Search Results

The die wear up to 80,800 hits on a prog-die setup for bare DP1180 steel was investigated in real production condition. In total, 31 die inserts with the combination of 11 die materials and 9 coatings were evaluated. The analytical results of die service life for each insert were provided by examining the evolution of surface wear on inserts and formed parts. The moments of appearance of die defects, propagation of die defects, and catastrophic failure were determined. Moreover, the surface roughness of the formed parts for each die insert was characterized using Wyko NT110 machine. The objectives of the current study are to evaluate the die durability of various tooling materials and coatings for flange operations on bare DP 1180 steel and update OEM tooling standards based on the experimental results. The current study provides the guidance for the die material and coating selections in large volume production for next generation AHSSs.

A pilot-main injection strategy is investigated for a part-load operating point in a single cylinder optical Diesel engine. As the energizing dwell between the pilot and main injections decreases below 200 μs, combustion noise reaches a minimum and a reduction of 3 dB is possible. This decrease in combustion noise is achieved without increased pollutant emissions. Injection schedules employed in the engine are analyzed with an injection analyzer to provide injection rates for each dwell tested. Two distinct injection events are observed even at the shortest dwell tested; rate shaping of the main injection occurs as the dwell is adjusted. High-speed elastic scattering imaging of liquid fuel is performed in the engine to examine initial liquid penetration rates.

The New Car Assessment Program (NCAP), introduced in 1979 by the U.S. National Highway Traffic Safety Administration, is a vehicle safety rating system that conducts crash test and provides motoring consumers with an assessment of the safety performance of new cars. Similar programs were then developed around the world, initially for Europe (EuroNCAP), Australia (ANCAP), Japan (JNCAP), China (CNCAP) and Korea (KNCAP). NCAP most recently reached Latin America (LatinNCAP) and Southeast Asia (AseanNCAP). Although the roots are similar, many NCAP programs have significant differences on the test procedures and rating schemes. This paper is a comparative analysis of the recent NCAP protocols to highlight the most important technical differences.

As vehicle fuel economy continues to grow in importance, the ability to accurately measure the level of efficiency on all driveline components is required. A standardized test procedure enables manufacturers and suppliers to measure component losses consistently and provides data to make comparisons. In addition, the procedure offers a reliable process to assess enablers for efficiency improvements. Previous published studies have outlined the development of a comprehensive test procedure to measure transfer case speed-dependent parasitic losses at key speed, load, and environmental conditions. This paper will take the same basic approach for the Power Transfer Units (PTUs) used on Front Wheel Drive (FWD) based All Wheel Drive (AWD) vehicles. Factors included in the assessment include single and multi-stage PTUs, fluid levels, break-in process, and temperature effects.

To investigate the effect of aeration on fluid-elastomer compatibility, 4 types of elastomers were aged in three gear lubes. The four types of elastomers include a production fluorinated rubber (FKM) and production hydrogenated nitrile rubber (HNBR) mixed by the part fabricator, a standard low temperature flexible fluorinated rubber (FKM, ES-4) and a standard ethylene-acrylic copolymer (AEM, ES-7) mixed by SAE J2643 approved rubber mixer. The three gear lubes are Fluid a, Fluid b and Fluid c, where Fluid b is a modified Fluid with additional friction modifier, and Fluid c is friction modified chemistry from a different additive supplier. The aeration effect tests were performed at 125°C for 504 hours. The aerated fluid aging test was performed by introducing air into fluid aging tubes as described in General Motors Company Materials Specification GMW16445, Appendix B, side-by-side with a standard ASTM D471 test.

One of the major problems that the automotive industry faces is reducing friction to increase efficiency. Researchers have shown that 30% of the fuel energy was consumed to overcome the friction forces between the moving parts of any automobile, Holmberg et al. [1]. The interface of the piston pin and pin bore is one of the areas that generate high friction under severe working conditions of high temperature and lack of lubrication. In this research, experimental investigation and theoretical simulation have been carried out to analyze the motion of the floating pin against pin bore. In the experimental study, the focus was on analyzing the floating pin motion by using a bench test rig to simulate the floating pin motion in an internal combustion engine. A motion data acquisition system was developed to capture and record the pin motion. Thousands of images were recorded and later analyzed by a code written by MATLAB.

Corrosion inhibitors (CIs) have been used for years to protect the supply and distribution hardware used for transportation of fuel from refineries and to buffer the potential organic acids present in an ethanol blended fuel to enhance storage stability. The impact of these inhibitors on spark-ignition engine fuel systems, specifically intake valve deposits, is known and presented in open literature. However, the relationship of the corrosion inhibitors to the powertrain intake valve deposit performance is not understood. This paper has two purposes: to present and discuss a second market place survey of corrosion inhibitors and how they vary in concentration in the final blended fuel, specifically E85 (Ethanol Fuel Blends); and, to show how the variation in the concentrations of the components of the CIs impacts the operation and performance of vehicles, specifically, the effects on intake valve deposit formation.

