engine TOYOTA PRIUS 2001 Service Repair Manual

ENGINE
ENGINE ± INZ-FXE ENGINE
182EG01
182EG02
43
1NZ-FXE ENGINE
DESCRIPTION
The Prius uses the 1NZ-FXE engine that has been newly developed for hybrid system application. Based on
the 1NZ-FE engine, the high-expansion ratio Atkinson cycle has been adopted. It is an in-line 4-cylinder,
1.5-liter, 16-valve DOHC engine.
This engine has adopted the VVT-i (Variable Valve Timing-intelligent) system has been developed to realize
high performance, quietness, fuel economy and clean emissions.
± REFERENCE ±
Atkinson Cycle: Proposed by an English engineer named James Atkinson, this thermal cycle enables the com-
pression stroke and the expansion stroke of the mechanism to be set independently of each other. Later, this con-
cept was realized by the American R. H. Miller, who developed a system called the Miller Cycle in which the
opening and closing timing of the intake valves was made adjustable. Because this system does not generate
high output, there is no practical application for this system unless it is combined with a supercharger; however,
this system offers a high level of thermal efficiency.
On Prius, this weak point can be covered by combining the Atkinson cycle engine with THS.

ENGINE ± 1NZ-FXE ENGINE
182EG03
N.m
120
110
100
90
80
Torque
1000 2000 3000 4000 5000
Engine Speed (rpm)kW
60
50
40
30
20
10
Output
0 44

Engine Specifications 
Engine Type1NZ-FXE1NZ-FE (ECHO)
No. of Cyls. & Arrangement4-Cylinder, In-line

Valve Mechanism16 Valve DOHC, Chain Drive

Combustion ChamberPentroof Type

ManifoldsCross-Flow

Fuel SystemSFI

Displacement cm3 (cu. in.)1497 (91.3)

Bore x Stroke mm (in.)75.0 x 84.7 (2.95 x 3.33)

Compression Ratio13.0 : 110.5 : 1
Max. Output [SAE-NET]52 kW @ 4500 rpm
70 HP @ 4500 rpm81 kW @ 6000 rpm
108 HP @ 6000 rpm
Max. Torque [SAE-NET]111 N.m @ 4200 rpm
82 lb-ft @ 4200 rpm142 N.m @ 4200 rpm
105 lb-ft @ 4200 rpm
IntakeOpen18
±25 BTDC±7
53 BTDC
Valve
IntakeClose72
115 ABDC52
±8 ABDCValve
Timing
ExhaustOpen34 BBDC42 BBDCg
ExhaustClose2 AT D C

Fuel Octane Number RON91 or more

Oil GradeAPI SJ EC or ILSAC


Performance Curve 

ENGINE ± 1NZ-FXE ENGINE45
FEATURES OF 1NZ-FXE ENGINE
The 1NZ-FXE engine has been able to achieve the following performance through the adoption of the items
listed below.
(1) High performance and fuel economy
(2) Low noise and vibration
(3) Lightweight and compact design
(4) Good serviceability
(5) Clean emission
Item
(1)(2)(3)(4)(5)1NZ-FE
The VVT-i system is used.
High-expansion Atkinson cycle has been adopted.
An offset crankshaft has been adopted.
A cylinder block made of aluminum has been adopted.
A stainless steel exhaust manifold is used for weight reduction.
A rearward exhaust layout has been adopted to realize the early
activation of the catalyst.
HC Adsorber and catalyst system has been adopted.
Fuel returnless system has been adopted.
12-hole type fuel injectors have been adopted.
The DIS (Direct Ignition System) makes ignition timing
adjustment unnecessary.
Quick connectors are used to connect the fuel hose with the
fuel pipes.
The oil filter is installed diagonally downward.
A timing chain has been adopted.
A vacuum system that detects leaks in the evaporative
emission control system has been adopted.
The vapor reducing fuel tank system has been adopted.
This system reduces the amount of fuel vapor that is generated.

ENGINE ± 1NZ-FXE ENGINE
182EG04
Valve Angle 33.5
Water Jacket 46
ENGINE PROPER
1. Cylinder Head

The angle of the intake and exhaust valves is narrowed and set at 33.5 to permit a compact cylinder head.

As a result of installing the injector in the intake port of the cylinder head, the contact of the fuel against
the intake port wall has been minimized and fuel economy has been improved.

A water jacket has been provided between the exhaust port and the spark plug boss in order to maintain
the combustion chamber wall temperature uniform, thus improving the cooling performance of the com-
bustion chamber and the area around the spark plug.

ENGINE ± 1NZ-FXE ENGINE
182EG05
FrontExhaust Side
Crankshaft Center
Bore Center
8 mm
Intake Side12 mm
182EG06
Taper Squish Shape47
2. Cylinder Block

A cylinder block made of aluminum alloy has been adopted to realize a significant amount of weight reduc-
tion.

A water pump swirl chamber and an inlet passage to the pump are provided in the cylinder block.

The rear portion of the cylinder block has been shaped conically to improve the coupling rigidity with the
transaxle.

Through the adoption of the offset crankshaft, the bore center has been shifted 12 mm towards the intake,
in relation to the crankshaft center. Thus, the side force when the maximum pressure is applied has been
reduced and the heat efficiency has been improved. And as a result, fuel economy has been improved.

