function mappingsexportAction()
 {
     $this->checkVersion();
     if (isset($_GET['go'])) {
         header(sprintf('Content-Disposition: attachment;filename="vaf-export-%s.csv"', time()));
         header('Content-Type: text/csv');
         $stream = fopen("php://output", 'w');
         $exporter = new Elite_Vafimporter_Model_ProductFitments_CSV_Export();
         $exporter->export($stream);
         exit;
     }
     $this->loadLayout();
     $this->_setActiveMenu('vaf/export');
     $block = $this->getLayout()->createBlock('core/template')->setTemplate('vafimporter/mappings_export.phtml');
     $this->_addContent($block);
     $this->renderLayout();
 }
<?php

require_once 'config.php';
$stream = fopen("php://output", 'w');
$exporter = new Elite_Vafimporter_Model_ProductFitments_CSV_Export();
$exporter->export($stream);