Read Excel default working directory from Delphi Ole container

I have an application to call Excel in the background, but when I close
the excel dialog box popup, I do not want user to see the dialog box, I
save the spread sheet before close, but Excel creat a file in the
working directory, second time Excel popupp twice dialog box for
workplace file, if I can access working directory from Excel. I can
delete this file every time I run the application. anybody can help me
thanks in adavance !