1MZ-FE Engine Control System - al tech page

ENGINE — 1MZ-FE ENGINE

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ENGINE CONTROL SYSTEM JDESCRIPTION The construction and functions of the new 1MZ-FE engine includes the following modifications and additions in comparison with the 1MZ-FE engine installed on the ’98 ES300 as the base: System SFI Sequential Multipot Fuel Injection

ESA Electronic Spark Advance

Outline The newly adopted L-type SFI system directly measures the intake air flow by means of the hot-wire type air flow meter.

RX300

’98 ES300

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The newly adopted air assisted fuel injection system facilitates fuel atomization for the improvement of emission control performance and fuel economy.

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Ignition timing is determined by the ECM based on signals from various sensors. Corrects ignition timing in response to engine knocking.

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The torque control correction during gear shifting has been used to minimized the shift shock.

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2 knock sensors are used to further improve knock detection.

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IAC (Idle Air Control)

A rotary solenoid type IAC system controls the first idle and idle speeds.

VVT-i Variable Valve Timingintelligent

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(1-Coil Type)

(2-Coil Type)

Controls the intake camshaft to an optimal valve timing in accordance with the engine condition.

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ACIS Acoustic Control Induction System

This system changes the intake manifold length over in three stages according to the engine rpm and throttle valve opening to improve the performance at all engine speeds.

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Active Control Engine Mount

The damper characteristic of the front engine mount insulator is varied to reduce idling vibration.

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A/F Sensor and Oxygen Sensor Heater Control

Maintain the temperature of the A/F sensor and oxygen sensors at an appropriate level to increase accuracy of detection of the oxygen concentration in the exhaust gas.

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Air Fuel Ratio Feedback control

The precision air fuel ratio feedback control has been improved through the adoption of the air-fuel ratio sensor and oxygen sensor.

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Engine Immobilizer

Prohibits fuel delivery and ignition if an attempt is made to start the engine with an invalid ignition key.

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Function to communicate with multiplex communication system

Communicates with the body ECM, A/C ECU, etc., on the body side, to input/output necessary signals.

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*: Calfornia only

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JCONSTRUCTION The configuration of the engine control system in the new 1MZ-FE engine for RX300 is as shown in the following chart. Shaded portions differ from the 1MZ-FE engine for ’98 ES300. SENSORS

MASS AIR FLOW METER CRANKSHAFT POSITION SENSOR

ACTUATORS

VG #10~#60

NE

(Crankshaft Angle Signal) VVT CAM ANGLE SENOSR Right Bank Left Bank ENGINE COOLANT TEMP. SENSOR INTAKE AIR TEMP. SENSOR

THROTTLE POSITION SENSOR (Throttle Position Signal) IGNITION SWITCH

VV1

IGT1~6

HEATED OXYGEN SENSOR KNOCK SENSOR (Right Bank & Left Bank) NEUTRAL START SWITCH STARTER RELAY A/C COMP PRESSURE SWITCH COOLING FAN RELAY POWER STEERING OIL PRESSURE SWITCH

STOP LIGHT SWITCH VAPOR PRESSURE SENSOR TRAC ECU* DATA LINK CONNECTOR 1 DATA LINK CONNECTOR 3 TRANSPONDER KEY AMPLIFIER AIR FUEL RATIO SENSOR (Right Bank & Left Bank) EFI MAIN RELAY

No. 1 ~ No. 6 INJECTOR ESA IGNITION COIL with IGNITER

VV2

SPARK PLUGS THW THA

RSO

IAC CONTROL VALVE

VTA1

FC

IGSW STA

VEHICLE SPEED SENSOR COMBINATION METER

EFI

SPD

ACMG

OXS

HTS

KNKR KNKL NSW

ECM

OC1 OC2

STA PRE CF

EVAP1

PS STP PTNK

TPC W

TRC ENG TC

IMLD

SIL

HAFR HAFL

TXCT

FUEL PUMP CONTROL CIRCUIT OPENING RELAY AIR CONDITIONING CONTROL AIR CONDITIONING ECU HEATED OXYGEN SENSOR HEATER

VVT-i CONTROL VVT-i Solenoid VSV RH VVT-i Solenoid VSV LH EVAP CONTROL VSV VAPOR PRESSURE CONTROL VSV MALFUNCTION INDICATOR LAMP THEFT DETERRENT INDICATOR LIGHT LAMP*2

AIR FUEL RATIO SENSOR HEATER (Right Bank & Left Bank)

RXCK

CODE

AFR AFL +B

MPX2 MPX1 BATT

*: Applicable only to vehicles equipped with the TRAC System.

