OM 606 (6-cylinder)

The OM 601 by Mercedes-Benz is a four cylinder - diesel engine with indirect injection , the 1983 mid-size model 190 D was introduced. The inline engine is technically closely related to the five- and six-cylinder derivatives OM 602 and OM 603 , the u. a. also in the series W124 (predecessor of today's E-class) were used.

The engine block is made of cast iron, as in its predecessor with dry cylinder liners made of centrifugal casting , and the cylinder head made of light metal . A duplex timing chain drives the series injection pumpfrom Bosch and an overhead camshaft , which per cylinder, two valves via tappets with hydraulic lash adjuster operated. Mixture preparation takes place in prechambers with ball heads, glow plugs and surface pin injectors.

The OM 601 is not only much more compact than its predecessor OM 615, but also significantly lighter. Compared to the previous series, the engine block has been made more modern, with more stiffening ribs and thinner walls pulled down over the center of the crankshaft. The OM 601 is 49 kg lighter than the OM 615 (with oil and water). In addition, it offers higher torque and higher peak power with lower fuel consumption and pollutant emissions.

The OM 602 and OM 603 engines differ from the OM 601 only in the larger number of cylinders. All basic dimensions as well as cylinder bore and stroke are the same (except for the larger displacement versions). They also have an identical liter capacity and almost the same curve of the torque curve. All pistons, connecting rods, pre-chambers and injection nozzles are identical.

The three engines are from the start of production equipped with a so-called serpentine drive: the ancillaries (fan, water pump, alternator , steering servo pump and, if necessary, air conditioning ) are driven by a V-ribbed belt with automatic tensioning device instead of several V-belts.

By a motor-remote encapsulation, the noise emissions of vehicles equipped with the new engines are particularly low; less than half as loud as comparable drives. 

Noteworthy is also the thermostat - controlled fuel preheating through a coolant-to-fuel heat exchanger , which is available in all OM601 to OM603 engines. As a result, clogging of the fuel filter with solid flocculations from the diesel fuel is almost impossible even in wintry conditions.

The engines OM 601 to 603 with the robust Bosch In-Line Injection Pumps (R-ESP) can not only be operated with biodiesel , but also without major modifications with vegetable oil (such as rapeseed oil ). The injection start should then be adjusted to the tougher fuel, ensuring reliable operation up to +5 C °.

History 

The OM 601 was introduced in 1983 in the 190 D series. From 1984 he was also installed in the 124 series . Here, the larger variants OM 602 and OM 603 were also used, which drove the models 200 D, 250 D and 300 D and thus replaced the predecessors OM 615, OM 616 and OM 617 .

Initially, all engines of this series were only available as a naturally aspirated engine , later versions with turbocharging were added. These turbos had a striking feature in the Series 124 and 201 Passenger Cars: the intake air demand was so great that the normally installed air duct in the engine compartment did not function adequately. A young development engineer suggested the conspicuous feature of the "gill slits" in the front right fenderto grab. The 190 D 2.5 Turbo five-cylinder six gill slots were inserted; in the larger Mercedes 300 D Turbo six-cylinder, there were five, each in the right front fender in front of the wheel. With turbocharging, the smaller engine delivers 90 or 93 kW (122 or 126 hp), the large three-liter initially 105 kW (143 hp), later 108 kW (147 hp). Later also Saugdieselmodelle were delivered with gills.

Versions with 15% more displacement were available for use in transporters ( T 1 ) and as industrial engines. The six-cylinder OM 603 engine with turbocharging was also installed in the passenger car of the S-Class 126 series for the USA . Later, it was used with increased displacement (3.5 L) in the 126 series and in the subsequent 140 series.

As part of the "Diesel '89" development program, all engines of the OM 601 to 603 series were modified. Particulate emissions have been reduced by about 40 percent by improving the combustion process. As a result, they now worked virtually smoke-free and fulfilled the strict particle limits in the USA even without particulate filters . This success was achieved by a newly designed pre-chamber with oblique injection , which ensures more efficient combustion. In addition, the injection pumps receivedAll diesel naturally aspirated a height correction can to keep emissions low even at high altitude. These modifications also slightly increased performance. An optional oxidation catalyst coupled with exhaust gas recirculation further reduced exhaust emissions. 

Direct injection engine OM 602 DE 29 LA 

Over time, the engines of this series have been modernized and gradually replaced in 1993 by the types OM 604, OM 605 and OM 606 with four valves per cylinder, which there was also some with turbocharger. However, the proven prechamber injection was retained, with the exception of the E 290 210 and T1N (Sprinter) turbo diesel. This had a direct injection variant of the OM 602 with EDC distributor injection pump from Bosch .

The five-cylinder engine type OM 602 DE 29 LA (OM 602.982) with a displacement of 2.9 liters takes an exceptional position. It was installed in the early years of the E-Class 210 and in the T1N (Sprinter) with turbocharging and intercooling. This was the first Mercedes passenger car diesel with direct injection, however still without common rail system (CDI) and four-valve technology. Despite pilot injection and very restrained power design, the engine had the typical loud noise of a first-generation direct injection engine. To reduce the noise level was a much more extensive insulation than before necessary.

The engine was installed in the E-Class 210 with 95 kW (129 hp), in the G-Class with 88 kW (120 hp) and in the Sprinter truck with 90 kW (122 hp), as well as in the Unimog U90 (408 ) and UX100 (409).

Licensed construction OM 662 

For the SsangYong Motor Company in Korea Musso, Korando and Rexton have developed another offshoot of this engine, which was manufactured under license by Ssangyong. It is based on the OM 602 DE 29 LA, but was upgraded to prechamber injection and was given the name OM 662. This engine was not used by Mercedes-Benz itself, but it is there in the spare parts program. The engine was offered with (88 kW) and without turbocharger (70-72 kW).

From 2004 SsangYong modified the engine on its own: It was reduced to 2696 cc (86.2 × 92.4) and converted to four-valve technology including common-rail direct injection. So the engine has now 121 kW (165 hp) and has a torque of 340 Nm in a speed range of 1800-3250 / min.

Technical Data 

Four-cylinder 

Five-cylinder

Six-cylinder