2001 TOYOTA PRIUS ignition system

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
165EG25
Camshaft
Position
Sensor
Crankshaft
Position
Sensor
Various
SensorsG2
NEECM
IGT1
IGT2
IGT3
IGT4
IGF+BIgnition Coil
(with Igniter)
No.1
Cylinder
No.2
Cylinder
No.3
Cylinder
No.4
Cylinder61

IGNITION SYSTEM
1. General
A DIS (Direct Ignition System) has been adopted. The DIS improves the ignition timing accuracy, reduces
high-voltage loss, and enhances the overall reliability of the ignition system by eliminating the distributor.
The DIS in 1NZ-FXE engine is an independent ignition system which has one ignition coil (with igniter) for
each cylinder.
2. Ignition Coil
The DIS provides 4 ignition coils, one for each cylinder. The spark plug caps, which provide contact to the
spark plugs, are integrated with an ignition coil. Also, an igniter is enclosed to simplify the system.
3. Spark Plug
Iridium-tipped spark plugs have been adopted to realize a 60,000-mile (100,000 km) maintenance-free op-
eration. Their center electrode is made of iridium, which excels in wear resistance. As a result, the center
electrode is made with a smaller diameter and improved the ignition performance.

CHARGING AND STARTING SYSTEM
MG1 and MG2 (Motor Generator No.1 and 2) have been adopted in the charging system, and the convention-
al generator has been discontinued.
Furthermore, due to the adoption of MG1 for the starting system, the conventional starter has been discontin-
ued.

ENGINE ± 1NZ-FXE ENGINE62
ENGINE CONTROL SYSTEM
1. General
The engine control system for the 1NZ-FXE engine has following system.
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.
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.
VVT-i
Variable Valve
Timing-intelligentControls the intake camshaft to an optimal valve timing in accordance with
the engine condition.
ETCS-i
Electronic
Throttle Control
System-intelligentOptimally controls the throttle valve opening in accordance with the ECM,
and the conditions of the engine and the vehicle, and comprehensively
controls the ISC and cruise control system.
Fuel Pump Control
Fuel pump operation is controlled by signal from the ECM.

To stop the fuel pump during operation of the SRS airbag.
Oxygen Sensor Heater
ControlMaintains the temperature of the oxygen sensors at an appropriate level to
increase accuracy of detection of the oxygen concentration in the exhaust gas.
Evaporative Emission
Control

The ECM controls the purge flow of evaporative emissions (HC) in the
charcoal canister in accordance with engine conditions.

Using 3 VSVs and a vapor pressure sensor, the ECM detects any
evaporative emission leakage occurring between the fuel tank and the
charcoal canister, and vapor reducing fuel tank through the changes in the
tank pressure. For details, see page 79.
Toyota HCAC System
The ECM controls the VSV (for Toyota HCAC System) to improve the clean
emission performance of the exhaust gas when the temperature of the TWC
is low. For details, see page 58.
Air Conditioning
Cut-Off ControlBy turning the air conditioning compressor OFF in accordance with the
engine condition, drivability is maintained.
Cooling Fan ControlRadiator cooling fan operation is controlled by signals from ECM based on
the engine coolant temperature sensor signal (THW).
HV Immobiliser
Prohibits fuel delivery, ignition, and starting the HV system if an attempt is
made to start the HV system with an invalid ignition key. For details, see page
80.
DiagnosisWhen the ECM detects a malfunction, the ECM diagnoses and memorizes
the failed section.
Fail-SafeWhen the ECM detects a malfunction, the ECM stops or controls the engine
according to the data already stored in memory.

ENGINE ± 1NZ-FXE ENGINE
No.4 INJECTOR
SPARK PLUGS
No.2 INJECTOR
No.1 INJECTOR
No.3 INJECTOR SENSORS ACTUATORS
SFI
#10
CRANKSHAFT POSITION
SENSORNE
CAMSHAFT POSITION
SENSORG2
THROTTLE POSITION SENSORVTA
VTA2
COMBINATION METER
SPD

Vehicle Speed Signal
HEATED OXYGEN SENSOR
(Bank 1, Sensor 1)OX1A
HEATED OXYGEN SENSOR
(Bank 1, Sensor 2)OX1B
AMBIENT TEMP. SENSORTA M
ESA
IGT1

IGT4
IGF
THROTTLE CONTROL
MOTORETCS-i
M
ECM
ENGINE COOLANT TEMP.
SENSORTHW
INTAKE AIR TEMP. SENSORTHA
MASS AIR FLOW METERVG
IGNITION SWITCHIGSW
KNOCK SENSORKNK1
OIL PRESSURE SWITCHMOPS
CAMSHAFT TIMING OIL
CONTROL VALVE OCV
VVT-i
Bank 1, Sensor 2
Bank 1, Sensor 1HT1A
HT1B
#20
#30
#40
OXYGEN SENSOR HEATER
CONTROL
HEATED OXYGEN SENSOR
HEATER
CIRCUIT OPENING RELAYFUEL PUMP CONTROLFC
IGNITION COIL
with IGNITER
63
2. Construction
The configuration of the engine control system in the INZ-FXE engine is shown in the following chart.
(Continued)

ENGINE ± 1NZ-FXE ENGINE
182EG23
VSV (for TOYOTA
HCAC System)VSV (for EVAP)Oil Control Valve
ECMIgnition Coil
with IgniterVSV (for Purge Flow Switching Valve)
Charcoal Canister
Vapor
Pressure
Sensor
Trap Filter
VSV (for Canister
Closed Valve) DLC 3
Heated Oxygen Sensor
(Bank 1, Sensor 2)
Heated Oxygen Sensor
(Bank 1, Sensor 1) Engien Coolant
Temp. Sensor Camshaft
Position
Sensor
Injector Crankshaft
Position
Sensor Knock
Sensor Throttle
Control
Motor Mass Air
Flow Meter 66
4. Layout of Components

ENGINE ± 1NZ-FXE ENGINE
182EG39
Front Airbag
Sensors
(RH and LH)Airbag
Sensor
AssemblyHV
ECUCircuit
Opening
Relay
Fuel Pump
Motor ECM73
7. Fuel Pump Control
A fuel cut control is adopted to stop the fuel pump when the SRS airbag is deployed, thus helping reduce fuel
leakage.
In this system, the airbag deployment signal from the airbag sensor assembly is detected by the HV ECU,
send the signal to ECM, which turns OFF the circuit opening relay.
After the fuel cut control has been activated, turning the ignition switch from OFF to ON cancels the fuel cut
control, thus engine can be restarted.

