Acura CSX. Instruction — page 91

28

11

11

VTC System

VTEC System

K20Z2 engine

K20Z3 engine

11-38

Fuel and Emissions Systems

MAXIMUM VTC ADVANCE 25 °

TDC

EX

IN 1

IN 2

EX

IN 2

IN 1

MAXIMUM VTC ADVANCE 25 °

SHORT OVERLAP

LONG OVERLAP

LOW SPEED VALVE TIMING

HIGH SPEED VALVE TIMING

EX

IN

EX

IN

IN (LOW LIFT)

LOW SPEED VALVE TIMING

HIGH SPEED VALVE TIMING

EX

IN

EX

IN

• The VTC system makes continuous intake valve timing changes based on operating conditions.
• Intake valve timing is optimized to allow the engine to produce maximum power.
• Cam angle is advanced to obtain the EGR effect and reduce pumping loss. The intake valve is closed quickly to

reduce the entry of the air/fuel mixture into the intake port and improve the charging effect.

• The system reduces the cam advance at idle, stabilizes combustion, and reduces engine speed.
• If a malfunction occurs, the VTC system control is disabled and the valve timing is fixed at the fully retarded position.

• The VTEC system changes the cam profile to correspond to the engine speed. It maximizes torque at low engine

speed and output at high engine speed.

• The low lift cam is used at low engine speeds, and the high lift cam is used at high engine speeds.

08/08/21 14:13:40 61SNR030_110_0038

13

31

VTEC/VTC

System Diagram

Camshaft Position (CMP) Sensor A

11-39

VTC
RETARD
CHAMBER

From No. 3
ALTERNATOR
(10 A) FUSE

VARIOUS
SENSORS

ECM/PCM

CMP SENSOR A

INTAKE
CAMSHAFT

VTC
ADVANCE
CHAMBER

ADVANCE

RETARD

VANE

VTC ACTUATOR

VANE

HOUSING

From
OIL PUMP

VTC OIL CONTROL
SOLENOID VALVE

SPOOL
VALVE

ROCKER ARM
OIL CONTROL
SOLENOID

ROCKER
ARM OIL
PRESSURE
SWITCH

BLK

BLK

GRN/YEL

BLU/BLK

BLK/YEL

BLU/WHT

BLU/WHT

YEL

BRN/YEL

BLK

BRN/YEL

VTC STRAINER

O-RING

MAGNET

TERMINAL

DRAIN

DRAIN

CMP sensor A detects camshaft angle position for the VTC system.

08/08/21 14:13:41 61SNR030_110_0039

12

33

13

Intake Air System

Catalytic Converter System

Positive Crankcase Ventilation (PCV) System

Intake Air Bypass Control Thermal Valve

Three Way Catalytic Converter (TWC)

11-40

Fuel and Emissions Systems

OUT

IN

VALVE

WAX
ELEMENT

INJECTOR

INTAKE AIR
BYPASS CONTROL
THERMAL VALVE

FRONT OF
VEHICLE

HOUSING

THREE WAY
CATALYST

BREATHER PIPE

INTAKE
MANIFOLD

PCV HOSE

PCV VALVE

: BLOW-BY VAPOR

: FRESH AIR

This system supplies air for engine needs.

When the engine is cold, the intake air bypass control
thermal valve sends air to the injector.
The amount of air is regulated by engine coolant
temperature. Once the engine is hot, the intake air
bypass control thermal valve closes, stopping air to the
injector.

The TWC converts hydrocarbons (HC), carbon
monoxide (CO), and oxides of nitrogen (NOx) in the
exhaust gas to carbon dioxide (CO ), nitrogen (N ), and
water vapor.

The PCV valve prevents blow-by gasses from escaping
into the atmosphere by venting them into the intake
manifold.

2

2

* : This illustration shows K20Z2 engine

08/08/21 14:13:41 61SNR030_110_0040

35

36

37

Exhaust Gas Recirculation (EGR) System
(K20Z2 engine)

Evaporative Emission (EVAP) Control
System

EGR Valve

EVAP Canister

EVAP Canister Purge Valve

Fuel Tank Pressure (FTP) Sensor

EVAP Canister Vent Shut Valve

11-41

TERMINAL

COIL

OUT

IN

O-RING

TERMINAL

SENSOR UNIT

O-RING

VALVE

O-RING

TERMINAL

Refer to the system diagram to see a functional layout
of the system.

The EGR valve lowers peak combustion temperatures
and reduces oxides of nitrogen emissions (NOx) by
recirculating exhaust gas through the intake manifold
and into the combustion chambers.

Refer to the system diagram to see a functional layout
of the system.

The EVAP canister temporarily stores fuel vapor from
the fuel tank until it can be purged back into the engine
and burned.

When the engine coolant temperature is below 60 °C
(140 °F), the ECM/PCM turns off the EVAP canister
purge valve which cuts vacuum to the EVAP canister.

The FTP sensor converts fuel tank absolute pressure
into an electrical input to the ECM/PCM.

The EVAP canister vent shut valve is on the EVAP
canister.
The EVAP canister vent shut valve controls the venting
of the EVAP canister.

08/08/21 14:13:42 61SNR030_110_0041

Оцените статью
Инструкции по ремонту
Добавить комментарий