The effects of using blended renewable diesel fuel (30% vol.), obtained from Rapeseed Methyl Ester (RME) and Hydrotreated Vegetable Oil (HVO), in a Euro 5 small displacement passenger car diesel engine have been evaluated in this paper. The hydraulic behavior of the common rail injection system was verified in terms of injected volume and injection rate with both RME and HVO blends fuelling in comparison with commercial diesel. Further, the spray obtained with RME B30 was analyzed and compared with diesel in terms of global shape and penetration, to investigate the potential differences in the air-fuel mixing process. Then, the impact of a biofuel blend usage on engine performance at full load was first analyzed, adopting the same reference calibration for all the tested fuels.

The light-medium load operating range (4-7 bar net IMEP) presents many challenges for advanced low temperature combustion strategies utilizing low cetane fuels (specifically, 87-octane gasoline) in light-duty, high-speed engines. The overly lean overall air-fuel ratio (Φ≺0.4) sometimes requires unrealistically high inlet temperatures and/or high inlet boost conditions to initiate autoignition at engine speeds in excess of 1500 RPM. The objective of this work is to identify and quantify the effects of variation in input parameters on overall engine operation. Input parameters including inlet temperature, inlet pressure, injection timing/duration, injection pressure, and engine speed were varied in a ~0.5L single-cylinder engine based on a production General Motors 1.9L 4-cylinder high-speed diesel engine.

This paper investigates changes in fuel economy of a mid-size sedan at various engine cooling fan power levels and front grille opening areas. A full vehicle model was built using MATLAB Simulink to calculate the fuel economy (MPG). The model utilized inputs from aerodynamic wind tunnel testing as well as FTP and MVEG dynamometer tests results. Simulation and testing was carried out at three front opening areas and three engine cooling fan power levels. The results provide a guideline for optimizing the front grille opening vs. engine cooling fan power combination at various driving conditions.

Cooled exhaust gas recirculation (EGR) is widely used in diesel engines to control engine-out NOx (oxides of nitrogen) emissions. A portion of the exhaust gases is re-circulated into the intake manifold of the engine after cooling it through a heat exchanger. EGR cooler heat exchangers, however, tend to lose efficiency and have increased pressure drop as deposit forms on the heat exchanger surface due to transport of soot particles and condensing species to the cooler walls. In this study, condensation of water vapor and hydrocarbons at the exit of the EGR cooler was visualized using a fiberscope coupled to a camera equipped with a complementary metal oxide semiconductor (CMOS) color sensor. A multi-cylinder diesel engine was used to produce a range of engine-out hydrocarbon concentrations. Both surface and bulk gas condensation were observed with the visualization setup over a range of EGR cooler coolant temperatures.

Diesel engine developers are continually striving to reduce harmful NOx emissions through various calibration and hardware strategies. One strategy being implemented in production Diesel engines involves utilizing cooled exhaust gas recirculation (EGR). Although there is a significant NOx reduction potential by utilizing cooled EGR, there are also several issues associated with it, such as EGR cooler fouling and a reduction in cooler effectiveness that can occur over time. The exact cause of these issues and many others related to cooler fouling are not clearly understood. One such unanswered issue or phenomenon that has been observed in both field tested and lab tested EGR coolers is that of a recovery in EGR cooler effectiveness after a shutdown or after cycling between various conditions.

Chrysler, Ford, General Motors, the U.S. Environmental Protection Agency (EPA) and the California Air Resources Board (CARB) have collaborated over the past two years to develop an efficiency test for mobile air conditioner (MAC) systems. Because the effect of efficiency differences between different MAC systems and different technologies is relatively small compared to overall vehicle fuel consumption, quantifying these differences has been challenging. The objective of this program was to develop a single dynamic test procedure that is capable of discerning small efficiency differences, and is generally representative of mobile air conditioner usage in the United States. The test was designed to be conducted in existing test facilities, using existing equipment, and within a sufficiently short time to fit standard test facility scheduling. Representative ambient climate conditions for the U.S. were chosen, as well as other test parameters, and a solar load was included.

