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Technical Paper

Trade-off Analysis and Systematic Optimization of Heavy-Duty Diesel Hybrid Powertrain

2020-04-14
2020-01-0847
In recent years, while significant progress has been made in development of hybrid and battery electric vehicles for passenger car and light-duty applications to meet future fuel economy targets, application of hybrid powertrains to heavy-duty truck applications has been very limited. The relatively lower energy and power density of batteries in comparison to diesel fuel as well as the operating profiles of most of the heavy-duty trucks make the application of hybrid powertrain for these applications more challenging. The high torque and power requirements of heavy-duty trucks over a long operating range, the majority of which is at constant cruise point, along with a high payback period, complexity, cost, weight and range anxiety, make the hybrid and battery electric solution less attractive than a conventional powertrain.
Technical Paper

Effect of Battery Temperature on Fuel Economy and Battery Aging when using the Equivalent Consumption Minimization Strategy for Hybrid Electric Vehicles

2020-04-14
2020-01-1188
Battery temperature variations have a strong effect on battery aging and battery performance. Significant temperature changes will lead to different battery behaviors. This influences the performance of the Hybrid Electric Vehicle (HEV) energy management strategies. This paper investigates how variations in battery temperature will affect Lithium-ion battery aging and fuel economy of an HEV. The control strategy used is the Equivalent Consumption Minimization Strategy (ECMS) which is a well-known energy management strategy for HEVs. The studied vehicle is a Honda Civic Hybrid and the studied battery is the ANR26650 cell from A123 System. Vehicle simulations are done using multiple combinations of highway and city drive cycles. Multiple outside air temperatures are simulated, each with six ECMS penalty factors for each combination of drive cycles. Battery aging is evaluated using a semi-empirical model combined with the accumulated Ah-throughput method.
Technical Paper

Determination of Octane Index and K in a 2L, 4-cylinder turbocharged SI engine using the PRF method

2020-04-14
2020-01-0552
Research Octane Number (RON) and Motor Octane Number (MON) have traditionally been used to describe fuel anti-knock quality. The test conditions for MON are harsher than those for RON, causing the RON for a particular fuel to be higher than the MON. Researchers have proposed the anti-knock performance can be described using the Octane Index (OI), defined as OI=RON-K(RON-MON), where ‘K’ is a weighing factor between RON and MON. The K-factor indicates that at a particular operating condition, knock tolerance is better described by RON as K approaches a value of 1, and MON as K approaches a value of 0. Previous studies claim that K-factor is dependent only on the engine combustion system and the speed-load point, and that it is independent of fuel chemistry. In these studies, K was determined experimentally using linear regression. In this particular study, K was determined using the PRF method for two test fuels; EPA certification tier 2 and tier 3 fuel.
Technical Paper

Investigation of Diesel/Natural Gas RCCI Combustion Using Multiple Reaction Mechanisms at Various Engine Operating Conditions

2020-04-14
2020-01-0801
Past experimental studies conducted by the current authors on a 13 liter 16.7:1 compression ratio heavy-duty diesel engine have shown that diesel /natural gas Reactivity Controlled Compression Ignition (RCCI) combustion targeting low NOx emissions becomes progressively difficult to control as the engine load is increased due to difficulty in controlling reactivity levels at higher loads. For the current study, CFD investigations were conducted using the SAGE combustion solver in Converge with the application of Rahimi mechanism. Studies were conducted at a load of 5 bar BMEP to validate the simulation results against RCCI test data. In the low load study, it was found that the Rahimi mechanism was not able to predict the RCCI combustion behavior for diesel injection timings advanced beyond 30bTDC. This behavior was found at multiple engine speed and load points.
Technical Paper

Experimental Investigation of the Compression Ignition Process of High Reactivity Gasoline Fuels and E10 Certification Gasoline using a High-Pressure Direct Injection Gasoline Injector

2020-04-14
2020-01-0323
Gasoline compression ignition (GCI) technology shows potential to obtain high thermal efficiencies while maintaining relatively low soot and NOx emissions in light-duty engine applications. Recent experimental studies and numerical simulations have indicated that high reactivity gasoline-like fuels can further enable the benefits of GCI combustion. However, there is limited combustion data in the literature studying the gasoline compression ignition process at relevant in-cylinder conditions which are required for further optimizing combustion system designs. This study investigates the temporal and spatial evolution of the compression ignition process of various high reactivity gasolines with research octane numbers (RON) of 71, 74 and 82, as well as conventional RON 97 E10 gasoline fuel. Combustion visualizations were conducted in an optically accessible constant volume combustion chamber.
Technical Paper

