One of those little pebbles was on display at the SAE World Congress in Detroit this week: the Dedicated-EGR demonstration vehicle from the Southwest Research Institute (SwRI). The basic idea behind EGR is that the system captures the exhaust gas from the cylinders and reroutes it back into the engine intake, which isn't a new idea. What SwRI is doing that's different, according to SwRI's Chris Chadwell, is that the system then runs a cylinder "rich," with about 30 percent more fuel there. "The natural by-products of rich combustion are hydrogen and carbon monoxide, both of which are very high octane," Chadwell told AutoblogGreen. "In effect, what you are doing is increasing the octane of your reactants." This not only improves engine knock, but it also increase fuel economy by up to 15 percent. It's also operating in the real world. SwRI drove the car to Cobo Hall this week and has been testing the vehicle for a while. This is the third phase of SwRI's High-Efficiency Dilute Gasoline Engine (HEDGE) technology program and the group says that, with turbocharging and supercharging, the vehicle starts and cruises like the stock version, but it accelerates better.
The vehicle starts and cruises like the stock version, but it accelerates better.
The parts that need to be added to the powertrain are the cooled EGR loop, a high-energy ignition system, new software and a special mixer to spread the exhaust gas around. That all sounds simple, but Chadwell said that there is no specific price for this product that the organization is able to share. He did say that they expect the technology to cost under $100 per percentage point of MPG improvement, so we extrapolated that out to a maximum cost of $1,500 per vehicle for a 15 percent improvement. But, Chadwell said, "We feel we are well under that."
You can read a lot more over at SwRI and here. We've got some videos and the official press release on the SAE appearance below.
Advanced combustion technology improves fuel economy, lowers emissions
Engine, Emissions, & Vehicle Research
The drive to 54.5 miles per gallon just got shorter with SwRI's Dedicated-EGR™ Demonstration Vehicle. The patented D-EGR™ technology was developed as part of the HEDGE®consortium, led by SwRI, headquartered in San Antonio.
Detroit - April 8, 2014 - Southwest Research Institute® (SwRI) announced preliminary test results of its patented Dedicated-Exhaust Gas Recirculation (D-EGR™) demonstration vehicle today at the SAE World Congress. The results prove the advanced combustion technology increases engine efficiency while simultaneously lowering exhaust emissions.
Dedicated-EGR is a novel engine architecture up to 15 percent more efficient than today's mainstream engines while simultaneously improving performance. It allows manufacturers to address future, more aggressive Corporate Average Fuel Economy (CAFE) standards and meet LEV III/Tier 3 emissions levels cost-effectively.
SwRI's D-EGR demonstration vehicle began as a mid-size sedan with a current-production 4-cylinder 2.0 L gasoline engine. The engine was modified so that exhaust from one dedicated cylinder is run with a rich mixture of fuel and air to reform hydrocarbon fuel into carbon monoxide and hydrogen. The reformulated exhaust gas is then cooled and looped into a patented mixer where the EGR and reformate are mixed with fresh air before going into the engine intake. A team of engineers designed several new parts for the advanced combustion concept - the cooled EGR loop, the EGR mixer and high-energy ignition system - as well as engine-control software that enables in-cylinder fuel reformation.
"The D-EGR concept takes the best attributes of regular cooled EGR and combines them with in-cylinder reformer technology. We segregate the exhaust of a cylinder of the engine so that one cylinder provides all of the recirculated exhaust gas back into the intake manifold," said Dr. Terry Alger, assistant director in SwRI's Engine, Emissions and Vehicle Research Division.
"By running one cylinder rich, the excess fuel is reformed into hydrogen and carbon monoxide," added Chris Chadwell, manager of SwRI's Spark Ignition Engine R&D section. "The in-cylinder reformation slightly reduces the carbon dioxide and water vapor while producing large volumes of carbon monoxide, which is a good fuel, and hydrogen, which is an outstanding fuel. That provides an octane boost and a flammability boost, and extends the EGR limit of the engine."
Designed from the start to demonstrate production feasibility, a D-EGR-configured engine can be integrated into almost any spark-ignited engine architecture. Because there are few additional components, it fits comfortably in an existing engine compartment without altering the engine's footprint.
"Our engineers initially developed and demonstrated D-EGR technology in an engine test cell through SwRI's HEDGE® (High-Efficiency Dilute Gasoline Engine) consortia," said SwRI Executive Vice President Walt Downing. "Under SwRI's internal research program, our engineers were able to solve the technical problems with making a D-EGR engine fit under the hood and operate on a current-production sedan. In 15 months, we took the concept from the laboratory to production viability."
By 2025, automobile manufacturers will have to meet CAFE standards of 54.5 miles per gallon. The Environmental Protection Agency is also expected to release new, more stringent emissions standards. Those two factors mean there is considerable industry focus on simultaneously improving both emissions and fuel efficiency, challenges which SwRI's demonstration vehicle addresses.
"When considering the high-efficiency alternatives out there today, we feel that our Dedicated-EGR technology is not only a high-efficiency, low-emissions alternative, but it's the most cost-effective market-ready solution currently available," Alger said.
For downloadable media assets about the D-EGR technology, please visit: degr.swri.org.