Overall cycle time and prototype testing are significantly decreased by assessment of cooling module performance in the design stage itself. Hence, Front End Cooling and Thermal Management are essential components of the vehicle design process. Performance of the cooling module depends upon a variety of factors like frontal opening, air flow, under-hood sub-systems, module positioning, front grill design, fan operation. Effects of design modifications on the engine cooling performance are quantified by utilizing computational fluid dynamics (CFD) tool FluentTM. Vehicle frontal configuration is captured in the CFD model considering cabin, cargo and underbody components. Heat Exchanger module is modelled as a porous medium to simulate the fluid flow. Performance data for the Heat Exchanger module is generated using the 1D KuliTM software. In this paper, CFD simulation of Front End Cooling is performed for maximum torque and maximum power operating conditions.
The use of Wankel rotary engines as a range extender has been recognised as an appealing method to enhance the performance of Hybrid Electric Vehicles (HEV). They are effective alternatives to conventional reciprocating piston engines due to their considerable merits such as lightness, compactness, and higher power-to-weight ratio. However, further improvements on Wankel engines in terms of fuel economy and emissions are still needed. The objective of this work is to provide an engine modelling methodology that is particularly suitable for the theoretical studies on Wankel engine dynamics and new control development. In this paper, a control-oriented model is developed for a 225CS Wankel rotary engine produced by Advanced Innovative Engineering (UK) Ltd. Through a synthesis grey-box approach that combines State Space (SS) and artificial Neural Networks (NN), a model is derived by leveraging both first-principle knowledge and engine test data.
The effects of driving cycles and fuel composition on emissions from on-road motorcycles were studied with the objectives of understanding the effects of established drive cycles, quantifying the emissions from a more rigorous drive cycle, and determining the emission differences between various certification test fuels. Chassis dynamometer emissions testing was conducted on three motorcycles with engine displacements of 300 cc, 750 cc and 1200 cc. All of the motorcycles were Class II North American certified motorcycles with fuel injection and three-way catalysts. The motorcycles were tested using the North American certification cycle, also known as the Federal Test Procedure (FTP); the World Motorcycle Transit Cycle (WMTC); and a trial cycle based on real-world motorcycle driving, informally named the ‘Real World Driving Cycle’ (RWDC).
Improving the energy performance of batteries will certainly increase the reliability of electric aircraft and thus their penetration into the market. To achieve this goal, battery management systems are required to keep the temperature below the safety limits and make the temperature distribution as even as possible within the battery pack and cells. Li-ion batteries are suitable for electric aircraft due to their high specific energy and advantage of energy density. In this study, 20 14.6 Ah prismatic batteries were connected in 2 parallel 10 series. Three-dimensional thermal analysis was performed for forced and natural transport conditions under 4 different discharge rates (0.5C, 1C, 2C, 2.5C) of the batteries. The study was conducted with Ansys Fluent. The NTGK Empirical model was chosen and a simple algorithm was used. A second order upwind method was chosen for pressure, momentum and energy equations. Batteries were tested for mesh independency.
This paper presents several methods to improve the exhaust gas temperature of a modern diesel engine. A high exhaust gas temperature is needed to improve the after-treatment system efficiency and particulate filter regeneration in low engine loads. This study is based on experimental measurements of a Stage 5 level off-road diesel engine. The effect of the different heating methods determined over steady state runs and emission and performance are presented with standard emission transient test procedure (NRTC). In the first step of the study, an intake air restriction and an exhaust gas restriction method are compared. The intake restriction produces better fuel economy over the measuring cycle. However, with the exhaust restriction, higher exhaust gas temperature can be achieved in low engine loads. In the second phase of study, the intake air restriction method was implemented in the research engine.
Gas engines (fuelled with CNG, LNG or Biogas) for generation of power and heat are, to this date, taking up larger shares of the market with respect to diesel engines. In order to meet the limit imposed by the TA-Luft regulations on heavy duty engines, lean combustion represents a viable solution for achieving lower emissions as well as efficiency levels comparable with diesel engines. Leaner mixtures however affect the combustion stability as the flame propagation velocity and consequently heat release rate are slowed down. As a strategy to deliver higher ignition energy, an active pre-chamber may be used. This work focuses on assessing the performance of two pre-chambers with different nozzle orifice diameters, in a stationary heavy-duty engine for power generation, operating at different loads, equivalence ratios and spark timings.
