A novel ICE ON/OFF control strategy for hybrid electric bus based on route information
Abstract: ICE ON/OFF control strategy is critical for fuel economy in the hybrid electric vehicle (HEV). The fuel cumsumption cut off at ICE is at OFF state when the vehicle stops especially at vehicle jams. It significantly profits for more fuel saving. Motor-only drive mode is rarely used in real-time control because of the power system meet the uncertain driver demand. Battery state of charge (SOC) balance also affects ICE ON/OFF control decision. ICE ON/OFF state optimization is still a critical problem that is rarely effectively resolved. Minimum Principle was used in real-time control and has a global optimization in many papers. However, there is no paper to apply this algorithm in ICE ON/OFF control optimization. This paper introduces a novel control method using Minimum Principle to select an appropriate ICE state, which extracts rules from the optimal results applied to real-time control based on predicted route information.
Design harmonization techniques to model vehicle lightweighting across diverse powertrains
Vehicle lightweighting and advanced powertrains, including hybrid electric systems and high efficiency engines, have the potential to increase fuel economy and decrease life cycle energy and greenhouse gas (GHG) emissions. However, the energy and GHG impact over the entire vehicle life cycle is dependent on the energy and emissions required to produce lightweight materials and fuels. Recent work has used life cycle assessment (LCA) to evaluate diverse vehicles and fuels using a novel design harmonization technique. The current work describes this approach in further detail and provides an example of its application for a moderate lightweighting scenario for an internal combustion vehicle (ICV), hybrid electric vehicle (HEV) and plug-in hybrid electric vehicle (PHEV). This type of apples-to-apples comparison is enabled by functional equivalency metrics, which are defined as part of the design harmonization technique and held constant across all vehicles.
Aerodynamic Analysis of Cooling Airflow for Different Front-End Designs of a Heavy-Duty Cab-over-Engine Truck
This paper deals with the analysis of cooling airflow for two different front-end designs of a heavy truck. The first design is a cab-over-engine (COE) cab; the second is a Soft Nose (SN) cab, which in this case is basically an elongation of the grille area of the COE cab to obtain a smoother shape of the cab. The SN model used in this investigation was extended 200mm from the COE front. Computational Fluid Dynamics (CFD) was used as the tool for examining the aerodynamic properties of the vehicle models. The configurations were evaluated both with inactive and active heat exchangers, in order to examine the effect of heating the air on the drag co-efficient and also to determine the cooling capacity of the different models. A sub- study was performed where different opening percentages of the grille area was investigated to determine the minimum percentage opening that would be needed to achieve a radiator Top Tank Temperature (TTT) value below a target limit of 100°C.
Temperature Measurements of the Piston Optical Window in a Research Compression Ignition Engine via Thermography and Thermocouples
Internal combustion engines are characterized by high pressure and temperature loads on pistons and cylinders. The heat generated by the combustion process is dissipated by means of water and oil cooling systems. For the best design and optimization of the engine components is necessary to know the components temperature in order to estimate the thermal flows. The purpose of this work is to measure the piston sapphire window temperature in a research optically accessible engine by combining two different techniques: thermocouples measurements and thermography. The first is a well consolidated method that provides a reliable value of temperature. On the other hand, it requires high technical level to be applied because of the use of linkage systems to support the thermocouples wires or even more skills when wireless data transmission is set.
Powertrain Warm-up Optimization Involving Simplified Split Cooling With Integrated Waste Heat Recovery and Reuse.
This study is a continuation of the earlier study published in SAE #2016-01-0647. The earlier test results have proven that the previously proposed engine cooling circuit when combined with exhaust heat recovery and reuse could expedite the warm-up process after cold-start and has improved the fuel economy by up to 4%. With the earlier concept being evolved further, the study discussed in this paper explores further improvements that can be made to the cooling circuit to further expedite the warm-up process. In particular, with some changes to the cooling circuit, the heat recovered from the exhaust gas can be reused right away to heat up the heat exchangers for engine oil, CVT oil and cabin heater before the coolant is recirculated into the engine. Next, the thermostat opening temperature and leakage rate can also be optimized to prolong the heat recirculation period.
