▁st ov es ▁force ▁the ▁g ases ▁and ▁smoke ▁that ▁result ▁from ▁incomplete ▁comb ust ion ▁of ▁fu els ▁such ▁as ▁bi om ass ▁back ▁into ▁the ▁cook st ove ' s ▁fl ame , ▁where ▁the ▁heat ▁of ▁the ▁fl ame ▁then ▁continues ▁to ▁comb ust ▁the ▁particles ▁in ▁the ▁smoke ▁until ▁almost ▁complete ▁comb ust ion ▁has ▁occurred , ▁reducing ▁em issions . ▁Typ ical ▁gas ifier ▁st ov es ▁are ▁known ▁as ▁Top ▁Lit ▁Up d raft ▁( TL UD ) ▁st ov es ▁because ▁some ▁fuel ▁is ▁lit ▁on ▁top ▁of ▁the ▁st ove , ▁forcing ▁comb ust ible ▁products ▁to ▁pass ▁through ▁the ▁fl ame ▁front ▁before ▁being ▁em itted ▁into ▁the ▁air . ▁ ▁Classification ▁of ▁cook ▁st ov es ▁ ▁Classification ▁of ▁cook ▁st ov es ▁ 1 . ▁Three - stone ▁fire ▁ 2 . ▁Early ▁" IC S " ▁" Im pro ved ▁Cook ▁Sto ves " ▁to ▁ 1 9 9 0 s ▁( cl ay / cer am ic / bu ckets ) ▁ 3 . ▁F uel - control led ▁st ov es ▁( main ly ▁Ro cket ▁st ov es ) ▁a . ▁Simple ▁( port able ) ▁b . ▁Station ary ▁( w / ▁chim ney ) ▁c . ▁For ced - air ▁( FA ) ▁ 4 . ▁Sem i - gas ifiers ▁( main ly ▁China ▁and ▁V esto ) ▁w / ▁some ▁air ▁control ▁ 5 . ▁Gas ifiers ▁(" m icro - " ▁for ▁cook