Mercedes-Benz OM668 engine
{{no footnotes|date=November 2017}}
{{Infobox automobile engine
| image = 1999 Mercedes-Benz A160 CDI Avantgarde in Mondsilver Met, engine.jpg
| aka =
| manufacturer = Daimler AG
| configuration = Inline-four engine
| production = 1997-
| predecessor =
| successor = Mercedes-Benz OM640
| bore = {{convert|80|mm|in|abbr=on}}
| stroke = {{convert|84|mm|in|abbr=on}}
| displacement = {{convert|1689|cc|L|1|abbr=on|disp=flip}}
| length =
| diameter =
| width =
| height =
| weight =
| block =
| head =
| valvetrain = DOHC 4 valves x cyl.
| supercharger =
| turbocharger = Single turbo with intercooler
| fuelsystem = Common Rail
| fueltype = Diesel
| oilsystem =
| coolingsystem = Water cooled
| power = {{cvt|44-70|kW|PS|0}}
| specpower =
| torque = {{convert|160-180|Nm|lbft|0|abbr=on}}
| compression =
| fuelcon =
| specfuelcon =
| oilcon =
| name = Mercedes-Benz OM668 engine
}}
The Mercedes-Benz OM668 engine is a {{convert|1689|cc|L|1|disp=flip|adj=on}} diesel inline-four engine manufactured by the Mercedes-Benz division of Daimler AG. It was used in the Mercedes-Benz W168 from 1997 to 2004 and the Mercedes-Benz W414 from 2001 to 2005.
Description
The OM 668 makes use of the common rail system. Compared to the otto engine M 166 it has 4 valves per cylinder instead of two. Two chain driven overhead camshafts are used. The intake camshaft is driven by a chain, the exhaust camshaft is connected to the intake camshaft with a gear. Another chain drives the oil pump from the crankshaft. All engines have a turbocharger and all engines with more than {{cvt|44|kW|PS|0}} also have an intercooler. In 1997 the OM 668 was the smallest diesel engine by Mercedes-Benz.
There are no mechanical differences between the engines, except from the {{cvt|44|kW|PS|0}} engine, which does not have an intercooler. In 2001, the camshaft and turbocharger were modified slightly. This increased the rated power, but not the torque, due to the weak clutch of the Mercedes-Benz W 168.
Without any physical changes to the engine, the power can be increased to {{cvt|88|kW|PS|0}} by simply changing the software of the ECU. This does not decrease the durability of the robust engine. Due to the increased torque of up to {{cvt|200|Nm|lbft|0}}, the clutch of the W 168 may wear out faster, if the rated power is increased.
The OM668 later developed into the Thielert Centurion 1.7 aero engine
Models
| class="wikitable"
| style="background:#CCCCCC;text-align:left" | Engine* | style="background:#CCCCCC;text-align:left" | Name | style="background:#CCCCCC;text-align:left" | Power | style="background:#CCCCCC;text-align:left" | Torque | style="background:#CCCCCC;text-align:left" | Model |
| OM 668 DE 17 A
|668.941 |{{cvt|44|kW|PS hp|0}} at 3600 rpm |{{cvt|160|Nm|lbft|0}} at 1500–2400 rpm |A 160 CDI (1997 - 2001) |
| OM 668 DE 17 LA red.
|668.940 red. |{{cvt|55|kW|PS hp|0}} at 3600 rpm |{{cvt|160|Nm|lbft|0}} at 1500–2800 rpm |A 160 CDI (2001 - 2004) and Vaneo CDI |
| OM 668 DE 17 LA
|668.940 |{{cvt|66|kW|PS hp|0}} at 4200 rpm |{{cvt|180|Nm|lbft|0}} at 1600–3200 rpm |A 170 CDI (1997 - 2001) and Vaneo 1.7 CDI |
| OM 668 DE 17 LA
|668.942 |{{cvt|70|kW|PS hp|0}} at 4200 rpm |{{cvt|180|Nm|lbft|0}} at 1600–3600 rpm |A 170 CDI (2001 - 2004) |
668 = engine series,
DE = Direkteinspritzung (common rail injection),
17 = approximate Displacement in dl,
A = Abgasturbolader (turbocharger),
L = Ladeluftkühler (intercooler),
red. = reduced power
Other applications
The OM668 is the basis for the Thielert Centurion 1.7 aircraft engine and for the engine of concept car Rinspeed Presto.
See also
Sources
- A-Klasse manual (MOPF 2001)
- [http://www.jesmb.de/engine.htm Technical data]
- [http://www.elchfans.de/aklasse_w168/a-klasse_w168.php?st=1 W 168/OM 668 on Elchfans.de]