Toshiba TV29C90 problem; Image fades to black...

[Bert]

b [reverend_rogers@yahoo.com] said:

Gummo ha escrito:
My son's fridge/freezer has been leaking gas tonight. It doesn't look good
for the fridge - I told him to turn it off and open the kitchen window.

The question is, although Curry's one year guarantee expired a year ago and
knowing that, by law, the appliance should last at least 5 years before
something like this happens, who do I hold responsible? Currys or Hoover?

Gummo

cross posted to sci electronics repair. maybe someone there cn shed
some light on the cause .

On the basis that fridge coolant is a, in a secret life, really an
electronic component?

 

[Sam Goldwasser]

Bert <Albert@coldmail.com.invalid> writes:

said:

Gummo ha escrito:
My son's fridge/freezer has been leaking gas tonight. It doesn't look good
for the fridge - I told him to turn it off and open the kitchen window.

The question is, although Curry's one year guarantee expired a year ago and
knowing that, by law, the appliance should last at least 5 years before
something like this happens, who do I hold responsible? Currys or Hoover?

Gummo

cross posted to sci electronics repair. maybe someone there cn shed
some light on the cause .

On the basis that fridge coolant is a, in a secret life, really an
electronic component?

Degreaser?

Or, that it's an electronic problem once the compressor burns out.

Seriously, perflectly legitimate to post here.

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

 

[Captain Midnight]

"Yukio YANO" <yano@shaw.ca> wrote in message
news:Tr7Jh.13286$DN.1062@pd7urf2no...

b wrote:
Gummo ha escrito:
My son's fridge/freezer has been leaking gas tonight. It doesn't look
good
for the fridge - I told him to turn it off and open the kitchen window.

The question is, although Curry's one year guarantee expired a year ago
and
knowing that, by law, the appliance should last at least 5 years before
something like this happens, who do I hold responsible? Currys or
Hoover?

Gummo

cross posted to sci electronics repair. maybe someone there cn shed
some light on the cause .

There is a 5 year warranty on the Compressor !

There is NO guaranty on defrosting using a Knife or Icepick !!

I regularly used to tell my junior Technicians, "Don't bother trying to
speed up defrosting the Lab Freezers with a knife or icepick". Just put
it on a dolly and put it out on the loading dock for the dump , and save
everybody a lot of time and trouble.
The proper way to Defrost a freezer is Just unplug the freezer and place
a large pan of hot water in the freezer and close the door, replace the
pan with more hot water until all the ice melts. All you need to do is
scratch the Evaporator to destroy it !! This is NOT covered under
warranty.

Yukio YANO

I use a hair dryer on low heat even though I own a heat gun. Above freezing
air is practically as effective as hot air. Air flow is more important than
temperature. Still air has a boundary layer, that acts like insulation, you
want to keep broken.Water forms a boundary layer too. That's why bath water
feels warmer when you move after a period of soaking.

 

[Homer J Simpson]

"Captain Midnight" <Notany@twip.invalid> wrote in message
news:45f5cf8d$0$4876$4c368faf@roadrunner.com...

I use a hair dryer on low heat even though I own a heat gun. Above
freezing
air is practically as effective as hot air. Air flow is more important
than
temperature. Still air has a boundary layer, that acts like insulation,
you
want to keep broken.Water forms a boundary layer too. That's why bath
water
feels warmer when you move after a period of soaking.

I've used a fan heater on low.

 

[James Sweet]

There is NO guaranty on defrosting using a Knife or Icepick !!

I regularly used to tell my junior Technicians, "Don't bother trying to
speed up defrosting the Lab Freezers with a knife or icepick". Just put
it on a dolly and put it out on the loading dock for the dump , and save
everybody a lot of time and trouble.
The proper way to Defrost a freezer is Just unplug the freezer and place
a large pan of hot water in the freezer and close the door, replace the
pan with more hot water until all the ice melts. All you need to do is
scratch the Evaporator to destroy it !! This is NOT covered under warranty.

What would be nice is a valve to short circuit the metering device and
let the hot vapor from the compressor flow straight into the evaporator
coils. That would defrost it in a matter of minutes. I've heard of a few
very old refrigerators that worked this way but nothing modern does it.

