Apparatus and method for evaluation of fluid flow within a combustion chamber

The invention provides an apparatus which simulates fluid flow patterns within a chamber. The apparatus includes a chamber having a mechanism to enable viewing of the inside of the chamber. A simulated head member is associated with the chamber to enable fluid to pass through the member into the chamber. A mechanism to exhaust fluid from the chamber is also associated therewith. A member is positioned within the chamber to simulate a piston position within the chamber. Lightweight members are within the chamber to visually define the fluid flow patterns within the chamber. Also, a method of evaluating cylinder head port, combustion chamber, and valve head designs is disclosed.

BACKGROUND AND SUMMARY OF THE INVENTION 
The present invention relates to design of inlet valve ports, valve 
shrouding and the combustion chamber of a cylinder head of an internal 
combustion engine and, more particularly, to an apparatus and a method for 
analyzing particular designs of the inlet valve shrouding of particular 
cylinder heads. 
In designing cylinder heads for combustion chambers of internal combustion 
engines, it is desirable to know the type of fluid flow pattern present 
within the cylinder while the cylinder valves are open and the cylinder is 
being filled with a fluid stream of air and fuel. The type of fluid flow 
pattern aids the designer in determining optimum characteristics for that 
particular combustion chamber and cylinder head. Also, the optimum fluid 
flow pattern aids the engine in producing more power and in reducing 
emissions. 
Generally, two types of fluid flow patterns exist in combustion chambers of 
automotive internal combustion engines. One type is what is known as a 
swirl pattern. The fluid flow in a swirl pattern travels along the 
combustion chamber wall in an arcuate path substantially about the axis of 
the cylinder bore. The fluid flow moves in a helical pattern, as seen in 
FIG. 5. 
The second type of fluid flow pattern is what is known as tumble flow. 
Tumble flow follows a substantially arcuate path substantially transverse 
to the axis of the cylinder bore, as shown in FIGS. 2-4. 
Tumble flow is believed to offer significant advantages over other types of 
flow in that it promotes mixing of fuel and air within the combustion 
chambers which reduces the ignition delay period or in other words 
increases the burn rate of the engine's air/fuel. As a result, tumble flow 
promotes combustion stability within the combustion chambers for 
combustion. Additionally, tumble flow provides for better emission 
characteristics and results in improved engine operating economy. Thus, it 
is desirable to have combustion chambers which exhibit tumble flow 
characteristics. 
With the advantages provided by tumble flow, the question arises as to why 
all combustion chambers do not have tumble flow. It is believed that 
apparatus does not exist which enable viewing of the flow patterns within 
a combustion cylinder to enable determination of the flow patterns within 
the combustion cylinder. 
Therefore, it is desirous to have an apparatus which enables a 
determination of whether or not tumble flow will exist in a combustion 
chamber for a particular cylinder head. Also, the apparatus should provide 
information useful in the design of the cylinder heads which produce 
tumble flow. The apparatus should enable evaluation of tumble flow in the 
combustion cylinder in an attempt to optimize the flow pattern. 
Accordingly, it is an object of the present invention to provide the art 
with such an apparatus. 
The present invention provides the art with an apparatus which enables 
viewing of flow patterns within a simulated combustion chamber. The 
present invention provides information useful in designing inlet valve 
ports of cylinder heads which produce tumble flow in their respective 
combustion cylinders. The present invention enables adjustment of a 
simulated piston to simulate various positions of a piston during the 
stroke of the piston in the simulated combustion chamber to enable 
analysis of the flow patterns within the combustion chamber cylinder. The 
simulated piston in the subject apparatus is in the form of a porus screen 
so that a continuous flow of air can pass from the valved inlet port of 
the cylinder head into the combustion chamber. The apparatus also uses 
visible and trackable lightweight members in the combustion chamber which 
move with the air flow away from the valved inlet ports toward the 
simulated piston or screen. When the lightweight members engage the piston 
simulator, they move along its surface in a manner similar to the flow 
pattern of air in an engine with a non-porus piston. Movement of the 
lightweight members away from the simulated piston and toward the valved 
inlet port simulates the air flow in an engine with a non-porus piston 
even though the general direction of air flow in the subject apparatus is 
from the ports to and through the simulated piston. 
