Post by thread:[EE]: I am looking for a small positive displaceme

I want to build the following invention for a client. There is no NDA. A air mover of some sort forces air up a tube and out some jets on the windshield/windscreen of a car/truck. The air is heated via compression and possibly an electric heater. The hot air defrosts the WS and melts thin coatings of ice. The "Hottie" as I am calling it, is powered from an Auxillary Lead Acid Battery that is charged by the vehicle alternator. When the engine is not running , the Hottie can still defrost the glass and also heat the WS wipers. I plan to put a set of jets across the top of the WS, anchored and shaped so they offer little wind resistance. The battery will disconnect when it is out of SOA. ( Safe Operating Area ) Optionally, the Hottie may turn the wipers on if snow/sleet falls and keep the WS free of snow accumulation. Even when the vehicle is unoccupied. There will sensors ( don't know what yet ) that will detect the WS is fogged or iced. The main vehicle battery will not be discharged. Everything will fit in the engine compartment. Has anyone suggestions for the air mover ? cc

On Fri, 2008-02-29 at 13:17 -0700, Cedric Chang wrote: {Quote hidden}> I want to build the following invention for a client. There is no > NDA. A air mover of some sort forces air up a tube and out some jets > on the windshield/windscreen of a car/truck. The air is heated via > compression and possibly an electric heater. The hot air defrosts > the WS and melts thin coatings of ice. > > The "Hottie" as I am calling it, is powered from an Auxillary Lead > Acid Battery that is charged by the vehicle alternator. When the > engine is not running , the Hottie can still defrost the glass and > also heat the WS wipers. I plan to put a set of jets across the top > of the WS, anchored and shaped so they offer little wind resistance. > The battery will disconnect when it is out of SOA. ( Safe Operating > Area ) Optionally, the Hottie may turn the wipers on if snow/sleet > falls and keep the WS free of snow accumulation. Even when the > vehicle is unoccupied. > > There will sensors ( don't know what yet ) that will detect the WS is > fogged or iced. > > The main vehicle battery will not be discharged. Everything will fit > in the engine compartment. > > Has anyone suggestions for the air mover ? There are devices here that instead of blowing hot air on the windshield simply heat up the windshield fluid. MUCH faster defrosting with warm windshield fluid then warm air IMHO. TTYL

: : On Fri, 2008-02-29 at 13:17 -0700, Cedric Chang wrote: : > I want to build the following invention for a client. There is no : > NDA. A air mover of some sort forces air up a tube and out some jets : > on the windshield/windscreen of a car/truck. The air is heated via : > compression and possibly an electric heater. The hot air defrosts : > the WS and melts thin coatings of ice. : > Compressing the gas will heat it, but as soon as it expands it will cool again. If you have heat loss from your compressor to nozzle (as you will), the gas will be even colder than the ambient temperature. Oops! Regards, Gordon Williams

Cedric Chang wrote: {Quote hidden}> I want to build the following invention for a client. There is no > NDA. A air mover of some sort forces air up a tube and out some jets > on the windshield/windscreen of a car/truck. The air is heated via > compression and possibly an electric heater. The hot air defrosts > the WS and melts thin coatings of ice. > > The "Hottie" as I am calling it, is powered from an Auxillary Lead > Acid Battery that is charged by the vehicle alternator. When the > engine is not running , the Hottie can still defrost the glass and > also heat the WS wipers. I plan to put a set of jets across the top > of the WS, anchored and shaped so they offer little wind resistance. > The battery will disconnect when it is out of SOA. ( Safe Operating > Area ) Optionally, the Hottie may turn the wipers on if snow/sleet > falls and keep the WS free of snow accumulation. Even when the > vehicle is unoccupied. > > There will sensors ( don't know what yet ) that will detect the WS is > fogged or iced. > > The main vehicle battery will not be discharged. Everything will fit > in the engine compartment. > > Has anyone suggestions for the air mover ? > > cc > You could use heated air from the manifold when the engine is running to the save energy otherwise used to heat the air while the engine is running. Experimentation with a computer style fan may work. or use water that has antifreeze non corrosive (salt?) agent and recycle the water :-) Roy

Here being where ? cc {Quote hidden}> On Feb 29, 2008, at 1:45 PM, Herbert Graf wrote: > > > On Fri, 2008-02-29 at 13:17 -0700, Cedric Chang wrote: >> I want to build the following invention for a client. There is no >> NDA. A air mover of some sort forces air up a tube and out some jets >> on the windshield/windscreen of a car/truck. The air is heated via >> compression and possibly an electric heater. The hot air defrosts >> the WS and melts thin coatings of ice. >> >> The "Hottie" as I am calling it, is powered from an Auxillary Lead >> Acid Battery that is charged by the vehicle alternator. When the >> engine is not running , the Hottie can still defrost the glass and >> also heat the WS wipers. I plan to put a set of jets across the top >> of the WS, anchored and shaped so they offer little wind resistance. >> The battery will disconnect when it is out of SOA. ( Safe Operating >> Area ) Optionally, the Hottie may turn the wipers on if snow/sleet >> falls and keep the WS free of snow accumulation. Even when the >> vehicle is unoccupied. >> >> There will sensors ( don't know what yet ) that will detect the WS is >> fogged or iced. >> >> The main vehicle battery will not be discharged. Everything will fit >> in the engine compartment. >> >> Has anyone suggestions for the air mover ? > > There are devices here that instead of blowing hot air on the > windshield > simply heat up the windshield fluid. MUCH faster defrosting with warm > windshield fluid then warm air IMHO. > > TTYL > --

