Vintage Ad: GM’s Hybrid Stir-Lec 1 – 1969 Chevy Volt Predecessor

GM Opel Stir-Lec 1 001 900

GM experimented with a number of electric cars in the 60s (as well as other alternative propulsion systems). Although they tried all sorts of exotic (expensive) battery technologies, such as the silver-zinc batteries in the 1966 Electrovair, range was still a disappointing 40+ miles, and the cells were shot after 100 recharges. So an on-board generator was called for, and GM went exotic with that too, using a Stirling engine in the back of a modified Opel Kadett to feed the 14 conventional lead-acid batteries in front, which fed a 3-phase induction motor driving the rear wheels. 


I’d forgotten about this car until I stumbled into this ad in a 1969 Hot Rod I was perusing for possible material. I didn’t expect it would be this, given the source. Googling only brings up one image of the Stir-lec in motion.  Apparently it had a top speed of 55 mph, but no other details are available. GM presumably used the Sterling (Heat Cycle) engine, which is externally heated by a wide variety of fuels, because it emitted very low emissions. And of course it was almost totally silent.

Sterling engines have been around since their invention in the early 1800s, but have found little practical application due to their low power-to-weight ratio. But some are now being used in some non-nuclear submarines while submerged, fueled by diesel (and liquid oxygen) precisely because they are so quiet.