From the following detailed description taken in conjunction with the 
accompanying drawings and claims, other objects and advantages of the 
present invention will become apparent to those skilled in the art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Turning to the Figures, particularly FIG. 1, an apparatus for simulating 
fluid flow patterns in a chamber is illustrated. Generally, the apparatus 
includes a generally tubular member 10 forming a chamber 12, a mechanism 
14 for directing fluid such as air into the chamber 12 and a mechanism 16 
for discharging the fluid from the chamber 12. 
The mechanism 14 for enabling fluid to enter into the chamber is preferably 
a modified cylinder head 18. Generally the cylinder head 18 includes one 
or more inlet passage or port 20, one or more poppet type valves 22 and a 
mechanism 24 for adjusting the valves 22 within the port 20. 
The adjustment mechanism 24 generally includes a rotatable member 26 which 
may be adjusted to change the distance a lower enlarged head portion 22' 
of the valve 22 travel away from its seat 23. A bracket 28 mounts the 
rotatable member 26 to enable the rotatable member 26 to contact the upper 
end portion or stem portion of the valve. The rotatable member 26 
overcomes the force of the valve spring 30 to enable the valves 22 to move 
away from its seat 23. The rotatable member 26 is finely adjustable in 
very small increments to control the opening distance between the valves 
22 and their seats 23, which is commonly known as valve lift. 
The head 18 may include an exhaust port and a valve but the exhaust valves 
are maintained in the closed operative position. Alternately, a head 18 
could be used that did not include the exhaust port or valve. 
The valve inlet port 20 generally includes one or more passages to be 
tested. In a three or four valve type of head, two inlet valve ports would 
be present. The present invention enables a working simulation of modified 
heads to aid in optimizing the design of the intake port and the 
combustion chamber. The lift of the intake valve of the particular head 
can be adjusted by the adjustment mechanism 24. Ordinarily, the 
configuration and length of the port short side, designated with reference 
numeral 32, will effect the tumble of the fluid flow pattern within the 
chamber 12. Generally, a port short side having a smaller radius will 
tumble at a lower valve lift than a port short side with a larger radius. 
The head 18 also includes a peripheral edge or lip portion 34 to enable the 
head 18 to rest against or seat on the end of the chamber forming tubular 
member. The lip 34 could include apertures to enable fasteners to pass 
therethrough to secure the head 18 to the chamber forming member 10. 
The mechanism 16 for enabling fluid flow is generally comprised of a flow 
bench 49 which includes an air box 42, a flow control valve 44, a flow 
meter 46, and a blower 48. The flow bench 40 enables the chamber forming 
member to be secured thereto to provide a support for the head 18. The 
flow control valve 44 controls the air flow through the chamber 12 and 
through the system. The flow meter 46 provides a device to measure the 
quantity of flow moving through the head 18 and the chamber 12. The flow 
control valve 44 may be adjusted in response to the flow meter to provide 
a desired flow through the chamber 12. The blower 48 draws fluid through 
the head 18, the chamber 12, the air box 42 and eventually exhausts the 
fluid out exhaust port 50. Thus, the blower 48 creates the pressure 
differential between the inlet port 20 and exhaust port 50 to draw fluid 
through the system. 
The chamber 12 includes a transparent cylindrical tube 60 having radially 
outward extending flanges 62 and 64 to enable securement of the head 18 
and flow table 40, respectively, with the cylinder tube 60. The 
transparency of the cylinder tube 60 enables the operator to view the flow 
within the cylinder tube 60. The cylindrical tube 60 may be sized to 
correspond with desired sizes of particular vehicle combustion chamber 
cylinders which are to be tested. 
Within the cylinder tube 60 is a member 66 which simulates the position of 
a piston within a combustion chamber cylinder. The member 66 includes a 
screen 68 and an outer peripheral band 70. The screen 68 enables the fluid 
flow to pass through the member 66. The member 66 is vertically adjustable 
within the cylinder 60 by rod 72. The rod 72 enables the member 66 to be 
positioned at any desired vertical position along the cylinder tube 60. 
