In an Adaptive Cycle Engine (ACE), thermodynamics favors combustion starting while the compressed, premixed air and fuel are still flowing into the cylinder through the transfer valve. Since the flow velocity is typically high, and is predicted to reach sonic conditions by the time the transfer valve closes, the flame might be subjected to extensive stretch, thus leading to aerodynamic quenching. It is also unclear whether a single spark, or even a succession of sparks, will be sufficient to achieve complete combustion. Given that the first ACE prototype is still being built, this issue is addressed by numerical simulation using the G-equation model, which accounts for the effect of flame stretching, over a 3D domain representing a flat-piston ACE cylinder, both with inward- and outward-opening valves. RNG K-Epsilon turbulence model was used to approximate the highly turbulent flow field. It was found that the flame would suffer local blow-off under most operating conditions, but the blow-off is never complete so that the regions affected are later re-ignited by the remaining parts of the flame, and…

In a hydraulic system, parameter variation, contamination, and/or operating conditions can lead to instabilities in the pressure response. The resultant erratic pressure profile produces reduced performance that can lead to hardware damage. Specifically, in a transmission control system, the inability to track pressure commands can result in various types of slip and disturbances to the driveline. Therefore, it is advantageous to identify such pressure events and take remedial actions. The challenge is to detect the condition in the least amount of time while minimizing false alarms. In this study, cross and auto-correlation techniques are evaluated for the detection of pressure disturbances. The performance of the detectors is measured in terms of speed of detection and robustness to: 1) measurement noise, and 2) disturbance parameter uncertainty (frequency and amplitude). The implications in terms of computations and memory utilization of implementing the detectors in real-time embedded systems are also discussed. Both simulation and hardware examples are presented. The hardware experiment is performed in a hydraulic system with low damping composed of a solenoid and a regulator valve…

Thermal development of automotive applications is a lot more complex than it used to be in the past. Specifically, for Plug-in Hybrid Electric Vehicles (PHEVs), all the sub-systems are so intertwined that it’s hard to analyze them as sub-systems only. A system level solution is needed for proper sizing of components. For early thermal development, a co-simulation method can ensure that we take into account the inter-dependency of all the thermal features in the car. As for example a large PHEV battery may need to be passively cooled by refrigerant, which is in turns associated with the interior HVAC cooling system. For proper sizing of the condenser, chiller etc., one has to account for the battery cooling and cabin cooling as one system. There are also many thermal actuators on a PHEV, e.g. control valves, pulse-width-module (PWM) pumps, electric compressor, electric coolant heaters etc. Smart controls and calibration development early in the product development can impact sizing of front end cooling modules and other heat exchangers significantly. The design of hardware and software has to…

In this paper, based on the design of composite magnetic circuit, a new type of high-speed electromagnetic actuator (NHSEMA) with permanent magnetic was invented, which has the characteristics of low power consumption, strong electromagnetic force and high response. Those characteristics were systematically and deeply studied by means of theoretical analysis, numerical simulation and experiment. The magnetic network topology method was proposed to subdivide the structure of the NHSEMA, and construct the static characteristics simulation model of NHSEMA, with taking into account the magnetic flux leakage and edge flux of the system. The accuracy of simulation model of the NHSEMA was verified by set up the test platform. The error is about 3.1%, which proves that the model can achieve both calculation accuracy and speed. The static electromagnetic characteristics, energy conversion and magnetic flux distribution of NHSEMA were studied by using magnetic network topology simulation model. The research shows that compared with the traditional high-speed electromagnetic actuator (THSEMA), the electromagnetic force of NHSEMA is increased by about 30% under the same current driving. Meanwhile, the Joule…

The deformation of fuel injection system components cannot be disregarded as the pressure of the system increases. In particular, the control plunger and the needle of the solenoid injector tend to deform under high working pressure. Their deformation directly affects the volume of the control plunger chamber and the cross-section area of the fuel that enters the sac. A change in chamber volume influences the characteristics of needle movement, whereas a change in cross-section area influences needle movement and injection quantity. Consequently, the deformation of the injector bring difficulties to the precise control of the fuel injection system. In this study, a ADINA (a finite-element software) model of a BOSCH solenoid injector is established to calculate the structural deformation of the nozzle, the needle and the control plunger under different pressures. The accuracy of the model is validated using experimental data published in prior studies. The validated model is used to calculate the structural deformations of the injector components when the solenoid valve is non-energized and energized. Corresponding results indicate that the maximum deformation location…

