CodeIgniter custom_result_object class parameter

在我的模型中，我有：

function select_by_limit($start, $limit) {
    $this->db->from($this->_table.' a');
    $this->db->join('zone b', "a.id_zona = b.id_zona", 'left');
    $this->db->join('tip_proprietate c', "a.id_tip_proprietate = c.id_tip_proprietate");
    $this->db->limit($limit, $start);
    $query = $this->db->get_compiled_select();
    $result = $this->db->query($query);
    return $result->custom_result_object('Proprietati');
}

所以我使用自定义对象类Ownerati。但是，我怎样才能发送一个参数，以便在构造函数中获取它呢？

public function __construct($resolution = 270){
    $this->_resolution = $resolution;
}

控制器

class foo extends CI_Controller {
    protected $_resolution;
    public function __construct($resolution = 270){
        $this->_resolution = $resolution;
    }

将$resolution传递给模型函数

public function using_model($start, $limit, $this->resolution);

在模型中

function select_by_limit($start, $limit, $resolution) {
    //whatever happens here....