Toyota COMPUTER-CONTROLLED SYSTEM Training Manual page 76

EFI - Functions of Engine EC U
FUNCTIONS OF ENGINE EC U
The Engine ECU calculates the basic fuel
injection duration in accordance with two
signals : 1) the intake manifold pressure signal
from the manifold pressure sensor (in D-type
EFI), or the intake air volume signal from the air
flow meter (in L-type EFI) ; and 2) the engine
speed signal . It bases its calculations on a
program stored in its memory .
The Engine ECU also determines the optimum
fuel injection duration for each engine condition
based on signals from various other sensors .
Control by the Engine ECU of the fuel pump, fuel
pressure-up function, and cold start injector are
covered in the section on the fuel system (See
page 53), and control of the oxygen sensor
heater is covered in the section on the other
control systems (See page 113) .
1 . FUEL INJECTION METHODS AND
INJECTION TIMIN G
Fuel injection methods include the method in
which fuel is injected by the injectors into all
cylinders simultaneously, the method in which
the cylinders are arranged into several groups
and fuel is injected into groups of cylinders in
sequence, and the method in which fuel is
injected into each cylinder separately . Fuel
injection timing can also differ depending on the
engine model, with some engines being started
at all times with a predetermined timing and
other engines being started with an injection
timing calculated by the ECU in accordance with
the intake air volume, engine speed, etc .
The basic fuel injection methods and injection
timing are as follows :
INJECTION METHODS
INJECTION TIMING ENGINES* '
Intake stroke Ignition Fuel injection
4A-GE (D-type EFI, 1989 an d
before )
4A-FE ( en ines w/o lea n g
5 ' mixture sensor )
3 3
S
63
1S-E, 2S-E, 3S-FE, 5S-F E
SIMULTANEOU
2 t
t
5M-GE, 6M-G E
4
4Y- E
0° 360° 720`
22R-E, 22R-TE
Crankshaft angle OHP 54
3VZ-E, 3F-E*
2
Note : This graph shows the injection timing for the
3E-E
2E-E
6M-GE engine .
,
2RZ-E, 2TZ-F E
Intake stroke -
Ignition Fuel injectio n
~T .
5 t
3
1G-GE
2 GROUPS 6
4A-GE ( L-type EFI )
2 3 3
d
4
'
4A GE (D type EFI, 1989 a n
.
)
f t
0° 360° 720°
e r
a
Crankshaft angle OHP 54
4A-GZ E
Note : This graph shows the injection timing for th e
1G-GE engine .
66