The 18-month Sentience project has the end goal of developing advanced vehicles which can utilize technologies such as GPS and telemetry to improve fuel efficiency and emissions.

Three particular areas of focus for Sentience have been on Enhanced Acceleration/Deceleration (EAD) in which the vehicle speed is controlled to meet actual and virtual speed limits; Optimized Engine Load (OEL) in which the hybrid powertrain systems are managed using advanced route knowledge in such a way as to make optimal use of recharging opportunities; and Enhanced Air-Conditioning (EAC) control in which temperature set-points are adjusted prior to and following temporary stops.

The human-machine interface (HMI) for Sentience is based on a Nokia N95 mobile phone. Click to enlarge.

A key visual element of the implementation of Sentience within the demonstrator vehicle is a human-machine interface (HMI) developed by Orange and based on a Nokia N95 mobile phone. This device also provides the communications link that delivers route data for the vehicle’s control system.

The HMI provides appropriate feedback to the driver—for example, of the prevailing speed limit at the vehicle’s current location—as well as input configuration information. To provide an integration infrastructure for the demonstration vehicle a telecoms protocol was defined and implemented by Ricardo and Orange for communication between the HMI and the Ricardo rCube rapid prototyping controller used to supervise the Sentience EAD functions. The design of the HMI architecture was deliberately intended to accommodate the integration of real-time traffic data in a future implementation.

Enhanced Acceleration/Deceleration (EAD). The project team unveiled the Sentience research vehicle—based on a Ford Escape Hybrid—at a press launch in early March 2009. At that time the vehicle exhibited the Enhanced Acceleration/Deceleration (EAD) control strategy.

EAD is implemented on the Sentience demonstrator vehicle through an advanced form of adaptive cruise control linked to the hybrid powertrain system of the vehicle. Based on route information—which could in a production setting be integrated with a commercial navigation system—the Sentience vehicle will calculate and follow an optimal driving strategy.

Its control system adjusts vehicle speed, acceleration and deceleration via its adaptive cruise control. Using GPS and mapping data it takes into account the speed limits, traffic conditions, the road’s gradient and features including bends and even speed bumps, as well as less predictable road features including roundabouts and traffic lights. The river can override the system at any time.

Moreover, the data provided by the mapping and navigational systems is also used to optimize the recharging strategy of the hybrid’s batteries, thus increasing the potential availability of electric-only mode in urban environments.

Although not implemented on the project vehicle, the EAD implementation has the necessary in-built links to work with real-time traffic information in order to update its strategy according to prevailing conditions and areas of congestion. In track based tests, the EAD strategy alone has demonstrated fuel savings of between 5 and 24%t depending upon traffic conditions and route topology. In evening tests on public roads in ‘real-world’ conditions in the vicinity of TRL, achieved mean savings at all times in excess of 5%.

Enhanced Air Conditioning. Since its initial unveiling, testing and development of the Sentience vehicle has been actively progressed using climatically controlled test facilities at the Ricardo Midlands Technical Centre. A new Enhanced Air Conditioning (EAC) control strategy has now been successfully developed which manages the air conditioning system in parallel with the hybrid powertrain.

This is particularly useful in urban traffic with frequent stop/start transitions. In the test vehicle, the air conditioning compressor is driven by the engine so that when the hybrid powertrain operates in electric only mode or the vehicle is stationary, the air conditioning system does not operate. By linking the EAC and powertrain control strategies however, knowledge of when the combustion engine may be stopped allows the system to plan an appropriate and more efficient cooling strategy.

Cabin air temperature can thus be maintained within a narrow range while maximizing the opportunities for the gasoline engine to switch off—and hence minimizing the time that the engine is run solely to drive the air conditioning.

The measured fuel saving in summer driving of in excess of 9% is entirely due to the optimized control of the air conditioning system, as this is completely independent of the vehicle’s EAD strategy, which could not be used for a defined regulatory drive cycle such as the NEDC. The subject of a Ricardo patent application, the new EAC technology is also highly applicable to all types of hybrid vehicles, including the stop-start systems which are becoming increasingly common.

The Enhanced Air Conditioning (EAC) control system we have announced today is a further very tangible technology breakthrough for the Sentience project, which has already demonstrated the potential synergies to be realized by connecting the existing on-board systems of vehicles with mobile communications and advanced mapping technologies. EAC is highly applicable to a wide range of hybrid vehicle types from simple stop-start systems to plug-in hybrids, and Ricardo will seek to exploit this technology actively in its future client programs.

—Tom Robinson, Sentience project director for Ricardo