Thus, the member 66 may simulate different positions of the piston which 
correspond to a given valve lift. The simulated poston in the subject 
apparatus is in the form of a porus screen so that a continuous flow of 
air can pass from the valved inlet port of the cylinder head into the 
combustion chamber. The apparatus also uses visible and trackable 
lightweight members in the combustion chamber which move with the air flow 
away from the valved inlet ports toward the simulated piston or screen. 
When the lightweight members engage the piston simulator, they move along 
its surface in a manner similar to the flow pattern of air in an engine 
with a non-porus poston. Movement of the lightweight members away from the 
simulated piston and toward the valved inlet port simulates the air flow 
in the engine with a non-porus piston even though the general direction of 
air flow in the subject apparatus is from the ports to and through the 
simulated piston. 
A plurality of lightweight members 80 are positioned within the cylinder 
tube 60 above the member 66 within the space between the member 66 and the 
head 18. The member 66 maintains the members 80 within the simulated 
combustion chamber 12. The lightweight members 80 travel in the fluid 
stream entering from the port 20. The lightweight members 80 initially 
travel downwardly along and in the path defined by the a main and stronger 
portion of the fluid stream. Referring to FIG. 2, this main or stronger 
portion of the flow past the head 22' is created by the earlier referenced 
configuration of the seat 32 in relation to the head 22' and create the 
tumble flow shown in FIG. 2. The flow pattern in a real combustion chamber 
is simulated in the apparatus shown in FIG. 1 by a circular movement of 
the particles 80. Specifically, the particles first move downward with the 
stronger portion of the flow until they engage the screen 68. Thereafter, 
the movement is in a clockwise circular motion, first to the left along 
the screen 68 and then upwardly toward the valve head 22'. This pattern 
simulates the pattern shown in FIG. 2 by containing the particles 80 in 
said cylinder tube 60 to provide visual tracking of fluid flow entering 
tube 60 and hence simulate inlet flow into a combustion chamber cylinder 
of an internal combustion engine. 
The members 80 are generally formed from a colored foam material and are 
spherical in shape. The lightweight members 80 are either coated with a 
fluorescent coating or paint or formed from a fluorescent type foam to 
enable better visualization within the chamber 12. 
An illumination mechanism 90 is utilized to provide better viewing of the 
flow pattern of the lightweight members 80. When florescent materials are 
utilized, the illumination mechanism 90 is generally an ultraviolet light, 
black light or the like to provide light rays which cause the lightweight 
members to fluoresce thereby providing high visibility of the lightweight 
members 80. 
In use, the blower 48 is energized to create a pressure differential across 
the inlet port 20 and the exhaust port 50. Fluid is drawn through the port 
20 past the valve 22 and into the chamber 12. With a desirable tumble 
inducing port design, the fluid is drawn past the valve 22 into the 
chamber 12 and a portion will circulate within chamber 12 before being 
drawn through the screen 68 in member 66. The lightweight members 80 are 
drawn into the fluid path and along the fluid stream in the patterns 
typically illustrated in FIGS. 2-5. The members 80 are shown suspended in 
a pattern caused by the air flow as illustrated in FIG. 1. The particular 
fluid path in the chamber 12 is dependent upon the size of the cylinder, 
position of the member 66, the head porting design, and the valve lift at 
a particular air flow rate through the system. The valve lift may be 
adjusted by the mechanism 24 to provide the particular head 18 with 
alternate valve lifts to optimize the flow path within the cylinder tube 
60. 
The illumination mechanism 90 is illuminated to provide better viewing of 
the lightweight fluorescent members 80 within the chamber 12. Generally a 
video camera or the like is utilized to record a visual impression of the 
flow path or pattern within the chamber 12 as indicated by movement of 
members 80. From the information provided by the visualization of the flow 
pattern, the designer can further work to optimize the above 
characteristics to provide optimum tumble flow. 
FIGS. 2-4 illustrate the tumble flow path within a cylinder. Generally, the 
flow is in an arcuate or circular path transverse to the axis of the 
cylinder. The tumble flow pattern provides the internal combustion engine 
with the above described characteristics. FIG. 5 illustrates a spiral type 
of flow within a combustion chamber. 
While the above describes a preferred embodiment of the present invention, 
it will be understood that modifications, variations and alterations may 
be made to the present invention without deviating from the scope and fair 
meaning of the subjoined claims.