PHPMailer y PHPExcel enviar sin escribir en disco

require 'PHPMailer-master/PHPMailerAutoload.php';
include("function_envia_mail_rck.php");

//https://github.com/PHPMailer/PHPMailer/wiki/Tutorial

/*    -----------------------         */
require_once 'PHPExcel-1.8/Classes/PHPExcel.php';

// Create new PHPExcel object

$objPHPExcel = new PHPExcel();
  $hoja_activa = 0;
  $border_style= array('borders' => array('allborders' => array('style' => PHPExcel_Style_Border::BORDER_THIN) ));
  $objPHPExcel->setActiveSheetIndex($hoja_activa)
  ->setCellValue('B1', 'CAR�TULA AUDITOR�A');

$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'Excel2007'); //'Excel5');

ob_start();
$objWriter->save('php://output');
  
$arch = ob_get_contents();
// ob_end_clean();


mandarMail($para="mail@mail.gov.ar", $asunto="hola test 3", $mensaje="hola test 3", $adjunto=$arch);

aca es donde lo adjunta: