Analysis of CO2 Reduction Mechanism by Eco-Driving with Light Duty Diesel Freight Vehicle in Real Traffic Conditions

The Eco-Driving technique which includes measures such as preventing sudden acceleration and shifting-up at lower engine speed is attractive because it has an immediate effect on reduction of CO₂ emissions from vehicles with minimal effort. In order to determine the main factors for reducing CO₂ emissions by Eco-Driving, tests on urban roads were conducted with a light duty diesel freight vehicle operated by five test drivers under two driving scenarios: one with typical operations and one with Eco-Driving operations. As a result, under conditions of a mean vehicle speed of about 15km/h, the amount of CO₂ emissions emitted during Eco-Driving operations by the test drivers were less than those of typical operations by 15% or more. It was determined that while under Eco-Driving operations, CO₂ emissions in acceleration modes were greatly reduced. Other modes like cruising, deceleration, and idling produced less CO₂ reductions. The results showed that CO₂ emissions decreased because Eco-Driving operations reduced the required driving energy because of more moderate vehicle accelerations. Furthermore, analysis of the actual history of engine speed and load on the engine map under vehicle starting and acceleration conditions revealed that Eco-Driving operations, which included shifting-up at lower engine speeds and using higher load, increased the frequency of engine operation in the range with highest thermal efficiency, and this resulted in CO₂ emissions reduction.