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Engine and aftertreatment solutions have been identified to meet the upcoming ultra-low NOX regulations on heavy duty vehicles in the United States and Europe. These standards will require changes to current conventional aftertreatment systems for dealing with low exhaust temperature scenarios while increasing the useful life of the engine and aftertreatment system. Previous studies have shown feasibility of meeting the US EPA and California Air Resource Board (CARB) requirements. This work includes a 15L diesel engine equipped with cylinder deactivation (CDA) and an aftertreatment system that was fully DAAAC aged to 800,000 miles. The aftertreatment system includes an e-heater (electric heater), light-off Selective Catalytic Reduction (LO-SCR) followed by a primary aftertreatment system containing a DPF and SCR.

Commercial vehicle powertrain is called to respect a challenging roadmap for CO2 emissions reduction, quite complex to achieve just improving technologies currently on the market. In this perspective alternative solutions are gaining interest, and the use of green H2 as fuel for ICE is considered a high potential solution with fast and easy adoption. NOx emission is still a problem for H2 ICE and can be managed operating the engine with lean air fuel ratio all over the engine map. This combustion strategy will challenge the boosting system as lean H2 combustion will require quite higher air flow compared to diesel for the same power density in steady state. Similar problem will show up in transient response particularly when acceleration starts from low load and the exhaust gases enthalpy is very poor and insufficient to spin the turbine. The analysis presented in this paper will show and quantify the positive impact that a supercharger has on both the above mentions problems.

Reducing criteria pollutants while reducing greenhouse gases is an active area of research for commercial on-road vehicles as well as for off-road machines. The heavy duty on-road sector has moved to reducing NOx by 82.5% compared to 2010 regulations while increasing the engine useful life from 435,000 to 650,000 miles by 2027 in the United States (US). An additional certification cycle, the Low Load Cycle (LLC), has been added focusing on part load operation having tight NOx emissions levels. In addition to NOx, the total CO2 emissions from the vehicle will also be reduced for various model years. The off-road market is following with a 90% NOx reduction target compared to Tier 4 Final for 130-560 kW engines along with greenhouse gas targets that are still being established. The off-road market will also need to certify with a Low Load Application Cycle (LLAC), a version of which was proposed for evaluation in 2021.

Cold spray (CS) is a rapidly developing solid-state repair and coating process, wherein metal deposition is produced without significant heating or melting of metal powder. Solid state bonding of powder particles is produced by impact of high-velocity powder particles on a substrate. In CS process, metal powder particles typically of Aluminum or Copper are suspended in light weight carrier gas medium. Here high pressure and high temperature carrier gas is expanded through a converging-diverging nozzle to generate supersonic gas velocity at nozzle exit. The CS process typically uses Helium as the carrier gas due to its low molecular weight, but Helium gas is quite expensive. This warrants a need to explore alternate carrier gases to make the CS repair process more economical. Researchers are exploring another viable option of using pure Nitrogen as a carrier gas due to its significant cost benefits over Helium.

The commercial vehicle industry continues to move in the direction of improving brake thermal efficiency while meeting more stringent diesel engine emission requirements. This study focused on demonstrating future emissions by using an exhaust burner upstream of a conventional aftertreatment system. This work highlights system results over the low load cycle (LLC) and many other pertinent cycles (Beverage Cycle, and Stay Hot Cycle, New York Bus Cycle). These efforts complement previous works showing system performance over the Heavy-Duty FTP and World Harmonized Transient Cycle (WHTC). The exhaust burner is used to raise and maintain the Selective Catalytic Reduction (SCR) catalyst at its optimal temperature over these cycles for efficient NOX reduction. This work showed that tailpipe NOX is significantly improved over these cycles with the exhaust burner.

Coil springs are crucial components of the clutch damper. Quantifying the stresses accumulated on them during operation is crucial in the prediction of remaining usable spring life. This paper demonstrates the use of a mathematical model-based approach in predicting the behavior of localized stresses on the spring used in clutch dampers. An equivalent cantilever beam model for spring coils solved using the theory of elastic stability is utilized to predict the spring response in operation, a contact model that translates the spring response into localized stresses due to wear and iterative wear model that accounts for surface morphology and change in geometry due to wear is illustrated in this paper for the prediction of wear.

