BMW M51

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BMW
BMW M51 in an E36 from 1993

BMW M51 in an E36 from 1993
M51
Production period: 1991-2000
Manufacturer: BMW
Working principle: diesel
Motor design: Inline six-cylinder
Valve control: OHC
Displacement: 2497 cm 3
Mixture preparation: Swirl chamber injection
Engine charging: turbocharger
Power: 85 - 105 kW
Max. Torque: 222-280 Nm
Previous model: BMW M21
Successor: BMW M57

The BMW M51 is an in-line six-cylinder diesel engine from the car manufacturer BMW . The swirl chamber engine with distributor injection pump was produced in series from 1991 to 2000; pre-series production started on April 2, 1990 at the BMW plant in Steyr . The predecessor is the M21 , the successor is the M57 , a common rail diesel with direct injection , which has been produced since 1998 .

technology

M51 engine without charge air cooler, recognizable by the intake air duct. From the intake manifold, the pipe does not lead down to the intercooler, but bends directly to the side towards the exhaust side of the engine.

The M51 is a water cooled turbocharged inline six-cylinder - diesel engine with Bosch VP20- swirl chamber injection . Some engine variants have an intercooler in addition to the turbocharger; these engines can be recognized in BMW vehicles by the tds logo . The M51 has a from gray cast iron produced engine block and a chain-driven overhead camshaft , two valves per cylinder actuated. Unlike its predecessor, the M51 has hydraulic valve clearance compensation with hydraulic valve lifters . The bore and stroke of all engines are 80 × 82.8 mm, which results in a displacement of 2497 cm³, but BMW also specifies 2498 cm³ in its operating instructions. The compression of the engine is 22: 1. The fuel injection is controlled by the Bosch DDE 2.1 engine control unit .

The engine was also used in the Opel Omega and replaced the four-cylinder turbodiesel engine with a displacement of 2.3 l. Opel praised the smooth running, the high torque at low engine speeds and the low fuel consumption at the same time. In this version, the diesel engine had exhaust gas turbocharging with charge air cooling as well as electronically controlled injection, exhaust gas recirculation (recirculation rate up to 35% of the total volume flow) and an oxidation catalytic converter with a volume of 1.8 l, tailored to this engine. The maximum boost pressure of the exhaust gas turbocharger was 1 bar. With 38.5 kW per liter of displacement, a remarkable power density was achieved. In addition to reducing nitrogen oxide emissions , the charge air cooling also reduced the thermal load on the engine. The last BMW M51 for the Opel Omega was produced on November 27, 2000.

With the introduction of diesel engines in the 7 series ( BMW 725tds ) in April 1996, there was a revised version of the M51D25 OL , the M51D25TÜ OL (TÜ = technical revision). This engine achieves the highest torque of 280 Nm at a speed of 2200 min −1 . The increase in maximum torque by 20 Nm was achieved through a series of detailed improvements: Injection and mixture formation were re-tuned and the exhaust gas turbocharger was further developed thermodynamically. In addition, the air mass supplied to the engine is no longer determined via boost pressure and charge air temperature, as was previously the case, but directly via a hot-film air mass meter . The digital diesel electronics (DDE) are now networked via the CAN bus .

Oil with a viscosity of SAE 5W-40 is recommended for lubricating the engine .

Data

engine Displacement Bore × stroke Power at min −1 Torque at min -1 construction time
M51D25 UL 2.5 l (2497 cm³) 80 mm x 82.8 mm 85 kW (115 PS) at 4800 222 Nm at 1900 1991-1997
M51D25 OL 105 kW (143 hp) at 4800 260 Nm at 2200 1991-1996
25 DT A 96 kW (131 PS) at 4500 250 Nm at 2200 1994-2000
M51D25TÜ UL 85 kW (115 PS) at 4800 230 Nm at 1900 1996-1998
M51D25TÜ OL 105 kW (143 hp) at 4800 280 Nm at 2200 1996-1998
M51D25TÜ OL 105 kW (143 hp) at 4600 1998-2000
M51D25M1 B 100 kW (136 hp) at 4400 270 Nm at 2300 1994-2001

UL and OL stand for lower and upper performance level.

A.Only for Opel Omega B

swell

commitment

M51D25 UL
  • 2.5 l (2497 cm³), 85 kW, 222 Nm
M51D25 OL
  • 2.5 l (2497 cm³), 105 kW, 260 Nm
    • 1993–1996 BMW E36 325tds
    • 1991–1996 BMW E34 525tds
M51D25TÜ UL
  • 2.5 liters (2497 cm³), 85 kW, 230 Nm
    • 1996–1998 BMW E36 325td
M51D25TÜ OL
  • 2.5 liters (2497 cc), 105 kW, 280 Nm
    • 1996–1998 BMW E36 325tds
    • 1996–2000 BMW E39 525tds
    • 1996–1998 BMW E38 725tds
25 DT
  • 2.5 liters (2497 cm³), 96 kW, 250 Nm
M51D25M1

Individual evidence

  1. ↑ M51 goes into pre-production at the Steyr plant
  2. ↑ Information on M41 engines. Engine data at bmwheaven.com
  3. ↑ BMW E38 7 Series 725 tds technical data
  4. ↑ a b c d The BMW sport diesel: From 524td E28 to 530d E39 to BMW M550d F10
  5. ↑ a b c d e f g h Etzold: This is how it's done: care - wait - repair. Volume 102, BMW 5 Series E39 Delius Klasing Verlag. Pages 12 and 13
  6. ↑ a b c d e f g Heinz-Ewo von Brand, Karlheinz Breitwieser, Ekkehard Giebel, Eckhard Zickwolff: The engines in the new Opel Omega . In: MTZ Motortechnische Zeitschrift . No. 4 , April 1994, ISSN  0024-8525 , pp. 198-206 .
  7. ↑ BMW AG (Ed.): Discontinued M51 for Opel, Steyr . The last 6-cylinder turbodiesel M51 is produced for the Opel Omega. November 27, 2000 ( bmw-grouparchiv.de [accessed on February 13, 2017] archive signature FJ-1458-1).
  8. ↑ BMW: Series 7 with diesel engine . In: MTZ Motortechnische Zeitschrift . No. 2 , February 1996, ISSN  0024-8525 , p. 70 .
  9. ↑ Overview of engine oil qualities . Page 7
  10. ↑ Automobile Catalog: 1997 Range Rover 2.5 DSE (model for Europe) specifications & performance data review . Retrieved May 1, 2016