According to John Grabowski :
Chris, In a situation such as this I would put a heat detector in the garage
connected to the smoke alarms. That would eliminate the nuisance alarms
from car exhaust and anything else. You would need to use smoke detectors
that have an auxiliary contact such as the ESL brand by GE. The heat
detector would not have an alarm on it, but if you needed one you could also
connect a remote using a smoke detector with a relay in it.

How compatible are the gang-trip lines on smoke/heat detectors? I've never
seen a unit that claims to have a "standard" interconnect. The ones
I've looked at insist on only ganging with smoke alarms from the same
manufacturer.
--
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.