2001 TOYOTA PRIUS Service Repair Manual

NEW MODEL OUTLINE
MAIN MECHANISM
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14
THS operation
Starting and traveling at low load
When the engine efficiency is low such as when starting,
traveling at low load or the engine is stopped, permitting
travel by MG2; (however the engine may start under
SOC (State Of Charge) of the HV battery.)
Normal traveling
The engine energy is divided into two. One portion
directly drives the wheels. The other portion drives
MG1 to drive MG2 by generated power, which also
drives the wheels.
Full acceleration
In addition to the 2-way system for normal travelling,
the drive power of MG2 is further supplemented by the
power stored in the HV battery, resulting in powerful
and smooth acceleration.
Deceleration or braking
The wheels drive MG2 which acts as the generator for
regenerative power generation. The power recovered
by generation is stored in the HV battery.
Stopped
When the vehicle is stopped, the engine stops automat-
ically. However, when it is necessary to charge the HV
battery or to run the air conditioner compressor, the
engine will not stop.

NEW MODEL OUTLINE
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182EG03
kW
60
50
40
30
20
10 N´m
120
11 0
100
90
80
Engine Speed (rpm) 1,000 2,000 3,000 4,000 5,000(52/4,500)
(111/4,200)
Torque
Output
15
HV Battery Charging
When high load operation is continued, the engine
does not stop to charge the HV battery even
if the vehicle is stopped, in order to keep the
HV battery charged to a given level. (when
ªREADYº light is ON.) ;however, the engine does
not charge the HV battery when the lever is
shifted into the ªNº position.
The engine speed may also be increased during normal
traveling in order to charge the HV battery.
1NZ-FXE Engine
The new Prius is fitted with a 1.5
gasoline engine which has been developed for the use with the TOYOTA
hybrid system. A mass of leading-edge technology has been implemented to achieve excellent fuel economy,
low emissions, light weight, compactness, and low vibration and noise.
Outline of the 1NZ-FXE Engine Engine performance curve
1NZ-FXE
Displacement (m
)1,497
TypeDOHC 4 valves
Bore y Stroke (mm)75.0 y 84.7
Compression ratio13.0
Maximum output [kW (HP)/rpm]52 (70)/4,500
Maximum torque [N´m (lb´ft)/rpm]111 (82)/4,200
FuelGasoline

NEW MODEL OUTLINE
MAIN MECHANISM
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16
4 Features of the 1NZ-FXE engine
1. Highly efficient and high expansion ratio gasoline engine
Adoption of a super fuel-efficient engine developed for use with THS. Its high expansion ratio cycle is achieved by applying the
Atkinson cycle*1 which obtains high thermal efficiency.
2. Reduction in frictional loss
The maximum engine speed is set at 4,500 rpm to reduce frictional resistance, thereby producing a highly efficient low-speed
engine.

An offset crankshaft with 12 mm deviation from the center axis of the cylinder bore is utilized to reduce frictional resistance
of the piston.

Frictional resistance is reduced through the use of low tension valve springs and piston rings.

Lightweight design has been adopted for reciprocating engine parts.
The above measures for reducing frictional loss contribute to improved fuel economy.
3. VVT-i (Variable Valve Timing -intelligent)
The timing of the opening and closing of the intake valves is controlled by the computer according to driving conditions, such
as engine speed and level of acceleration. Thus, smooth intake and exhaust are achieved to greatly improve torque in the low
and medium speed zones. This also contributes to better fuel economy and purification of exhaust gas. Then the VVT-i function
is used to reduce vibration when the engine starts.
4. Compact, lightweight, and low emission
Adoption of an aluminum cylinder block and compact design of parts. And, by positioning the catalytic converter near the engine
for a backwards exhaust layout, we have been able to reduce emissions when the engine is cold started.
*1 : Atkinson Cycle: Proposed by an English engineer named James Atkinson, this thermal cycle enables the compression stroke
and the expansion stroke of the mechanism to be set independently of each other.
Suspension
MacPherson strut type suspension with L-shape
lower arms has been adopted in the front and
torsion beam with toe control link suspension
in the rear. Also, each component part is opti-
mally located and tuned for both excellent con-
trollability and enhanced riding comfort.
EMPS (Electric Motor-assisted Power Steering)
System
Vehicle speed sensing type electric motor-assisted power steering is fitted as standard. Unlike conventional
hydraulic power steering, EMPS does not depend on an engine for its power source, providing a steering feel
in no way inferior to conventional steering when the engine has stopped. Thus it is suitable for the HV system.
Other merits include improved fuel economy through energy conservation, lighter weight, and no need to fill
the power steering fluid.

NEW MODEL OUTLINE
MAIN EQUIPMENT
182MO20
[Information Screen]
This screen indicates the direction of energy trans-
mission. It is also possible to check the current drive
method (engine, motor or both) and status of power
generation by the engine and that of charging regen-
erative energy.
This screen indicates the average fuel consumption,
amount of recovered energy and fuel consumption for
that moment. Average fuel consumption is displayed
at 5-minutes intervals. The recovered energy display
indicates the amount of energy recovered over the past
5 minutes, with each mark representing 50Wh.
182BE36
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A range of features for comfort - the more you use them,
the better they get.
Multi-Information Display

The 5.8º wide touch panel type multi-information color LCD
is standard.

Energy monitor, fuel consumption and other vehicle information
screens, audio operation status and audio operation screen can
be indicated on the multi-information display. The outside tem-
perature are also indicated on the screen.
[Audio system]

An AM/FM cassette and 4-speaker system compatible with the
multi-information display has been adopted.

As the touch panel type display is used to operate the audio sys-
tem, the multi-information display simultaneously indicates the
operating status of the audio system.

The antenna provided is a collapsible style pole antenna posi-
tioned at the center of the roof.
[GPS Voice Navigation]

A GPS (Global Positioning System) voice navigation system
is optional.

The multi-information display can show the map on favorite
type among turn list, arrow display and enlarged intersection.

Using DVD (Digital Versatile Disk) as a memory source for map
data, a large quantity of information can be processed.
 Main Function of the Multi-information Display
ScreenFunction
Enlargement / reduction, rotation and move-
ment of map
Mapscreen
Indication of current position and direction of
travel
Map screen
displayCorrection of current positiondis lay(option)Setting, change and indication of route()
Voice guidance
Indication of enlarged intersections
Memory and indication of map position
Audio screenStatus of audio equipment and audio opera-
tion screen indication
InformationEnergy monitor screen indicationInformationscreenFuel consumption screen indication
Adj t tSound quality adjustment screen indicationAdjustmentscreenImage quality adjustment screen indicationscreenNo indication
On-screenAudio status indicationOn screenindicationWarning indication
Interrupt screenWarning indication
DiagnosisscreenDisplays system diagnosisscreen
displayDisplays various types of coefficient settings