 

[DaveM]

"James Sweet" <jamessweet@hotmail.com> wrote in message
news:t6oJh.11544$mh7.3573@trnddc04...

There is NO guaranty on defrosting using a Knife or Icepick !!

I regularly used to tell my junior Technicians, "Don't bother trying to speed
up defrosting the Lab Freezers with a knife or icepick". Just put it on a
dolly and put it out on the loading dock for the dump , and save everybody a
lot of time and trouble.
The proper way to Defrost a freezer is Just unplug the freezer and place a
large pan of hot water in the freezer and close the door, replace the pan
with more hot water until all the ice melts. All you need to do is scratch
the Evaporator to destroy it !! This is NOT covered under warranty.



What would be nice is a valve to short circuit the metering device and let the
hot vapor from the compressor flow straight into the evaporator coils. That
would defrost it in a matter of minutes. I've heard of a few very old
refrigerators that worked this way but nothing modern does it.

Admittedly not a refrigerator, but still a refrigeration system, heat pump HVAC
systems do exactly that... the valves in the system are arranged and switched
so that as the condenser on the outside unit collects frost and eventually ices
up (heat pump mode), the system reverses the valves and the condenser is heated
and the ice melts (defrost mode). When the system determines that the ice has
melted, it switches the valves back to heat mode.
In defrost mode, the system is essentially an air conditioner.

--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Life is like a roll of toilet paper; the closer to the end, the faster it goes.

 

[Homer J Simpson]

"James Sweet" <jamessweet@hotmail.com> wrote in message
news:t6oJh.11544$mh7.3573@trnddc04...

What would be nice is a valve to short circuit the metering device and let
the hot vapor from the compressor flow straight into the evaporator coils.
That would defrost it in a matter of minutes. I've heard of a few very old
refrigerators that worked this way but nothing modern does it.

One more thing to go wrong with a sealed unit.

 

[James Sweet]

What would be nice is a valve to short circuit the metering device and let the
hot vapor from the compressor flow straight into the evaporator coils. That
would defrost it in a matter of minutes. I've heard of a few very old
refrigerators that worked this way but nothing modern does it.



Admittedly not a refrigerator, but still a refrigeration system, heat pump HVAC
systems do exactly that... the valves in the system are arranged and switched
so that as the condenser on the outside unit collects frost and eventually ices
up (heat pump mode), the system reverses the valves and the condenser is heated
and the ice melts (defrost mode). When the system determines that the ice has
melted, it switches the valves back to heat mode.
In defrost mode, the system is essentially an air conditioner.

Yes I'm quite familiar with those having installed several of them. Most
heat pumps you'll find out there don't actually sense frost buildup but
rather have a simple interval timer which triggers a defrost cycle every
30, 60, or 90 minutes. A defrost termination thermostat senses the
temperature of the line out of the outdoor coil (which is the evaporator
in heating mode) and returns the the unit to heating mode when this
trips. I modified my own unit with a surplus vacuum operated sensor I
found, it has a diaphragm which uses the pressure drop from the fan
across the coil when it ices up to trip a switch which is then reset by
a capillary tube and bulb in the location where the original DT
thermostat was located. In my climate this dramatically reduced the
number of energy wasting unnecessary defrost cycles, not sure how well
it would work elsewhere. It's a big boost to comfort as well, my backup
heat is a gas furnace so I can only run one or the other, a defrost
cycle means an icy blast of cold air which can drop the room temperature
by several degrees. A/C is very efficient when the condenser is down
near freezing. Other methods have been tried in the past but all I've
seen until very recently are the timers. Some very high end units today
use a demand defrost system which monitors trends in the evaporator
temperature to determine when a defrost is necessary, I have no
experience with these so I can't say whether they work well or not.

 

[James Sweet]

Homer J Simpson wrote:

"James Sweet" <jamessweet@hotmail.com> wrote in message
news:t6oJh.11544$mh7.3573@trnddc04...


What would be nice is a valve to short circuit the metering device and let
the hot vapor from the compressor flow straight into the evaporator coils.
That would defrost it in a matter of minutes. I've heard of a few very old
refrigerators that worked this way but nothing modern does it.


One more thing to go wrong with a sealed unit.

Yeah well so is an ice pick in the evaporator.

