DS1 is 1.5yo and i dont know how to make him nap - help!

[tostaky]

because DS2 has arrived and I need at least an hour a day of rest from DS1...
He will go to sleep in his car seat if im driving or if i take him in his puschair for a walk after lunch... but id love to be able to put him in his cot and he would sleep on his own.
if i do that now, he'll scream for hours (well, not hours but for as long i can stand to let him scream ie. 15 mins)
what should i do?

thx