Korean Institute of Machinery & Materials

Korean Institute of Machinery & Materials

Independent South Korea Research Center Validates Eco-Friendly Features of Eaton Hybrid Electric Power Systems

“The real road test showed 36 percent higher fuel efficiency. The chassis dynamometer tests were even better, showing 42 to 54 percent higher fuel efficiency. Meanwhile, NOX and CO2 emissions were reduced by 45 and 35 percent respectively. CO emissions were reduced by 30 percent.”

Dr. Dongsoo Jeong
Director and head of the Green Car Research & Development Center at the Korean Institute of Machinery & Materials (KIMM).

Background

According to Dr. Dongsoo Jeong, director and head of the Green Car Research & Development Center at the Korean Institute of Machinery & Materials (KIMM), the commercialization and adaptation of hybrid vehicle technology is spreading widely around the world and should continue to do so well into the future. He cites a Frost & Sullivan study that estimates the penetration of commercial hybrid vehicles will double from 80,000 to 160,000 units by 2016 in Europe and North America.

Dr. Jeong would like to see similar growth in South Korea, where he says the development of commercial hybrid vehicles started somewhat late and is still in its initial stages.

That’s why he spearheaded a recent KIMM project centered on evaluating the fuel efficiency improvements and emissions reductions of eight hybrid electric transit buses. The vehicles were manufactured by Daewoo Bus and equipped with 6-liter diesel engines, Li-ion type batteries, and parallel-type hybrid electric drive units.

Eaton’s staff in South Korea and the Korea Petroleum Association assisted with the project.

Based in Daejeon, South Korea, KIMM was established in 1976 to help contribute to the development of new technologies within the country through reliability testing and various research and development projects.

Challenge

The test buses operated in six different cities in South Korea, including Seoul, Busan, Goacheon, Yeosu, Daejeon and Daegu.

To help ensure accuracy, testing included the neutral evaluation of real-life, on-road vehicle performance. In one test, KIMM made arrangements to have a hybrid bus delivered to Booil Bus Company in Busan. There, fuel consumption data was gathered on a traditional diesel-powered bus with an automatic transmission and a diesel-powered hybrid bus with an Eaton hybrid drive unit that included an Eaton 6-speed automated manual transmission.

Similarly specified vehicles were also tested in shuttle bus applications in order to gather data in both moderate and heavy traffic conditions. “During trial runs in all of the cities we found that the potential for fuel savings was high when comparing a hybrid bus to a normal diesel bus,” notes Dr. Jeong. “However, we were unable to confirm emissions reductions because equipment was not prepared to make the measurements.”

Solution

To counter that, a chassis dynamometer test facility for heavy-duty vehicles was used at Forhuman Engineering Inc. in Ansan, South Korea.

There, exhaust analyzers were used to measure emission gases such as hydrocarbon (HC), carbon monoxide (CO), nitrogen oxides (NOX), carbon
dioxide (CO2) and other particulate matters. Dynamometer testing included two types of driving cycles, which Dr. Jeong describes as a Busan city mode and an SAE JE05 mode. Fuel consumption measurements were also taken.

“The Busan city mode, with extended operating time and longer distances, is the closest mode to the real road driving patterns of a city bus in Korea,” says Dr. Jeong. “JE05 mode is an official driving cycle that is widely used in other countries. It is composed of moderate acceleration and deceleration driving patterns and high-velocity driving.”

Result

Regardless of mode, emission reductions were astounding. So were the fuel efficiency gains results, and not only from the dynamometer tests, but also from the road tests on all eight of the buses with Eaton hybrid electric systems.

“The real road test showed 36 percent higher fuel efficiency,” adds Dr. Jeong. “The chassis dynamometer tests were even better, showing 42 to 54 percent higher fuel efficiency. Meanwhile, NOX and CO2 emissions were reduced by 45 and 35 percent respectively. CO emissions were reduced by 30 percent.”

Dr. Jeong attributes a significant amount of the fuel savings to the regenerative braking function and the ISG (Idle Stop and Go) function on the Eaton hybrid power systems. Regenerative braking is activated when the hybrid buses are decelerating and the energy that would normally be lost is absorbed in the battery. The ISG function is activated when both the foot and parking brakes are applied, again conserving fuel with the diesel engine off. The engine will return to running when the driver releases the parking brake.

Overall, the outlook for commercial vehicle hybrid growth in South Korea is off to a good start.