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.
This paper describes the development of GM 10-Speed Allison Heavy Duty (HD) Transmission. The trend of engine power and towing capacity in the automotive heavy-duty truck segment has been steadily climbing for a past 10 years. The development of GM 10-Speed Allison Heavy Duty Transmission is designed to be best in class for towing performance with no compromise in fuel economy. GM 10-Speed Allison Heavy Duty Transmission also gives the customers the option to order an integrated power transfer unit to improve the installation of power transfer or generation accessories. GM Allison HD truly brings the best of towing performance and fuel economy to the customers.
National concerns over energy consumption and emissions from the transportation sector have prompted regulatory agencies to implement aggressive fuel economy targets for light-duty vehicles through the NHTSA/EPA corporate average fuel economy (CAFE) program. Automotive manufacturers have responded by bringing competitive technologies to market that maximize efficiency while meeting or exceeding consumer performance and comfort expectations. In a collaborative effort between Toyota Motor Corporation, Argonne National Laboratory (ANL), and the National Renewable Energy Laboratory (NREL), the real-world savings of one such technology is evaluated. A commercially available Toyota Highlander equipped with two-phase cold storage technology was tested at ANL’s chassis dynamometer testing facility. The cold storage technology maintains the thermal state of air-conditioning evaporators to enable longer and more frequent engine off operation in vehicles equipped with start-stop functionality.
The traffic volume of commercial vehicles is large in Chinese mountainous area. The heavy, frequent workload and the unreasonable driver’s habits of those commercial vehicles on mountainous roads will increase the fuel consumption. In order to improve the vehicle fuel economy, this paper design and study an intelligent speed planning system based on the driver’s behavior, which aims to planned the economy speed during the commercial vehicle runs on the mountain road. By combining the vehicle characteristic parameters with the feature of the mountain road for reminding the driver of the current vehicle speed in the form of human-computer interaction, the system could guide the driver to drive the commercial vehicle at a safe and economical speed, and thus improving fuel economy. An automotive parameter estimation model, a road feature parameter calculation model and an economic speed planning for the top place of a ramp were obtained based on the automotive dynamics.
Achieving robust ignitability for compression ignition of diesel engines at cold conditions is traditionally challenging due to insufficient fuel vaporization, heavy wall impingement, and thick wall films. Gasoline compression ignition (GCI) has shown good potential to offer enhanced NOx-soot tradeoff with diesel-like fuel efficiency, but it is unknown how the volatility and reactivity of the fuel will affect ignition under very cold conditions. Therefore, it is important to investigate the impact of fuel physical and chemical properties on ignition under pressures and temperatures relevant to practical engine operating conditions during cold weather. In this paper, 0-D and 3-D computational fluid dynamics (CFD) simulations of GCI combustion at cold conditions were performed.
2020 SAE Congress - Technical Paper Abstract "Smart Solutions for Electric Vehicle Suspensions" Session: Steering, Chassis and Suspension Authors: Peter Kuhn, SGL Technologies GmbH, Meitingen, Germany William D. Pinch, SGL Technologies LLC, Charlotte, NC USA Abstract: Battery Electric Vehicles (BEVs) Programs are becoming the vehicle of choice globally. This is driven by heightened vehicle emissions requirements and improved fuel economy performance. Vehicle requirements will be rolled down to Subsystems and Components. Subsystem requirements will be divided into upper and lower control planes with Kinematic performance targets discussed. Various types of front and rear suspensions will be identified and analyzed including MacPherson & Chapman Strut, Short-Long Arm (SLA), and various Multi-link arrangements. At the component level the use of innovative, lightweight composite materials provides a significant advantage.
In the last few years, the effect of diabatic test conditions on compressor performance maps has been widely investigated leading some Authors to propose different correction models. The accuracy of turbocharger performance map constitute the basis for the tuning and validation of a numerical 1D procedure, usually adopted for the engine-turbocharger matching. Actually, it is common practice in automotive applications to use simulation codes, which require as an input the value of efficiency. Therefore, the ability to correct the measured performance maps taking into account internal heat transfer would allow the implementation of commercial simulation codes used for engine-turbocharger matching calculations. The practical purpose of an adiabatic test program is to obtain an accurate measurement of the work transfer, and of the real efficiency of compressor and turbine (unaffected by internal and external heat transfer rates).
