Sistemul-de-Pornire-al-Motoarelor-DOC
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
Fig.13 Schema electrica cu termostart cu bujii incan<strong>de</strong>scente<br />
si electroventil:<br />
1 – contact; 2 – rezistenta termostaarterului; 3 – lampa <strong>de</strong><br />
control; 4 – electroventil; 5 – bujii incan<strong>de</strong>scente; ro – rosu;<br />
g<strong>al</strong>ben; v – ver<strong>de</strong>.<br />
Preanc<strong>al</strong>zirea cu lichi<strong>de</strong> <strong>de</strong> pornire are in ultimul timp o<br />
larga raspandire. Componenta <strong>de</strong> baza a multor lichi<strong>de</strong> <strong>de</strong><br />
pornire estee eterul etilic, care se caracterizeaza prin<br />
temperature scaazuta la autoaprin<strong>de</strong>re(180 – 200) 0 C la<br />
presiunea atmosferica, prin presiune ridicata a vaporilor<br />
saturati si limite largi <strong>de</strong> aprin<strong>de</strong>re. Pentru a evita mersul dur <strong>al</strong><br />
motorului, in lichi<strong>de</strong>le <strong>de</strong> pornire se introduce componente ca<br />
<strong>al</strong><strong>de</strong>hi<strong>de</strong>, etili, amine, nitrate ssi <strong>al</strong>te combinatii.<br />
Se cunosc astazi mai multe tipuri <strong>de</strong> lichi<strong>de</strong> <strong>de</strong> pornire,<br />
printre care: lichidul “Arctica” – Rusia, “Sevron” – Standrd Oil,<br />
SUA, “K<strong>al</strong>teks” – Anglia, “Start – Pilot” – Franta, “Sinclair<br />
Pentaining” - SUA, E.N.20 si E – 30 – Cehia. Toate au drept<br />
component <strong>de</strong> baza eterul etilic, in proportii <strong>de</strong> pana 60 – 70 %,<br />
asigurand pornirea pana la – 50 0 C, cum este cazul lichidului<br />
rusesc “Arctica”. Lichidul <strong>de</strong> pornire “Start Pilot”, in varianta<br />
standard, este compus din: eter etilic 25 – 35 %, amestec <strong>de</strong><br />
butan, propan si hexan 15 – 25 %, propil butil 10 – 20% si in<br />
rest <strong>al</strong>ti compusi, asigurand pornirea la – 25 ……30 0 C.<br />
Cateodata, pentru usurarea aprin<strong>de</strong>rii si pornirii motorului,<br />
impreuna cu lichidul se foloseste un gaz fierbinte necon<strong>de</strong>nsat,<br />
<strong>de</strong> tip metan.<br />
Lichidul <strong>de</strong> pornire se poate introduce in motor fie prin<br />
adaugare la combustibilul <strong>de</strong> baza, amestecul obtinut prin<br />
sistemul <strong>de</strong> <strong>al</strong>imentare intrand in cilindrii motorului, fie prin<br />
pulverizarea lichidului in colectorul <strong>de</strong> admisie <strong>al</strong> motorului, cu<br />
ajutorul unor dispozitive speci<strong>al</strong>e.<br />
23