How To: Add Pressure Input for PC-V

[barbagris]

Geezuz! What are you building now - a Star Gate Portal?

 

[sleeves]

Mate - A question - how high up are you? - ambient temps?. I have an idea forming.

Gday I,m about 1018 HPA, ambient temps go from about -3degC to 35degC sometimes in one day.

Enlighten me with your idea

 

[sleeves]

Oh this is golden

I respond to this with Zodiac Mindwarp and Prime Mover. I especially like the way the spaceship becomes an armoured car...

 

[Ishrub]

Trumped ya!

Remember this is the Age of the Orange

 

[barbagris]

Gday I,m about 1018 HPA, ambient temps go from about -3degC to 35degC sometimes in one day.

Enlighten me with your idea

sea-level ish? - my idea is still very young.

 

[sleeves]

sea-level ish? - my idea is still very young.

Oddly we are up on a hill and can look down on lakes, but by the looks of the pressure reading it is sea level so if global warming rises the sea level I could be stuffed.

 

[barbagris]

Oddly we are up on a hill and can look down on lakes, but by the looks of the pressure reading it is sea level so if global warming rises the sea level I could be stuffed

Yeah - Altitude there seems low - much like my mum. She lives on a hilltop and looks down over the valley - at the astonishing altitude of iirc 60 metres. My bike did NOT run the same there as it does here. And - my guess - now - with hindsight - TPS based tuning.

I have not actually slept well for a couple of nights now as I keep waking with EUREKA moments at 4AM. Despite heavy medication to avoid such.
I need to pull all my thoughts together before addressing them to the world. But there is a **** load of info out there and HONESTLY I realise how little most of us know and less still how to use.

So apropos of nothing at all - Here is an example of my headaches:- from "Calculators for Density Altitude and Engine Tuning": Use the ISA standard values for conditions at sea level. P = 101325 Pa T = 15 deg C The air density is calculated to be: D = (101325) / (287.05 * (15 + 273.15)) = 1.2250 kg/m3

15 degrees C - that's winter. We were at 37°C last week. And nowhere near 1013hPa - My gut says I had about 19-20% less O² available - So it needed to use 19-20% less fuel-ish to maintain lambda. This is obviously countered by running the engine harder to compensate. But ............................

 

[sleeves]

Yeah - Altitude there seems low - much like my mum. She lives on a hilltop and looks down over the valley - at the astonishing altitude of iirc 60 metres. My bike did NOT run the same there as it does here. And - my guess - now - with hindsight - TPS based tuning.

I have not actually slept well for a couple of nights now as I keep waking with EUREKA moments at 4AM. Despite heavy medication to avoid such.
I need to pull all my thoughts together before addressing them to the world. But there is a **** load of info out there and HONESTLY I realise how little most of us know and less still how to use.

So apropos of nothing at all - Here is an example of my headaches:- from "Calculators for Density Altitude and Engine Tuning": Use the ISA standard values for conditions at sea level. P = 101325 Pa T = 15 deg C The air density is calculated to be: D = (101325) / (287.05 * (15 + 273.15)) = 1.2250 kg/m3

15 degrees C - that's winter. We were at 37°C last week. And nowhere near 1013hPa - My gut says I had about 19-20% less O² available - So it needed to use 19-20% less fuel-ish to maintain lambda. This is obviously countered by running the engine harder to compensate. But ............................

What really screws with my head is the inlet "pressures" are actually vacuum but the readings are based absolute pressure. We talk about zero pressure at ground level but its actually one bar. To make sense of this we call sea level 0 bar and absolute zero -1bar.

There's also temperature, one guy (assuming it was a guy) froze water and made this 0, boiled water made it 100, and scaled accordingly this was Celsius. Another guy made a scale and then marked the scale when water froze and marked the scale when water boiled, this was Farenheit. Neither were wrong but I prefer Celsius.

