Maybach GO 5
The Maybach GO 5 engine was a high-speed diesel engine from Maybach-Motorenbau GmbH for installation in high-speed railcars of the Deutsche Reichsbahn Gesellschaft . It was the most common diesel engine in DR vehicles and shaped the development of the 302 kW power class of diesel multiple units for the Deutsche Reichsbahn Gesellschaft. The engines were created through further development of the engines used in the heavy-duty combustion engine railcars with diesel engines. The biggest difference to the predecessor vehicles was the design as a naturally aspirated engine . Even before the Second World War , there were numerous further developments with the type GO 6 used at the SVT Leipzig and SVT Cologne and with the GO 56 used with the type Ruhr . At the same time as its creation, the GO 5h type of the 210 hp multiple unit appeared . This engine was designed as a half version of the GO 5 as a six-cylinder engine. The engines were mainly used in railcars with electrical power transmission. After the Second World War, there were numerous further developments with the same external dimensions. The type GTO 56 was released as an exchange engine for the railcars remaining with the DB , and the 12 V 170 DR engine was produced in large numbers by ČKD Prague especially for use with the M 262.0 railcars and as exchange engines for the Deutsche Reichsbahn (1945-1993 ) remaining vehicles. The characteristic concept of the railcars equipped with this engine with the axle arrangement 2'Bo ', whereby the diesel engine was mounted in the running bogie, the electric traction motors in the drive bogie, lasted for about 30 years.
Structure and components
Basic structure
The housing for the motor is made of silumin and is divided into two parts. The upper part is the crankcase and guides the V-shaped cylinder liners and pistons. The lower part serves as an oil pan. The parting line between the upper and lower part is in the middle of the crankshaft. The upper and lower part are connected by 28 anchor bolts. Four nuts from these anchor bolts are designed as suspension eyes and are used to lift the motor. The engine has 12 cylinders that are arranged in a V-shape at an angle of 60 °.
The twelve individual cylinder liners are made of gray cast iron and are screwed to the upper part of the engine with side flanges. Each cylinder is controlled by an intake and exhaust valve mounted in the cylinder head. The fuel injection nozzle and a combined safety / decompression valve are also located in the cylinder head. The cylinder heads on the left cylinder side as seen from the flywheel each have a starting aid valve that can be pneumatically controlled. The cylinder heads are covered with a continuous hood made of aluminum.
The crankshaft is supported by seven ball bearings in the engine housing . The bearing of the main connecting rod with the crankshaft is also designed with ball bearings. The piston connecting rods used on the right cylinder side as seen from the flywheel are articulated to the main connecting rod in the shape of a fork. The connecting rods are connected to the pistons by a hollow piston pin. These are fixed in the connecting rod and slidingly mounted in the piston. The pistons are made of an aluminum-silicon alloy and have a total of six piston rings , the lowest of which is an oil control ring . In the first design, the crankshaft was designed without counterweights, later crankshafts with counterweights were used for better running.
The valves are designed to be suspended. They are each controlled by a camshaft mounted on each cylinder side with sliding bearings , the connection between the camshaft and the valves is established via rocker arms . On the valve side, the rocker arms are provided with hemispherical pressure pans, this guarantees central and low-wear actuation. The two camshafts are driven by the crankshaft via a gear train.
At the rear end of the engine, a friction vibration damper is attached to the crankshaft to connect the engine to the generator and the fluid transmission. A flywheel is attached to the front end of the crankshaft . Behind the flywheel driver is the gear for driving the gear drive for the camshafts and the lubricating oil pump, which is mounted in a removable cover in the lower part of the housing.
Fuel system and engine control
The engine works with direct fuel injection. On each cylinder side there is a diesel injection pump for the diesel injection system of the respective cylinder side. The injection pump was manufactured by the company Deckel and had a delivery piston for each cylinder on the side. The pump delivers the fuel via lines to the injection nozzles in the cylinder head. It was driven by the gear train and, depending on the speed, finely adjusted with a speed controller .
The diesel engine is controlled with speed regulation in four speed levels and one possible short-term overload level. The speed controller adjusts the filling linkage of the injection pump and works on the basis of oil pressure. It ensures the idling and maximum speed limitation and can set the injection pump to zero delivery at an oil pressure of less than 4.8 bar in the lubricating oil circuit and thus switch off the diesel engine.
The engine is started with the help of a battery-powered starter with hydraulic power transmission or the generator with electrical power transmission. The regulator sets the diesel injection pump to full delivery, which is regulated back to idle immediately after ignition. Alternatively, the engine can also be started pneumatically. The already mentioned starting valves are charged with compressed air via a starting distributor.
The engine has three tanks of 300 l each. These containers are attached to the ceiling of the machine room and connected to one another via a collecting line. The containers are filled through two filling lines on each side of the vehicle. The vehicle can be temporarily refueled with a hand pump.
Cooling and lubrication system
The motors are cooled with water. It can be assumed from the sectional photo that it is a cooling system with wet cylinder liners. The water spaces of the individual cylinders are connected to one another by cast-on nozzles and are filled from the cylinder head through a cooling water header. There is a drain valve at the lowest point of the water jackets.
The spur gears driven by the crankshaft drive a single-stage gear pump for the lubrication system of the bearings, connecting rods and cylinders. The oil sump is cooled by the fresh air drawn in for the combustion process.
