Ricardo Powertrain Award


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Introduction:
The engine used in the FSAE competition by Oakland University is a Honda 600cc
engine. Knowledge of this engine at Oakland has been growing as it was the chosen
engine for these last few years. The Honda engine used on the 2004 and 2003 car is an
F4i engine, while in the 2002 car and prior to that the F2 was used. The restrictor in the
intake system makes the engine operate very differently to the stock engine. DTA Fast
and Haltech controllers were used by the Oakland team to map the restricted engine.
1D engine simulation software packages are becoming very popular in engine design
efforts as they reduce the amount of expensive dynamometer testing required and also
make development quicker. The Oakland University team started an effort towards
engine modeling during the 2004 season. The engine modeling with Wave software
donated for this purpose by Ricardo is described in this report.



2 Experimental data
2.1 Flow bench experiments
Flow bench testing is a method of determining flow characteristics of engine cylinder
heads. As engine performance is highly dependent on engine breathing capability, flow
testing of heads and manifolds is used to improve flow characteristics. The tests reported
here were done at a steady vacuum of 28” of water below atmospheric pressure for inlet,
and 28” of water above atmospheric for exhaust. Flow rates were recorded at 1mm
increments, starting with zero lift to check for leakages and maximum lift was 9mm.
Flow tests were performed one cylinder at a time by using a bore tube adaptor that
connected the head to the flow bench. The bore tube adaptor had the same diameter as
the engine bore (67mm), and was slightly longer (or higher) than the bore (72mm). All
tests were performed at wide open throttle.

Head:
The head tested was an available F2 head from a disassembled engine, Original springs
were replaced by very soft compression springs to facilitate the rapid adjustment of valve
lift.

Intake Manifolds:
1. Stock intake manifold from the F4i engine.
2. Formula 2002 intake manifold as used in competition.
3. Formula 2003 intake manifold as used in the 2003 competition.
Testing Procedure:
Bore tube adaptor assembled to head on Cylinder #1. A temporary bellmouth was built
out of clay to the inlet runner, this aids the air to enter the port. Flow test started at zero
lift where leakages were checked to be small (they were always zero in our tests). Flow
tests at 28” H2O for valve lifts from 1mm to 9mm every 1mm were performed. Then
mounted the manifolds listed above and repeated flow tests at all valve lifts
Changed flow bench setup from inlet testing (i.e. suction) to exhaust testing (i.e.
blowing). Flow tested exhaust port from 1mm to 9mm at 1mm increments. Then
mounted the bore tube adaptor to cylinder2. Flow tested exhaust, changed flow bench to
inlet testing and repeated all inlet tests as for cylinder 1.




Results and Comments:
Figure 1 shows that the stock intake hardly restricts the head. The 2002 and 2003 intakes
show the dominant effect of the restrictor. Not much variability between 2002 and 2003
intakes, and not much variability between the runners of the 2003 intake. Hence no need
to trim the individual cylinders injector timings. The coefficients of discharge were then
calculated from the measured flows so that they were available for engine modeling.