Ford researchers are testing a fuel efficiency-focused cruise control system in real-world driving conditions.
“This advanced system works within the context of an existing speed control system, so it doesn’t require any additional hardware, infrastructure resources, or the Internet,” explained Steve Szwabowski, a Ford controls researcher, during a recent media event at the automaker’s research and advanced engineering center in Dearborn, MI.
With a traditional cruise control system, the driver sets a speed target and vehicle speed is maintained as accurately as possible under a variety of load and operating conditions. With Ford’s research-based advanced cruise control technology, fuel consumption becomes part of the equation.
“We’re using onboard information to understand both the speed and the torque trajectory for a specific vehicle, in order to get the best overall fuel economy for the road conditions,” Szwabowski said about the research-based dynamic cruise control technology.
Tony D’Amato, research engineer, said that the system can take advantage of a road grade “to time a torque-demand reduction and, in some cases, decouple the transmission to reduce powertrain losses, which results in enhanced fuel economy.”
Devising an appropriate vehicle speed range for a fuel-sipping cruise control speed setting is no easy task for the researchers.
Said Szwabowski: “One of the key things is determining how much of a speed variation is needed to achieve a certain fuel economy benefit. Keep in mind that reducing speed by itself doesn’t necessarily enhance fuel economy.”
To understand the various trade-offs associated with a fuel-saving cruise control system, researchers are driving several different Ford vehicle models on hills and other road gradients. "Fuel economy depends on the vehicle and its powertrain configuration, including the gear ratios of the transmission and the performance map of the engine,” said Szwabowski.
According to D’Amato, transmission gear ratios and other relevant information are used to estimate the speed and torque profile so that minimal energy is required for the vehicle to traverse a road segment, all done while respecting speed limits and other driveability constraints.
Although a driver can avoid heavy accelerations and hard braking to conserve fuel, a smart cruise control system could complement the overall fuel economy score for a particular driving event.
Szwabowski explained: “Because there are differences in terms of the best operating speed for a given condition, it can be hard for a driver to achieve optimal fuel efficiency. And that’s because the driver doesn’t know exactly what the performance map of the engine is. The driver is also not calculating all of the constraints, such as the final drive ratio of the transmission.”
Ford’s fuel-efficient cruise control research technology analyzes and reacts to current road conditions as well as predicted road conditions in real time.
“What we envision for this technology in a production application is a cruise control system in which the driver has the option of using a fuel-saving selectable mode,” said Szwabowski.
Preliminary estimates indicate that Ford’s advanced cruise control technology could improve fuel efficiency up to 10%, depending on the driving route.