On Sat, 2008-03-01 at 11:25 +1300, Roy wrote: > You could use heated air from the manifold when the engine is running to > the save energy otherwise used to heat the air while the engine is running. Unfortunately when it's cold it can take a surprising amount of time for an idling engine to get anywhere near warm enough to put a dent on defrosting a windsheild. Trust me, I know, it was -25C (about -13F) last night here... TTYL

On Fri, 2008-02-29 at 15:50 -0700, Cedric Chang wrote: > Here being where ? > cc Toronto, Canada, although I'm pretty sure anywhere where it gets cold enough to need a defrosting of a windshield will have it. This is specifically the product I'm speaking of: http://tinyurl.com/335fjq www.canadiantire.ca/browse/product_detail.jsp?FOLDER%3C% 3Efolder_id=1408474396672419&bmUID=1204333464269&PRODUCT%3C% 3Eprd_id=845524443285107&assortment=primary&fromSearch=true TTYL

How would I recycle the anti-freeze/water ? cc On Feb 29, 2008, at 3:25 PM, Roy wrote: {Quote hidden}> Cedric Chang wrote: >> I want to build the following invention for a client. There is no >> NDA. A air mover of some sort forces air up a tube and out some jets >> on the windshield/windscreen of a car/truck. The air is heated via >> compression and possibly an electric heater. The hot air defrosts >> the WS and melts thin coatings of ice. >> > Experimentation with a computer style fan may work. > > or use water that has antifreeze non corrosive (salt?) agent and > recycle the water :-) > > Roy > >

On Fri, 2008-02-29 at 18:44 -0700, Cedric Chang wrote: > How would I recycle the anti-freeze/water ? > cc Well, normally you wouldn't, how many times do you have to do it? During my normal car use I go through about 2 litres (~1/2 gallon) a month when it's really bad weather wise, but that's for more then just defrosting the windscreen (mostly getting dirty spray off the windscreen when I'm driving behind someone and the road is slushy). TTYL

>> You could use heated air from the manifold when the >> engine is running to >> the save energy otherwise used to heat the air while the >> engine is running. > Unfortunately when it's cold it can take a surprising > amount of time for > an idling engine to get anywhere near warm enough to put a > dent on > defrosting a windsheild. Trust me, I know, it was -25C > (about -13F) last > night here... >From startup, how long can you hold your hand on the top of the exhaust pipe where it leaves the manifold? (We'll let you not place it there until the pipe rises above 0 C to save you some skin, but count those seconds into the period. Hand off (new meaning to the term) occurs around 55C - 60C unless you have asbestos hands. Russell

On Sat, 2008-03-01 at 14:58 +1300, Apptech wrote: > >> You could use heated air from the manifold when the > >> engine is running to > >> the save energy otherwise used to heat the air while the > >> engine is running. > > > Unfortunately when it's cold it can take a surprising > > amount of time for > > an idling engine to get anywhere near warm enough to put a > > dent on > > defrosting a windsheild. Trust me, I know, it was -25C > > (about -13F) last > > night here... > > >From startup, how long can you hold your hand on the top of > the exhaust pipe where it leaves the manifold? (We'll let > you not place it there until the pipe rises above 0 C to > save you some skin, but count those seconds into the period. > Hand off (new meaning to the term) occurs around 55C - 60C > unless you have asbestos hands. Right, but what do you do when the temp of that pipe reaches 300 or 400C or even higher? (I'm unsure of the exact temp, I do know that the O2 sensors need to be at about 800C to operate, and I also know from experience that the pipes are hot enough to light transmission fluid on fire instantly). Frankly there are many MUCH easier ways to get heat then trying to build something that can operate safely through such a wide variation of temperature, which is why it is almost never done. TTYL

{Quote hidden}> > On Feb 29, 2008, at 10:09 PM, Herbert Graf wrote: > > > On Sat, 2008-03-01 at 14:58 +1300, Apptech wrote: >>>> You could use heated air from the manifold when the >>>> engine is running to >>>> the save energy otherwise used to heat the air while the >>>> engine is running. >> >>> Unfortunately when it's cold it can take a surprising >>> amount of time for >>> an idling engine to get anywhere near warm enough to put a >>> dent on >>> defrosting a windsheild. Trust me, I know, it was -25C >>> (about -13F) last >>> night here... >> >>> From startup, how long can you hold your hand on the top of >> the exhaust pipe where it leaves the manifold? (We'll let >> you not place it there until the pipe rises above 0 C to >> save you some skin, but count those seconds into the period. >> Hand off (new meaning to the term) occurs around 55C - 60C >> unless you have asbestos hands. > > Right, but what do you do when the temp of that pipe reaches 300 or > 400C > or even higher? (I'm unsure of the exact temp, I do know that the O2 > sensors need to be at about 800C to operate, and I also know from > experience that the pipes are hot enough to light transmission > fluid on > fire instantly). > > Frankly there are many MUCH easier ways to get heat then trying to > build > something that can operate safely through such a wide variation of > temperature, which is why it is almost never done. > > TTYL Not to mention the difficulty of attaching an add-on unit to said pipes. I guess you could blow air through a pipe attached to the exhaust and monitor the output temp and mix in ambient air to keep the temp at the right level. cc