Deriving the validation protocol for isolator switches used in Commercial vehicles
Automotive business is more focused towards delivering a highly durable and reliable product at an optimum cost. Anything falling short of customer expectation, will damage the reputation of the manufacturer. To exterminate this, all automotive components undergo stringent testing protocol during the design validation phase. Nevertheless, there are certain factors in the field which are seldom captured during design validation. This project aims at optimizing a validation methodology for Isolator switch based on field usage and conditions. Isolator switch is the main control switch which connects/disconnects the electrical loads from its source; battery. This switch is used in the electrical circuit of the vehicle to prevent the unwanted draining of battery when it is not needed (or) vehicle is in switched off state. In the electrical version of this switch uses electromagnetic coils to short the contacts.
Analysis of the Effects of Diesel Injection Parameters in a Heavy Duty Iso-Butanol/Diesel Reactivity Controlled Compression Ignition (RCCI) Engine
An advanced 3D-CFD computational study was done in order to study the simultaneous effects of diesel injection pressure and single injection timing on the amounts of pollutant emissions and engine performance in a heavy duty, single cylinder iso-butanol/Diesel reactivity controlled compression ignition (RCCI) engine. A reduced chemical n-heptane-n-butanol-PAH mechanism which consists of 76 species and 349 reactions was used to simulate the combustion process of the dual-fuel diesel engine. The baseline operation case was validated with Wang et al. research work and good agreements between in-cylinder mean pressure, the rate of heat release and amounts of pollutant emissions such as NOx, Particulate Matter (PM), unburnt hydrocarbons (UHC) and carbon monoxide (CO) was obtained. Twenty-one different strategies based on two variables (diesel direct injection timing and diesel injection pressure) have been investigated.
Ultra-High Fuel Injection Pressure with Massive EGR to Enable Simultaneous Reduction of Soot and NOx Emissions
In this study both double and triple injection strategies were used with fuel pressures up to 300 and 250 MPa respectively. Tests were conducted at medium load conditions with cooled, high pressure EGR at a ratio of 40% and higher. A four-cylinder production engine, featuring double turbochargers with one variable geometry turbocharger, was tested. The double injection strategy consisted of a 20% close coupled pilot injection while the triple injection strategy introduced a post injection consisting of 10% the total cycle fuel. Results of this study do not indicate an advantage to extreme fuel pressure. The increased air entrainment reduces soot while increasing the premixed burn heat release, mean cylinder temperature and NOx. Compared to the double injection scheme, triple injections achieved much lower soot for the same EGR rate with only a small NOx penalty.
Methodology and Tools to Predict GDI Injector Tip Wetting as Predecessor of Tip Sooting
With upcoming emission regulations particle emissions for GDI engines are challenging engine and injector developers. Despite the introduction of GPFs, engine-out emission should be optimized to avoid extra cost and exhaust backpressure. Engine tests with a state of the art Miller GDI engine showed up to 200% increased particle emissions over the test duration due to injector deposit related diffusion flames. No spray altering deposits have been found inside the injector nozzle. To optimize this tip sooting behavior a tool chain is presented which involves injector multiphase simulations, a spray simulation coupled with a wallfilm model and testing. First the flow inside the injector is analyzed based on a 3D-XRay model. The next step is a Lagrangian spray simulation coupled with a wallfilm module which is used to simulate the fuel impingement on the injector tip and counter-bores.
Development of New 3.5 L V6 Turbocharged Gasoline (Direct Injection) Engine
Toyota Motor Corporation has been developing new platforms and powertrains based on the principles of Toyota New Global Architecture (TNGA) to contribute to better environment and to pursue driving pleasure. Based on this concept, the innovative combustion concept to realize high speed combustion was established in order to achieve both the power performance and the fuel economy at the highest level, and it was introduced to the market in 2017 as 2.5L Naturally Aspirated conventional and Hybrid Vehicle engines for new Camry. For the renewal of Lexus flagship model LS for the first time in 11 years aiming for unparalleled performances in four axes, "power performance" "driving pleasure" "fuel economy" and "quietness", a new 3.5L V6 twin turbo engine was developed.
