Session dies in CodeIgniter

I have an app built in CI and I would like that sessions don't die unless users close their browser. In my config file I have the following:

$config['sess_cookie_name']     = 'ci_session';
$config['sess_expiration']      = 0;
$config['se开发者_StackOverflow中文版ss_encrypt_cookie']  = FALSE;
$config['sess_use_database']    = FALSE;
$config['sess_table_name']      = 'ci_sessions';
$config['sess_match_ip']        = FALSE;
$config['sess_match_useragent'] = TRUE;
$config['sess_time_to_update']  = 0;

But session still dies after a period of time, is there any other configuration I need to do? Maybe directly on the server that might be causing the session to die? Thanks!

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http://www.php.net/manual/en/session.configuration.php#ini.session.gc-maxlifetime

by default, PHP sessions are garbage collected after 24 minutes.