MULTIPLEX COMMUNICATION SYSTEM

BODY ECU AIR CONDITIONER/METER ECU

BATTERY

ENGINE — 1MZ-FE ENGINE

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JENGINE CONTROL SYSTEM DIAGRAM ABS Unit Fuel Pressure Control Relay

Park/Neutral Position Switch

Meter Unit

Start Switch

Vehicle Speed Signal

Electronic Controlled Transmission Solenoid Valves

Fuel Pressure Regulator

MIL A/C Amplifier Fuel Pump

DLC3

Stop Light Switch Electric Load Switch

Battery

ECM ORVR Breather Line

VSV (for EVAP Purge Control) Pressure Sensor VSV (Pressure Control)

Fuel Filter

VSV (for Acoustic Control Induction System)

IAC Valve

Mass Air Flow Meter Intake Air Temp. Sensor

Oil Control Valve (for VVT Control) Injector Throttle Position Sensor Camshaft Position Sensor Oil Control Valve

EI Camshaft Position Sensor

A/F Sensor Warm-Up-TWC

ECT Sesnor RPM Sensor

Knock Sensor

TWC Heated Oxygen Sensor A/F Sensor 157EG20 Warm-Up-TWC

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JLAYOUT OF COMPONENTS

Knock Sensor Throttle Position Sensor

ECM

O2 Sensor IAC Valve Water Temperature Sensor

Injector

Ignition Coil with Built-in Ignite

Cam Position Sensor Crank Position Sensor A/F Sensor Cam Position Sensor

Air Flow Meter OCV

157EG21

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JVVT-i CONTROL SYSTEM General D This system controls the intake camshaft valve timing so as to obtain balance between the engine output, fuel consumption and emission control performance. The actual intake side valve timing is fed back by means of the cam position sensor for constant control to the target valve timing. Throttle Position Sensor OCV (RH bank) Cam Position Sensor (RH bank) OCV (LH bank)

Cam Position Sensor (LH bank)

Water Temperature Sensor

ECM

Air Flow Meter Crank Position Sensor 157EG22

ECM Crank Position Sensor

Target Valve Timing

Air Flow Meter

Feedback

Throttle Position Sensor Water Temperature Sensor

Correction

Cam Position Sensor

Actual Valve Timing

OCV Duty Control

157EG23

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JCONSTRUCTION AND FUNCTIONS Construction The camshaft on the exhaust side is driven by the timing belt from the crankshaft pulley, and the camshaft on the intake side is driven by the gear train from the exhaust side. The camshaft drive gear (exhaust side) is combined with a scissors gear to reduce the gear noise due to torque variation. The camshaft driven gear (intake side) is integrated with the VVT-i actuator to vary the intake camshaft valve timing.

Crankshaft Timing Pulley

Timing Belt

Drive Gear (scissors gear)

Exhaust Camshaft

Driven gear Intake Camshaft (VVT-i Actuator) Valve timing Varying Portion

VVT-i Actuator Intake Camshaft

Cam Position Sensor

Exhaust Camshaft

Crankshaft 157EG22

Cam Position Sensor

Cam Position Sensor

VVT-i Actuator

157EG24

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The ECM distributes the pressure generated by the oil pump into the advance side and retard side by means of the OCV (oil control valve) installed on the side wall of the cylinder head for adjusting the pressures before and after the VVT-i controller vane to control the intake camshaft phase.

VVT-i Controller This controller consists of the housing driven from the exhaust camshaft and the vane coupled with the intake camshaft. The oil pressure sent from the advance or retard side path at the intake camshaft causes rotation in the VVT-i controller vane circumferential direction to vary the intake valve timing continuously. Vane Seal

Housing (fixed on driven gear)

Vane Portion (fixed on intake camshaft)

Driven Gear

This illustration shows the angle advance state. 157EG25

OCV (Oil Control Valve) The oil control valve spool position is varied to constantly obtain the optimum valve timing according to the duty signal sent from the ECM. The latest timing position is set by the spring force while the engine is stopped.

VVT-i Pulley Timing Advance Chamber

VVT-i Pulley Timing Retard Chamber

Spool Valve

Sleeve

Drain Spring

Connector

Drain Oil Pressure

Coil

Plunger 157EG26

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Operation (Hydraulic System) The OCV selects the path to the VVT-i actuator according to the advance, retard or hold signal from the ECM. The VVT-i actuator rotates the camshaft in the timing advance or retard position or holds it according to the position where the fluid pressure is applied. Operation

OCV drive signal

Advance

VVT-i Actuator

Description

Advance Signal

ECM Duty Ratio

When the OCV is positioned as illustrated at left by the advance signal from the ECM, the resultant fluid pressure is applied to the timing advance side vane chamber to rotate the camshaft in the timing advance direction.

Fluid Pressure 157EG27

157EG28

Delay

Rotating Direction Vane (fixed on intake camshaft)

157EG35

Retard Signal

ECM Duty Ratio

When the OCV is positioned as illustrated at left by the retard signal from the ECM, the resultant fluid pressure is applied to the timing retard side vane chamber to rotate the camshaft in the timing retard direction.