This IC engine amelioration tackles the hurdling barrier of ICE’s intrinsic efficacy limit through innovative mechanical design of a consolidated system encompassing intake bypass and coordinating injection mechanism. To be specific, a CFD-optimized passage is constructed alongside the intake and injection design which utilizes multi-stage variable mixing precisely, taking full advantage of exhaust temperature elevation. Regenerative heat gained through exhaust system gives rise to flexible amount of thermal dynamics adjustment to the intake. Furthermore, variable geometry intake port is developed based on maximizing air-fuel interaction rate under different circumstances, where high temperature turbulence optimization is implemented in ANSYS Fluent. Pin-slider mechanic design at intake interface enables modular variable intake routing supporting engine efficiency promotion. Regarding ECU development, integrated valve, intake airflow, as well as injection control are designed to cooperate with each other under the supervisory control module. First, optimal controlled valve system is devised at the junction of bypass, which achieves improved response accuracy and combustion sufficiency with flow and temperature regulation. Secondly, a closed-loop injection control strategy fulfills variable in-cylinder combustion tuning with…

Roll forming assemblies are generally neat and robust, but there are structural integrity risks involved too if the forming procedures and design features do not complement each other. Specifically, in solenoid valves, an imprecised roller crimping (or forming) adversely affect the desired magnetic performance of the valves. Furthermore, in-depth evaluations of the formed shape using hardware and lab testing are extremely challenging cost wise and time consuming as well. However, utilizing simulation technique such as finite element analysis (FEA) to understand the in-sights of roller formed assemblies of a solenoid valve (or other products) could be an effective way to minimize overall cost and time involved in the product development. Therefore, a three-dimensional non-linear FEA model of roller crimping simulation was established in ANSYS Workbench Mechanical, and the predicted results were correlated with real hardware data to prove the technique & process adopted. Then the design was improved computationally to eliminate the magnetic Core's flux-bridge distortion issue of a solenoid valve, and finally the design was validated through hardware testing.

In this study, a 500-hour test cycle was used to evaluate the durability of a prototype high pressure common rail injection system operating up to 1800 bar with E10 gasoline. Some aspects of the hardware were modified from their baseline design in order to accommodate an opposed-piston, two-stroke engine application and mitigate the impacts of exposure to gasoline. Overall system performance was maintained throughout testing as fueling rate and rail pressure targets were continuously achieved. Although evidence of vapor formation in the low-pressure part of the system was observed, there was no significant physical damage to the associated components. Injectors showed no deviation in their flow characteristics after exposure to gasoline and high resolution imaging of the nozzle tips and pilot valve assemblies did not indicate the presence of cavitation damage. The high pressure pump did not exhibit any performance degradation during gasoline testing and teardown analysis after 500 hours showed no evidence of cavitation erosion. Despite the lack of lubricity-improving additives in the gasoline, all other fuel-wetted components survived the test cycle without any…

Investigation into fuel system warranty has led to the need to develop cost effective, robust materials that are resistant to both fuel and aggressive cleaners. Acetal (POM) is the current material that is used universally by OEM’s throughout the fuel system for its excellent performance in fuel and relatively low cost, but lacks resistance to strong acidic solutions. Acid containing wheel cleaning solutions are increasingly being used by customers to clean their aluminum and magnesium wheels. Due to the proximity of the fuel modules to the wheel openings, acidic wheel cleaners chemically attack the POM resulting in cracks. FCA worked closely with suppliers in recent years to develop cost effective, acid resistant POM materials that can withstand the stress-cracking at severe acid concentrations and meet FCA’s functional requirements. Other material alternatives that were considered outside of the acetal family provided adequate resistance but had other design and functional issues that would drive up cost. Our study included three unique vehicle flange designs molded in both types of POM and subjected to an extensive acid exposure…

Exhaust systems traditionally require a given amount of muffler volume to reduce sound levels appropriately. However, as hybridization continues, package space is limited, reducing available muffler space, requiring alternative solutions to attenuate exhaust sound with less volume. Passive exhaust valvesare a key solution, leveraging the physics of the exhaust (flow, temperature, and pressure) to cycle the valve. Passive exhaust valves are typically closed under low flow conditions (low engine speeds and loads), which helps reduce low-frequency boom, moderately increasing backpressure when it is not detrimental to engine efficiency. Conversely, under higher engine speed and load operating conditions, as when power is on demand, exhaust flow increases, and backpressure is critical to achieve desired power output, thus the passive valve opens to reduce its impact. And, such valves are often positioned within the muffler, fully immersed and exposed to exhaust heat, humidity, and corrosion, as well as the vibrations from road and engine loads. A next-generation passive valve is detailed in this paper, describing the engineering development to evolve the design, as well as the operating…