Quote:
Originally Posted by jamesqf
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I'm not having much luck with that link.
Quote:
Originally Posted by jamesqf
I'd really question the need for water injection. After all, the turbo is designed to extract power from the hot exhaust gas stream.
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The installation location was inspired by the
Squires Turbo System but we have different goals. They want to stuff more fuel and air into the engine and I want to use the residual exhaust stream energy to generate electricity. However, I agree with many of
their claims about a rear-mounted turbine:
- lower turbine inlet - more so with water injection to further convert waste heat into more exhaust stream pressure.
- turbine outlet closer to lowest possible outlet pressure - to improve the pressure ratio and energy extraction.
- simpler plumbing - since I'm converting the turbine power to electric power near the traction battery, no compressed gas piping to the engine. It will be much easier to work on as the muffler volume and location is easily reached.
By injecting water, I'm making the exhaust pipe into a steam boiler. Then the turbine can extract the additonal mechanical energy from the enhanced exhaust stream. But this is why we test, to find out if it is necessary.
In a normal turbo installation, significant turbine power occurs when the engine is operated in high-power regions. But our Prius typically operates in low power regions with more modest gas flows and heat. Water injection allows this lower flow rate, lower energy stream to get a kinetic boost to generate hopefully a significant power boost that we add to the traction battery.
We really won't know the true metrics until the system is integrated. Obviously when in hybrid mode and the engine is off, there won't be any turbine power extracted. My expectation is in normal urban traffic with more modest exhaust-gas and heat flow, water injection will extract usable energy. Then when accelerating or climbing a hill, water injection will not be needed.
SOME TESTING EQUIPMENTS
- lower left - 3" magnet with 1" center hole
- upper left - early, low rpm test spindle that became unstable at higher rpms
- right - brass plumbing valve stem used as solid shaft for faster rpm and early, aluminum disk test
Bob Wilson