CodeIgniter - 从我的库中加载系统库不起作用

Question

我试图让我的图书馆发送电子邮件 在我的控制器中，我设置为：

$this->load->library('MY_Email'); // My library has been loaded

档案MY_Email.php

class MY_Email {
    public $ci;
    public $config;
    public $email;

    public function __construct () {
        $ci = &get_instance();
        $ci->load->config('email');
        $this->config = array(
            'protocol'     => $ci->config->item('email_protocol'),
            'smtp_host'    => $ci->config->item('email_smtp_host'),
            'smtp_port'    => $ci->config->item('email_smtp_port'),
            'smtp_timeout' => $ci->config->item('email_smtp_timeout'),
            'smtp_user'    => $ci->config->item('email_smtp_user'),
            'smtp_pass'    => $ci->config->item('email_smtp_pass'),
            'charset'      => $ci->config->item('email_charset'),
            'mailtype'     => $ci->config->item('email_mailtype'),
            'validation'   => $ci->config->item('email_validation')
        );

        $ci->load->library('email', $this->config);

        /*This line print `Undefined property: Controller::$email` and result is NULL*/
        var_dump($ci->email); die;
    }
}

我错了什么？ 感谢您的帮助