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0-D and 1-D Modeling and Numerics, 2017

Papers in the session cover zero-dimensional, one-dimensional, and quasi-dimensional models for simulation of SI and CI engines with respect to: engine breathing, boosting, and acoustics; SI combustion and emissions; CI combustion and emissions; fundamentals of engine thermodynamics; numerical modeling of gas dynamics; thermal management; mechanical and lubrication systems; system level models for controls; and system level models for vehicle fuel economy and emissions predictions.

0-D and 1-D Modeling and Numerics, 2018

Papers in the session cover zero-dimensional, one-dimensional, and quasi-dimensional models for simulation of SI and CI engines with respect to: engine breathing, boosting, and acoustics; SI combustion and emissions; CI combustion and emissions; fundamentals of engine thermodynamics; numerical modeling of gas dynamics; thermal management; mechanical and lubrication systems; system level models for controls; and system level models for vehicle fuel economy and emissions predictions.
Technical Paper

0D/1D Turbulent Combustion Model Assessment from an Ultra-Lean Spark Ignition Engine

This paper focuses on an assessment of predictive combustion model using a 0D/1D simulation tool under high load, different excess air ratio λ , and different combustion stabilities (based on coefficient of variation of indicated mean effective pressure COVimep). To consider that, crank angle resolved data of experimental pressure of 500 cycles are recorded under engine speed 1000 RPM and 2000 RPM, wide-open throttle, and λ=1.0, 1.42, 1.7, and 2.0. Firstly, model calibration is conducted using 18 cases at 2000 RPM using 500 cycle-averaged in-cylinder pressure to find optimized model constants. Then, the model constants are unchanged for other cases. Next, different cycle-averaged pressure data are used as inputs in the simulation based on the COVimep for studying sensitivity of the turbulent model constants. The simulation is conducted using 1D simulation software GT-Power.
Technical Paper

0D/3D Simulations of Combustion in Gasoline Engines Operated with Multiple Spark Plug Technology

A simulation method is presented for the analysis of combustion in spark ignition (SI) engines operated at elevated exhaust gas recirculation (EGR) level and employing multiple spark plug technology. The modeling is based on a zero-dimensional (0D) stochastic reactor model for SI engines (SI-SRM). The model is built on a probability density function (PDF) approach for turbulent reactive flows that enables for detailed chemistry consideration. Calculations were carried out for one, two, and three spark plugs. Capability of the SI-SRM to simulate engines with multiple spark plug (multiple ignitions) systems has been verified by comparison to the results from a three-dimensional (3D) computational fluid dynamics (CFD) model. Numerical simulations were carried for part load operating points with 12.5%, 20%, and 25% of EGR. At high load, the engine was operated at knock limit with 0%, and 20% of EGR and different inlet valve closure timing.
Technical Paper

1-D Modeling and Experimental Evaluation of Secondary Air Injection System for a Small SI Engine

In order to comply with the existing emission norms of BSIII in India or EURO III and beyond that also, it is not sufficient to use the catalytic converter technology alone over the wide range of engine operating maps. Different studies across the world have proved that the cost, drivability, operating range against AFR, heat dissipation rate characteristics of catalytic converter limit their use in startup and idling conditions. One common way to tackle this condition is to use the Secondary Air Injection (SAI) system. In this system, small amount of air is injected after the exhaust port to initiate the thermal oxidation of gases. The right amount of air injected at the right time and at right location will reduce the emission by 37-90%. In the following study, SI engine vehicle with single cylinder, 160 cc and having carburetor is used as a test vehicle to evaluate the performance of SAI. The SAI system is modeled in AVL BOOST software and validated against the experimental data.
Journal Article

1-D Simulation Study of Divided Exhaust Period for a Highly Downsized Turbocharged SI Engine - Scavenge Valve Optimization

