Show J U III I Practical Instruction i in In Motor By A. A R. R ROCHE 1 Former U. U S. S Aviation Motor I tor nod and JD Inspector p tO c c ons Nor ot of or Shot Shop 4 4 E. E Sst cl Tt Ts with Tic The Herald j 4 41 m n Heat H cat Losses Explained When wo we air all It becomes heaVed heated and if iC we compress it II rapidly enough for Cor or instance if it we pump a tire with a hand pump the pump be becomes becomes becomes be- be comes VCr very hot and this is not entirely entire entire- ly hy due to the friction of or the J JIn in the pump but partially duo to the tho work of compressing the air The very ven same thing occurs when we compress gas gns or a mixture of ot gasoline air Ir IrIn In a a. cylinder As we compress ss gas In Inan Inan inan an e cylinder It is heated to a certain extent then we have the heat of ot the tho electric spark park which we us use to ignite tho the gas Tho The heat of the electric elec e- e spark sparl together tog with the heat lent of or compression Is sufficient to I ignite or start the mixture burning Then Thenis as the tho S' S gas II burns burn Its temperature and pressure will riso very rapidly It IC tho the gas gons were burned in tho the open tho the temperature tem torn would rise very ery high but wh when n burned Jn a confined c cylinder lIn er eror or space under pressure the 1110 temperature tempera tempera- ture Increases as the gas burns Tho Iho increase In pre pressure suro adds to tho lie heat as in th case casc of oC pumping up the tire lire as docs does also the burn burning ins ins- of oC the fuel Cuel Therefore wo o obtain a temperature temper temper- aturo or gas pras as engine between 2000 and 2500 OO degrees degres el Fahrenheit You can fl uro this as a a. white hot flame Let us imagine that wo we have o a cylinder cyl cI inder and piston so arranged that wo SO may compress a charge chargo of oC tn gas and then cork or lock tho the piston so that it Il cannot bo be moved od and let us also Imagine that there th rc is absolutely no leakage Now If we Ignite this com corn pressed gas our temperature and pressure pres sure will instantly run up very high but should we C leave lea It for tor a a. few Cew minutes minutes min min- b before fore testing utes sn say four minutes the tho pres pressure we wo would find but a very er few tew ounces of or pressure left lert In the cyl cyl- inder Now ow th the tho reason for tor this is that the tIre cool cylinder c and the tho cool piston hav ab absorbed obed all aU the heat of oC the time cx- cx and as tho the heat subsided the pres pressure ure subsided also in other words I the hot gases have Q been contracted b by cooling or or in other words heat and I pressure can be considered d ns as one ono and I internal combustion combustion combus combus- tho the II samo U 10 tiling thinS In an nn tion lion engine en ln I Now 0 we will stretch our Imagination tion a peg or two further We e will Imagine that we have a e cylinder that thatis is not only capable of oC having ha gus gas compress com com- press d In it and then the piston locked but also o maintain at ut a a heat boat from 2300 to 2700 degrees Fahrenheit This Thill temperature h by the wa way is fur far I above the tIme m molting incIting point of or iron Now ow I If Ir we can cnn compress the gas and amid fire Ire Irethe the cylinder at this temperature we will find that the pre pressure o iuro will romain ro- ro main maln er very highs high in the cylinder us its long IonS longas as ns wo main maintain lain tho the temperature in the cylinder This Is because the cylinder and the piston platon will not cool the hot gases after aCter the explosion The Ie result is fj there Is no loss or radiation of ot heat from the tho explosion which is called lIed h hat at lo loss s. s With tire the 1 very best gasoline K Kwe we make malee u use o of only onh about 0 0 pt r roC of oC the heat value of the fuel fue other fuel c cother other words we e lose about fifths of th the lie heat or pow power r T the fuel wo Wi use uso anti and the fuel today is rather low In the Baom but has hns more heat units than of hl higher her Baume test Still th thi of ot today must must- bo be preheated ber tho manifold In order il proper ro To show where this tins heat heal or Ot orI 1 goes suppose our fuel were cent fuel value alu about 5 p pr perc r Ct this Is consumed in friction cent Is lost in radiation mostly 1 water Jacket and about 40 pt pu goes out of oC the exhaust piper lost This leaves only about 1 cent in tho the form torm of power an n nwe we lose a portion of ot this in ff I before it Is delivered to wheels These figures are tiro only proximate but should servo ser to tohle t gi Idea where the power goes fo tor stance and arid while we are aro power ask yourself this cU ci u when your our engine engine- boils bolls on a agets M JI gets very hot and refuses to 0 PJ I knocks s Where her Is all the pO that I had when I started out pie pic Pistons c cylinders and alT valT to such n. n degree t talve It valves alve would not sent seat resulting through h expansion all an tho the h l' l lis is lost through tho ho exhaust pIpe the lubricating value o of Q 0 born hurnel un an |