Delphi Narrows Quarterly Net Loss  CHICAGO (Reuters) - Auto parts supplier Delphi Corp.  &lt;A HREF="http://www.investor.reuters.com/FullQuote.aspx?ticker=DPH.N target=/stocks/quickinfo/fullquote"&gt;DPH.N&lt;/A&gt; on Monday posted a smaller quarterly loss as lower  restructuring charges offset the effects of North American  motor vehicle production cuts and rising materials costs.