This tutorial is based on the  CI docs (CodeIgniter Email Library)…

Simply create a new file called the email.php, add the $config array in that file as defined below. Then save the file at config/email.php and it will be used automatically. You will NOT need to use the $this->email->initialize() function if you save your preferences in a config file.

I was able to get this to work by putting all the settings into application/config/email.php.

$config['useragent'] = 'CodeIgniter';
$config['protocol'] = 'smtp';
//$config['mailpath'] = '/usr/sbin/sendmail';
$config['smtp_host'] = 'ssl://';
$config['smtp_user'] = '[email protected]';
$config['smtp_pass'] = 'YOURPASSWORDHERE';
$config['smtp_port'] = 465; 
$config['smtp_timeout'] = 5;
$config['wordwrap'] = TRUE;
$config['wrapchars'] = 76;
$config['mailtype'] = 'html';
$config['charset'] = 'utf-8';
$config['validate'] = FALSE;
$config['priority'] = 3;
$config['crlf'] = "\r\n";
$config['newline'] = "\r\n";
$config['bcc_batch_mode'] = FALSE;
$config['bcc_batch_size'] = 200;

Then, in one of the controller methods I have something like:

$this->load->library('email'); // Note: no $config param needed
$this->email->from('[email protected]', '[email protected]');
$this->email->to('[email protected]');
$this->email->subject('Test email from CI and Gmail');
$this->email->message('This is a test.');