Fluid Pressure 157EG29

157EG30

157EG36

Hold

Hold Signal

ECM Duty Ratio Fluid Pressure 157EG31

157EG32

157EG37

The ECM calculates the target timing angle according to the traveling state to perform control as described above. After setting at the target timing, the valve timing is held by keeping the OCV in the neutral position unless the traveling state changes. This adjusts the valve timing at the desired target position and prevents the engine oil from running out when it is unnecessary.

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ECM In proportion to the engine speed, intake air volume, throttle position and coolant temperature, the ECM searches an optimal valve timing under each driving condition and control the camshaft timing oil control valve. In addition, ECM uses signal from the VVT sensors and the crankshaft position sensor to detect the actual valve timing, thus performing feedback control to achieve the target valve timing. " Operation During Various Driving Condition A Full Load Perfomance Range

4

Engine Load

Range

Range

Range Range Operation state

1

Range

During idling

1

At light load

2

At medium load

3

In low to medium speed range with heavy load

4

In high speed range with heavy load

5

Engine Speed Valve timing EX EX

z

Objective Eliminating overlap to reIN duce blow back to the inLatest timing take side Decreasing overlap to !IN eliminate blow back to the To retard side intake side IN

EX To advance side

INz EX

To advance side

IN

At low temperatures

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Upon starting/ stopping the engine

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EX

EX

3

2 151EG74

Effect Stabilized idling rpm Better fuel economy Ensured engine stability

Increasing overlap to increase internal EGR for pumping loss elimination

Better fuel economy Improved emission control

Advancing the intake valve close timing for volumetric efficiency improvement

Improved torque in low to medium speed range

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Retarding the intake valve close timing for volumetric To retard side efficiency improvement

Improved output

Eliminating overlap to prevent blow back to the intake side for reduction of IN fuel increase at low temperatures, and stabilizing the Latest timing idling rpm for decreasing fast idle rotation

Stabilized fast idle rpm Better fuel economy

Eliminating overlap to eliminate blow back to the Latest timing intake side

Improved startability

IN

EX

5

ENGINE — 1MZ-FE ENGINE

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JSFI (Sequential Multipot Fuel Injection) SYSTEM D The L-type SFI system is adopted to adjust fuel injection volume by directly measuring the intake air flow with a hot-wire type air flow meter. D An air assist type fuel injection system is adopted to improve emission control and fuel economy be facilitating fuel atomization.

Air-Fuel Ratio and Feedback Control As illustrated below, the conventional oxygen sensor is characterized by a sudden change in its output voltage at the threshold of the stoichiometric air-fuel ratio (14.7 to 1). In contrast, the air-fuel ratio sensor output a voltage that is approximately proportionate to the existing air-fuel ratio by converting the oxygen density to the voltage. As a result, the detection precision of the air-fuel ratio has been improved. Air-Fuel Ratio Sensor 3.3V

ECM AF−

(V) 1

Oxygen Sensor

2.2

3.0V

0.1 11

151EG30

Oxygen Sensor Output

Air-Fuel Ratio Sensor

(V) 4.2 Air-Fuel Ratio Sensor Output

AF+

14.7 Air-Fuel Ratio

19

Output Characteristics

151EG31

The precision of the air-fuel feedback control has been improved through the adoption of the air-fuel ratio sensor. As illustrated below, if the existing air-fuel ratio diverts from the stoichiometric air-fuel ratio, the conventional oxygen sensor used to correct the air-fuel ratio at a constant proportion. However, with the air-fuel ratio sensor, the ECM can determine the extent of diversion from the stoichiometric air-fuel ratio and execute an immediate correction. Rich " Stoichiometric Air-Fuel Ratio # Lean

Injection Volume

Previous (Oxygen Sensor) New (Air Fuel Ratio Sensor)

Disorder

New

Previous Correction at a Constant Proportion Immediate Correction

151EG32

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JACIS (ACOUSTIC CONTROL INDUCTION SYSTEM) CONTROL General The ECM intake control valve is opened/closed according to the engine rpm and throttle valve opening to vary the intake manifold length in three stages for improving the torque under heavy load in the medium speed range.

Operation Relationships between engine rpm and throttle valve opening 1 Engine speed below 2,700 rpm and throttle valve opening at 30 degrees or more (Low speed range with heavy load) 2 Engine speed between 2,700 and 3,700 rpm and throttle valve opening at 30 degrees or more (Medium speed range with heavy load) 3 Engine speed up to 3,700 rpm with throttle valve opening at 30 degrees or less, and full range with engine speed above 3,700 rpm (Idling range, light load range and high speed range)

Throttle Valve Opening

2700r/min 3700r/min

2

1

3

30° 3

3 Engine rpm 157EG33

157EG10

1

Low speed range with heavy load

157EG11

2

Medium speed range with heavy load

157EG12

3

Idling range, light load range and high speed range