csv_from_result() and rares characters?

[eluser]chefnelone[/eluser]
Hello,

I'm using csv_from_result(); to generate a csv file:

Code:

$this->load->dbutil();
$queryForCsv = $this->db->query("SELECT * FROM membership_area");
$delimiter = ";";
$dataForCsv = $this->dbutil->csv_from_result($queryForCsv, $delimiter);

$pathCsv = '/clients.csv';
write_file($pathCsv, $dataForCsv);

problem is: if there are texts in the membership_area table with rare characters (ñ,°, á, é...) generate a csv file with mistakes.

Examples:
4° generates 4¬∫
Años generates A√±os

How can I solve this?
Thanks