Commercial vehicles are moving in the direction of improving brake thermal efficiency while also meeting future diesel emission requirements. This study is focused on improving efficiency by replacing the variable geometry turbine (VGT) turbocharger with a high-efficiency fixed geometry turbocharger. Engine-out (EO) NOX emissions are maintained by providing the required amount of exhaust gas recirculation (EGR) using a 48 V motor driven EGR pump downstream of the EGR cooler. This engine is also equipped with cylinder deactivation (CDA) hardware such that the engine can be optimized at low load operation using the combination of the high-efficiency turbocharger, EGR pump and CDA. The exhaust aftertreatment system has been shown to meet 2027 emissions using the baseline engine hardware as it includes a close coupled light-off SCR followed by a downstream SCR system.

Commercial vehicles require fast aftertreatment heat up in order to move the selective catalyst reduction (SCR) into the most efficient temperature range to meet upcoming NOx regulations. Heavy duty cylinder deactivation (CDA) is an important technology to meet these regulations. One of the challenges with implementing CDA in the heavy-duty market is to ensure acceptable engine and vehicle vibration. The purpose of this paper is to mitigate CDA vibration on a vehicle to acceptable levels. Emphasis was placed at the idle operating condition. Idle is the most challenging operating mode to enable, as deactivating cylinders reduces the frequency of the forcing function due to engine firing, which leads to a need to isolate these lower frequencies. A focused modal analysis of the engine (source), frame (path), and cabin (path/receiver) was used to characterize the vehicle system.

Commercial vehicles require continual improvements in order to meet fuel emission standards, improve diesel aftertreatment system performance and optimize vehicle fuel economy. Aftertreatment systems require significant space claim which makes vehicle packaging a challenge. Today’s diesel engines require valvetrain lash adjustment settings at distinct intervals to ensure proper valvetrain performance. This requires removing the engine rocker cover to access the valvetrain rocker arms for setting lash. Setting lash for compact vehicle applications sometimes requires removing the aftertreatment system to provide access to the rocker cover prior to setting lash. Then, the rocker cover is reinstalled followed by the aftertreatment system making the lash setting process time consuming and complex.

Vehicle noise emission requirements are becoming more stringent each passing year. Pass-by noise requirement for passenger vehicles is now 74 dB (A) in some parts of the world. The common focus areas for noise treatment in the vehicle are primarily on three sub-systems i.e., engine compartment, exhaust systems and power train systems. Down- sizing and down- speeding of engines, without compromising on power output, has meant use of boosting technologies that have produced challenges in order to design low-noise intake systems which minimize losses and also meet today’s vehicle emission regulations. In a boosted system, there are a variety of potential noise sources in the intake system. Thus an understanding of the noise source strength in each component of the intake system is needed. One such boosting system consists of Turbo-Super configuration with various components, including an air box, supercharger, an outlet manifold, and an intercooler.

Helical gears are commonly used instead of spur gears due to their potential higher load carrying capacity, efficiency and lower noise. Transmission Error (TE) is defined as deviation from perfect motion transfer by a gear pair. TE is dominant source of gear whine noise and hence gears pairs are generally analyzed and designed for low TE. In the process of designing helical gears for lower TE, the shuttling moment can become a significant excitation source. Shuttling moment is caused due to shifting of the centroid of tooth normal force back and forth across the lead. The amount of shuttling force or moment is produced by combination of design parameters, misalignment and manufacturing errors. Limited details are available on this excitation and its effect on overall noise radiated from gear box or transmission at its gear mesh frequency and harmonics.

Emission, fuel economy and productivity in non-road mobile machinery (NRMM) depend largely on drive cycles. Understanding drive cycles can provide the in-depth information and knowledge that help the system integrator better optimize the vehicle management system. Some non-road engine test cycles already exist nowadays. However, these cycles are mainly for engine emission regulation purpose, and not closely tied to real world applications. Therefore, from both industries and academia, it has been the common practice to instrument and retrofit a vehicle, assign a professional driver operate the retrofitted vehicle for real testing, and compare the results to the baseline vehicle under the similar operating conditions. Obviously this approach is time consuming and resource intensive. In this paper, we attempt to address this issue by introducing a method of constructing standard drive cycles from in-field operation data.