An efficient turbocharger turbine benefits the engine in many aspects, such as better transient response, lower 〖NO〗_x emissions and better fuel economy. The turbine performance can be further improved by injecting the secondary flow through an injector over the shroud section. The secondary flow can effectively reduce the vortex separation on the suction side and reduce associated losses. A secondary flow injection system can be integrated to a conventional turbine without affecting its original design parameters, including the rotor, volute, and back disk. Therefore, the swallowing capacity and thrust loading characteristics are kept the same as the original turbine, thereby maintaining the same turbocharger-engine matching and turbine-compressor matching.
The application of variable valve actuation (VVA) has been well demonstrated for improvements in fuel economy and reduced emissions in spark-ignited (SI) and diesel engine applications. The current research numerically investigates effects of VVA in a prototype heavy-duty Gasoline Compression Ignition (GCI) engine modified from a MY2013 Cummins ISX15 heavy-duty diesel engine. For the GCI engine system, the geometric compression ratio was modified to 15.7, and the RON92 gasoline was assumed as a fuel . In a sister paper, a 3-D CFD analysis was conducted to characterize effects of reduced effective compression ratios on the fuel efficiency improvements and reduced soot & NOx emissions for RON92 GCI combustion at mid-to-high engine load conditions. As a follow-up, the current research conducted a 1-D system level analysis to evaluate the effects of VVA on the boost system requirements for the RON92 GCI combustion.
Due to increasing standards in fuel consumption, battery electric vehicles (BEV) and plug in electric hybrid vehicles (PHEV), are becoming more commonplace in the automotive industry. Batteries used in such applications require methods of thermal management to promote longer life, higher efficiency and performance. A common method of keeping the battery cool, in high heat conditions, is to use a water to refrigerant chiller. The already existing automotive air conditioning system is leveraged to enable the use of such a chiller. The added thermal transient load of the battery adds complexity to the refrigeration system. Balancing the thermal comfort of the occupants with temperature requirements of battery drives challenges to the overall system capacity. The sudden change in battery cooling loads can noticeably degrade the evaporator heat rejection. In extreme cases the battery cooling load can cause complete loss of refrigerant flow to the evaporator.
Maintaining the fuel temperature and fuel system components below certain values is an important design objective. Predicting these temperature is therefore one of the key parts of the vehicles thermal management process. One of the physical processes affecting fuel tank temperature is fuel vaporization, which is controlled by the vapor pressure in the tank, fuel composition and fuel temperature. Models are developed to enable the computation of the fuel temperature, fuel vaporization rate in the tank, fuel temperatures along the fuel supply lines, and follows its path to the charcoal canister and into the engine intake. For Diesel fuel systems where a fuel return line is used to return excess fluid back to the fuel tank, an energy balance will be considered to calculate the heat added from the high-pressure pump and vehicle under-hood and underbody.
More stringent Federal emission regulations and fuel economy requirements have driven the automotive industry toward more sophisticated vehicle thermal management systems to best utilize the waste heat and improve driveline efficiency. The final drive unit in light and heavy duty trucks usually consists of geared transmission and differential housed in a lubricated axle. The automotive rear axles is one of the major sources of power loss in the driveline due to gear friction, churning and bearing loss and have a significant effect on overall vehicle fuel economy. These losses vary significantly with the viscosity of the lubricant. Also the temperatures of the lubricant are critical to the overall axle performance in terms of power losses, fatigue life and wear.
Due to the advantages of low weight, low emission and good fuel economy, downsized turbocharged gasoline direct injection (GDI) engines are widely-applied nowadays. However, Low-Speed Pre-Ignition (LSPI) phenomenon observed in these engines restricts their improvement of performance. Some researchers have shown that auto-ignition of lubricant in the combustion chamber has a great effect on the LSPI frequency. To study the auto-ignition characteristics of lubricant, an innovative single droplet auto-ignition measurement system for lubricant and its mixture is designed and developed, with better accuracy and effectiveness. The experiments are carried out by hanging lubricant droplets on the thermocouple node under active thermo-atmosphere provided by a small Dibble burner. The auto-ignition process of lubricant droplets is recorded by a high-speed camera.