This paper proposes a model-based “Cascaded Dual Extended Kalman Filter” (CDEKF) for combined vehicle state estimation, namely, tire vertical forces and parameter identification. A sensitivity analysis is first carried out to recognize the vehicle inertial parameters that have significant effects on tire normal forces. Next, the combined estimation process is separated in two components. The first component is designed to identify the vehicle mass and estimate the longitudinal forces while the second component identifies the location of center of gravity and estimates the tire normal forces. A Dual extended Kalman filter is designed for each component for combined state estimation and parameter identification. Simulation results verify that the proposed method can precisely estimate the tire normal forces and accurately identify the inertial parameters.

Cost and robustness are key factors in the design of diesel engines for low power density applications. Although compression ignition engines can produce very high power density output with turbocharging, naturally aspirated (NA) engines have advantages in terms of reduced cost and avoidance of system complexity. This work explores the use of direct injection (DI) and exhaust gas recirculation (EGR) in NA engines using experimental data from a single-cylinder research diesel engine. The engine was operated with a fixed atmospheric intake manifold pressure over a map of speed, air-to-fuel ratio, EGR, fuel injection pressure and injection timing. Conventional gaseous engine-out emissions were measured along with high speed cylinder pressure data to show the load limits and resulting emissions of the NA-DI engine studied. Well known reductions in NOX with increasing levels of EGR were confirmed with a corresponding loss in peak power output.

An investigation of high speed direct injection (DI) compression ignition (CI) engine combustion fueled with gasoline injected using a triple-pulse strategy in the low temperature combustion (LTC) regime is presented. This work aims to extend the operation ranges for a light-duty diesel engine, operating on gasoline, that have been identified in previous work via extended controllability of the injection process. The single-cylinder engine (SCE) was operated at full load (16 bar IMEP, 2500 rev/min) and computational simulations of the in-cylinder processes were performed using a multi-dimensional CFD code, KIVA-ERC-Chemkin, that features improved sub-models and the Chemkin library. The oxidation chemistry of the fuel was calculated using a reduced mechanism for primary reference fuel combustion chosen to match ignition characteristics of the gasoline fuel used for the SCE experiments.

An iterative learning control (ILC) algorithm has been developed for a test cell electro-hydraulic, fully flexible valve actuation system to track valve lift profile under steady-state and transient operation. A dynamic model of the plant was obtained from experimental data to design and verify the ILC algorithm. The ILC is implemented in a prototype controller. The learned control input for two different lift profiles can be used for engine transient tests. Simulation and bench test are conducted to verify the effectiveness and robustness of this approach. The simple structure of the ILC in implementation and low cost in computation are other crucial factors to recommend the ILC. It does not totally depend on the system model during the design procedure. Therefore, it has relatively higher robustness to perturbation and modeling errors than other control methods for repetitive tasks.

Spot, or distributed, cooling and heating is an energy efficient way of delivering comfort to an occupant in the car. This paper describes an approach to distributed cooling in the vehicle. A two passenger CFD model of an SUV cabin was developed to obtain the solar and convective thermal loads on the vehicle, characterize the interior thermal environment and accurately evaluate the fluid-thermal environment around the occupants. The present paper focuses on the design and CFD analysis of the energy efficient HVAC system with spot cooling. The CFD model was validated with wind tunnel data for its overall accuracy. A baseline system with conventional HVAC air was first analyzed at mid and high ambient conditions. The airflow and cooling delivered to the driver and the passenger was calculated. Subsequently, spot cooling was analyzed in conjunction with a much lower conventional HVAC airflow.

With a tighter regulatory environment, reduction of hydrocarbon (HC) and NOx emissions during cold-start has emerged as a major challenge for diesel engines. In the complex diesel aftertreatment system, more than 90% of engine-out NOx is removed in the underfloor SCR. However, the combination of low temperature exhaust and heat sink over DOC delays the SCR light-off during the cold start. In fact, the first 350 seconds during the cold light-duty FTP75 cycle contribute more than 50% of the total NOx tailpipe emission due to the low SCR temperature. For a fast SCR light-off, electrically heated catalyst (EHC) technology has been suggested to be an effective solution as a rapid warm-up strategy. In this work, the EHC, placed in front of DOC, utilizes both electrical power and hydrocarbon fuel. The smart energy management during the cold-start was crucial to optimize the EHC integrated aftertreatment system.

As vehicle fuel economy continues to grow in importance, the ability to accurately measure the level of parasitic losses on all driveline components is required. A standardized comparison procedure enables manufacturers and suppliers to measure component losses consistently, in addition to offering a reliable process to assess enablers for efficiency improvements. This paper reviews the development of a comprehensive test procedure to measure transfer case speed-dependent parasitic losses at key speed, load, and environmental conditions. This procedure was validated for repeatability considering variations in soak time, temperature measurement positions on the transfer case, and test operating conditions. Additional assessments of spin loss at low ambient temperatures, and the effect of component break-in on spin loss were also conducted.