Exhaust system
The combustion exhaust gases from the engine are fed to the muffler through two exhaust manifolds. It is hung transversely on the front of the machine bogie. An exhaust manifold leads from the muffler into the exhaust riser pipe , which is also hinged at roof height and connected to an ejector nozzle on the car roof. The riser is surrounded by two concentric protective pipes, between which used cooling air is discharged through the ejector nozzle with the exhaust gases over the roof. The ejector nozzle is hung at a suitable height above the car roof so as not to bother the travelers with the exhaust gases from the engine.
Technical specifications
| Parameter | unit | value | comment |
|---|---|---|---|
| rated capacity | kW | 302 | |
| Torque at nominal power | Nm | 2060 | |
| Rated speed | min -1 | 1,400 | |
| Idle speed | min -1 | 800 | |
| Number of cylinders | 12 | ||
| Cylinder diameter | mm | 150 | |
| Piston stroke | mm | 200 | |
| Stroke volume | cm³ | 42,412 | |
| Compression ratio | 15: 1 | ||
| mean piston speed | m / s | 9.3 | |
| medium work pressure | bar | 6.24 | |
| Injection pressure | bar | 200 | |
| highest ignition pressure | bar | 66.5 | with 5-hole nozzle |
| bar | 57 | with 4-hole nozzle | |
| Firing order | 1R-6L-2R-5L-4R-3L-6R-1L-5R-2L-3R-4L | ||
| Inlet valve diameter | mm | 72 | |
| Exhaust valve diameter | mm | 68 | |
| Minimum lubricating oil pressure | bar | 4.8 | |
| Fuel consumption | g / kWh | 250 | at full load |
| Oil supply | l | 45 | |
| Cooling water supply | l | 35 | |
| Engine ground | kg | 2,030 | with accessories, without supplies |
| Motor length | mm | 2,409 | |
| Engine width | mm | 1.106 | |
| Engine height | mm | 1,263 | |
| Material for crankshaft | St 29 | ||
| Material for connecting rod | VCN 25 | later St 30 | |
| Material for pistons | EC 124 | ||
| Material for cylinder liner | Special gray cast iron | ||
| Material for motor housing | Silumin | ||
| Procurement price | RM | 33,250 | with accessories |
Vehicles equipped with the engine for delivery
| model series | first delivery | Reichsbahn sketch sheet or type designation | Power transmission | Vehicle received | comment |
|---|---|---|---|---|---|
| DR 877 | 1932 | electric | j | Transport Museum Nuremberg | |
| DR 137 149… 232 | 1933 | SVT Hamburg | electric | j | Leipzig Central Station |
| DR 137 094 to 110, 137 164 to 223 | 1935 | Railcar with a standard layout | electric | j | Stralsund depot |
| DR 137 028 to 030 | 1934 | BC4ivT-32a | electric | n | |
| DR 137 031… 093 | 1934 | Railcar with an Essen layout | electric | n | |
| DR 137 058… 079 | 1934 | Railcar with express train car layout | electric | j | Railway depot at Berlin-Schöneweide station |
| DR 137 068 to 073 | 1934 | Railcar with a modified express train car layout | electric | n | |
| Railcar 905-930 | 1937 | Railcars similar to the 300 kW vehicles | hydraulic | j |
Operating experience
Although the GO 5 motors at Maybach-Motorenbau GmbH had already undergone a long period of development, teething troubles were not absent in everyday operation, especially since they were fully challenged when using the flying hamburger .
The roller bearings of the connecting rod with the crankshaft and the needle bearings of the connecting rod with the cylinder piston proved to be inadequate and had to be replaced by other roller bearings. Piston seizures occurred in everyday operation and on the engine test bench , for which the lack of preheating of the engine cooling water was originally assumed to be the cause. Since some piston jams occurred afterwards, the material of the pistons was changed to the aluminum-silicon compound, which was then exclusively used by Maybach. The piston material was harder and made it possible to save a bronze bushing for mounting with the connecting rod. For this purpose, the clearance of the piston in the cylinder has been increased.
The cylinder liners occasionally cracked, which were stopped by bandages. With the further developed engine types GO 6 and GO 56 , they were made stronger from the start.
In the most heavily loaded central crankshaft bearing, further damage to the roller bearings occurred during operation, with which the engine could initially continue to operate. As a remedy, however, screw-on counterweights were introduced, with the help of which around 80% of the rotating masses could be balanced. As a result of this renovation, the time between two repairs (damage or scheduled overhaul) could be increased from 33,000 km to 54,000 km.
In the early days, deficiencies were observed in the diesel injection pumps , which led to earlier injection times and large amounts of fuel at lower speeds. This was not critical for vehicles with electric power transmission. This fact was worse in the case of the railcars with mechanical power transmission , where excessive speeds when changing gears occurred when idling.
By January 1, 1937, a total of 146 engines had been produced for a wide variety of vehicle types.
literature
- Heinz R. Kurz: "The railcars of the Reichsbahn-Bauarten", EK-Verlag, Freiburg 1988, ISBN 3-88255-803-2
- Heinz R. Kurz: "Flying Trains", EK-Verlag, Freiburg 1994, ISBN 3-88255-237-9
Web links
Individual evidence
- ↑ Heinz R. Kurz: "From flying from Hamburg to flying from Cologne", EK-Verlag, Freiburg, ISBN 3-88255-237-9 , page 25
- ^ Heinz R. Kurz: "Flying Trains", EK-Verlag, Freiburg, ISBN 3-88255-237-9 , page 19, image 2605 d
- ^ Heinz R. Kurz: "The railcars of the Reichsbahn-Bauarten", EK-Verlag, Freiburg 1988, ISBN 3-88255-803-2 , page 258