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Technical Paper

Semi-Volatile Organic Compounds From a Combined Dual Port Injection/Direct-Injection Technology Light-Duty Gasoline Vehicle

2019-09-09
2019-24-0051
Gasoline direct injection (GDI) has changed the exhaust composition in comparison with the older port fuel injection (PFI) systems. More recently, light-duty vehicle engine manufactures have combined these two technologies to take advantage of the knock benefits and fuel economy of GDI with the low particulate emission of PFI. These dual injection strategy engines have made a significant change in the combustion emission composition produced by these engines. Understanding the impact of these changes is essential for automotive companies and aftertreatment developers. A novel sampling system was designed to sample the entire exhaust generated by a dual injection strategy gasoline vehicle using the United States Federal Test Procedure (FTP). This sampling system was capable of measuring the regulated emissions as well as collecting the entire exhaust from the vehicle for unregulated emissions.
Technical Paper

Development of a Natural Gas Engine with Diesel Engine-like Efficiency Using Computational Fluid Dynamics

2019-04-02
2019-01-0225
Present day natural gas engines have a significant efficiency disadvantage but benefit with low carbon-dioxide emissions and cheap three-way catalysis aftertreatment. The aim of this work is to improve the efficiency of a natural gas engine on par with a diesel engine. A Cummins-Westport ISX12-G (diesel) engine is used for the study. A baseline model is validated in three-dimensional Computational Fluid Dynamics (CFD). The challenge of this project is adapting the diesel engine for the natural gas fuel, so that the increased squish area of the diesel engine piston can be used to accomplish faster natural gas burn rates. A further increase efficiency is achieved by switching to D-EGR technology. D-EGR is a concept where one or more cylinders are run with excess fueling and its exhaust stream, containing H2 and CO, is cooled and fed into the intake stream. With D-EGR although there is an in-cylinder presence of a reactive H2-CO reformate, there is also higher levels of dilution.
Technical Paper

Durability Study of a High Pressure Common Rail Fuel Injection System Using Lubricity Additive Dosed Gasoline-Like Fuel - Additional Cycle Runtime and Teardown Analysis

2019-04-02
2019-01-0263
This study is a continuation of previous work assessing the robustness of a Cummins XPI common rail injection system operating with gasoline-like fuel. All the hardware from the original study was retained except for the high pressure pump head and check valves which were replaced due to cavitation damage. An additional 400 hour NATO cycle was run on the refurbished fuel system to achieve a total exposure time of 800 hours and detect any other significant failure modes. As in the initial investigation, fuel system parameters including pressures, temperatures and flow rates were logged on a test bench to monitor performance over time. Fuel and lubricant samples were taken every 50 hours to assess fuel consistency, metallic wear, and interaction between fuel and oil. High fidelity driving torque and flow measurements were made to compare overall system performance when operating with both diesel and light distillate fuel.
Technical Paper

Multi-Domain Optimization for Fuel Economy Improvement of HD Trucks

2019-04-02
2019-01-0312
Fuel usage negatively impacts the environment and is a significant portion of operational costs of moving freight globally. Reducing fuel consumption is key to lessening environmental impacts and maximizing freight efficiency, thereby increasing the profit margin of logistic operators. In this paper, fuel economy improvements of a cab-over style 49T heavy duty Foton truck powered by a Cummins 12-liter engine are studied and systematically applied for the China market. Most fuel efficiency improvements are found within the vehicle design when compared to opportunities available at the engine level. Vehicle design (improved aerodynamics), component selection/matching (low rolling resistance tires), and powertrain electronic features integration (shift schedule/electronic trim) offer the largest opportunities for lowering fuel consumption.
Technical Paper

Test Methodology to Quantify and Analyze Energy Consumption of Connected and Automated Vehicles

2019-04-02
2019-01-0116
A new generation of vehicle dynamics and powertrain control technologies are being developed to leverage information streams enabled via vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) connectivity [1, 2, 3, 4, 5]. While algorithms that use these connected information streams to enable improvements in energy efficiency are being studied in detail, methodologies to quantify and analyze these improvements on a vehicle have not yet been explored fully. A procedure to test and accurately measure energy-consumption benefits of a connected and automated vehicle (CAV) is presented. The first part of the test methodology enables testing in a controlled environment. A traffic simulator is built to model traffic flow in Fort Worth, Texas with sufficient accuracy. The benefits of a traffic simulator are two-fold: (1) generation of repeatable traffic scenarios and (2) evaluation of the robustness of control algorithms by introducing disturbances.
Technical Paper

A Comprehensive CFD-FEA Conjugate Heat Transfer Analysis for Diesel and Gasoline Engines

