releases compression fuel ignites cylinder exhaust intake
The
four
-
stroke
engine
works
by
heating
fuel
and
air
in
a
.
During
the
first
stroke
,
the
valve
lets
fuel
and
air
into
the
cylinder
.
Then
the
valve
closes
during
the
stroke
.
A
piston
moves
up
to
condense
the
air
and
.
Then
the
mixture
during
the
power
stroke
.
The
final
stroke
gas
.
This
is
the
stroke
.
Source
:
Jim
D
.
Dearholt
"
Career
Paths
Mechanics
"
Express
Publishing
201
2