Page 1 of 2000

ENGINE - 2AZ-FE ENGINE EG-4
FEATURES OF 2AZ-FE ENGINE
The 2AZ-FE engine has achieved the following performance through the use of the items listed below.
(1) High performance and reliability
(2) Low noise and vibration
(3) Lightweight and compact design
(4) Good serviceability
(5) Clean emission and fuel economy
Section
Item(1)(2)(3)(4)(5)
Engine
A cylinder block made of aluminum alloy along with a
magnesium alloy die-cast cylinder head cover is used.
Engine
ProperA taper squish shape is used for the combustion chamber.p
A resin gear balance shaft is used.
Vl
A timing chain and chain tensioner are used.
Va l v e
MechanismThe shim-less type valve lifters are used.MechanismThe VVT-i system is used.
A chacoal filter is used in the air cleaner cap.
Intake andIntake manifold made of plastic is used.Intake and
ExhaustThe linkless-type throttle body is used.
SystemA thin-wall ceramic TWC (Three-Way Catalytic converter)
is used.
The fuel returnless system is used.
Fuel
System
Quick connectors are used to connect the fuel hose with the
fuel pipe.
System12-hole type fuel injectors with high atomizing performance
are used.
Ignition
SystemIridium-tipped spark plugs are used.
Charging
SystemThe segment conductor type generator is used.
Starting
SystemPS (Planetary reduction-Segment conductor motor) type
starter is used.
The ETCS-i is used.
Engine
Control
The DIS (Direct Ignition System) makes ignition timing
adjustment unnecessary.
Control
SystemThe non-contact type sensor is used in the throttle position
sensor.
The planar type air-fuel ratio sensor is used.
Page 6 of 2000
ENGINE - 2AZ-FE ENGINE
01MEG01Y
Taper Squish Shape : Resin Coating
240EG45
Plastic Region Tightening BoltsEG-9
5. Piston
The piston is made of aluminum alloy and skirt area is made compact and lightweight.
The piston head portion uses a taper squish shape to improve the fuel combustion efficiency.
The piston skirt has been coated with resin to reduce the friction loss.
6. Connecting Rod
The connecting rods and caps are made of
high-strength steel for weight reduction.
Nut-less type plastic region tightening bolts are
used on the connecting rod for a lighter design.
The connecting rod bearings are reduced in
width to reduce friction.
Page 9 of 2000
ENGINE - 2AZ-FE ENGINE
240EG46 181EG10
VVT-i ControllerIntake CamshaftExhaust
Camshaft
Chain
Te n s i o n e r
Chain Damper
Chain SlipperCamshaft
Va l v e
Lifter
Service Tip
The adjustment of the valve clearance is accomplished by selecting and replacing the appropriate
valve lifters.
A total of 35 valve lifters are available in 0.02 mm (0.008 in.) increments, from 5.06 mm (0.199 in.)
to 5.74 mm (0.226 in.). For details, refer to 2006 RAV4 Repair Manual (Pub. No. RM01M1U).
EG-12
VA LV E M E C H A N I S M
1. General
The VVT-i system is used to improve fuel economy, engine performance and reduce exhaust emissions.
For details of VVT-i system, see page EG-48.
The intake and exhaust camshafts are driven by a timing chain.
Along with the increase in the amount of valve lift, the shim-less type valve lifter is used. This valve lifter
increases the cam contact surface.
Page 19 of 2000
ENGINE - 2AZ-FE ENGINE
01MEG30Y
Fuel Pump Assembly
Fuel Filter
Pressure Regulator
Quick Connector
Injector
Fuel Tank
Canister EG-22
FUEL SYSTEM
1. General
The fuel returnless system is used to reduce evaporative emissions.
A fuel cut control is used to stop the fuel pump when the SRS airbag is deployed in a front or side collision.
For details, see page EG-53.
A quick connector is used in the fuel main pipe to improve serviceability.
The 12-hole type fuel injector is used.
The ORVR (On-board Refueling Vapor Recovery) system is used. For details, see page EG-54.
Page 20 of 2000
ENGINE - 2AZ-FE ENGINE
185EG16
Pulsation
Dumper
Pressure Regulator
Fuel Pump
AssemblyFuel Tank
Fuel Filter
Fuel Pump
DR011EG18
EG-23
2. Fuel Returnless System
Fuel returnless system is used to reduce the evaporative emission. As shown below, by integrating the fuel
filter and pressure regulator with fuel pump assembly, the fuel return system in which the fuel returns from
the engine area is discontinued and temperature rise inside the fuel tank is prevented.
3. Fuel Injector
The 12-hole type injector is used. By modifying its
injector nozzle to a taper shape, this injector has
achieved high atomizing performance of fuel. In
addition, the injector provides good performance
with the lightweight moving parts and the
optimized magnetic circuit.
Page 27 of 2000

