Geeks: Heat Transfer Calculation Help
11-05-2002, 07:58 AM
#1
Member
Thread Starter
Join Date: Sep 2000
Posts: 55
Geeks: Heat Transfer Calculation Help
Don't read this if your not a geek:
What is the average weight of a maxima engine with and without a transmission?
What is the percent iron versus aluminum?
What do you think the average temperature of your engine is after running it for twenty minutes?
Now all this is not meant to be exact. This is a guesstimate, although I would like good numbers for iron, aluminum, and weights.
What I am attempting to do for the hell of it is calculate how much heat comes off of an engine after it has run for twenty minutes.
MCdeltaT = mass of engine * heat capacity of metals * (Temp of engine - 50 F).
What is the average weight of a maxima engine with and without a transmission?
What is the percent iron versus aluminum?
What do you think the average temperature of your engine is after running it for twenty minutes?
Now all this is not meant to be exact. This is a guesstimate, although I would like good numbers for iron, aluminum, and weights.
What I am attempting to do for the hell of it is calculate how much heat comes off of an engine after it has run for twenty minutes.
MCdeltaT = mass of engine * heat capacity of metals * (Temp of engine - 50 F).
11-05-2002, 09:47 AM
#2
the density of AL is .10 lbs/in^3. just take a rough measurement of the engine block to get the weight. since the main engine block is AL, do you even need to consider the other components? As for the temperature, you can find the temp of combustion and that will be the heat on the inside wall of the cylinder. anything on combustion should have some info on that. use that to find the heat on the outside wall of the cylinder.
if you are trying to find the heat inside the engine bay after its running for 20 min, use a thermomenter. =P but it will be different if you are sitting still or moving.
if you are trying to find the heat inside the engine bay after its running for 20 min, use a thermomenter. =P but it will be different if you are sitting still or moving.
11-05-2002, 10:27 AM
#3
vicodin ... gift of life
Join Date: Apr 2002
Location: norcal
Posts: 5,401
Originally posted by vinnieloo
the density of AL is .10 lbs/in^3. just take a rough measurement of the engine block to get the weight. since the main engine block is AL, do you even need to consider the other components? As for the temperature, you can find the temp of combustion and that will be the heat on the inside wall of the cylinder. anything on combustion should have some info on that. use that to find the heat on the outside wall of the cylinder.
if you are trying to find the heat inside the engine bay after its running for 20 min, use a thermomenter. =P but it will be different if you are sitting still or moving.
the density of AL is .10 lbs/in^3. just take a rough measurement of the engine block to get the weight. since the main engine block is AL, do you even need to consider the other components? As for the temperature, you can find the temp of combustion and that will be the heat on the inside wall of the cylinder. anything on combustion should have some info on that. use that to find the heat on the outside wall of the cylinder.
if you are trying to find the heat inside the engine bay after its running for 20 min, use a thermomenter. =P but it will be different if you are sitting still or moving.
11-05-2002, 12:33 PM
#7
vinnieloo: Remember that the block is an aluminum alloy, not pure aluminum. You'd have to do a lot more research to find out the true density of the block. You'd also be estimating the volume by measuring its dimensions. You may as well place the block in water and see how much it displaces to get an accurate reading 
rp95se: are you taking thermo or something?
-hype
rp95se: are you taking thermo or something?
-hype
11-05-2002, 12:52 PM
#9
Guest
Posts: n/a
Re: Geeks: Heat Transfer Calculation Help
These are all reallllly ballpark guesstimates:
- VQ engine block (including heads): 450 lbs
- " w/ tranny: 600 lbs
- 20% iron alloy(camshafts, crankshaft, rods, pistons, valves, pullies)
- 5% cast iron (exhaust manifolds)
- Average temperature of the engine block after running for 20 min would be equivalent to the coolant temp, so I'd guess ~180 degF
As Hype mentioned, the engine is an Al alloy, not pure Al. You should be able to look up the thermal properties for various Al alloys, though, and get some ballpark values. Do the same for the Fe alloy.
Like I said, these are realllly ballpark guesstimates.
- VQ engine block (including heads): 450 lbs
- " w/ tranny: 600 lbs
- 20% iron alloy(camshafts, crankshaft, rods, pistons, valves, pullies)
- 5% cast iron (exhaust manifolds)
- Average temperature of the engine block after running for 20 min would be equivalent to the coolant temp, so I'd guess ~180 degF
As Hype mentioned, the engine is an Al alloy, not pure Al. You should be able to look up the thermal properties for various Al alloys, though, and get some ballpark values. Do the same for the Fe alloy.
