QlikView help has an explanation of incremental loading from log files like below.
Buffer (Incremental) Load * From LogFile.txt (ansi, txt, delimiter is '\t', embedded labels); // you need to define the location where the qvd is generated
other wise as DataNibbler mentioned you can loop through the files and can just load the file which has filetime() equals to today().
or if you are allow to move the log files to separate folder then you can use the execute command to move the log file immediately after loading data from it. in that case you will only have one log file in the log folder per day.