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This work investigates the injection processes of an eight-hole direct-injection gasoline injector from the Engine Combustion Network (ECN) effort on gasoline sprays (Spray G). Experiments are performed at identical operating conditions by multiple institutions using standardized procedures to provide high-quality target datasets for CFD spray modeling improvement. The initial conditions set by the ECN gasoline spray community (Spray G: Ambient temperature: 573 K, ambient density: 3.5 kg/m3 (∼6 bar), fuel: iso-octane, and injection pressure: 200 bar) are examined along with additional conditions to extend the dataset covering a broader operating range. Two institutes evaluated the liquid and vapor penetration characteristics of a particular 8-hole, 80° full-angle, Spray G injector (injector #28) using Mie scattering (liquid) and schlieren (vapor).

The effects of hydrogen ratio and exhaust gas recirculation (EGR) on combustion and emissions in a hydrogen/diesel dual-fuel premixed charge compression ignition (PCCI) engine were investigated. The control of combustion phasing could be improved using hydrogen enrichment and EGR due to the retarded combustion phasing with a higher hydrogen ratio. The indicated mean effective pressure (IMEP) was increased with a higher hydrogen ratio because the hydrogen enrichment intensified the high temperature reactions and thus decreased the combustion duration. Hydrocarbon (HC) and carbon monoxide (CO) emissions were reduced significantly in a hydrogen/diesel dual-fuel PCCI mode with a similar NOx emissions level as that of the diesel PCCI mode.

Traditional in-tank gasoline and diesel fuel pumps require high power, 120 W or more, in fuel systems that have high flow requirements, high pressure requirements, or both. One method to reduce power consumption is to improve efficiency by using a brushless motor rather than the traditional brush style motor. The brushless motor technology also eliminates the brush to commutator interface which improves the pump's robustness to fuel and reduces flow variation. Additional benefits are provided by the controller which provides motor commutation since it enables closed loop pump speed control, pump diagnostics, and the opportunity for additional sensor interfaces to improve the fuel delivery system architecture. This paper describes the brushless motor technology, design optimization strategy for fuel pump applications, selected design, and resulting torque and efficiency performance improvements.

The compression ignition combustion fuelled with hydrogen and dimethyl-ether was investigated. Exhaust gas recirculation was applied to reduce noise and nitrogen oxide (NOx) emission. When dimethyl-ether was injected earlier, combustion showed two-stage ignitions known as low temperature reaction and high temperature reaction. With advanced dimethyl-ether injection, combustion temperature and in-cylinder pressure rise were lowered which resulted in high carbon monoxide and hydrocarbon emissions. However, NOx emission was decreased due to relatively low combustion temperature. The engine combustion showed only high temperature reaction when dimethyl-ether was injected near top dead center. When exhaust gas recirculation gas was added, the in-cylinder pressure and heat release rate were decreased. However, it retarded combustion phase resulting in higher indicated mean effective pressure.

Advances in engine technology including Gasoline Direct injection (GDi), Dual Independent Cam Phasing (DICP), advanced valvetrain and boosting have allowed the simultaneous reductions of fuel consumption and emissions with increased engine power density. The utilization of fuels containing ethanol provides additional improvements in power density and potential for lower emissions due to the high octane rating and evaporative cooling of ethanol in the fuel. In this paper results are presented from a flexible fuel engine capable of operating with blends from E0-E85. The increased geometric compression ratio, (from 9.2 to 11.85) can be reduced to a lower effective compression ratio using advanced valvetrain operating on an Early Intake Valve Closing (EIVC) or Late Intake Valve Closing (LIVC) strategy. DICP with a high authority intake phaser is used to enable compression ratio management.

A high-frequency electrical resonance-based ignition concept is in development to replace conventional spark ignition functionality for gasoline engines employing various types of fuel injection methods. The concept provides the benefit of a continuous discharge phase and the electrical power of the discharge can also be adjusted to the needs of the combustion conditions. This concept employs an alternative method of generating high voltages, using inductors and capacitors trimmed such that the supplied energy steadily increases the output voltage. This configuration is widely known as Tesla transformer and has been engineered to operate in a modern gasoline engine combustion environment. This development allows very high break down voltages to be generated and the power into the spark itself can be influenced.

Operation of flex fuel vehicles requires operation with a range of fuel properties. The significant differences in the heat of vaporization and energy density of E0-E100 fuels and the effect on spray development need to be fully comprehended when developing engine control strategies. Limited enthalpy for fuel vaporization needs to be accounted for when developing injection strategies for cold start, homogeneous and stratified operation. Spray imaging of multi-hole gasoline injectors with fuels ranging from E0 to E100 and environmental conditions that represent engine operating points from ambient cold start to hot conditions was performed in a spray chamber. Schlieren visualization technique was used to characterize the sprays and the results were compared with Laser Mie scattering and Back-lighting technique. Open chamber experiments were utilized to provide input and validation of a CFD model.

