New to excel Help

[sway]

hello
I am new to this forum and not good with excel.

this is a brief explaination of what i need to do to kick things off. I hop somebosy can help

have a calculation for temperature that i have 25 deg figures for. I need to be able to create a excel calculation for any given value (in deg). I have a table of values run from a line of best fit basis.

so far my equation is eg

D1=(A1*B1)*C1

F1=D1/ratio in table pre determinded by the temp in E1


Can anybody help

Scott

[email protected]

[BenjieLop]

hello
I am new to this forum and not good with excel.

this is a brief explaination of what i need to do to kick things off. I hop somebosy can help

have a calculation for temperature that i have 25 deg figures for. I need to be able to create a excel calculation for any given value (in deg). I have a table of values run from a line of best fit basis.

so far my equation is eg

D1=(A1*B1)*C1

F1=D1/ratio in table pre determinded by the temp in E1


Can anybody help

Scott

[email protected]

In Cell D1, enter this formula

=A1*B1*C1

and in Cell F1, your formula will look like

=D1/ratio from table predetermined by the temp in E1

I believe that the "ratio from table predetermined by the temp in E1" can be a value obtained using the VLOOKUP function. I am assuming that for every temperature in Cell E1, there is a corresponding ratio. Perhaps if I know how the table looks like, I can give you a more specific formula to use.

Regards.

[sway]

Thanks. Here is a breakdown of the equation and what it represents etc
Its basically to work out a fuel injection ratio for a water/methanol injection system.

the equation goes

peak fuel useage (petrol)x injector duty cycle (percentage) x AFR (air fuel ratio)

This part gives the amount of airflow in the same unit as the fuel injected.

This airflo figure needs to be then divided by the water injection ratio in a table to give the correct amount to be injected.

The first part i have the equation for but at the moment i have to add the water injection ratio manually. This is not a problem but i would like to replace the water injection ratio box with air temperature to make it idiot proof.
From the look of the Vlookup facility i could get it to referance the water injection ratio using the air temp as an index. This has moved the game up a level and again more complicated.

I have the ratios for 0,25,50,75,100,125 etc etc. If i was to use VLOOKUP i presume it would only be able to give an answer for 0 25 50 75 etc. Ultimatly i would like it to allow the user to input any number within the range i have figures for (0-300 deg C) and it adds the ratio to the equation.

Im not sure if i have explained all this suitably. If its possible to give me any assistance it would be greatly appreciated.

Scott

example of table

air temp ................Ratio
25................ 177.5
50................ 62
75 ................ 36.5
100............... 25.6
etc etc

[BenjieLop]

Thanks. Here is a breakdown of the equation and what it represents etc
Its basically to work out a fuel injection ratio for a water/methanol injection system.

the equation goes

peak fuel useage (petrol)x injector duty cycle (percentage) x AFR (air fuel ratio)

This part gives the amount of airflow in the same unit as the fuel injected.

This airflo figure needs to be then divided by the water injection ratio in a table to give the correct amount to be injected.

The first part i have the equation for but at the moment i have to add the water injection ratio manually. This is not a problem but i would like to replace the water injection ratio box with air temperature to make it idiot proof.
From the look of the Vlookup facility i could get it to referance the water injection ratio using the air temp as an index. This has moved the game up a level and again more complicated.

I have the ratios for 0,25,50,75,100,125 etc etc. If i was to use VLOOKUP i presume it would only be able to give an answer for 0 25 50 75 etc. Ultimatly i would like it to allow the user to input any number within the range i have figures for (0-300 deg C) and it adds the ratio to the equation.

Im not sure if i have explained all this suitably. If its possible to give me any assistance it would be greatly appreciated.

Scott

example of table

air temp ................Ratio
25................ 177.5
50................ 62
75 ................ 36.5
100............... 25.6
etc etc

ASSUME that your Air Temp/Ratio table has this range : X2:Y100

Hence, your "ratio from table predetermined by the temp in E1" is obtained by using this VLOOKUP formula:

=vlookup(E1,$X$2:$Y$100,2)

and, as you stated, this formula is sort of limited as it will only give you the ratio for temperatures such as 0, 25, 50, 75, 100, etc. It is a good start though.

I do not know, at this point, how the Air Temp and the Ratio are corellated in your table. Is there a formula that relates the two factors? Or, will the ratio at any given air temperature (besides 0, 25, 50,etc.) be interpolated? As soon as we know how the Ratio and the Air Temp are related, then we can derive a formula that will apply to your situation.

If you want you can email me directly at

BenjieLopathoustondotrrdotcom

and we'll see if we can work out a formula for your use.

Regards.