SYSTEME D'ADMISSION DU MELANGE AIR-COMBUSTIBLE D'UN MOTEUR

ENGINE INDUCTION SYSTEM

Abrégé anglais

C-4029
ENGINE INDUCTION SYSTEM
Abstract of the Disclosure
An internal combustion engine has a tuned
induction system with an air cleaner connected by a
conduit with a separate plenum mounted on a manifold
with individual runners connecting with the engine
cylinders. A throttle body having a throttle to
control induction air flow is located between the
plenum and the manifold with its runners such that the
plenum is not subject to reduced manifold pressures
resulting from throttling the air flow.

Revendications

Claims
The embodiments of the invention in which an
exclusive property or privilege is claimed are defined
as follows:
1. An internal combustion engine having an
induction system with a plenum disposed upstream of
intake runners, said plenum being connected in series
with an upstream air filter and having a throttle body
with a throttle valve to control intake air flow,
characterized in that the throttle body (9) is located
directly at the outlet of the plenum (10) between the
plenum (10) and a manifold including the intake runners
(7,8).
2. An internal combustion engine according to
Claim 1, characterized in that the throttle body (9),
along with the manifold and intake runners (7,8) is
mounted on the cylinder head (2), and that the plenum
(10) is set directly on the throttle body (9).
3. An internal combustion engine according to
Claim 2, characterized in that the throttle body (9)
opens into the plenum (10) at a location spaced from
the side walls of the plenum (10).

4. An internal combustion engine having an
induction system with a plenum disposed upstream of and
defining a sole flow path to intake runners, said
plenum being connected in series with an upstream air
filter and having a throttle body with a throttle valve
to control intake air flow, wherein the throttle body
(9) is located at the outlet of the plenum (10) between
the plenum (10) and a manifold including the intake
runners (7,8).

Description

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~-2716 C-4029
ENGINE INDUCTION SYSTEM
_.
Technical Field
The invention relates to tuned induction
systems for internal combustion engines of the type in
which a~collector or plenum preceding individual intake
runners is connected to an air filter, and in which a
throttle body with a throttle valve is provided in
order to control the air flow. An internal combustion
engine with an induction system of this type is shown
in United States patent 4,628,873.
~ackground
In the known internal combustion engine, the
plenum is attached to an end wall of the motor vehicle
engine compartment. Relatively long intake runners
lead rectilinearly from the plenum to the cylinder
head. A throttle body with a throttle valve to control
the quantity of air is provided at the inlet of the
plenum. ~he air inducted by the internal combustion
enyine flows from an air intake tube throuyh an air
filter and the throttle body into the plenum, and from
there through the individual intake runners into
associated combustion chamhers of the internal
combustion engine.
The configuration o the intake system
ac~ording to the above-mentioned U.S. patent 4,628,873
provides relatively long intake headers running
rectilinearly, which leads to advantageous gas velocity
conditions. This results in an increase in torque at
low engine speeds, and reduces undesirable exhaust and
noise emissions.
For reasons concerning the environmental
compatibility of motor vehicles, it is advantageous if
they are operated at relatively low enyine speeds.

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However, drivers take advantage of the ability to drive
at low to medium engine speeds only if sufficient
torgue is also available at the same time.
Summary of the Invention
An object of the invention is therefore that
of conf~gurinq an internal combustion engine with a
tuned induction system of the kind mentioned initially
in such a way that the engine has the highest possible
torque at medium to low engine speeds.
According to the invention, this object is
obtained by locating throttle body at the outlet of the
plenum between the plenum and an intake manifold with
individual runners.
This very simple configuration results,
surprisingly, in a definite improvement in the torque
of the internal combustion engine at medium to low
engine speeds. In addition, there is a reduction in
noise and a decrease in noxious components in the
exhaust. A reason for these positive effects is
assumed to be the fact that in the arrangement
according to the invention, air can flow into the
throttle body from a large-volume, unpressurized/
non-turbulent plenum volume. In the plenum of the
internal combustion engine according to the
25 above-mentioned patent 4,628,873 the pressure in the
plenum is influenced by changes in the setting of the
throttle valve and by the intake vacuum of the internal
combustion engine, so that the plenum pressure
fluctuates.
In one desirable embodiment of the invention,
the throttle body along with the intake manifold is
mounted on the cylinder head, and the plenum is set
directly on the throttle body. With this

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configuration, it is not necessary to attach the plenum
to one wall of the engine compartment, so that the
assembly process is simpler.
Air can flow from all dir~ctions from the
plenum into the throttle body in a uniform manner if
the throttle body opens into the plenum at a distance
from the side walls of the plenum.
The invention may have many embodiments, one
of which is illustrated in the drawing and is described
below.
Brief Drawing Description
In the drawing:
Figure 1 shows a partially sectioned end view
of an internal combustion engine according to the
invention and;
Figure 2 shows schematically a portion of the
induction system of the internal combustion engine
according to Figure 1.
Detailed Description
The internal combustion engine shown in Figure
1 has a cylinder block 1 on which is mounted a cylinder
head 2, with exhaust and intake valves 5, 6
respectively, controlled by camshafts 3, 4.
To the right of the cylinder head 2 in the
drawing is an ,ntake manifold with runners 7, 8 which
connects upwardly with a throttle body 9. An intake
plenum 10 is mounted on the throttle body 9.
Combustion air drawn in by the internal combustion
engine flows through an intake tube 11 into an air
filter 12, rom there through a conduit 13 into an
airflow meter 14, and then into the plenum 10, from
which it passes through the throttle body 9 into the
intake manifold and runners 7, 8. The engine is a

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fuel-injection internal combustion engine having
injectors 15, by means of which fuel is injected into
the intake runners 7, 8 as shown in Figure 1.
Figure 2 shows how air flows from the intake
tube 11 to one of the intake runners 8. Note that the
throttle~ body 9 opens into the plenum 10 at a distance
from the side walls of the plenum 10. As a result, air
can flow uniformly from all sides into the throttle
body 9.

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