Alleviating the Magnetic Effects on Magnetometers using Vehicle Kinematics for Yaw Estimation for Autonomous Ground Vehicles

2020-04-14
2020-01-1025
Autonomous vehicle operation is dependent upon accurate position estimation and thus a major concern of implementing the autonomous navigation is obtaining robust and accurate data from sensors. This is especially true, in case of Inertial Measurement Unit (IMU) sensor data. The IMU consists of a 3-axis gyro, 3-axis accelerometer, and 3-axis magnetometer. The IMU provides vehicle orientation in 3D space in terms of yaw, roll and pitch. Out of which, yaw is a major parameter to control the ground vehicle’s lateral position during navigation. The accelerometer is responsible for attitude (roll-pitch) estimates and magnetometer is responsible for yaw estimates. However, the magnetometer is prone to environmental magnetic disturbances which induce errors in the measurement.
Technical Paper

Numerical Parametric Study of a Six-Stroke Gasoline Compression Ignition (GCI) Engine Combustion- Part II

2020-04-14
2020-01-0780
In order to extend the operability limit of the gasoline compression ignition (GCI) engine, as an avenue for low temperature combustion (LTC) regime, the effects of parametric variations of engine operating conditions on the performance of six-stroke GCI (6S-GCI) engine cycle are numerically investigated, using an in-house 3D CFD code coupled with high-fidelity physical sub-models along with the Chemkin library. The combustion and emissions were calculated using a skeletal chemical kinetics mechanism for a 14-component gasoline surrogate fuel. Authors' previous study highlighted the effects of the variation of injection timing and split ratio on the overall performance of the 6S-GCI engine and the unique mixing-controlled burning mode of the charge mixtures during the two additional strokes. As a continuing effort, the present study details the parametric studies of initial gas temperature, boost pressure, fuel injection pressure, compression ratio, and EGR ratio.
Technical Paper

A Connected Controls and Optimization System for Vehicle Dynamics and Powertrain Operation on a Light-Duty Plug-in Multi-Mode Hybrid Electric Vehicle

2020-04-14
2020-01-0591
This paper presents an overview of the connected controls and optimization system for vehicle dynamics and powertrain operation on a light-duty plug-in multi-mode hybrid electric vehicle developed as part of the DOE ARPA-E NEXTCAR program by Michigan Technological University in partnership with General Motors Co. The objective is to enable a 20% reduction in overall energy consumption and a 6% increase in electric vehicle range of a plug-in hybrid electric vehicle through the utilization of connected and automated vehicle technologies. Technologies developed to achieve this goal were developed in two categories, the vehicle control level and the powertrain control level. Tools at the vehicle control level include Eco Routing, Coordinated Adaptive Cruise Control (CACC), Eco Approach and Departure (EcoAND) and in-situ vehicle parameter characterization.
Technical Paper

Utilization of vehicle connectivity for improved energy consumption of a speed harmonized cohort of vehicles.

2020-04-14
2020-01-0587
Improving vehicle response through advanced knowledge of traffic behavior can lead to large improvements in energy consumption for the single isolated vehicle. This energy savings across multiple vehicles can even be larger if they travel together as a cohort in harmonization. Additionally, if the vehicles have enough information about their immediate path of travel, and other vehicles’ in that path (and their respective critical forward looking information), they can safely drive close enough to each other to share aerodynamic load. These energy savings can be upwards of multiple percentage points, and are dependent on several criteria. This analysis looks at criteria that contributes to energy savings for a cohort of vehicles in synchronous motion, as well as describes a study that allows for better understanding of the potential benefits of different types of cohorted vehicles in different platoon arrangements.
Technical Paper

Mobile Robot Localization Evaluations with Visual Odometry in Varying Environments using Festo-Robotino

2020-04-14
2020-01-1022
Autonomous ground vehicles can use a variety of techniques to navigate the environment and deduce their motion and location from sensory inputs. Visual Odometry can provide a means for an autonomous vehicle to gain orientation and position information from camera images recording frames as the vehicle moves. This is especially useful when global positioning system (GPS) information is unavailable, or wheel encoder measurements are unreliable. Feature-based visual odometry algorithms extract corner points from image frames, thus detecting patterns of feature point movement over time. From this information, it is possible to estimate the camera, i.e. the vehicle’s motion. Visual odometry has its own set of challenges, such as detecting an insufficient number of points, poor camera setup, and fast passing objects interrupting the scene. This paper investigates the effects of various disturbances on visual odometry.
Technical Paper

