procedure TForm1.Button1Click(Sender: TObject);
var
  S   :String;
  List:TStringList;
begin
  S:='AA=12 BB=34 CC=56 DD=78';
  List:=TStringList.Create;
  List.Delimiter    :=#32;
  List.DelimitedText:=S;
  ShowMessage(List.Values['BB']);
  List.Free;
end;