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If I understand your question correctly: The ideal diesel and otto cycle efficiency calculations do not account for heat transfer from the engine to the coolant. This will account for around 40% of the total fuel heating value. Mechanical losses depend on what accessories are attached to the...

Also, the compression ignition permits higher a/f ratios to be used.

I don't have a link, but an old Spearco catalog I have plots Efficiency on the left y-axis, Outlet Flow in CFM on the x-axis. There are multiple efficiency lines for various vehicle speeds, and one pressure drop line (right y-axis). The data all assumes a set boost pressure (10 psi).

It could be due to blade erosion. I've seen photos of comopressor blades that have been worn down due to water injection before the turbo.

Thank you EngJW. That seems to be the part I was missing, how the displacement of a rotary is rated. The rotor also spins at 1/3 the output shaft speed, so Flow= Output Shaft Speed x Rated Displacement x Volumetric Efficiency x 2/3 This seems to match well with the dyno numbers.

I know how to calculate the volume flow of a 4-stroke piston engine, Engine Speed x Displacement x Volumetric Efficiency / 2. How can a similiar calculation be done for a Wankel engine? I've read the previous topics on this board and scoured Google but came with no satisfactory results.

At lower engine RPMs and little load situations (cruise) the turbine, if connected directly to the crankshaft, will be be of no benefit and will be a drag on the engine. A turbine requires a certain amount of exhaust flow before it spools up, or in the case of turbocompounding starts making...

I should add my comments apply to US vehicles, so it is understood where I am coming from.

A big obstacle for increased performance in IC engines is the need for the exhaust temperature to be high enough for the catalytic converter to operate. Because of this, we have California emmissions-compliant cars with 8.X:1 compression ratios, and the near extinction of turbocharged gasoline...

Yes, I've seen that chart- One of the reasons I got interested in the subject! I did find research report that has some interesting knock-threshhold tests: http://naca.larc.nasa.gov/reports/1946/naca-tn-1131/naca-tn-1131.pdf

This is a fascinating thread. Here is another link to the patent: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=/netahtml/srchnum.htm&r=1&f=G&l=50&s1=4,862,859.WKU.&OS=PN/4,862,859&RS=PN/4,862,859

Running some calculations, it looks like putting an intercooler after a positive displacement supercharger will result in lower pressure after the blower, all else being equal (vs. non-intercooled). My reasoning is that the blower alone is what determines the mass air-flow into the engine...

After a quick search, I couldn't find a chart on the internet, but there is the "Generalized Compressibility Chart" which gives the gas law for a real gas, Z=Pv/RT. For an Ideal gas, the Compressibility Factor, Z, is 1, thus resulting in Pv=RT. Z is a function of: Reduced Pressure...

Here are some further clarifications: For a steady flowing gas, if there is a temperature change, energy has either been added to it or removed. For relatively low velocity change between points 1 and 2: Change in Energy=Cp x (T2-T1). where Cp is Specific heat at constant pressure, assumed...

Edit to last line above: Now, as explained by other members there is evaportaion which does cause the temperature to lower.

Chumley, Let's get some context here: My post was in reply to SBBlue's opening post: "According to my calculations, dropping the pressure of a container of air from one atmosphere of pressure to one-fourth atmosphere will drop the temperature from 80 deg F (assumed ambient) to something like...

SBBlue: I think you assumed the expansion across the throttle is isentropic, which is far from the case. A turbine, with high isentropic efficiency will take energy (heat) out of a fluid stream and turn it into shaft work, leaving the fluid cooler. A throttle does not extract energy from the...

Someone can correct me if I'm wrong, but I believe most non-racing DOHC engines have VE in the 100% range at peak torque, and around 90% at peak HP. If this is just for turbocharger selection, just say 90-100% and you should be fine. I don't think they will suggest a turbo that puts you within...

On the NACA site is a great paper: http://naca.larc.nasa.gov/reports/1946/naca-tn-1131/naca-tn-1131.pdf which charts the effect of Compression Ratio, Spark Advance, Inlet Air Temp, Coolant Temp, and Engine Speed against knock-limited IMEP (Proportional to torque) for 3 different fuels. Does...

Pat- Thanks for the site! Lots of good stuff there, I'll be combing through it. You can cool air below ambient temperature using an air/water intercooler with ice, or dry-ice. I just used "ambient temperature" as an example, since I'm basically trying to find out if the only reason you have...