An analytical energy-budget model for diesel droplet impingement on an inclined solid wall

2020-04-14
2020-01-1158
The study of spray-wall interaction is of great importance to understand the dynamics that occur during fuel impingement onto chamber wall or piston surfaces in internal combustion engines. The maximum spreading length after droplet impingement on wall is approved that it can provide a quantitative estimation of heat transfer and energy transformation for spray-wall interaction and further influence air-fuel mixing and hydrocarbon and particle emissions at combusting conditions. In this paper, an analytical model of a single diesel droplet impinging on the wall with different inclined angle (α) under isothermal conditions (liquid droplet and wall with the same temperature) is developed in terms of β_m (the ratio of maximum spreading length to initial droplet diameter) to understand the detailed impinging dynamic process.
Technical Paper

The Utilization of Onboard Sensor Measurements for Estimating Driveline Damping

2019-06-05
2019-01-1529
The proliferation of small silicon micro-chips has led to a large assortment of low-cost transducers for data acquisition. Production vehicles on average exploit more than 60 on board sensors, and that number is projected to increase beyond 200 per vehicle by 2020. Such a large increase in sensors is leading the fourth industrial revolution of connectivity and autonomy. One major downfall to installing many sensors is compromises in their accuracy and processing power due to cost limitations for high volume production. The same common errors in data acquisition such as sampling, quantization, and multiplexing on the CAN bus must be accounted for when utilizing an entire array of vehicle sensors. A huge advantage of onboard sensors is the ability to calculate vehicle parameters during a daily drive cycle to update ECU calibration factors in real time. One such parameter is driveline damping, which changes with gear state and drive mode. A damping value is desired for every gear state.
Journal Article

Multi-Physics and CFD Analysis of an Enclosed Coaxial Carbon Nanotube Speaker for Automotive Exhaust Noise Cancellation

2019-06-05
2019-01-1569
Automotive exhaust noise is one of the major sources of noise pollution and it is controlled by passive control system (mufflers) and active control system (loudspeakers and active control algorithm). Mufflers are heavy, bulky and large in size while loudspeakers have a working temperature limitation. Carbon nanotube (CNT) speakers generate sound due to the thermoacoustic effect. CNT speakers are also lightweight, flexible, have acoustic and light transparency as well as high operating temperature. These properties make them ideal to overcome the limitations of the current exhaust noise control systems. An enclosed, coaxial CNT speaker is designed for exhaust noise cancellation application. The development of a 3D multi-physics (coupling of electrical, thermal and acoustical domains) model, for the coaxial speaker is discussed in this paper. The model is used to simulate the sound pressure level, input power versus ambient temperature and efficiency.
Technical Paper

PHEV Real World Driving Cycle Energy and Fuel and Consumption Reduction Potential for Connected and Automated Vehicles

2019-04-02
2019-01-0307
This paper presents real-world driving energy and fuel consumption results for the second-generation Chevrolet Volt plug-in hybrid electric vehicle (PHEV). A drive cycle, local to Michigan Technological University, was designed to mimic urban and highway driving test cycles in terms of distance, transients and average velocity, but with significant elevation changes to establish an energy intensive real-world driving cycle for assessing potential energy savings for connected and automated vehicle (CAV) control. The investigation began by establishing baseline and repeatability of energy consumption at various battery states of charge. It was determined that drive cycle energy consumption under a randomized set of boundary conditions varied within 3.6% of mean energy consumption regardless of initial battery state of charge.
Technical Paper

Impinged Diesel Spray Combustion Evaluation for Indirect Air-Fuel Mixing Processes and Its Comparison with Non-Vaporing Impinging Spray Under Diesel Engine Conditions

2019-04-02
2019-01-0267
Under low-temperature combustion for the high fuel efficiency and low emissions achievement, the fuel impingement often occurs in diesel engines with direct injection especially for a short distance between the injector and piston head/cylinder wall. Spray impingement plays an important role in the mixing-controlled combustion phase since it affects the air-fuel mixing rate through the disrupted event by the impingement. However, the degree of air entrainment into the spray is hard to be directly evaluated. Since the high spray expansion rate could allow more opportunity for fuel to mix with air, in this study, the expansion rate of impinged flame is quantified and compared with the spray expansion rate under non-vaporizing conditions. The experiments were conducted in a constant volume combustion chamber with an ambient density of 22.8 kg/m3 and the injection pressure of 150 MPa.
Technical Paper