Like I said, these are realllly ballpark guesstimates.
Originally posted by rp95se
Don't read this if your not a geek:
What is the average weight of a maxima engine with and without a transmission?
What is the percent iron versus aluminum?
What do you think the average temperature of your engine is after running it for twenty minutes?
Now all this is not meant to be exact. This is a guesstimate, although I would like good numbers for iron, aluminum, and weights.
What I am attempting to do for the hell of it is calculate how much heat comes off of an engine after it has run for twenty minutes.
MCdeltaT = mass of engine * heat capacity of metals * (Temp of engine - 50 F).
Don't read this if your not a geek:
What is the average weight of a maxima engine with and without a transmission?
What is the percent iron versus aluminum?
What do you think the average temperature of your engine is after running it for twenty minutes?
Now all this is not meant to be exact. This is a guesstimate, although I would like good numbers for iron, aluminum, and weights.
What I am attempting to do for the hell of it is calculate how much heat comes off of an engine after it has run for twenty minutes.
MCdeltaT = mass of engine * heat capacity of metals * (Temp of engine - 50 F).
11-05-2002, 12:58 PM
#10
Re: Re: Geeks: Heat Transfer Calculation Help
Originally posted by Keven97SE
These are all reallllly ballpark guesstimates:
- VQ engine block (including heads): 450 lbs
- " w/ tranny: 600 lbs
- 20% iron alloy(camshafts, crankshaft, rods, pistons, valves, pullies)
- 5% cast iron (exhaust manifolds)
- Average temperature of the engine block after running for 20 min would be equivalent to the coolant temp, so I'd guess ~180 degF
As Hype mentioned, the engine is an Al alloy, not pure Al. You should be able to look up the thermal properties for various Al alloys, though, and get some ballpark values. Do the same for the Fe alloy.
Like I said, these are realllly ballpark guesstimates.
These are all reallllly ballpark guesstimates:
- VQ engine block (including heads): 450 lbs
- " w/ tranny: 600 lbs
- 20% iron alloy(camshafts, crankshaft, rods, pistons, valves, pullies)
- 5% cast iron (exhaust manifolds)
- Average temperature of the engine block after running for 20 min would be equivalent to the coolant temp, so I'd guess ~180 degF
As Hype mentioned, the engine is an Al alloy, not pure Al. You should be able to look up the thermal properties for various Al alloys, though, and get some ballpark values. Do the same for the Fe alloy.
Like I said, these are realllly ballpark guesstimates.
11-05-2002, 01:01 PM
#11
I knew Keven would chime in here with his advanced Maxima/thermo information The calculations are already super ballpark, but would it matter that the 5 spds and autos have a different mass? I know a lot of the weight is due to internals, so in this situation are you only dealing with the metal that conduct the heat (i.e. the case)?
May as well learn something from this post
-hype
The calculations are already super ballpark, but would it matter that the 5 spds and autos have a different mass? I know a lot of the weight is due to internals, so in this situation are you only dealing with the metal that conduct the heat (i.e. the case)?May as well learn something from this post
-hype
11-05-2002, 01:01 PM
#12
Guest
Posts: n/a
Re: Re: Re: Geeks: Heat Transfer Calculation Help
Well, based on my #s above, 450 - 450*0.25 = 337 lbs for the block and heads. Heads are ~50 lbs each, so I guess ~200-250 for just the block. Seems a bit on the high side to me. I may have overestimated.
Originally posted by MadMax95
How much do you suppose just the block weighs?
How much do you suppose just the block weighs?
11-05-2002, 01:04 PM
#13
Re: Re: Re: Re: Geeks: Heat Transfer Calculation Help
Originally posted by Keven97SE
Well, based on my #s above, 450 - 450*0.25 = 337 lbs for the block and heads. Heads are ~50 lbs each, so I guess ~200-250 for just the block. Seems a bit on the high side to me. I may have overestimated.
Well, based on my #s above, 450 - 450*0.25 = 337 lbs for the block and heads. Heads are ~50 lbs each, so I guess ~200-250 for just the block. Seems a bit on the high side to me. I may have overestimated.
