Multi-Stage Induction; Outline; System Composition - Suzuki DF200 Service Manual

MULTI-STAGE INDUCTION

OUTLINE

The multi-stage induction system is designed to improve the
intake efficiency by changing the intake tract volume in accor-
dance with the engine speed.
This system improves low and mid range torque and increases
power output at the higher rpm ranges.

SYSTEM COMPOSITION

Located between the STBD and PORT banks, a collector
assembly provides air for the low/mid range intake tract and high
speed range tracts. Mounted on the collector are two throttle
bodies, VSV (Vacuum Switching Valve), vacuum tank, depres-
sion chamber for operating the system and the shut off valve for
switching the intake tract. System connection components
include one check valve and hose to form the vacuum passage.
• VACUUM TANK
The vacuum tank stores vacuum created during engine opera-
tion. The vacuum tank' purpose is to supply a stable vacuum to
the depression chamber under the varying vacuum conditions
normally occurring within the collector, thereby making it possi-
ble to control the shut off valve accurately.
A hose and check valve connects one side of the vacuum tank
to the collector. The other side of the tank is connected to the
VSV with a hose.
• VSV (Vacuum switching valve)
One side of the VSV is connected via hose to the vacuum tank,
the other side is connected via hose to the depression chamber.
The VSV receives operating signals from the ECM. When the
ECM signals OFF, the VSV releases vacuum to the atmosphere.
When the ECM signals ON, the VSV supplies vacuum to the
depression chamber.
• DEPRESSION CHAMBER
The depression chamber is designed to open/close the shut off
valve.
When vacuum is applied to the depression chamber, the rod in
the chamber is pulled in closing the shut off valve.
When vacuum is not applied to the chamber, the rod returns to
the original position, opening the shut off valve.
ENGINE CONTROL SYSTEM
1. Collector assembly
2
1
1. Vacuum tank
2. Check valve
1
1. VSV (Vacuum switching valve)
1
1. Depression chamber
3-31
1