Help with my "speeding up time" script

Hi, I’m trying to get it so that my game speeds up faster and faster once the timer (which is counting downwards) reaches 30, and then goes back to normal timescale after the counter hits 1.

I have this script below so far but I have no idea what to put to increase the speed faster and faster, would it be Time.timeScale += 0.1f * Time.deltaTime i’m totally guessing here!?

#pragma strict
var countdownTimer : countdownTimer;

function Update(){

if (countdownTimer.seconds <=30){

//speed up time x2
Time.timeScale = 2f;

if (countdownTimer.seconds <=1){

//reset time to normal again
Time.timeScale = 1f;


Pretty much.

if (countdownTimer.seconds <= 30) {
    // clamp at 2 (optional)
    if (Time.timeScale <= 2.0f) {
        Time.timeScale += 0.1f * Time.deltaTime;