Correction
The block alone: 62lbs
Crank alone: 37lbs
11-05-2002, 01:04 PM
#14
Guest
Posts: n/a
The auto tranny weighs ~70 lbs more than the 5speed. A lot of that is due to the additional fluid and the torque converter, though. The case is bigger, though. I'd guess the case alone weighs 30-40 lbs more.
Originally posted by xHypex
I knew Keven would chime in here with his advanced Maxima/thermo information The calculations are already super ballpark, but would it matter that the 5 spds and autos have a different mass? I know a lot of the weight is due to internals, so in this situation are you only dealing with the metal that conduct the heat (i.e. the case)?
May as well learn something from this post
-hype
I knew Keven would chime in here with his advanced Maxima/thermo information
The calculations are already super ballpark, but would it matter that the 5 spds and autos have a different mass? I know a lot of the weight is due to internals, so in this situation are you only dealing with the metal that conduct the heat (i.e. the case)?May as well learn something from this post
-hype
11-05-2002, 08:37 PM
#15
Member
Join Date: Apr 2002
Posts: 139
The only specific weights (for a 2001) I could find were:
Crankshaft: 15.88 kg
Piston, Pin, Rod, and Rings: 0.757 kg each
Flywheel: 7.26 kg
As for the block itself I found several articles mentioning the 4th gen block was 50% lighter than the 3rd gens. Another article said the 4th gen block was 49 kg lighter than the 3rd gen. This implies the 4th gen block is about 49 kg (108 lbs). I don't know how much heavier (or lighter) a 5th gen block is but I assume they're relatively close. Madmax95 says the block weighs 62 lbs so the 108 number probably includes the headers but I'm just guessing.
Of course, I'm still not quite sure what you want to do with all this. The equation you originally quoted would only give you the amount of thermal energy stored in the parts (and note your equation should be using the specific heat capacity of the compounds in question, but that's spliting hairs). The stored thermal energy will only tell you how much heat the engine would give off after you shut it down. It doesn't tell you anything about how much heat it gives off while running. Also, you can't forget about the cooling system. Water has 8 times the specific heat capacity of iron so even if only 2 L of the coolant systems 9 or so litres is in the engine and header that's the equivalent of 16 kg (~32lbs) of steel (roughly reduce this by 25% for 50/50 mix antifreeze). If you're trying to figure out how much heat will be given off in total (after shutdown) you should probably include the entire coolant system.
Anyway, for the record, some of the specific heat capacities you'd be interested in are:
Aluminum: 900 J/kgC
Aluminum Alloy: 700-1000 J/kgC (depending on type)
Iron: 448 J/kgC
Water: 4186 J/kgC
Crankshaft: 15.88 kg
Piston, Pin, Rod, and Rings: 0.757 kg each
Flywheel: 7.26 kg
As for the block itself I found several articles mentioning the 4th gen block was 50% lighter than the 3rd gens. Another article said the 4th gen block was 49 kg lighter than the 3rd gen. This implies the 4th gen block is about 49 kg (108 lbs). I don't know how much heavier (or lighter) a 5th gen block is but I assume they're relatively close. Madmax95 says the block weighs 62 lbs so the 108 number probably includes the headers but I'm just guessing.
Of course, I'm still not quite sure what you want to do with all this. The equation you originally quoted would only give you the amount of thermal energy stored in the parts (and note your equation should be using the specific heat capacity of the compounds in question, but that's spliting hairs). The stored thermal energy will only tell you how much heat the engine would give off after you shut it down. It doesn't tell you anything about how much heat it gives off while running. Also, you can't forget about the cooling system. Water has 8 times the specific heat capacity of iron so even if only 2 L of the coolant systems 9 or so litres is in the engine and header that's the equivalent of 16 kg (~32lbs) of steel (roughly reduce this by 25% for 50/50 mix antifreeze). If you're trying to figure out how much heat will be given off in total (after shutdown) you should probably include the entire coolant system.
Anyway, for the record, some of the specific heat capacities you'd be interested in are:
Aluminum: 900 J/kgC
Aluminum Alloy: 700-1000 J/kgC (depending on type)
Iron: 448 J/kgC
Water: 4186 J/kgC
11-06-2002, 05:22 AM
#16
Senior Member
Join Date: Sep 2000
Posts: 2,117
rp95se >>
Originally posted by rp95se
...What I am attempting to do...is calculate how much heat comes off of an engine after it has run for twenty minutes...