 

[Homer J Simpson]

"James Sweet" <jamessweet@hotmail.com> wrote in message
news:GToJh.11780$mh7.8835@trnddc04...

One more thing to go wrong with a sealed unit.

Yeah well so is an ice pick in the evaporator.

So is an ice pick in the eye!

 

[Sam Goldwasser]

James Sweet <jamessweet@hotmail.com> writes:

There is NO guaranty on defrosting using a Knife or Icepick !!

I regularly used to tell my junior Technicians, "Don't bother trying to
speed up defrosting the Lab Freezers with a knife or icepick". Just put
it on a dolly and put it out on the loading dock for the dump , and save
everybody a lot of time and trouble.
The proper way to Defrost a freezer is Just unplug the freezer and place
a large pan of hot water in the freezer and close the door, replace the
pan with more hot water until all the ice melts. All you need to do is
scratch the Evaporator to destroy it !! This is NOT covered under warranty.

What would be nice is a valve to short circuit the metering device and
let the hot vapor from the compressor flow straight into the evaporator
coils. That would defrost it in a matter of minutes. I've heard of a few
very old refrigerators that worked this way but nothing modern does it.

Cost, cost, cost, cost.

What's wrong with a couple pans of hot water, rags at bottom, close the door,
wait an hour while you do something else! People who have to have instant
gratification for a task that's performed once a year if that!

--- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
+Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
| Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

Important: Anything sent to the email address in the message header above is
ignored unless my full name AND either lasers or electronics is included in the
subject line. Or, you can contact me via the Feedback Form in the FAQs.

 

[DaveM]

"James Sweet" <jamessweet@hotmail.com> wrote in message
news:rPoJh.11757$mh7.4952@trnddc04...

What would be nice is a valve to short circuit the metering device and let
the hot vapor from the compressor flow straight into the evaporator coils.
That would defrost it in a matter of minutes. I've heard of a few very old
refrigerators that worked this way but nothing modern does it.



Admittedly not a refrigerator, but still a refrigeration system, heat pump
HVAC systems do exactly that... the valves in the system are arranged and
switched so that as the condenser on the outside unit collects frost and
eventually ices up (heat pump mode), the system reverses the valves and the
condenser is heated and the ice melts (defrost mode). When the system
determines that the ice has melted, it switches the valves back to heat mode.
In defrost mode, the system is essentially an air conditioner.



Yes I'm quite familiar with those having installed several of them. Most heat
pumps you'll find out there don't actually sense frost buildup but rather have
a simple interval timer which triggers a defrost cycle every 30, 60, or 90
minutes. A defrost termination thermostat senses the temperature of the line
out of the outdoor coil (which is the evaporator in heating mode) and returns
the the unit to heating mode when this trips. I modified my own unit with a
surplus vacuum operated sensor I found, it has a diaphragm which uses the
pressure drop from the fan across the coil when it ices up to trip a switch
which is then reset by a capillary tube and bulb in the location where the
original DT thermostat was located. In my climate this dramatically reduced
the number of energy wasting unnecessary defrost cycles, not sure how well it
would work elsewhere. It's a big boost to comfort as well, my backup heat is a
gas furnace so I can only run one or the other, a defrost cycle means an icy
blast of cold air which can drop the room temperature by several degrees. A/C
is very efficient when the condenser is down near freezing. Other methods have
been tried in the past but all I've seen until very recently are the timers.
Some very high end units today use a demand defrost system which monitors
trends in the evaporator temperature to determine when a defrost is necessary,
I have no experience with these so I can't say whether they work well or not.

Yeppers... Until a few years ago, I had an old GE Weathertron heat pump system.
Terribly inefficient by today's standards, but it got the job done. It had a
vacuum sensor in the outside unit that sensed a drop in air pressure inside the
coils, whereupon it switched into defrost mode. It ran the auxillary heat
strips while in defrost mode to keep from cooling the house while in defrost. A
capillary sensed the coil temperature and switched back into heat pump mode when
the coil temp got high enough. It worked quite well; only went into defrost
when necessary.

Scared me the first time I saw it defrosting... the big column of vapor steaming
up from the unit was awesome. I thought the thing was on fire!!

I had to replace the entire system when the compressor locked up after 25 or so
years of operation. Don't know how the Lennox system I bought as the
replacement determines that it needs to defrost... could be a timer. But it
seems to work well, even in sub-freezing temps and high Florida humidity.