Study of Gasoline Particulate Matter Index with Refinery Blends
The downsizing and turbocharging of gasoline direct injection (GDI) engines to meet future fuel economy standards will make future particulate matter (PM) emissions targets challenging to meet. This is mainly due to the fundamental change in the combustion process in GDI engines compared to conventional port fuel injection (PFI) engines. Auto manufacturers have linked PM emissions to gasoline formulations. Researchers at the Honda Motor Company developed the particulate matter index (PMI) as a measure for gasoline sooting tendency. In this paper, 59 gasoline blend stocks from seven refineries were collected in order to study the compositional effect of real refinery streams on gasoline PMI. 580 gasoline blends were made from the 59 blend stocks. No traditional metrics of fuel quality were found to correlate well with the particulate matter index. Reformate and FCC Naphtha contribute most significantly to the PMI of gasoline.
eFlite Dedicated Hybrid Transmission for Pacifica
Electrified powertrains will play a growing role in meeting global fuel consumption and CO2 requirements. In support of this, FCA has developed its first dedicated hybrid transmission (the eFlite), used in the Chrysler Pacifica PHEV. The Chrysler Pacifica is the industry’s first electrified minivan. The new eFlite hybrid transmission architecture optimizes performance, fuel economy, mass, packaging and NVH. The transmission is an electrically variable FWD transaxle with an input split configuration and incorporates two electric motors, both capable of driving in EV mode. The lubrication and cooling system makes use of two pumps, one electrically operated and one mechanically driven. The Chrysler Pacifica has a 16kWh lithium ion battery and a 3.6-liter Pentastar engine which offers total system power of 260 hp with 84 MPGe, 33 miles of all electric range and 566 miles total driving range.
Experimental and Numerical Study of the DrivAer Model Aerodynamics
The DrivAer model, a detailed generic open source vehicle geometry, was introduced a few years ago and accepted widely from industry and academia for research in the field of automotive aerodynamics. This paper presents the evaluation of the aerodynamic properties of the 25% scale DrivAer model in both, CFD and in wind tunnel experiment. The results not only include aerodynamic drag and lift but also provide detailed investigations of the flow field around the vehicle. In addition to the available geometries of the DrivAer model individual changes were introduced, created by morphing the geometry of the baseline model. A good correlation between CFD and experiment could be achieved by using a CFD setup including the geometry of the wind tunnel test section. The results give insight into the aerodynamics of the DrivAer model and lead to a better understanding of the flow around the vehicle.
Magna’s New Ultralight Door - A Comparative LCA Study of the Lightweight Design as per ISO 14040/44 LCA Standards and CSA Group LCA Guidance Document for Auto Parts
In response to ever more challenging global fuel economy and environmental regulations, automakers will rely on lightweighting to continue to meet the established goals. As “bolt-on” sub-assemblies, closure panels provide a unique opportunity to tailor the vehicle mass to achieve local environmental compliance relative to a global vehicle platform while maintaining equivalent functionality and safety performance. This paper is aimed at communicating the results of a life cycle assessment (LCA) study which compares the lightweight auto parts of the new Magna’s Ultralight Door design to the conventional auto parts of the baseline 2016 MY Chrysler 200C 6 cyl, 3.6 L, automatic 9-spd, an ICE vehicle (gasoline fueled) built and driven for 250,000 km in North America. Magna International Inc., in cooperation with the U.S. DOE and partners Fiat Chrysler Automobiles (FCA) US and Grupo Antolin, developed a new ultralight door architecture in 2017.
Investigation of Flow Conditions and Tumble near the Spark Plug in a DI Optical Engine at Ignition
Tumble motion plays a significant role in modern spark-ignition (SI) engines in that it increases mixing of air/fuel for homogeneous combustion and increases flame propagation for higher thermal efficiency and lower combustion variability. Cycle-by-cycle variations in the flow near the spark plug introduce variability to the initial flame kernel development, stretching, and convection and this variability is carried over to the entire combustion process. The design of current direct injection spark ignition (DI SI) engines aim to have a tumble flow in the vicinity of the spark plug at the time of ignition. This work investigates how the flow condition changes in the vicinity of the spark plug throughout the compression stroke via particle imaging velocimetry (PIV) and high speed imaging of a long ignition discharge arc channel and its stretching. The influence of tumble level and of fuel injection timing and fuel injection pressure are studied.