In regard to the elevation an oxygen density you are correct this is where a WBO2 comes in with auto tune to compensate as the AT goes up there's less oxygen so the WBO2 should (I say should) and lean the mixture to suit. This is probably why they are stock set at 20% ??

In South Island of NZ there's some ranges called the Crown Ranges, near Cardrona (Google it, Cardrona Pub) good scenery, superb road, you climb very high very quickly bike is always running like rubbish at top as I leave AT at +/-5% trimming, comes right on way down again, next time I should allow more trims to experiment but its a long way from home sadly.

Its also usually a **** sight colder down there than home which should mean more O2 also.

I think it may be hard to calculate as higher altitude means less O2 but colder air temps means denser air and more O2. Now I'm confusing myself, off to bed with me.

 

[barbagris]

What really screws with my head is the inlet "pressures" are actually vacuum but the readings are based absolute pressure. We talk about zero pressure at ground level but its actually one bar. ..... I think it may be hard to calculate as higher altitude means less O2 but colder air temps means denser air and more O2. Now I'm confusing myself, off to bed with me.

I do understand the headache.

Now of course we have an "ISSUE" here. The Keihin ECU - almost certainly compensates for Barometric Change, Air Intake Temp Change as well as doing weird stuff like set different Lambda targets for F or L tables, transitional enrichment and a shag load of other stuff that only very few seem to understand - That Mr @Speedy occasionally makes my head ache. And then we lump a percentual enrichment/de-enrichment box in between said ECU and engine with no feedback on said compensatory measures and wonder WHY it'S not all tickety boo and pukka.

I am actually thinking of stopping the PCV from compensating and simply (for now) logging the AFR - Oh god! - I dunno - my head hurts again.

 

[barbagris]

one guy (assuming it was a guy)

It's all a bit complicated - but ---

The Celsius scale, previously known as the centigrade scale, is a temperature scale used by the International System of Units (SI). As an SI derived unit, it is used by all countries except the United States and Liberia. It is named after the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale. The degree Celsius (symbol: °C) can refer to a specific temperature on the Celsius scale as well as a unit to indicate a temperature interval, a difference between two temperatures or an uncertainty. Before being renamed to honor Anders Celsius in 1948, the unit was called centigrade, from the Latin centum, which means 100, and gradus, which means steps.

Before 1954, the Celsius scale was based on 0 °C for the freezing point of water and 100 °C for the boiling point of water at 1 atm pressure following a change introduced in 1743 by Jean-Pierre Christin to reverse the Celsius thermometer scale (from water boiling at 0 degrees and ice melting at 100 degrees). This scale is widely taught in schools today.

By international agreement, since 1954 the unit "degree Celsius" and the Celsius scale are defined by absolute zero and the triple point of Vienna Standard Mean Ocean Water (VSMOW), a specially purified water. This definition also precisely relates the Celsius scale to the Kelvin scale, which defines the SI base unit of thermodynamic temperature with symbol K. Absolute zero, the lowest temperature possible, is defined as being exactly 0 K and −273.15 °C. The temperature of the triple point of water is defined as exactly 273.16 K (0.01 °C; 32.02 °F).

The Fahrenheit scale is a temperature scale based on one proposed in 1724 by Dutch–German–Polish physicist Daniel Gabriel Fahrenheit (1686–1736). It uses the degree Fahrenheit (symbol: °F) as the unit. Several accounts of how he originally defined his scale exist. The lower defining point, 0 °F, was established as the temperature of a solution of brine made from equal parts of ice, water and salt (ammonium chloride). Further limits were established as the melting point of ice (32 °F) and his best estimate of the average human body temperature (96 °F, about 2.6 °F less than the modern value due to a later redefinition of the scale). The scale is now usually defined by two fixed points: the temperature at which water freezes into ice is defined as 32 °F, and the boiling point of water is defined to be 212 °F, a 180 °F separation, as defined at sea level and standard atmospheric pressure.

Of course this only matters to Americans. The rest of us know that the metric system not only works but does not depend on a system of volume based on liquid loss during a sea voyage or two.