The newly-announced Saturn Aura Greenline will be GM’s first production hybrid passenger car later this year. Apr. 16, 2006: Another GM Hybrid Without much fanfare, GM announced at the New York International Auto Show that it would have a hybrid passenger sedan in showrooms by the end of the year--its first production hybrid passenger car. The just-announced Saturn Aura Greenline Hybrid uses the same hybrid system as its SUV cousin, the Saturn VUE Greenline, which is due to go on sale shortly. Both Greenline hybrids feature a 2.4-liter in-line four-cylinder Ecotec engine with a Belt-Alternator-Starter (BAS) system augmented with a 36-Volt NiMH battery pack. Functionally, the Greenline hybrid system offers start-stop and regenerative braking--features expected in a simple Belt-Alternator-Starter system. Going beyond that, however, GM, developed a dual tensioner assembly for the hybrid accessory drive (the motor/generator package) that will transfer a small amount of torque to the drive system for very brief periods of time. GM is using the BAS-based Greenline hybrid system to try to deliver a simple hybrid architecture flexible enough--and low cost enough--to be applied globally on a broad spectrum of both powertrains and vehicles. The Greenline hybrid drive is GM's current mid-range hybrid solution, bracketed by the micro-hybrid on the Silverado, and the two-mode hybrids being applied first in its full-size SUVs. GM has yet to indicate performance specifications for the Aura Greenline or pricing, but odds are that it will be as competitively priced in its segment as the VUE Greenline is in its--which is to say, it will be a price-performer. Also at the New York auto show, Toyota introduced its flagship luxury hybrid. The Lexus LS 600h L is a state-of-the-art luxury sedan with a new 5.0-liter gasoline direct-injection V8 with large, high-output electric motors and a newly designed battery pack that combine to deliver more than 430 horsepower (321 kW). It is an elegant piece of engineering and craft. Lexus is positioning the 600h as delivering the power and performance of a 12-cylinder engine with best-in-class V8 fuel efficiency--i.e., likely in the low 20s, combined city and highway. Hmm. That's a fuel economy rating roughly comparable to that of one of GM's new non-hybrid Tahoe full-size SUVs. Once the two-mode hybrid Tahoe hits the streets next year, it might even prove to be more fuel-efficient than the Lexus 600h hybrid. For all the bad press GM gets about its gas-guzzling beasts, GM should also be recognized for getting in gear and rolling out a range of hybrid systems, the Greenline powertrains being just one. Although technically these Greenline hybrids are relatively weak hybrid systems, applied in the VUE they deliver a projected 20% improvement in fuel economy. That's not insignificant. With companies offering hybrid drivetrains in an increasing number of vehicle segments, the issue once again comes back to the consumer. What do consumers value? A 20% increase in fuel efficiency? What's the baseline? As long as buyers continue to go for more power and performance (even made "guilt-free" by the addition of a hybrid system), we will continue to deepen our addiction to fossil fuels, we will continue to dump an ever-increasing amount of greenhouse gases into the atmosphere, and we will continue to crank up the Earth's atmospheric thermostat.