A turbocharged 2.0L 4-cylinder direct injection spark ignition (DISI) engine designed for use with gasoline is simulated using one dimensional engine simulation. Engine design modifications - increased compression ratio, 2-step valve train with dual independent cam phasing and fuel injection timing - are considered in an effort to improve fuel economy with gasoline and take advantage of properties of ethanol fuel blends (up to E85). This paper discusses a methodology to use the simulation to quantitatively evaluate the design modification effects on fuel economy. Fuel consumption predictions from the simulation for each design are evaluated. The goal is to identify the best design with the constraints of hardware physical limitations, engine residual tolerance and knock tolerance. The result yields a specification for a 2-step valve train design and phasing requirements that can improve fuel economy for each compression ratio design.

The current paper presents a by cylinder IMEP estimator which operates completely free of direct cylinder pressure sensor measurement and which, when coupled with associated closed loop torque controller and commonly used engine control hardware, can provide significant improvement in the reduction to fuel sensitivity over conventional systems at minimal or no cost. Applications of the by cylinder estimator and closed loop torque/IMEP control are described including the use of the estimator during cold start before the O2 sensor is active. The application of the IMEP estimator and controller to cold start can provide significantly improved idle quality as well as enhanced robustness to degraded fuel quality. Closed loop combustion strategies using spark and fuel are described and experimental data from V6 engine testing are presented for the estimator and available closed loop controllers.

Most times in ECU system function testing, the sensor input signals are directly set to a known value in order to drive the corresponding software variable to within a range of an expected value. This works only if the transfer function from the physical signal input to the software variable is well defined such as the measurement on MAP, A/C pressure, etc. Nevertheless, there are times the transfer function is not clearly defined and it is difficult to drive the software variable to an expected value. One example is throttle position sensor (TPS) test in an electronic throttle control (ETC) system, where TPS is not directly driven by the driver accelerator pedal sensor (APS) and it is very difficult to get TPS to an expected range by only changing APS. This paper introduces a method to use feedback in an HIL based ECU testing system to control outputs to an expected range. In this case study, the signal to be controlled is connected back to the HIL system to provide feedback.

Ethanol offers significant potential for increasing the compression ratio of SI engines resulting from its high octane number and high latent heat of vaporization. A study was conducted to determine the knock-limited compression ratio of ethanol-gasoline blends to identify the potential for improved operating efficiency. To operate an SI engine in a flex fuel vehicle requires operating strategies that allow operation on a broad range of fuels from gasoline to E85. Since gasoline or low ethanol blend operation is inherently limited by knock at high loads, strategies must be identified which allow operation on these fuels with minimal fuel economy or power density tradeoffs. A single-cylinder direct-injection spark-ignited engine with fully variable hydraulic valve actuation (HVA) is operated at WOT and other high-load conditions to determine the knock-limited compression ratio (CR) of ethanol fuel blends. The geometric CR is varied by changing pistons, producing CR from 9.2 to 12.87.

Ever since the implementation of diagnostics and electronic control systems on automatic transmissions, various forms of transmission gear selection feedback has been used. The traditional mechanization uses a feedback switch with mechanical contacts that indicate the selected gear discretely or through a grey code output. Switch reliability above the industry standard was made possible through the use of non-contact technology. Multi-Hall mechanizations have been used by others in recent years however this type of product has been simplified by using a single linear Hall device; reducing component count and the number of connector interfaces. Furthermore, a reduction in the number of electrical connections led to improved system reliability and cost. Optimization of this package was made possible through the use of a multi-tool, multi-objective, single field focus using advanced design optimization software, robust engineering techniques and Shainin® tools.

Dimethyl ether (DME) as a high cetane number fuel and liquefied petroleum gas (LPG) as a high octane number fuel were supplied together to evaluate the controllability of combustion phase and improvement of power and exhaust emission in homogeneous charge compression ignition (HCCI) engine. Each fuel was injected at the intake port and in the cylinder separately during the same cycle, i.e., DME in the cylinder and LPG at the intake port, or vice versa. Direct injection timing was varied from 200 to 340 crank angle degree (CAD) while port injection timing was fixed at 20 CAD. In general, the experimental results showed that DME direct injection with LPG port injection was the better way to increase the IMEP and reduce emissions. The direct injection timing of high cetane number fuel was important to control the auto-ignition timing because the auto-ignition was occurred at proper area, where the air and high cetane number fuel were well mixed.

