Valve Assembly - SMART Series 451 Service Manual

SN_Typ 451_us.book Seite 33 Freitag, 30. November 2007 1:56 13

Valve assembly

The timing chain is driven by the crankshaft via the
crankshaft gear and thus drives the intake camshaft
via the camshaft adjuster and the exhaust camshaft
via the exhaust camshaft sprocket. The timing chain is
guided by a slide rail. A tensioning rail and chain
tensioner ensure that the chain is at the right tension
to prevent wear and noises.
Valve assembly
1 Exhaust camshaft sprocket
2 Exhaust camshaft
3 Camshaft adjuster
4 Intake camshaft
5 Crankshaft gear
6 Crankshaft
The intake and exhaust camshafts control the gas
exchange in the engine via the intake and exhaust
valves. Variable camshaft adjustment allows for
greater torque at low engine speeds and better
response time in the idle and partial-load ranges. At
the same time, the camshaft adjustment helps to
achieve the stipulated exhaust emissions limits.
7 Timing chain
8 Intake valve
9 Exhaust valve
10 Valve spring
11 Cup tappet
Introduction of the smart fortwo, Model Series 451
Valve assembly
P05.00-2082-00
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