Fuel efficiency and torque performance are two major challenges for highly downsized turbocharged engines. However, the inherent characteristics of the turbocharged SI engine such as negative PMEP, knock sensitivity and poor transient performance significantly limit its maximum potential. Conventional ways of improving the problems above normally concentrate solely on the engine side or turbocharger side leaving the exhaust manifold in between ignored. This paper investigates this neglected area by highlighting a novel means of gas exchange process. Divided Exhaust Period (DEP) is an alternative way of accomplishing the gas exchange process in turbocharged engines. The DEP concept engine features two exhaust valves but with separated function. The blow-down valve acts like a traditional turbocharged exhaust valve to evacuate the first portion of the exhaust gas to the turbine.
Technical Paper

1.2GPa Advanced High Strength Steel with High Formability

To reduce the Body in White (BIW) mass, it is necessary to expand the application of Advanced High-Strength Steels (AHSS) to complex shaped parts. In order to apply AHSS to complex shaped parts with thinner gauge, high formability steel is required. However, higher strength steels tend to display lower elongations, compared with low/medium strength steels. Current AHSS are applied to limited parts for this reason. The new 1.2GPa material, with high formability, was developed to solve this issue. The mechanical property targets for the high elongation 1.2GPa material were achieved by precise metallurgical optimization. Many material aspects were studied, such as formability, weldabilty, impact strength, and delayed fracture. As the result of this development, 1.2GPa AHSS has been applied to a new vehicle launched in 2013.The application of this material was the 1st in the world, and achieved a 11kg mass reduction.
Technical Paper

100% LPG Long Haul Truck Conversion - Economy and Environmental Benefits

Advanced Vehicle Technologies (AVT), a Ballarat Australia based company, has developed the World's first diesel to 100% LPG conversion for heavy haul trucks. There is no diesel required or utilized on the trucks. The engine is converted with minimal changes into a spark ignition engine with equivalent power and torque of the diesel. The patented technology is now deployed in 2 Mercedes Actros trucks. The power output in engine dynamometer testing exceeds that of the diesel (in excess of 370 kW power and 2700 Nm torque). In on-road application the power curve is matched to the diesel specifications to avoid potential downstream power-train stress. Testing at the Department of Transport Energy & Infrastructure, Regency Park, SA have shown the Euro 3 truck converted to LPG is between Euro 4 and Euro 5 NOx levels, CO2 levels 10% better than diesel on DT80 test and about even with diesel on CUEDC tests.
Technical Paper

15 Combustion Characteristics of an Improved Design of a Stratified Charge Spark Ignition Engine

The characteristics of the combustion process in an improved design of a novel spark ignition engine studied by means of Computational Fluid Dynamics are presented. The engine is designed to work at low average combustion temperatures to achieve very low NOx emissions. The engine is a two-stroke, two piston in-line engine. The main combustion occurs in four combustion pre-chambers that have an annular shape with a nozzle on the side facing the cylinder. Fuel is directly injected into the pre-chambers by using high-pressure fuel injectors. A progressive burning process is expected to keep the flame inside the pre-chambers while the fast ejection of combustion products should produce effective mixing with the cold air in the cylinder. This fast dilution should guarantee a temperature drop of the combustion products thus reducing the formation of NOx via a thermal path.
Technical Paper

15 Years of Transfer Path Analysis VINS in the Vehicle NVH Development - Selected Results

Transfer path analysis is a powerful tool to support the vehicle NVH development. On the one hand it is a fast method to gain an overview of the complex interplay in the vehicle noise generation process. On the other hand it can be used to identify critical noise paths and vehicle components responsible for specific noise phenomena. FEV has developed several tools, which are adapted to the considered noise phenomena: Powertrain induced interior noise and vibration is analyzed by VINS (Vehicle Interior Noise Simulation), which allows the deduction of improvement measures fast enough for application in the accelerated vehicle development process. Further on vehicle/powertrain combinations not realized in hardware can be evaluated by virtual installation of the powertrain in the vehicle, which is especially interesting in the context of engine downsizing from four to three or six to four cylinders.
Technical Paper


General Motors Powertrain Group (GMPTG) has developed an all new small block V8 engine, designated LS1, for introduction into the 1997 Corvette. This engine was designed to meet both customer requirements and competitive challenges while also meeting the ever increasing legislated requirements of emissions and fuel economy. This 5.7L V8 provides increased power and torque while delivering higher fuel economy. In addition, improvements in both QRD and NVH characteristics were made while meeting packaging constraints and achieving significant mass reductions.
Technical Paper

