Browse Publications Technical Papers 2018-01-0603

Utilization of ADAS for Improving Performance of Coasting in Neutral 2018-01-0603

It has been discussed in numerous prior studies that in-neutral coasting, or sailing, can accomplish considerable amount of fuel saving when properly used. The driving maneuver basically makes the vehicle sail in neutral gear when propulsion is unnecessary. By disengaging a clutch or shifting the gear to neutral, the vehicle may better utilize its kinetic energy by avoiding dragging from the engine side. This strategy has been carried over to series production recently in some of the vehicles on the market and has become one of the eco-mode features available in current vehicles. However, the duration of coasting must be long enough to attain more fuel economy benefit than Deceleration Fuel Cut-Off (DFCO) - which exists in all current vehicle powertrain controllers - can bring. Also, the transients during shifting back to drive gear can result in a drivability concern. The in-neutral coasting system should automatically shift to drive in case of nearby traffic for safe operation capability.
To mitigate those issues, this paper proposes an in-neutral coasting control algorithm that utilizes information from Advanced Driver Assistance System (ADAS). By monitoring driving condition ahead, such as distance and relative velocity to preceding vehicle, the algorithm can identify the appropriate coasting opportunity. The developed logic has been implemented in a test vehicle for validation and showed promising performance. The on-road test results and fuel economy analysis are presented with the description of the coasting algorithm.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 18% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.

Due to current capacity constraints, printed versions of our publications - including standards, technical papers, EDGE Reports, scholarly journal articles, books, and paint chips - may experience shipping delays of up to four to six weeks. We apologize for any inconvenience.