Through the use of a thin-walled cast iron liner in the cylinder bore, a distance of 8 mm between the bores
has been realized, resulting in a compact package. This liner is thin, so that boring is not possible.

By discontinuing the use of the rear oil seal retainer and by pressing the rear oil seal into the cylinder block,
a compact package has been realized.
3. Piston

The taper squish shaped piston has been
adopted to improve combustion chamber.

Low-tension piston rings have been adopted to
reduce friction and improve fuel economy and
oil consumption performance.

By increasing the mechining precision of the
cylinder bore diameter, the outer diameter of
the piston has been made into the one type.

ENGINE ± 1NZ-FXE ENGINE
171EG07
182EG07
Crankshaft Position
Sensor RotorOil HolePin
No.5 Journal
Balance Weight
No.1 Journal 48
4. Connecting Rod

The connecting rods are made of high-strength
material for weight reduction.

The connecting rod cap is held by bolts tight-
ened to plastic region.
5. Crankshaft

The crankshaft has 5 journals and 4 balance weights.

A crankshaft position sensor rotor has been pressed into the crankshaft to realize an integrated configura-
tion.

The surface roughness of the pins and journals have been improved for low-friction operation.

The bearing width has been reduced for low-friction operation.

ENGINE ± 1NZ-FXE ENGINE
171EG09
VVT-i ControllerTiming ChainExhaust Camshaft
Intake Camshaft
Chain Guide Chain Tension ArmChain Tensioner
171EG10
Exhaust Camshaft
Timing Rotor
Intake Camshaft
VVT-i Controller49
VALVE MECHANISM
1. General
Each cylinder has 2 intake valves and 2 exhaust valves.
The valves are directly opened and closed by 2 camshafts.
The intake and exhaust camshafts are driven by a roller timing chain.
The VVT-i system is used to improve fuel economy, engine performance and reduce exhaust emission.
2. Camshafts
In conjunction with the adoption of the VVT-i system, an oil passage is provided in the intake camshaft
in order to supply engine oil to the VVT-i system.
A VVT-i controller has been installed on the front of the intake camshaft to vary the timing of the intake
valves.
The timing rotor is provided behind the intake camshaft to trigger the camshaft position sensor.

ENGINE ± 1NZ-FXE ENGINE
165EG12
Camshaft
Valve Lifter
Valve
171EG12
Camshaft Sprockets
Timing
Chain
Chain Guide
Oil Jet
Crankshaft
Sprocket Chain
Tensioner
Chain
Tension
Arm 50
3. Intake and Exhaust Valve and Valve Lifter
Valve lifters with shimless valve adjustment have been adopted for weight reduction.
The adjustment of the valve clearance is accomplished by selecting and replacing the appropriate valve
lifters.
Narrower valve stems have been adopted to reduce the intake and exhaust resistance and for weight reduc-
tion.

Specifications  mm (in.)
Item
Intake ValveExhaust Valve
Face Diameter30.5 (1.2)25.5 (1.0)
Stem Diameter5.0 (0.20)5.0 (0.20)
4. Timing Chain
A roller timing chain with an 8.0 mm pitch has
been adopted to make the engine more compact
and reduce chain noise.
A material which has excellent wear resistance
has been selected for the timing chain to im-
prove reliability.
The timing chain is lubricated by engine oil
from an oil jet.
Chain tensioner, chain tension arm and chain
guide are established to reduce the engine noise
and friction loss.

ENGINE ± 1NZ-FXE ENGINE
171EG13
Spring
Plunger
Cam
Cam Spring Check Ball
171EG32171EG31
Service Hole for
Chain Tensioner
Oil Pump
Front ViewBack View51
5. Chain Tensioner
The chain tensioner uses a spring and oil pres-
sure to maintain proper chain tension at all
times.
The chain tensioner suppresses noise generated
by the chain.
A ratchet type half-back mechanism is used.
6. Timing Chain Cover
A single-piece, aluminum die-cast timing chain cover that entirely seals the front portion of the cylinder
block and the cylinder head has been adopted.
A service hole for the chain tensioner has been provided in the timing chain cover to improve serviceabili-
ty.

ENGINE ± 1NZ-FXE ENGINE
182EG08
182EG09
MAIN OIL HOLE
RELIEF
VA LV E
RELIEF
VA LV E
OIL FILTER
OIL PUMP
OIL STRAINER
CRANKSHAFT
JOURNAL
CONNECTING
RODOIL JET
PISTON OIL JET
TIMING CHAINCHAIN
TENSIONER
CYLINDER HEAD
CAMSHAFT TIMING
OIL CONTROL VALVE
FILTER
INTAKE
CAMSHAFT
JOURNALEXHAUST
CAMSHAFT
JOURNAL
CAMSHAFT TIMING
OIL CONTROL VALVE
VVT-i
OIL PAN 52
LUBRICATION SYSTEM

The lubrication circuit is fully pressurized and all oil passes through an oil filter.

A trochoid gear type oil pump, which is driven directly by the crankshaft, has been provided in the front
of the cylinder block.

The oil filter has been installed diagonally downward from the side of the cylinder block to improve ser-
viceability.