BMW S85

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S85B50

The BMW S85 is a V10 naturally aspirated engine with 40 valves that was installed in the E60 / E61 M5 and E63 / E64 M6 . Some inspirations from the Formula 1 V8 engine (P86) of the BMW Sauber F1 racing car were incorporated into the design . The engine replaced the S62 engine from the previous M5 (E39).

The S85 unit was the basis for the development of the S65 V8 engine of the 2008 BMW M3 . This unit is basically an S85, from which two cylinders have been subtracted and has no relationship whatsoever with the other S60 V8 engines BMWs .

technology

The S85B50 is a high-speed engine, created to get a lot of power out of a wide range of speeds. Its maximum speed is 8250 min −1 , it achieves over 74 kW (100 hp) per liter and has a very high compression ratio of 12.0: 1, which exceeds the S62 engine of the previous M5 at 11.5: 1. The engine has an output of over 74 kW more than its predecessor, the BMW S62 , with only slightly higher weight.

  • 5 liter V10 cylinder naturally aspirated engine with 90 ° cylinder angle
  • Four overhead camshafts
  • Four valves per cylinder
  • 10 individual throttle valves with electronic throttle valve control (EDR)
  • M high pressure double VANOS (details see below)
  • Ion current knock control (see below for details)
  • Hydraulic valve clearance compensation with bucket tappets
  • Three-way catalytic converter
  • On-board diagnosis
  • Oil supply controlled by lateral force (quasi-dry sump)
  • Forged crankshaft with five crank pins, ignition angle 90 ° / 54 °
  • Forged and cracked trapezoidal connecting rods made of 70MnVS4 steel
  • Crankcase manufactured in bedplate technology (details see below)
  • Firing order 1-6-5-10-2-7-3-8-4-9

VANOS

The engine has a variable camshaft adjustment for intake and exhaust camshafts, which can continuously change the valve timing controlled by a map, which leads to better cylinder filling in all load and speed ranges. This means more power, improved torque curve as well as good responsiveness, reduced consumption and lower emissions.

Ion current measurement

The use of conventional knock sensors was viewed as critical by the engine designers. In order to be able to reliably detect knocking tendencies at the high speeds of this engine, the ion current measurement was used, which was developed by Saab for their "Trionic" engine control. A voltage of 400 V is applied to the spark plugs between the ignition processes. The measurement of the current flow provides information about pressure, temperature and ion density. Current peaks are a sign of uncontrolled combustion processes. These peaks are filtered out, counted and, if certain criteria are met, evaluated as knock indicators. With this technology, the engine can work with the high compression ratio of 12: 1, which reduces fuel consumption and increases torque and power.

Casting technique

With this engine, BMW used a bedplate construction for the first time in a standard V-engine. The aluminum bedplate with gray cast iron inlays ensures very precise crankshaft bearings, especially it keeps the main bearing clearance within narrow limits over the entire operating temperature range. The cast iron inlays reduce the strong thermal expansion of the aluminum housing. They were provided with openings so that they can form a positive connection with the surrounding aluminum frame. At the same time, this construction helps to meet the acoustic requirements of the engine.

Data

Engine type Displacement Bore × stroke compression Power at 1 / min Torque at 1 / min Maximum speed year
S85B50 5.0L (4999 cm 3 ) 92 x 75.2 mm 12.0: 1 373 kW (507 hp) at 7750 520 Nm at 6100 8250 min −1 2005-2010

use

Awards

The S85B50 in 2005 for the first time at the International Engine of the Year - Award nominated and won in the following years in different categories:

  • International Engine of the Year (2005 and 2006)
  • Best Performance Engine (2005, 2006 and 2007)
  • Best New Engine (2005)
  • Best Above 4.0 Liter (2005, 2006, 2007 and 2008)

Individual evidence

  1. ↑ a b The drive for the new BMW M5. Press release. BMW Group PressClub Germany, June 23, 2004, accessed on October 18, 2016 .
Timeline of BMW gasoline engines for passenger cars since 1961
Number of cylinders Conception 1960s 1970s 1980s 1990s 2000s 2010s
0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th
3 1.5 l B38
4th (1.5–2.0 l) M10
M40
M42
M43
M44
N40
N42
N45
N46
N43
N13
N20
B48
High performance motor S14
6th Small six-cylinder (2.0-3.0 l) M20
M50
M52
M54
Large six-cylinder (2.5-3.5 l) M30
N52
N53
N54
N55
B58
High performance motor M88
S38
S50
S52
S54
S55
8th 3.0-4.4 l M60
M62
N62
N63
High performance motor S62
S63
S65
10 High performance motor S85
12 5.0-6.6 l M70
M73
N73
N74
High performance motor S70
Number of cylinders Conception 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th 9 0 1 2 3 4th 5 6th 7th 8th
1960s 1970s 1980s 1990s 2000s 2010s