ENGINE ± 1NZ-FXE ENGINE 78
Operation
Initially, the VSV (for canister closed valve) is closed, and the VSV (for EVAP) is open, enabling the VSV
(for purge flow switching valve) to keep the passage between the charcoal canister and the purge line open.
This causes a vacuum to be applied to the purge line, evaporator line, recirculation line, and the line from
the charcoal canister to the fuel tank.
Next, the VSV (for EVAP) is closed in order to maintain a vacuum from the VSV (for EVAP) to the inside
of the fuel tank. Then, any subsequent changes in the pressure are monitored by the vapor pressure sensor
in order to check for evaporative emission leaks.
Next, the VSV (for canister closed valve) and the VSV (for EVAP) open, enabling the VSV (for purge flow
switching valve) to keep the passage between the fuel tank and the purge line open. Then, the air in the fuel
tank is drawn in by the vacuum of the intake chamber, and the density of HC in the exhaust gases is measured
by the oxygen sensor to detect any leaks.
If a leak is detected, the malfunction indicator lamp (MIL) illuminates to inform the driver. Also, the diag-
nostic trouble code (DTC) can be accessed through the use of a hand-held tester.
For details on the DTCs, refer to the 2001 Prius Repair Manual (Pub. No.RM778U).
10. HV Immobiliser System
The HV immobiliser system has been designed to prevent the vehicle from being stolen. This system uses
a HV ECU that stores the ID code of the authorized ignition key. If an attempt is made to start the HV system
using an unauthorized key, the HV ECU prohibit fuel delivery, ignition, and starting the HD system effective-
ly disabling the engine.
For details see page 184 in the HV Immobiliser System section.
11. Diagnosis System
The diagnostic trouble codes can be output via DLC3 to an OBD-II scan tool or a hand-held tester. For details,
refer to the 2001 Prius Repair Manual (Pub. No.RM778U).

THS (TOYOTA HYBRID SYSTEM)
182TH24
ªREADYº LightOutput Control
Warning Light 26
DRIVING CHARACTERISTICS
Because the Prius uses a parallel series hybrid system, some aspects of its operation may differ from those of
existing automobiles, and may require precautions that are unique to this system.
1. Starting the THS
Make sure that the parking brake is engaged and that the shift lever is in the P position.
While depressing the brake pedal, turn the ignition switch to the START position. After this, the ªREADYº
light flashes.
The engine does not start when the shift lever is in the N position; it can only start in the P position. When
the external air temperature is low, the ªREADYº light may flash longer than usual.
As soon as the engine has started, the ªREADYº light illuminates steadily and a beeping sound is heard.
Several seconds after the engine warms up, the engine stops automatically, provided that the air conditioning
compressor does not need to operate and that the HV battery maintains a proper SOC (state of charge).
2. Start-Off
While keeping the brake pedal depressed, release
the parking brake, and move the shift lever to the
D position.
The vehicle has the same creeping movement as
the conventional automatic transmission vehicles.
Gradually release the brake pedal and slowly de-
press the accelerator pedal to start off.
At this time, the vehicle starts off powered only by
the MG2 (Motor Generator No.2)
NOTICE: The vehicle can be started off, provided that the ªREADYº light remains illuminated, even
if the engine remains stopped.
3. Acceleration
Depress the accelerator pedal to accelerate the vehicle.
If the engine remained stopped during start-off, the engine will start automatically during acceleration.
4. Downhill Driving
Move the shift lever to the B position as necessary in order to simultaneously apply the regenerative brake
and the engine friction brake.
5. Deceleration and Stopping
Depress the brake pedal to decelerate and to stop the vehicle.
Depressing the brake pedal causes the regenerative brake to activate automatically in the D or B position. (In
the regenerative brake system, kinetic energy is converted to electrical energy.) If the engine has warmed up,
the air conditioning compressor does not need to operate, and if the HV battery maintains a proper SOC (state
of charge), the engine stops automatically when the vehicle speed drops-even if the vehicle comes to a stop.
6. Parking
Push down the parking brake pedal, move the shift lever to the P position, and pull out the ignition key.
NOTICE: Make sure to pull out the ignition key after parking the vehicle because the vehicle can be
driven as long as the ªREADYº light remains illuminated even if the engine is stopped.
7. Other Characteristics and Precautions

If a drive wheel slips on slippery terrain, causing the front wheels to spin faster than the rear wheels, the
THS effects control to limit the slippage by restraining the drive force. (This also protects the planetary
gear from damage.)

When the HV battery temperature is too high or low, the output control warning light illuminates, alerting
the driver that output power may be limited.
This is not 2 malfunction. This condition may be corrected by avoiding sudden acceleration /decelaration,
after which the light will go out.

When the vehicle is stopped and the shift lever is in the N position, electricity is not generated even if the
engine is running. If the vehicle remains stopped for a long time, make sure to move the shift lever to the
P position. In heavy traffic, keep the shift lever in the D position.