1D and 3D CFD Investigation of Burning Process and Knock Occurrence in a Gasoline or CNG fuelled Two-Stroke SI Engine

The paper presents a combined experimental and numerical investigation of a small unit displacement two-stroke SI engine operated with gasoline and Natural Gas (CNG). A detailed multi-cycle 3D-CFD analysis of the scavenging process is at first performed in order to accurately characterize the engine behavior in terms of scavenging patterns and efficiency. Detailed CFD analyses are used to accurately model the complex set of physical and chemical processes and to properly estimate the fluid-dynamic behavior of the engine, where boundary conditions are provided by a in-house developed 1D model of the whole engine. It is in fact widely recognized that for two-stroke crankcase scavenged, carbureted engines the scavenging patterns (fuel short-circuiting, residual gas distribution, pointwise lambda field, etc.) plays a fundamental role on both of engine performance and tailpipe emissions.
Technical Paper

1D-3D Analysis of the Scavenging and Combustion Process in a Gasoline and Natural-Gas Fuelled Two-Stroke Engine

The paper presents a 1D-3D numerical model to simulate the scavenging and combustion processes in a small-size spark-ignition two-stroke engine. The engine is crankcase scavenged and can be operated with both gasoline and Natural Gas (NG). The analysis is performed with a modified version of the KIVA3V code, coupled to an in-house developed 1D model. A time-step based, two-way coupled procedure is fully described and validated against a reference test. Then, a 1D-3D simulation of the whole two-stroke engine is carried out in different operating conditions, for both gasoline and NG fuelling. Results are compared with experimental data including instantaneous pressure signals in the crankcase, in the cylinder and in the exhaust pipe. The procedure allows to characterize the scavenging process and quantify the fresh mixture short-circuiting, as well as to analyze the development of the NG combustion process for a diluted mixture, typically occurring in a two-stroke engine.
Technical Paper

2-D Temperature Measurements of Unburned Gas Mixture in an Engine by Two-line Excitation LIF Technique

Two-line excitation LIF (Laser-Induced Fluorescence) technique for 2-dimensional temperature measurements in an engine cylinder before ignition is presented. From the fundamental examinations, the combination of toluene tracer with a pair of excitation lines of 248nm and 266nm has been selected because of the high LIF intensity ratio and closer excitation wavelengths. In-cylinder thermometry is conducted using a visualized single cylinder spark ignition engine both in PFI (port-fuel-injection) and DI (direct-injection) operation. The accuracy of this technique is determined through the homogeneous PFI experiment. Temperature and fuel distribution in unburned mixture are measured simultaneously in DI operation. It exists a strong correlation between equivalence ratio and temperature inside the mixture. Temperature in the fuel rich region is lower than in the fuel lean region.
Technical Paper

2-step Variable Valve Actuation: System Optimization and Integration on an SI Engine

2-step variable valve actuation using early-intake valve closing is a strategy for high fuel economy on spark-ignited gasoline engines. Two discrete valve-lift profiles are used with continuously variable cam phasing. 2-step VVA systems are attractive because of their low cost/benefit, relative simplicity, and ease-of-packaging on new and existing engines. A 2-step VVA system was designed and integrated on a 4-valve-per-cylinder 4.2L line-6 engine. Simulation tools were used to develop valve lift profiles for high fuel economy and low NOx emissions. The intake lift profiles had equal lift for both valves and were designed for high airflow & residual capacity in order to minimize valvetrain switching during the EPA drive cycle. It was determined that an enhanced combustion system was needed to maximize fuel economy benefit with the selected valve lift profiles. A flow-efficient chamber mask was developed to increase in-cylinder tumble motion and combustion rates.
Technical Paper

