如何在codeigniter 3中设置会话不会在浏览器关闭时到期？

I would like to set the session in codeigniter version 3 not to expire on browser close. session should be retain for ever. Session should be destoryed when the user click the logout button. In previous version codeigniter used variable called "$config['sess_expire_on_close'] = FALSE;" but now in codeigniter version 3 we dont have that. how to set in config or create custom core controller to extend the session.

$config['sess_driver'] = 'database';
 $config['sess_use_database']   = TRUE;
$config['sess_cookie_name'] = 'ci_session';
 $config['sess_expiration'] = 60*60*24*180;
$config['sess_save_path'] = 'ci_sessions';
 $config['sess_match_ip'] = FALSE;
 $config['sess_time_to_update'] = 0;
  $config['sess_regenerate_destroy'] = FALSE;
      $config['cookie_prefix']  = '';
   $config['cookie_domain'] = '';
 $config['cookie_path']     = '/';
    $config['cookie_secure']    = FALSE;
   $config['cookie_httponly']   = FALSE;

I have an answer that is not related to codeigniter.
you may want to set session lifetime via ini

ini_set('session.gc_maxlifetime', 3600 * 2); //two hours
session_set_cookie_params(3600 * 2);
session_start();

also have a look here of how to combine it with CG Codeigniter increase session time out not working

Update You can set ini variables via htaccess or VirtualHost

$config['sess_expiration'] = 0;

Setting to 0 (zero) means expire when the browser is closed.

Source: config.php (~Line 335)