ENGINE - 2AZ-FE ENGINE EG-30
ENGINE CONTROL SYSTEM
1. General
The engine control system for the 2AZ-FE engine has the following systems.
System
Outline
SFI
Sequential Multiport
Fuel InjectionAn L-type SFI system directly detects the intake air volume with a hot-wire
type mass air flow meter.
The fuel injection system is a sequential multiport fuel injection system.
ESA
Electronic Spark
AdvanceIgnition timing is determined by the ECM based on signals from various sensors.
The ECM corrects ignition timing in response to engine knocking.
ETCS-i
Electronic
Optimally controls the throttle valve opening in accordance with the amount of
accelerator pedal effort and the condition of the engine and the vehicle.
Electronic
Throttle Control
System-intelligent
(See page-43)A linkless-type is used, without an accelerator cable.
An accelerator pedal position sensor is provided on the accelerator pedal.
A non-contact type throttle position sensor and accelerator pedal position
sensor are used.
VVT-i
Va r i a b l e Va l v e
Timing-intelligent
(See page EG-48)
Controls the intake camshaft to an optimal valve timing in accordance with the
engine condition.
Air-fuel Ratio
Sensor, Oxygen
Sensor Heater
ControlMaintains the temperature of the air-fuel ratio sensor or oxygen sensor at an
appropriate level to realize accuracy of detection of the oxygen concentration in
the exhaust gas.
Air Conditioning
Cut-off ControlBy turning the air conditioning compressor ON or OFF in accordance with the
engine condition, drivability is maintained.
Cooling Fan Control
(See page EG-52)Radiator cooling fan operation is controlled by signals from ECM based on the
engine coolant temperature sensor signal and the condition of the air
conditioning operation.
Fuel Pump Control
(See page EG-53)Fuel pump operation is controlled by signal from the ECM.
The fuel pump is stopped when the SRS driver’s and front passenger’s airbags
are deployed.
Evapotative Emission
The ECM controls the purge flow of evaporative emissions (HC) in the canister
in accordance with engine conditions.
Evapotative Emission
Control
(See page EG-54)Approximately five hours after the ignition switch has been turned OFF, the
ECM operates the canister pump module to detect any evaporative emission
leakage occurring in the EVAP (evaporative emission) control system through
changes in the 0.02 in. leak pressure.
Charging Control
(See page EG-65)The ECM regulates the charging voltage of the generator in accordance with the
driving conditions and the charging state of the battery.
(Continued)
Page 33 of 2000
ENGINE - 2AZ-FE ENGINE EG-36
5. Main Components of Engine Control System
General
The main components of the 2AZ-FE engine control system are as follows:
Component
OutlineQuantity
ECM32-bit CPU1
Mass Air Flow MeterHot-wire Type1
Crankshaft Position Sensor (Rotor Teeth)Pick-up Coil Type (36-2)1
Camshaft Position Sensor (Rotor Teeth)Pick-up Coil Type (3)1
Throttle Position SensorNon-contact Type1
Accelerator Pedal Position SensorNon-contact Type1
Knock SensorBuilt-in Piezoelectric Element Type
(Flat Type)1
Air-fuel Ratio Sensor
(Bank 1, Sensor 1)Type with Heater
(Planar Type)1
Heated Oxygen Sensor
(Bank 1, Sensor 2)Type with Heater
(Cup Type)1
Injector12-hole Type4
ECM
The 32-bit CPU of the ECM is used to increase the speed for processing the signals.
Page 35 of 2000

ENGINE - 2AZ-FE ENGINE
271EG45
Alumina
Dilation Layer
Alumina
Platinum
Electrode
Sensor Element (Zirconia)Heater AtmospherePlatinum
ElectrodeHeater
Atmosphere
Sensor Element
(Zirconia)
Planar Type Air-fuel Ratio Sensor Cup Type Heated Oxygen Sensor
204EG54
Temperature Sensing
Element
Platinum Hot-wire
ElementAir FlowIntake Air
Temperature
Sensor EG-38
2) Construction
The basic construction of the air-fuel ratio sensor and heated oxygen sensor is the same. However, they
are divided into the cup type and the planar type, according to the different types of heater construction
that are used.
The cup type sensor contains a sensor element that surrounds a heater.
The planar type sensor uses alumina, which excels in heat conductivity and insulation, to integrate a
sensor element with a heater, thus realizing the excellent warm-up performance of the sensor.
Warm-up Specification
Sensor TypePlanar TypeCup Type
Warm-up TimeApprox. 10 sec.Approx. 30 sec.
Mass Air Flow Meter
The compact and lightweight mass air flow meter, which is a plug-in type, allows a portion of the intake
air to flow through the detection area. By directly measuring the mass and the flow rate of the intake air,
the detection precision is ensured and the intake air resistance is reduced.
This mass air flow meter has a built-in intake air temperature sensor.