Cheers!!!
--
Dave M
MasonDG44 at comcast dot net (Just substitute the appropriate characters in the
address)

Life is like a roll of toilet paper; the closer to the end, the faster it goes.

 

[Homer J Simpson]

"DaveM" <masondg4499@comcast99.net> wrote in message
news:sPadnaR7F9HBgWrYnZ2dnUVZ_hmtnZ2d@comcast.com...

I had to replace the entire system when the compressor locked up after 25
or so years of operation. Don't know how the Lennox system I bought as
the replacement determines that it needs to defrost... could be a timer.
But it seems to work well, even in sub-freezing temps and high Florida
humidity.

These days you are better off to look at one of the Japanese split system
heat pumps.

 

[**THE-RFI-EMI-GUY**]

I assume the can is open on one end like a soup can, not a coke can. I
think the water is there to provide an airtight, frictionless seal for
more effect. Keeping the firercracker dry is tricky. This looks like a
good use for the hundreds of firecrackers I have left over!

What he is simulating is the explosion that happens in one of your cars
engine cylinders. A car engine operates on a series of small controlled
explosions. In your car, the explosive force drives a piston down,
pushing a connecting rod which in turn rotates a crankshaft. A car
engine has 4 to 8 cylinders which fire sequentially and smoothly. The
links below illustrate this with a single cylinder like a lawnmower
engine. These are "internal combustion engines".

My sister did a similar science project years ago with a coffee can
fitted with a spark plug and filled with a very small amount of gasoline
or ether. A plastic lid was placed on top and an ignition coil made a
spark which blew the plastic lid off. Not as dramatic as a fire cracker.

http://www.keveney.com/otto.html
http://en.wikipedia.org/wiki/Four-stroke_cycle

Dumb_Blonde wrote:

Thank you in advance for your time. I found a neat project to do with
my 14 year old son, but would like to know the science behind it so it
will be educational.

Here is the video link.

http://www.metacafe.com/watch/470767/firecracker_rocket_project_experiment/

It is a fire cracker experiment, and I know he will love it, but I am
clueless as to how this makes my car run.

--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"Š

"Treason doth never prosper: what's the reason?
For if it prosper, none dare call it treason."

"Follow The Money" ;-P

 

[Captain Midnight]

"Sam Goldwasser" <sam@blue.seas.upenn.edu> wrote in message
news:6wlki15nyg.fsf@blue.seas.upenn.edu...

What's wrong with a couple pans of hot water, rags at bottom, close the
door,
wait an hour while you do something else! People who have to have instant
gratification for a task that's performed once a year if that!

I love the gratification of my food not spoiling. What are you doing for
gratification while the pan is in the fridge? ;^)

I'm guessing it'd take at least 12 hours of hot water to completely defrost
my old fridge. I take out the panels and keep at it to get it all not just
enough to get some air flow. First time was when the defrost timer was only
working on every other cycle and ~ten years later to try and save it. Didn't
want to put any money into a 25 year old so didn't bother doing any
troubleshooting. Do they still sell fridges that aren't "frost free"?.

Actually it was 3 times. Didn't realize the timer had 2 cycles the first
time. IIRC the second cleaning was less than a year later. Soon enough I
knew it had a problem at any rate.

 

[Captain Midnight]

"**THE-RFI-EMI-GUY**" <rhyolite@nettally.com> wrote in message
news:45f72822$0$4929$4c368faf@roadrunner.com...

I assume the can is open on one end like a soup can, not a coke can. I
think the water is there to provide an airtight, frictionless seal for
more effect. Keeping the firercracker dry is tricky. This looks like a
good use for the hundreds of firecrackers I have left over!

What he is simulating is the explosion that happens in one of your cars
engine cylinders. A car engine operates on a series of small controlled
explosions. In your car, the explosive force drives a piston down,
pushing a connecting rod which in turn rotates a crankshaft. A car
engine has 4 to 8 cylinders which fire sequentially and smoothly. The
links below illustrate this with a single cylinder like a lawnmower
engine. These are "internal combustion engines".

