Sequential optimization of speed, thermal load, and power split in connected HEVs

Abstract

The emergence of connected and automated vehicles (CAVs) provides an unprecedented opportunity to capitalize on these technologies well beyond their original designed intents. While abundant evidence has been accumulated showing substantial fuel economy improvement benefits achieved through advanced powertrain control, the implications of the CAV operation on power and thermal management have not been fully investigated. In this paper, in order to explore the opportunities for the coordination between the onboard thermal management and the power split control, we present a sequential optimization solution for eco-driving speed trajectory planning, air conditioning (A/C) thermal load planning (ecocooling), and powertrain control in hybrid electric CAVs to evaluate the individual as well as the collective energy savings through proactive usage of traffic data for vehicle speed prediction. Simulation results over a real-world driving cycle show that compared to a baseline non-CAV, 11.9%, 14.2%, and 18.8% energy savings can be accumulated sequentially through speed, thermal load, and power split optimizations, respectively.

Thermal Responses of Connected HEVs Engine and Aftertreatment Systems to Eco-Driving

“…The SPM is therefore modified to represent vehicle acceleration and deceleration process and make predictions of the queuing dynamics. The details of queuing process modelling using the SPM can be found in our previous works [8], [10].…”

“…To illustrate our approach to traffic modeling, a sixintersection corridor on Plymouth Road in Ann Arbor (as in [10]) is modeled. The stretch of the road represented in the simulations is about 2.2 miles and has two lanes for each direction.…”

“…When the A/C is off, P aux is negligible and the SOC dynamics can be captured with P M/G as the input. Parameters ξ 1,···,9 in (1) are identified from experimental data collected from our test vehicle (2017 MY Prius) with sampling time T s = 1 sec, see [10] for more details on the experimental validation and the identified parameters of the model in (1).…”

MPC-based Precision Cooling Strategy (PCS) for Efficient Thermal Management of Automotive Air Conditioning System

“…In the definition, two major variables, temperature and flow rate of the cooling air, are considered to primarily impact the comfort. Compared with the average room temperature, which is commonly used as the performance metric in building HVAC control [15], [16] and also in our previous works [13], [14], [17], the choice of P DACP accounts for special characteristics of the automotive A/C system. In a passenger vehicle, occupants sit close to the vents and directly feel the temperature and the amount of air flow.…”

Combined Energy and Comfort Optimization of Air Conditioning System in Connected and Automated Vehicles

“…Our previous publications on automotive A/C energy management [9][10][11] have exploited the sensitivity of A/C system efficiency to vehicle speed and vehicle speed preview for reducing energy consumption. The average cabin temperature was used as the comfort metric in [9][10][11]. However, as shown in [12], the OTC may also depend on other variables.…”