2019-04-02
2019-01-0212
As the efforts to push capabilities of current engine hardware to their durability limits increases, more accurate and reliable analysis is necessary to ensure that designs are robust. This paper evaluates a method of Conjugate Heat Transfer (CHT) analysis for a gasoline and a diesel engine that combines combustion Computational Fluid Dynamics (CFD), engine Finite Element Analysis (FEA), and cooling jacket CFD with the goal of obtaining more accurate temperature distribution and heat loss predictions in an engine compared to standard de-coupled CFD and FEA analysis methods. This novel CHT technique was successfully applied to a 2.5 liter GM LHU gasoline engine at 3000 rpm and a 15.0 liter Cummins ISX heavy duty diesel engine operating at 1250 rpm. Combustion CFD simulations results for the gasoline and diesel engines are validated with the experimental data for cylinder pressure and heat release rate.
Technical Paper

An Exploratory Look at an Aggressive Miller Cycle for High BMEP Heavy-Duty Diesel Engines

2019-04-02
2019-01-0231
Through aggressive application of the Miller Cycle, using two-stage turbocharging, medium speed diesel marine and stationary power engines are demonstrating over 30 bar rated power BMEP, and over 50 percent brake thermal efficiency. The objective of this work was to use engine cycle simulation to assess the degree to which the aggressive application of the Miller Cycle could be scaled to displacements and speeds more typical of medium and heavy truck engines. A 9.2 liter six-cylinder diesel engine was modeled. Without increasing the peak cylinder pressure, improved efficiency and increased BMEP was demonstrated. The level of improvement was highly dependent on turbocharger efficiency - perhaps the most difficult parameter to scale from the larger engines. At 1600 rpm, and a combined turbocharger efficiency of 61 percent, the baseline BMEP of 24 bar was increased to over 26 bar, with a two percent fuel consumption improvement.
Technical Paper

Predictive GT-Power Simulation for VNT Matching to EIVC Strategy on a 1.6 L Turbocharged GDI Engine

2019-04-02
2019-01-0192
The use of early intake valve closing (EIVC) can lead to improvements in spark-ignition engine efficiency. One of the greatest barriers facing adoption of EIVC for high power-density applications is the challenge of boosting as EIVC strategies reduce volumetric efficiency. Turbochargers with variable nozzle turbines (VNT) have recently been developed for gasoline applications operating at high exhaust gas temperatures. The use of a single VNT as a boost device may provide a lower-cost option compared to two-stage boosting systems or 48 V electronic boost devices for some EIVC applications. A predictive model was created based on engine testing results from a 1.6 L turbocharged gasoline direct injection engine [1]. The model was tuned so that it predicted burn-rates and end-gas knock over an engine operating map with varying speeds, loads, compression ratios and fuel types.
Technical Paper

Development of Parametric Tool to Design Base Frame for Cummins Marine Application Engine

2019-04-02
2019-01-0798
A spread sheet based parametric tool is developed to design the base frame for a marine generator-set. Factors such as engine details, generator details, anti-vibration mount (AVM) etc., that determine the design of the base frame, are set as parameters in the spreadsheet. The spreadsheet has formulae to calculate channel specifications, and AVM deflections. It is linked to channel standards database and selects the optimal channel based on calculations. Similarly, the tool provides guidance in selection of AVM from supplier catalogues, helps to predict number of anti-vibration mounts required and their location on base frame. This spread sheet is integrated with a generic base frame 3D model and 2D print in “Creo 3d modelling software” (Creo), which is auto-updated based on calculated parameters in the spreadsheet. Using this tool, the user can generate a 3D-model and 2D print. This tool helps to standardize the design process and reduces design turnaround time considerably.
Technical Paper

The Thermodynamic Design, Analysis and Test of Cummins’ Supertruck 2 50% Brake Thermal Efficiency Engine System

2019-04-02
2019-01-0247
Current production heavy duty diesel engines have a brake thermal efficiency (BTE) between 43-46% [1]. In partnership with the United States Department of Energy (DOE) as part of the Supertruck 2 program, Cummins has undertaken a research program to develop a new heavy-duty diesel engine designed to deliver greater than 50% BTE without the use of waste heat recovery. A system level optimization focused on: increased compression ratio, higher injection rate, carefully matched highly efficient turbocharging, variable lube oil pump, variable cooling components, and low restriction after treatment designed to deliver 50% BTE at a target development point. This work will also illustrate the system level planning and understanding of interactions required to allow that same 50% BTE heavy duty diesel engine to be integrated with a waste heat recovery (WHR) system to deliver system level efficiency of 55% BTE at a single point.
Technical Paper

