Mercedes-Benz OM 668

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The OM 668 is a four-cylinder - Diesel engine ( in-line engine ) from Mercedes-Benz , which in 1997 from A-Class and from 2001 in the Vaneo was built. The successor model is the OM 640 .

technology

The OM 668 has common rail injection . He is in contrast to the same time built gasoline engine M 166 in four-valve technology run (16V). The valve control of the two overhead camshafts takes place via a control chain (duplex roller chain ), which drives the inlet camshaft; from there, a spur gear drives the exhaust camshaft. Another (single) roller chain connects the crankshaft with the oil pump. All variants are equipped with engine charging and - with the exception of the 44 kW / 60 PS engines - intercoolers . The then smallest diesel engine from Mercedes has a displacement of 1689 cm³ (bore 80 mm × stroke 84 mm).

In both models, the transversely installed engine drives the front wheels ( front-wheel drive ). As with the Otto engine, power is transmitted via a five-speed manual gearbox or a five-speed automatic.

variants

Motor (s) designation power Torque model
OM 668 DE 17 A 668.941 44 kW (60 PS) at 3600 rpm 160 Nm at 1500-2400 rpm A 160 CDI (until 2001)
OM 668 DE 17 LA red. 668.940 red. 55 kW (75 PS) at 3600 rpm 160 Nm at 1500-2800 rpm A 160 CDI (from 2001) and Vaneo CDI
OM 668 DE 17 LA 668.940 66 kW (90 PS) at 4200 rpm 180 Nm at 1600–3200 rpm A 170 CDI (until 2001) and Vaneo 1.7 CDI
OM 668 DE 17 LA 668,942 70 kW (95 PS) at 4200 rpm 180 Nm at 1600–3600 rpm A 170 CDI (from 2001)
(s)The engine designation is coded as follows:
M: engine, OM: oil engine, series: 3-digit, E: intake manifold injection, KE: port injection, DE: direct injection, ML: compressor, L: charge air cooling, A: exhaust gas turbocharger, red. : reduced performance / displacement, LS: performance increase

Mechanically, the engines are all the same, but the first A 160 CDI does not have a charge air cooler. For the facelift, only the camshaft and the turbocharger were revised, which is why the output increased slightly. The torque did not increase because the A 170 CDI was already throttled in terms of the weakly dimensioned clutch .

With this throttling, the power can be increased to around 88 kW (120 PS) and the torque to over 200 Nm with just a few interventions in the engine electronics ( chip tuning ). The engine's already long service life does not suffer from this; The A-Class clutch, which is considered weak, is exposed to very high loads.

Others

The aircraft engine manufacturer Thielert offers a version of the OM 668 adapted for aviation under the name Thielert Centurion 1.7 . This is the first new development of an aircraft engine for civil aviation since Porsche became involved .

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