My sister did a similar science project years ago with a coffee can
fitted with a spark plug and filled with a very small amount of gasoline
or ether. A plastic lid was placed on top and an ignition coil made a
spark which blew the plastic lid off. Not as dramatic as a fire cracker.

http://www.keveney.com/otto.html
http://en.wikipedia.org/wiki/Four-stroke_cycle

Dumb_Blonde wrote:

Thank you in advance for your time. I found a neat project to do with
my 14 year old son, but would like to know the science behind it so it
will be educational.

Here is the video link.


http://www.metacafe.com/watch/470767/firecracker_rocket_project_experiment/

It is a fire cracker experiment, and I know he will love it, but I am
clueless as to how this makes my car run.




--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"Š

Their is no explosion in a properly operating internal combustion engine.
The fuel merely heats the air. The expansion of the air pushes the piston.
An explosion called detonation or knock can put a hole in the piston. Some
engines require higher octane fuel to keep knock from occurring.

 

[Arfa Daily]

"Captain Midnight" <Notany@twip.invalid> wrote in message
news:45f732f5$0$8973$4c368faf@roadrunner.com...

"**THE-RFI-EMI-GUY**" <rhyolite@nettally.com> wrote in message
news:45f72822$0$4929$4c368faf@roadrunner.com...
I assume the can is open on one end like a soup can, not a coke can. I
think the water is there to provide an airtight, frictionless seal for
more effect. Keeping the firercracker dry is tricky. This looks like a
good use for the hundreds of firecrackers I have left over!

What he is simulating is the explosion that happens in one of your cars
engine cylinders. A car engine operates on a series of small controlled
explosions. In your car, the explosive force drives a piston down,
pushing a connecting rod which in turn rotates a crankshaft. A car
engine has 4 to 8 cylinders which fire sequentially and smoothly. The
links below illustrate this with a single cylinder like a lawnmower
engine. These are "internal combustion engines".

My sister did a similar science project years ago with a coffee can
fitted with a spark plug and filled with a very small amount of gasoline
or ether. A plastic lid was placed on top and an ignition coil made a
spark which blew the plastic lid off. Not as dramatic as a fire cracker.

http://www.keveney.com/otto.html
http://en.wikipedia.org/wiki/Four-stroke_cycle

Dumb_Blonde wrote:

Thank you in advance for your time. I found a neat project to do with
my 14 year old son, but would like to know the science behind it so it
will be educational.

Here is the video link.


http://www.metacafe.com/watch/470767/firecracker_rocket_project_experiment/

It is a fire cracker experiment, and I know he will love it, but I am
clueless as to how this makes my car run.




--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"Š


Their is no explosion in a properly operating internal combustion engine.
The fuel merely heats the air. The expansion of the air pushes the piston.
An explosion called detonation or knock can put a hole in the piston. Some
engines require higher octane fuel to keep knock from occurring.


That seems to me to be a misleading description of the principles of an

internal combustion engine. The fuel is mixed with the air in a very
carefully controlled ratio, highly compressed, and is then set light to,
either by a spark in the case of a gasoline engine, or by self ignition from
the rapid heating of the mixture during compression, in the case of a
diesel. It burns or combusts, and what comes out of the exhaust, after the
burning, is not air, but a fully reduced residue of the burning process. The
burning of the mixture under such intense pressure, in what is essentially a
fully contained space, takes place at such speed, it would usually be
considered to be representative of a controlled explosion. Detonation knock
is normally as a result of the timing of the ignition source not being ideal
for the engine in question. The detonation process should be started just
before the piston reaches top dead centre, so that by the time the burning
has spread fully from the initiating point - ie the spark plug - through the
entire mixture, and is thus at its fiercest, the piston has rolled over past
its point of being momentarily stationary, and is just beginning on its way
back down the cylinder. The rapidly burning ( exploding ? ) mixture will
then deliver maximum thrust to the piston, driving it down the cylinder
bore. If the mixture starts to burn too early, it will reach maximum energy
output before the piston has reached the top, so will oppose the upward
movement of the piston, which is still occuring, leading to the
pre-detonation knock.

Maybe it is just semantics, and some may disagree, but that has always been
my take on how an engine works, ever since I was first rebuilding them as a
kid, because I couldn't afford repair shop prices !!

