Automotive engineers use all the energy sources they can find when designing cars for maximum efficiency. That’s why the engineers of hybrid vehicles tap the energy that gets wasted when a hybrid’s brakes are applied. Instead of converting the motion of the vehicle into wasted heat via the brake pads, as ordinary cars do, hybrid vehicles have a small generator on each axle that converts the car’s movement into electricity. This electric power is then fed to the vehicle batteries. Most of the hybrid manufacturers refer to this as “Regenerative Braking.”
In any internal combustion-powered vehicle, there is another source of wasted energy that is usually ignored. This is the energy of the movement of the exhaust gases that exit the tailpipe. The service manager at McLoughlin in Milwaukie, OR, a full-service Chevrolet dealer, points out that using exhaust gas to power automotive sub-systems isn’t a new concept as superchargers have been doing it for years. The way superchargers work is to use the exhaust gases to spin a turbine that drives fresh air into the vehicle’s engine. This allows more air-fuel mixture to be exploded in the cylinders which produces more engine power.
Instead of spinning a supercharger, though, why not spin a generator? Well, the Japanese firm YGK recently unveiled a hybrid powertrain that does just that. In theory, an exhaust turbine-generator could be used to charge a battery pack or even charge a large capacitor for instantaneous use. YGR has named their exhaust energy recovery system the “EER-Hybrid” system. The stunning news is that it reportedly provides a 10-percent boost in overall vehicle MPG. This is a major improvement in efficiency.
It should be noted that EER systems are not new to those that race Formula One cars. For the last few years, various Formula One teams have been using exhaust gas recovery systems. The energy that they harvest from the powerful exhaust gasses exiting the engine are converted directly into electricity and this is fed back into the electrical system of the race car. It effectively eliminates the drag of an alternator on the car engine and this is a significant boost in power.
So, when will we see the use of EER systems on our street cars? The engineers at YGK are currently working Jaguar and other car manufacturers. In fact, Jaguar is putting an EER system on their new XJR-15 model. The XJR-15 is a supercar but the folks at Jaguar are looking to make a statement of the EER concept before it migrates down into their standard automobiles. Considering the fuel economy involved, it shouldn’t be long before we see a lot more of it on the street.
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