Influence of Elevated Injector Temperature on the Spray Characteristics of GDI Sprays

2019-04-02
2019-01-0268
When fuel at elevated temperatures is injected into an ambient environment at a pressure lower than the saturation pressure of the fuel, the fuel vaporizes in the nozzle and/or immediately upon exiting the nozzle; that is, it undergoes flash boiling. It is characterized by a two-phase flow regime co-located with primary breakup, which significantly affects the spray characteristics. Under flash boiling conditions, the near nozzle spray angle increases, which can lead to shorter penetration because of increased entrainment. In a multi-hole injector this can cause other impacts downstream resulting from the increased plume to plume interactions. To study the effect of injector temperature and injection pressure with real fuels, an experimental investigation of the spray characteristics of a summer grade gasoline fuel with 10% ethanol (E10) was conducted in an optically accessible constant volume spray vessel.
Technical Paper

Route-Optimized Energy Management of Connected and Automated Multi-Mode Plug-In Hybrid Electric Vehicle Using Dynamic Programming

2019-04-02
2019-01-1209
This paper presents a methodology to optimize the blending of charge-depleting (CD) and charge-sustaining (CS) modes in a multi-mode plug-in hybrid electric vehicle (PHEV) that reduces overall energy consumption when the selected route cannot be completely driven in all-electric mode. The PHEV used in this investigation is the second-generation Chevrolet Volt and as many as four instrumented vehicles were utilized simultaneously on road to acquire validation data. The optimization method used is dynamic programming (DP) paired with a reduced-order powertrain model to enable onboard embedded controller compatibility and computational efficiency in optimally blending CD, CS modes over the entire drive route.
Technical Paper

Computationally Efficient Reduced-Order Powertrain Model of a Multi-Mode Plug-In Hybrid Electric Vehicle for Connected and Automated Vehicles

2019-04-02
2019-01-1210
This paper presents the development of a reduced-order powertrain model for energy and SOC estimation of a multi-mode plug-in hybrid electric vehicle using only vehicle speed profile and route elevation as inputs. Such a model is intended to overcome the computational inefficiencies of higher fidelity powertrain and vehicle models in short and long horizon energy optimization efforts such as Coordinated Adaptive Cruise Control (CACC), Eco Approach and Departure (EcoAND), Eco Routing, and PHEV mode blending. The reduced-order powertrain model enables Connected and Automated Vehicles (CAVs) to utilize the onboard sensor and connected data to quickly react and plan their maneuvers to highly dynamic road conditions with minimal computational resources.
Technical Paper

Process for Study of Micro-pilot Diesel-NG Dual Fuel Combustion in a Constant Volume Combustion Vessel Utilizing the Premixed Pre-burn Procedure

2019-04-02
2019-01-1160
A constant volume spray and combustion vessel utilizing the pre-burn mixture procedure to generate pressure, temperature, and composition characteristic of near top dead center (TDC) conditions in compression ignition (CI) engines was modified with post pre-burn gas induction to incorporate premixed methane gas prior to diesel injection to simulate processes in dual fuel engines. Two variants of the methane induction system were developed and studied. The first used a high-flow modified direct injection injector and the second utilized auxiliary ports in the vessel that are used for normal intake and exhaust events. Flow, mixing, and limitations of the induction systems were studied. As a result of this study, the high-flow modified direct injection injector was selected because of its controlled actuation and rapid closure. Further studies of the induction system post pre-burn were conducted to determine the temperature limit of the methane auto-ignition.
Journal Article

Investigation and Optimization of Cam Actuation of an Over-Expanded Atkinson Cycle Spark-Ignited Engine

2019-04-02
2019-01-0250
An over-expanded spark ignited engine was investigated in this work via engine simulation with a design constrained, mechanically actuated Atkinson cycle mechanism. A conventional 4-stroke spark-ignited turbo-charged engine with a compression ratio of 9.2 and peak brake mean effective pressure of 22 bar was selected for the baseline engine. With geometry and design constraints including bore, stroke, compression ratio, clearance volume at top dead center (TDC) firing, and packaging, one over-expanded engine mechanism with over expansion ratio (OER) of 1.5 was designed. Starting with a validated 1D engine simulation model which included calibration of the in-cylinder heat transfer model and SI turbulent combustion model, investigations of the Atkinson engine including cam optimization was studied. The engine simulation study included the effects of offset of piston TDC locations as well as different durations of the 4-strokes due to the mechanism design.
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