Arfa

 

[Arfa Daily]

"Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
news:qiIJh.166$pP5.113@newsfe3-gui.ntli.net...

"Captain Midnight" <Notany@twip.invalid> wrote in message
news:45f732f5$0$8973$4c368faf@roadrunner.com...
"**THE-RFI-EMI-GUY**" <rhyolite@nettally.com> wrote in message
news:45f72822$0$4929$4c368faf@roadrunner.com...
I assume the can is open on one end like a soup can, not a coke can. I
think the water is there to provide an airtight, frictionless seal for
more effect. Keeping the firercracker dry is tricky. This looks like a
good use for the hundreds of firecrackers I have left over!

What he is simulating is the explosion that happens in one of your cars
engine cylinders. A car engine operates on a series of small controlled
explosions. In your car, the explosive force drives a piston down,
pushing a connecting rod which in turn rotates a crankshaft. A car
engine has 4 to 8 cylinders which fire sequentially and smoothly. The
links below illustrate this with a single cylinder like a lawnmower
engine. These are "internal combustion engines".

My sister did a similar science project years ago with a coffee can
fitted with a spark plug and filled with a very small amount of gasoline
or ether. A plastic lid was placed on top and an ignition coil made a
spark which blew the plastic lid off. Not as dramatic as a fire cracker.

http://www.keveney.com/otto.html
http://en.wikipedia.org/wiki/Four-stroke_cycle

Dumb_Blonde wrote:

Thank you in advance for your time. I found a neat project to do with
my 14 year old son, but would like to know the science behind it so it
will be educational.

Here is the video link.


http://www.metacafe.com/watch/470767/firecracker_rocket_project_experiment/

It is a fire cracker experiment, and I know he will love it, but I am
clueless as to how this makes my car run.




--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"Š


Their is no explosion in a properly operating internal combustion engine.
The fuel merely heats the air. The expansion of the air pushes the
piston.
An explosion called detonation or knock can put a hole in the piston.
Some
engines require higher octane fuel to keep knock from occurring.


That seems to me to be a misleading description of the principles of an
internal combustion engine. The fuel is mixed with the air in a very
carefully controlled ratio, highly compressed, and is then set light to,
either by a spark in the case of a gasoline engine, or by self ignition
from the rapid heating of the mixture during compression, in the case of a
diesel. It burns or combusts, and what comes out of the exhaust, after the
burning, is not air, but a fully reduced residue of the burning process.
The burning of the mixture under such intense pressure, in what is
essentially a fully contained space, takes place at such speed, it would
usually be considered to be representative of a controlled explosion.
Detonation knock is normally as a result of the timing of the ignition
source not being ideal for the engine in question. The detonation process
should be started just before the piston reaches top dead centre, so that
by the time the burning has spread fully from the initiating point - ie
the spark plug - through the entire mixture, and is thus at its fiercest,
the piston has rolled over past its point of being momentarily stationary,
and is just beginning on its way back down the cylinder. The rapidly
burning ( exploding ? ) mixture will then deliver maximum thrust to the
piston, driving it down the cylinder bore. If the mixture starts to burn
too early, it will reach maximum energy output before the piston has
reached the top, so will oppose the upward movement of the piston, which
is still occuring, leading to the pre-detonation knock.

Maybe it is just semantics, and some may disagree, but that has always
been my take on how an engine works, ever since I was first rebuilding
them as a kid, because I couldn't afford repair shop prices !!

Arfa

Just as a matter of interest, I just looked up the word " explosion " at

http://dictionary.reference.com/browse/explosion

and interestingly, the first result, 5th definition, specifically mentions
the internal combustion engine. The third result, definition 1a also seems
to cover it neatly, as does the twelfth

Arfa

 

[Arfa Daily]

"Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
news:1qIJh.168$7l1.162@newsfe4-gui.ntli.net...

"Arfa Daily" <arfa.daily@ntlworld.com> wrote in message
news:qiIJh.166$pP5.113@newsfe3-gui.ntli.net...

"Captain Midnight" <Notany@twip.invalid> wrote in message
news:45f732f5$0$8973$4c368faf@roadrunner.com...
"**THE-RFI-EMI-GUY**" <rhyolite@nettally.com> wrote in message
news:45f72822$0$4929$4c368faf@roadrunner.com...
I assume the can is open on one end like a soup can, not a coke can. I
think the water is there to provide an airtight, frictionless seal for
more effect. Keeping the firercracker dry is tricky. This looks like a
good use for the hundreds of firecrackers I have left over!