2006 Chevrolet Corvette Z06 Aluminum Spaceframe Design and Engineering Technology

The General Motors (GM) Corvette design team was challenged with providing a C6 Z06 vehicle spaceframe that maintained the structural performance of its C5 predecessor while reducing mass by at least 56 kg. An additional requirement inherent to the project was that the design must be integrated into the C6 assembly processes with minimal disruption, i.e. seamless integration. In response to this challenge, a collaborative team was formed, consisting of design engineers from General Motors, Alcoa and Dana Corporation. The result of this collaborative effort is an aluminum Z06 spaceframe that satisfies the high performance expectations of the vehicle while reducing the mass by approximately 62 kg. The frame consists of aluminum extrusions, castings and sheets joined by MIG welding, laser welding and self-piercing rivets. The extrusions are 6XXX series alloys, the castings are permanent mold A356 while the sheet panels are formed from the 5XXX series of alloys.
Technical Paper

2006 Chevrolet Corvette Z06 Aluminum Spaceframe Manufacturing Technology

In October 1999, General Motors contracted Dana Corporation to manufacture an all-aluminum spaceframe for the 2006 Chevrolet Corvette Z06. Corvette introduced its first ever all-aluminum frame (see Figure 1) to the world at the 2005 North American International Auto Show (NAIAS) in Detroit, Michigan. The creation of this spaceframe resulted in a significant mass reduction and was a key enabler for the program to achieve the vehicle level performance results required for a Z06 in an ever-growing market. Dana Corporation leveraged ALCOA's (Aluminum Company of America) proven design capabilities while incorporating new MIG welding, laser welding, Self-Pierce Riveting (SPR), and full spaceframe machining to join General Motors (GM) Metal Fabrication Division's (MFD) hydroformed rails to produce the Corvette Z06's yearly requirement of 7000 units. This paper describes the technologies utilized throughout the assembly line and their effect on the end product.
Technical Paper

2006 Corvette Z06 Carbon Fiber Fender- Engineering, Design, and Material Selection Considerations

General Motor's Corvette product engineering was given the challenge to find mass reduction opportunities on the painted body panels of the C6 Z06 through the utilization of carbon fiber reinforced composites (CFRC). The successful implementation of a carbon fiber hood on the 2004 C5 Commemorative Edition Z06 Corvette was the springboard for Corvette Team's appetite for a more extensive application of CFRC on the C6 Z06 model. Fenders were identified as the best application for the technology given their location on the front of the vehicle and the amount of mass saved. The C6 Z06 CFRC fenders provide 6kg reduction of vehicle mass as compared to the smaller RRIM fenders used on the Coupe and Convertible models.
Technical Paper

2006 Corvette Z06 Carbon Fiber Structural Composite Panels- Design, Manufacturing and Material Development Considerations

The General Motors Corvette Product Engineering Team is in a continual search for mass-reduction technologies which provide performance improvements that are affordable and add value for their customers. The structural composite panels of the C6 Z06 provided a unique opportunity to extend the use of carbon fiber reinforced materials to reduce mass and enhance performance. The entire vehicle set of composite panels was reviewed as candidates for material substitution, with the selection criteria based on the cost per kg of mass saved, tooling cost required, and the location of the mass to be saved. Priority was extended to mass savings at the front of the vehicle. After a carefully balanced selection process, two components, both requiring redesign because of the Z06’s wider stance, met the criteria: the Front Wheelhouse Outer Panel and Floor Panels. The current Floor Panels, first used on the C5, are large and are a balsawood-cored glass fiber reinforced composite design.
Technical Paper

2D Residual Gas Visualization in an Optical Direct Injection Spark Ignition Engine with IR Laser Absorption

The spatial distribution of internal exhaust gas recirculation (EGR) is evaluated in an optically accessible direct injection spark ignition engine using near infrared laser absorption to visualize the distribution of the H2O molecule. The obtained overall internal exhaust gas recirculation compares well to gas-exchange cycle calculations and the spatial distributions are consistent with those measured with inverse LIF. The experimental procedures described in this report are designed to be simple and rapidly implemented without the need to resort to unusual optical components. The necessary spectral data of the selected absorption line is obtained from the HITEMP database and is validated with prior experiments carried out in a reference cell. Laser speckle in the images is effectively reduced using a ballistic diffuser.