This paper presents a model-based control system for SCR urea dosing employing an embedded real-time SCR chemistry model and a NH3 sensor. The control algorithm consists of a number of control features designed to enhance ammonia storage control and closed-loop compensation using the mid-brick NH3 sensor. An adaptive control algorithm is developed to demonstrate robustness of the feedback control system to compensate for catalyst aging, urea injection malfunction, or dosing fluid concentration variation. Simulation and engine dynamometer testing following ESC and FTP emission cycles are used to demonstrate the advantages of this control approach for meeting both NOx emission requirements and NH3 slip targets. Furthermore this paper demonstrates potential of a NH3 sensor for on-board diagnostics. Additionally the feasibility of implementing model based algorithms in a 32-bit floating-point environment with an automotive controller is examined.

The combustion and exhaust emission characteristics of a DME fueled HCCI engine were investigated. Different fuel injection strategies were tested under various injection quantities and timings with exhaust gas recirculation (EGR). The combustion phase in HCCI was changed by an in-cylinder direct injection and EGR, due to changes in the in-cylinder temperature and mixture homogeneity. The gross indicated mean effective pressure (IMEPgross) increased and the hydrocarbon (HC) and carbon monoxide (CO) emissions decreased as the equivalence ratio was augmented. The IMEPgross with direct injection was greater than with the port injection due to retarded ignition timing resulting from latent heat of direct injected DME fuel. It was because that most of burn duration was completed before top dead center owing to higher ignitability for DME with high cetane number. However, HC and CO emissions were similar for both injection locations.

This paper presents a monitoring, feedback and control system for SCR urea dosing utilizing an embedded model and NH3 sensing after the SCR for loop closing control. A one-dimensional SCR model was developed and embedded in a Simulink/Matlab environment. This embedded model is utilized for on-line, real time control of 32.5% aqueous urea dosing in the exhaust stream. Engine testing and simulation are used with the embedded SCR model and NH3 sensor closed loop feedback to demonstrate the advantages of this control approach for meeting both NOx emission requirements and NH3 slip targets. The paper explores these advantages under heavy duty FTP cycle conditions. The potential benefits include SCR size optimization and fuel consumption rate reduction under certain operating conditions.

To confirm the correct operation and detect the potential errors in the ever more complicated automotive ECU application software are very challenging. This paper presents a new approach to detect potential ECU application software abnormal behavior based on the Mahalanobis Distance, the Mahalanobis-Taguchi System, and vehicle driving data playback capability with a simulator. Vehicle driving data is recorded by instrumentation calibration tools and played back on the test bench to stimulate the ECU. In our study, the normal behavior is characterized by the Mahalanobis Distance (MD), which is calculated from the data set logged while playing back the recorded vehicle maneuvers while the ECU is flashed with “baseline software” that was believed to be error free. Then the MDs were calculated from a new data set logged while playing back the same vehicle maneuvers while the ECU was flashed with the new software.

The combustion, knock characteristics and exhaust emissions in an engine were investigated under homogeneous charge compression ignition operation fueled with liquefied petroleum gas with regard to variable valve timing and the addition of di-methyl ether. Liquefied petroleum gas was injected at an intake port as the main fuel in a liquid phase using a liquefied injection system, while a small amount of di-methyl ether was also injected directly into the cylinder during the intake stroke as an ignition promoter. Different intake valve timings and fuel injection amount were tested in order to identify their effects on exhaust emissions, combustion and knock characteristics. The optimal intake valve open timing for the maximum indicated mean effective pressure was retarded as the λTOTAL was decreased. The start of combustion was affected by the intake valve open timing and the mixture strength (λTOTAL) due to the volumetric efficiency and latent heat of vaporization.

The spray characteristics of a swirl injector for direct-injection spark-ignition (DISI) engines were investigated for the generation of robust and well-atomized swirl spray. A highly-inclined tapered nozzle is applied as a test nozzle and the spray characteristics are compared with conventional nozzle and L-step nozzle. When the taper angle is 70°, an opened hollow cone spray is formed. This spray does not collapse with increasing fuel temperature and back pressure conditions. However, the taper angle should be optimized to avoid forming a locally rich area and to increase the spray volume. The droplet size of 70° tapered nozzle spray shows a value similar to that of the original swirl spray in the horizontal mainstream while it shows an increased value in the vertical mainstream. The deteriorated atomization characteristics of the tapered nozzle spray are improved by applying high fuel temperature injection without causing spray collapse.

Engine-out CO emission and fuel conversion efficiency were measured in a highly-dilute, low-temperature diesel combustion regime over a swirl ratio range of 1.44-7.12 and a wide range of injection timing. At fixed injection timing, an optimal swirl ratio for minimum CO emission and fuel consumption was found. At fixed swirl ratio, CO emission and fuel consumption generally decreased as injection timing was advanced. Moreover, a sudden decrease in CO emission was observed at early injection timings. Multi-dimensional numerical simulations, pressure-based measurements of ignition delay and apparent heat release, estimates of peak flame temperature, imaging of natural combustion luminosity and spray/wall interactions, and Laser Doppler Velocimeter (LDV) measurements of in-cylinder turbulence levels are employed to clarify the sources of the observed behavior.