<?php

    $modelos = explode(",","1,2,3,4");
        $query = sprintf("Select codigo_modelo, nome From modelos Where codigo_modelo in (%s)",
                implode(
                ',',
                array_map(
                    function() {
                       static $x = 0;
                       return ':cod_'.$x++;
                    },$modelos
                )
            )
        );
        echo $query; exit;