Development and Optimization of Variable flow AC Compressor for commercial vehicles to reduce parasitic losses and improving efficiency of HVAC system.
In modern era of commercial vehicle industry, comfort is one of the major parameter which improves vehicle running time that will lead to fleet owner's profitability. Air conditioning system is one such system whose primary function is to provide the preferred cooling and stabilize cabin temperature in hot climate conditions. Air-conditioned truck cabin not only gives better driver efficiency, along with comfortable environment for driver improving safety as well. AC compressor consumes power from engine directly affecting fuel economy and vehicle performance. With ever increasing demand for energy efficient systems and thermal comfort in automobiles, AC system needs to be optimized to deliver the required cooling performance with minimum AC power consumption. Hence reducing AC power consumption in vehicle is one of the key challenges for climate control engineers.
Using Multiple Photographs and USGS LiDAR to Improve Photogrammetric Accuracy
The accident reconstruction community relies on photogrammetry for taking measurements from photographs. Camera matching, a close-range photogrammetry method, is a particularly useful tool for locating accident scene evidence after time has passed and the evidence is no longer physically visible. In this method, objects within the accident scene that have remained unchanged are used as a reference for locating evidence that is no longer physically available at the scene such as tire marks, gouge marks and vehicle points of rest. Roadway lines, edges of pavement, sidewalks, signs, posts, buildings and other structures are recognizable scene features that, if unchanged between the time of accident and time of analysis, are beneficial to the photogrammetric process. In instances where these scene features are limited or do not exist, achieving accurate photogrammetric solutions can be challenging.
Real-time sequence testing of an automotive electric machine control systems
Recent reports highlighted the increasing demand for new features in road-going vehicles through electronics and software. Electronic control systems are expected to respond to input demands in real-time (circa: milliseconds) to ensure occupant and road user safety and comfort. System complexity and real-time computing requirements create significant challenges in proving the robustness of control systems, here robustness is the degree to which a system can function correctly in the presence of unexpected inputs. Despite the efforts of many vehicle manufacturers, evidence shows that faults still escape to customers incurring large warranty costs. This implies that existing test methods can be ineffective with the primary focus being on requirements validation. Evidence from other industries, e.g. IT and medical, suggests that difficult to find faults manifest due to complex interactions and sequences of events which can cause race conditions.
Correlation and verification of a tractor cab model using statistical energy analysis.
A model of a tractor cab was built using Statistical Energy Analysis (SEA) best practices. In this paper, it is shown how this model was correlated using data measured using a volume velocity source in the laboratory. After correlation, the model was excited using acoustic loads measured during tractor operation. It was found that the data predicted by the model is in good agreement with the data measured inside the cabin during this test.It was concluded that SEA can be used as an engineering tool to predict the behavior under many different conditions and can be used to guide the development process.
Lift-off Lengths in an Optical Heavy-Duty Engine Operated at High Load with Low and High Octane Number Fuels
Studies have shown that low temperature combustion (LTC), has the ability to decrease both soot and NOx emissions while maintaining high efficiency. LTC relies on long ignition delay, which is feasible through the use of high exhaust gas recirculation (EGR) in combination with high octane fuels. High efficiency is possible due to the rapid heat release at autoignition of the premixed or partially premixed fuel and air charge. This rapid combustion limits the load range of LTC, thereby diffusion like combustion is needed at higher loads. Earlier studies have shown that gasoline has the ability to reduce smoke emissions even at high load. This study aims to optically investigate the possible mechanisms behind the reduction of soot in comparison to diesel diffusion combustion, at high load operation (22 bar IMEP$_g$) in a heavy-duty truck engine. Primary reference fuels (PRF) were used as pump fuel surrogates.