check $this->upload->initialize($config); this works fine for me
$new_image_name = "imgName".time() . str_replace(str_split(' ()\\/,:*?"<>|'), '',
$_FILES['userfile']['name']);
$config = array();
$config['upload_path'] = './uploads/';
$config['allowed_types'] = 'gif|jpg|png|bmp|jpeg';
$config['file_name'] = $new_image_name;
$config['max_size'] = '0';
$config['upload_path'] = './uploads/';
$config['allowed_types'] = 'gif|jpg|png|mp4|jpeg';
$config['file_name'] = url_title("imgsclogo");
$config['max_size'] = '0';
$config['overwrite'] = FALSE;
$this->upload->initialize($config);
$this->upload->do_upload();
$data = $this->upload->data();
}