Vehicle Drive Cycle Fuel Economy Prediction Using Single Cylinder Engine Data

2019-04-02
2019-01-0628
The confluence of fuel economy improvement requirements and increased use of ethanol as a gasoline blend component has led to various studies into the efficiency and performance benefits to be had when using high octane number, high ethanol content fuels in modern engines. As part of a comprehensive study of the autoignition of fuels in both the CFR octane rating engine and a modern, direct injection, turbocharged spark ignited engine, a series of fuel blends were prepared with market relevant ranges of octane numbers and ethanol blends levels. The paper reports on the first part of this study where fuel flow measurements were done on a single cylinder research engine, utilizing a GM LHU combustion system, and then used to predict drive cycle fuel economy. For a range of engine speeds and manifold air pressures, spark timing was adjusted to achieve either the maximum brake torque (MBT) or a matched 50 % mass fraction burnt location.
Technical Paper

Cooling Fan Selection in Power Car Application Using CFD and FEA Analysis

2019-04-02
2019-01-0900
This paper describes the methodology used to select an application-based fan that has optimum operating characteristics in terms of cooling air flow rate, fan power, and noise. The selected fan is then evaluated for structural strength. To evaluate different fans, complete rail coach under-hood simulations were carried out using steady-state 3D computational fluid dynamics (CFD) approach. These simulations considered an actual, highly non-uniform flow field. For each fan option, fan power, air flow rate, and surface acoustic power was evaluated. Pressure profiles on the fan blades were studied to assess the effect of non-uniform downstream air passage designs. Surface acoustic power was calculated using broadband noise source (BNS) model in ANSYS Fluent®. Surface pressure profiles over fan blades imported from 3D CFD were used in finite element analysis (FEA) in ANSYS. Analyses were carried out for blade linear and non-linear properties.
Technical Paper

EGR Cooler Field Return Rate Evaluation Based on Product and Application Variation

2019-04-02
2019-01-0915
The automotive industry drives some of the most stringent product requirements to ensure long product life and customer satisfaction. To demonstrate compliance with these requirements new and more accurate evaluation methods are needed. Thermal fatigue life in EGR coolers for heavy duty diesel applications have historically been a critical focus for engine OEMs. Being able to accurately evaluate product return rates due to thermal fatigue failures gives the OEM confidence that all end users will be satisfied, and allows program management to properly make fiscal decisions. Additionally, weight and cost optimization can be conducted with greater confidence. This is accomplished by accounting for product variation and application variation in thermal fatigue life evaluations. Including these variations requires a simplified numerical method to calculate product life, as tens of thousands of samples will be run through the analysis to represent real life random variation.
Technical Paper

Effects of Dual Port Injection and Direct-Injection Technology on Combustion Emissions from Light-Duty Gasoline Vehicles

2019-04-02
2019-01-0999
Dual injection fuel systems combine the knock and fuel economy benefits of gasoline direct injection (GDI) technology with the lower particulate emissions of port fuel injection (PFI) systems. For many years, this technology was limited to smaller-volume, high-end, vehicle models, but these technologies are now becoming main stream. The combination of two fuel injection systems has an impact on the combustion emission composition as well as the consistency of control strategy and emissions. Understanding the impact of these changes is essential for fuel and fuel additive companies, automotive companies, and aftertreatment developers. This paper describes the effects of dual injection technology on both regulated and non-regulated combustion emissions from a 2018 Toyota Camry during several cold-start, 4-bag United States Federal Test Procedure (FTP) cycle.
Technical Paper

Deposit Reduction in SCR Aftertreatment Systems by Addition of Ti-Based Coordination Complex to UWS

2019-04-02
2019-01-0313
Formation of urea-derived deposits in selective catalytic reduction (SCR) aftertreatment systems continues to be problematic at temperatures at and below 215 °C. Several consequences of deposit formation include: NOx and NH3 slip, exhaust flow maldistribution, increased engine backpressure, and corrosion of aftertreatment components. Numerous methods have been developed to reduce deposit formation, but to date, there has been no solution for continuous low-temperature dosing of Urea-Water Solution (UWS). This manuscript presents a novel methodology for reducing low-temperature deposit formation in SCR aftertreatment systems. The methodology described herein involves incorporation and dissolution of an HNCO hydrolysis catalyst directly into the UWS. HNCO is a transient species formed by the thermolysis of urea upon injection of UWS into the aftertreatment system.
Technical Paper