...What I am attempting to do...is calculate how much heat comes off of an engine after it has run for twenty minutes...
11-06-2002, 06:53 AM
#17
Originally posted by Myrv
The only specific weights (for a 2001) I could find were:
Crankshaft: 15.88 kg
Piston, Pin, Rod, and Rings: 0.757 kg each
Flywheel: 7.26 kg
As for the block itself I found several articles mentioning the 4th gen block was 50% lighter than the 3rd gens. Another article said the 4th gen block was 49 kg lighter than the 3rd gen. This implies the 4th gen block is about 49 kg (108 lbs). I don't know how much heavier (or lighter) a 5th gen block is but I assume they're relatively close. Madmax95 says the block weighs 62 lbs so the 108 number probably includes the headers but I'm just guessing.
Of course, I'm still not quite sure what you want to do with all this. The equation you originally quoted would only give you the amount of thermal energy stored in the parts (and note your equation should be using the specific heat capacity of the compounds in question, but that's spliting hairs). The stored thermal energy will only tell you how much heat the engine would give off after you shut it down. It doesn't tell you anything about how much heat it gives off while running. Also, you can't forget about the cooling system. Water has 8 times the specific heat capacity of iron so even if only 2 L of the coolant systems 9 or so litres is in the engine and header that's the equivalent of 16 kg (~32lbs) of steel (roughly reduce this by 25% for 50/50 mix antifreeze). If you're trying to figure out how much heat will be given off in total (after shutdown) you should probably include the entire coolant system.
Anyway, for the record, some of the specific heat capacities you'd be interested in are:
Aluminum: 900 J/kgC
Aluminum Alloy: 700-1000 J/kgC (depending on type)
Iron: 448 J/kgC
Water: 4186 J/kgC
The only specific weights (for a 2001) I could find were:
Crankshaft: 15.88 kg
Piston, Pin, Rod, and Rings: 0.757 kg each
Flywheel: 7.26 kg
As for the block itself I found several articles mentioning the 4th gen block was 50% lighter than the 3rd gens. Another article said the 4th gen block was 49 kg lighter than the 3rd gen. This implies the 4th gen block is about 49 kg (108 lbs). I don't know how much heavier (or lighter) a 5th gen block is but I assume they're relatively close. Madmax95 says the block weighs 62 lbs so the 108 number probably includes the headers but I'm just guessing.
Of course, I'm still not quite sure what you want to do with all this. The equation you originally quoted would only give you the amount of thermal energy stored in the parts (and note your equation should be using the specific heat capacity of the compounds in question, but that's spliting hairs). The stored thermal energy will only tell you how much heat the engine would give off after you shut it down. It doesn't tell you anything about how much heat it gives off while running. Also, you can't forget about the cooling system. Water has 8 times the specific heat capacity of iron so even if only 2 L of the coolant systems 9 or so litres is in the engine and header that's the equivalent of 16 kg (~32lbs) of steel (roughly reduce this by 25% for 50/50 mix antifreeze). If you're trying to figure out how much heat will be given off in total (after shutdown) you should probably include the entire coolant system.
Anyway, for the record, some of the specific heat capacities you'd be interested in are:
Aluminum: 900 J/kgC
Aluminum Alloy: 700-1000 J/kgC (depending on type)
Iron: 448 J/kgC
Water: 4186 J/kgC
You a chemist or have a book handy?
11-06-2002, 07:52 AM
#18
Member
Join Date: Apr 2002
Posts: 139
Originally posted by MadMax95
You a chemist or have a book handy?
You a chemist or have a book handy?
11-06-2002, 07:57 AM
#19
Originally posted by Myrv
Actually I'm a physicist but I only knew the specific heat capacity of water off the top of my head (water has many unique properties and this one was hammered into me in my thermodynamics class). For the rest I had a book (one of my old textbooks to be exact).
Actually I'm a physicist but I only knew the specific heat capacity of water off the top of my head (water has many unique properties and this one was hammered into me in my thermodynamics class). For the rest I had a book (one of my old textbooks to be exact).
I didn't know whether to be impressed or scared that you came up with those numbers so quickly...
Thread
Thread Starter
Forum
Replies
Last Post
tarun900
4th Generation Maxima (1995-1999)
19
12-20-2021 06:57 PM
Derrick2k2SE
5th Generation Maxima (2000-2003)
9
11-19-2015 10:14 PM