Journal bearings are machine elements designed to produce smooth (low friction) motion between solid surfaces in relative motion and to generate a load support for mechanical components. In a Journal bearing, the entire load is carried by a thin film of fluid present between the rotating and the non-rotating elements. The thickness of the film is very sensitive to ambient temperature, radial clearance and misalignment. Though these parameters are difficult to control, it is important to consider these as noises while designing the Journal bearing. When noises in the design space are very strong, the conventional DOE and RSM methods suppress the effect of control factors and render them irrelevant in the design process. This leads to overdesigning the product, which in turn adds more cost. The main objective of this work is to design a bearing, which is insensitive to noises at each stage of the product life cycle.

Simulations used to estimate carbon dioxide (CO2) emissions and fuel consumption of medium- and heavy-duty vehicles over prescribed drive cycles often employ engine fuel maps consisting of engine measurements at numerous steady-state operating conditions. However, simulating the engine in this way has limitations as engine controls become more complex, particularly when attempting to use steady-state measurements to represent transient operation. This paper explores an alternative approach to vehicle simulation that uses a “cycle average” engine map rather than a steady state engine fuel map. The map contains engine CO2 values measured on an engine dynamometer on cycles derived from vehicle drive cycles for a range of generic vehicles. A similar cycle average mapping approach is developed for a powertrain (engine and transmission) in order to show the specific CO2 improvements due to powertrain optimization that would not be recognized in other approaches.

Cylinder deactivation (CDA) is an effective method to adjust the engine displacement for maximum output and improve fuel economy by adjusting the number of active cylinders in combustion engines. A Switching Roller Finger Follower (SRFF) is an economic solution for CDA that minimizes changes and preserves the overall width, height, or length of Dual Overhead Cam (DOHC) engines. The CDA SRFF provides the flexibility of either transferring or suppressing the camshaft movement to the valves influencing the engine performance and fuel economy by reducing the pumping losses. This paper addresses the performance and durability of the CDA SRFF system to meet the reliability for gasoline passenger car engines. Extensive tests were conducted to demonstrate the dynamic stability at high engine speeds and the system capacity of switching between high and low engine displacement within one camshaft revolution.

Several diesel passenger car boosting systems were studied to assess their impact on vehicle performance and fuel economy. A baseline 1.5L diesel engine model with a single VGT turbocharger was obtained through Gamma Technologies' fast running model library. This model was modified to explore multiple two stage boosting systems to represent the anticipated architecture of future engines. A series sequential turbocharged configuration and a series turbocharger-supercharger configuration were evaluated. The torque curves were increased from that of the original engine model to take advantage of the increased performance offered by two stage boosting. The peak cylinder pressure for all models was limited to 180 bar. Drive cycle analysis over the WLTP was performed using these engine architectures, while assessing the sensitivity to various system parameters. These parameters include: vehicle weight and aerodynamic drag, EGR target maps, level of downspeeding, and turbocharger inertia.

The objective of this paper is to provide a robust design solution for a Jet pump which is used for fuel removal from an Active Drain Liquid Trap (ADLT). This jet pump can work for both Gasoline and Diesel based automobiles. The major focus area of this paper, is improvement in the robustness of Jet pump performance parameters, such as motive flow and induced flow. A design study for such a two fuel application was first initiated using Taguchi's robust design approach. In order to reduce the inventory complexity and cost, a common design possibility was then addressed. Two approaches for robust design have been discussed, namely the Taguchi Methodology (Orthogonal Cross Array based design) and the Dual RSM (Response Surface Methodology) Technique. Results show that the Dual RSM provides improved performance with reduced variation, as compared to Taguchi's approach.

Computer simulation is commonly used to determine the impact of hybrid vehicle technology on fuel economy and performance. One input required for this approach is a drive cycle that represents the desired vehicle speed at each time step in the simulation. Due to computational hardware limitations, simulated drive cycle durations are required to be shorter than those actually driven by real vehicles. Hence there is a need to develop a representative drive cycle of smaller time duration. For example, it is desirable to develop a one hour drive cycle that can give the same fuel economy and performance results as a drive cycle spanning many weeks. Specifically for the design of hybrid systems, it is desired that certain characteristics of micro-trips within the full length cycle are well replicated in the representative cycle. Taking these requirements into account, a new methodology was developed and tested. This paper explains this methodology and the final results obtained.