Benchmarking a 2018 Toyota Camry 2.5-Liter Atkinson Cycle Engine with Cooled-EGR

2019-04-02
2019-01-0249
As part of the U.S. Environmental Protection Agency’s (EPA’s) continuing assessment of advanced light-duty automotive technologies in support of regulatory and compliance programs, a 2018 Toyota Camry A25A-FKS 4-cylinder, 2.5-liter, naturally aspirated, Atkinson Cycle engine with cooled exhaust gas recirculation (cEGR) was benchmarked. The engine was tested on an engine dynamometer with and without its 8-speed automatic transmission, and with the engine wiring harness tethered to a complete vehicle parked outside of the test cell. Engine and transmission torque, fuel flow, key engine temperatures and pressures, onboard diagnostics (OBD) data, and Controller Area Network (CAN) bus data were recorded. This paper documents the test results under idle, low, medium, and high load engine operation. Motoring torque, wide open throttle (WOT) torque and fuel consumption are measured during transient operation using both EPA Tier 2 and Tier 3 test fuels.
Technical Paper

Fuel Reforming and Catalyst Deactivation Investigated in Real Exhaust Environment

2019-04-02
2019-01-0315
Increased in-cylinder hydrogen levels have been shown to improve burn durations, combustion stability, HC emissions and knock resistance which can directly translate into enhanced engine efficiency. External fuel reformation can also be used to increase the hydrogen yield. During the High-Efficiency, Dilute Gasoline Engine (HEDGE) consortium at Southwest Research Institute (SwRI), the potential of increased hydrogen production in a dedicated-exhaust gas recirculation (D-EGR) engine was evaluated exploiting the water gas shift (WGS) and steam reformation (SR) reactions. It was found that neither approach could produce sustained hydrogen enrichment in a real exhaust environment, even while utilizing a lean-rich switching regeneration strategy. Platinum group metal (PGM) and Ni WGS catalysts were tested with a focus on hydrogen production and catalyst durability.
Technical Paper

Diagnostics of Field-Aged Three-Way Catalyst (TWC) on Stoichiometric Natural Gas Engines

2019-04-02
2019-01-0998
Three-way catalysts have been used in a variety of stoichiometric natural gas engines for emission control. During real-world operation, these catalysts have experienced a large number of temporary and permanent deactivations including thermal aging and chemical contamination. Thermal aging is typically induced either by high engine-out exhaust temperatures or the reaction exotherm generated on the catalysts. Chemical contamination originates from various inorganic species such as Phosphorous (P) and Sulfur (S) that contain in engine fluids, which can poison and/or mask the catalyst active components. Such deactivations are quite difficult to simulate under laboratory conditions, due to the fact that multiple deactivation modes may occur at the same time in the real-world operations. In this work, a set of field-aged TWCs has been analyzed through detailed laboratory research in order to identify and quantify the real-world aging mechanisms.
Technical Paper

Combined Benefits of Variable Valve Actuation and Low-Pressure EGR on SI Engine Efficiency Part 1: Part Load

2019-04-02
2019-01-0241
Modern spark ignited engines face multiple barriers to achieving higher thermal efficiency. This study investigated the potential of utilizing both continuously variable valve actuation (VVA) and low-pressure cooled exhaust gas recirculation (EGR) to improve engine thermal efficiency at part-load conditions. Six speed / load points were investigated on a 1.6 L turbocharged gasoline direct injection engine. A design of experiment (DoE) approach using the Box-Behnken surface response model was conducted. The DoE results revealed different brake specific fuel consumption (BSFC) responses to the valve phasing and the intake valve lift at different operating conditions. Further engine testing was carried out at each speed / load point to confirm the engine efficiency and combustion performance when targeting different valvetrain controls and EGR strategies. The results indicated that utilizing the VVA system could always reduce BSFC at the studied operating conditions.
Technical Paper

Combined Benefits of Variable Valve Actuation and Low-Pressure EGR on SI Engine Efficiency Part 2: High Load

2019-04-02
2019-01-0237
The abnormal autoignition of the unburned gas, namely knock, at high loads is a major challenge for modern spark ignited engines. Knock prevents the application of high compression ratios due to the increased unburned gas temperature, and it becomes increasingly severe for downsized engines with high specific powers. The current paper reports on the potential of utilizing continuously variable valve actuation (VVA) and low-pressure exhaust gas recirculation (EGR) to reduce knock tendency at high loads. Five speed / load points were investigated on a 1.6 L turbocharged gasoline direct injection engine. The brake specific fuel consumption (BSFC) response to the valve phasing and the intake valve lift was investigated with the design of experiment (DoE) approach. The DoE was conducted using a Box-Behnken surface response model. The results exhibited insensitive response of BSFC to intake valve lift and overlap.
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