Engine International VT365. Manual — part 5

ENGINE SYSTEMS

17

Air Management System (AMS)

Figure 11 Air Management System (AMS)

1.

Intake manifold

2.

EGR cooler

3.

Left cylinder head

4.

Left exhaust manifold

5.

Shielded tube exhaust assembly

6.

VGT with mounting bracket

7.

Air inlet duct

8.

Right cylinder head

9.

Right exhaust manifold

10. Exhaust tube assembly, right

18

ENGINE SYSTEMS

The Air Management system includes the
following:

•

Air filter assembly

•

Closed crankcase breather

•

Chassis mounted Charged Air Cooler (CAC)

•

Variable Geometry Turbocharger (VGT)

•

Intake manifold

•

Exhaust Gas Recirculation (EGR) system

•

Exhaust system

•

Catalytic converter– dependent on application

•

Catalyzed Diesel Particulate Filter (CDPF) –
dependent on application

ENGINE SYSTEMS

19

Figure 12 Air flow diagram

Air flow

Air enters and flows through the air filter assembly and
mixes with air from crankcase ventilation. The VGT
compresses the air mixture before it enters the Charge
Air Cooler (CAC). Cooled compressed air flows from
the CAC into the air intake manifold that directs air to
the intake ports for each cylinder head.

After combustion, hot exhaust gas is forced through
the exhaust manifolds to the EGR cooler and VGT.

•

Some hot exhaust gas is cooled in the EGR cooler
and flows through the EGR control valve back
through the air intake manifold to mix with filtered
air. This reduces nitrogen oxide (NOx) emissions
and noise.

•

The rest of the hot exhaust gas expands and flows
to the VGT, spins the turbine wheel, and flows
from the VGT outlet to the engine exhaust pipe.

•

The VGT compressor wheel, on the same shaft
as the turbine wheel, compresses the mixture of
filtered air and air from crankcase ventilation.

The VGT responds directly to engine loads. During
heavy load, an increased flow of exhaust gases turns
the turbine wheel faster. This increased speed turns
the compressor impeller faster and supplies more air
or greater boost to the intake manifold. Conversely,
when engine load is light, the flow of exhaust gases
decreases and less air is pumped into the intake
manifold.

20

ENGINE SYSTEMS

The VGT modifies more efficient exhaust flow
characteristics.

Charge Air Cooler (CAC)

Figure 13

Charge Air Cooler

1.

Air outlet

2.

Charge Air Cooler

3.

Air inlet

4.

Radiator

The CAC cooler is mounted on top of the radiator.
Air from the VGT is pushed through a network of
heat exchanger tubes before entering the air intake
manifold.

Outside air flowing over the tubes and

fins cools the charged air. Charged air is cooler and
denser than the uncooled air; cooler and denser
air improves the fuel-to-air ratio during combustion,
resulting in improved emission control and power
output.