What he is simulating is the explosion that happens in one of your cars
engine cylinders. A car engine operates on a series of small controlled
explosions. In your car, the explosive force drives a piston down,
pushing a connecting rod which in turn rotates a crankshaft. A car
engine has 4 to 8 cylinders which fire sequentially and smoothly. The
links below illustrate this with a single cylinder like a lawnmower
engine. These are "internal combustion engines".

My sister did a similar science project years ago with a coffee can
fitted with a spark plug and filled with a very small amount of
gasoline
or ether. A plastic lid was placed on top and an ignition coil made a
spark which blew the plastic lid off. Not as dramatic as a fire
cracker.

http://www.keveney.com/otto.html
http://en.wikipedia.org/wiki/Four-stroke_cycle

Dumb_Blonde wrote:

Thank you in advance for your time. I found a neat project to do with
my 14 year old son, but would like to know the science behind it so it
will be educational.

Here is the video link.


http://www.metacafe.com/watch/470767/firecracker_rocket_project_experiment/

It is a fire cracker experiment, and I know he will love it, but I am
clueless as to how this makes my car run.




--
Joe Leikhim K4SAT
"The RFI-EMI-GUY"Š


Their is no explosion in a properly operating internal combustion
engine.
The fuel merely heats the air. The expansion of the air pushes the
piston.
An explosion called detonation or knock can put a hole in the piston.
Some
engines require higher octane fuel to keep knock from occurring.


That seems to me to be a misleading description of the principles of an
internal combustion engine. The fuel is mixed with the air in a very
carefully controlled ratio, highly compressed, and is then set light to,
either by a spark in the case of a gasoline engine, or by self ignition
from the rapid heating of the mixture during compression, in the case of
a diesel. It burns or combusts, and what comes out of the exhaust, after
the burning, is not air, but a fully reduced residue of the burning
process. The burning of the mixture under such intense pressure, in what
is essentially a fully contained space, takes place at such speed, it
would usually be considered to be representative of a controlled
explosion. Detonation knock is normally as a result of the timing of the
ignition source not being ideal for the engine in question. The
detonation process should be started just before the piston reaches top
dead centre, so that by the time the burning has spread fully from the
initiating point - ie the spark plug - through the entire mixture, and is
thus at its fiercest, the piston has rolled over past its point of being
momentarily stationary, and is just beginning on its way back down the
cylinder. The rapidly burning ( exploding ? ) mixture will then deliver
maximum thrust to the piston, driving it down the cylinder bore. If the
mixture starts to burn too early, it will reach maximum energy output
before the piston has reached the top, so will oppose the upward movement
of the piston, which is still occuring, leading to the pre-detonation
knock.

Maybe it is just semantics, and some may disagree, but that has always
been my take on how an engine works, ever since I was first rebuilding
them as a kid, because I couldn't afford repair shop prices !!

Arfa

Just as a matter of interest, I just looked up the word " explosion " at

http://dictionary.reference.com/browse/explosion

and interestingly, the first result, 5th definition, specifically mentions
the internal combustion engine. The third result, definition 1a also seems
to cover it neatly, as does the twelfth

Arfa
Ah, it could be a question of semantics ! It's just occured to me what you

were saying. It is the pressure wave from the burning ( although I still
think " exploding " covers it also ) mixture that drives the piston down,
and not the actual burning mixture ( flame front is it called ? ), which
should not actually touch the top of the piston before it burns out, and can
cause damage, if it does. Yep ! that's it I reckon. We're both on the same
page now. Sorry ...

Arfa

 

[James Sweet]

Cost, cost, cost, cost.

What's wrong with a couple pans of hot water, rags at bottom, close the door,
wait an hour while you do something else! People who have to have instant
gratification for a task that's performed once a year if that!

I was actually thinking more along the lines of domestic refrigerators
where a defrost element is turned on on a regular basis so you have to
pay for the power that uses, then you pay again to pump that heat back
out of the freezer. Using the compressor to defrost would be ~3x as
efficient and it would put the heat exactly where it's needed.