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Ternary blends of butanol-biodiesel-diesel with different blending ratios were tested inside a constant volume chamber under various ambient temperatures so as to investigate the spray and combustion characteristics of the fuels. Applying the high speed imaging, a sudden drop in spray penetration was observed at ambient temperature of 800 K and 900 K for fuels with certain blending ratio, but not at 1000 K and 1200 K. When the spray penetration of the butanol-biodiesel-diesel blends was compared to that of the biodiesel-diesel blends under non-combusting environment, a sudden drop in spray penetration length was also observed at 1100 K. The results indicated that for the non-combusting case, the tip of the spray jet erupted into a plume sometime after injection for the butanol-biodiesel-diesel blend at an ambient temperature of 1100 K. Such phenomenon was not seen with the biodiesel-diesel blend, neither with the same fuel but at a lower ambient temperature of 900 K.

Excessive wind noise is one of the most complained problems by owners of new vehicles as evidenced by JD Power Initial Quality Study (IQS) in recent years. After the vehicle speed surpasses 100 km/h, wind noise is gradually becoming the dominant noise source. In an effort to reduce aeroacoustic noise level, Beamforming (BF) is a very effective noise source identification technique used during vehicle wind noise development phases. In this work, based on the planar BF methodology, a large semi-circle microphone array is designed in accordance with the desired resolution and dynamic range pertaining to actual noise source distribution on a typical passenger vehicle. Acoustic array calibration and mapping deformation correction are accomplished by multi-point source method, and the Doppler Effect due to wind is corrected by the location calibration method.

Artificial intelligence turns out an increasingly important role in autonomous driving system (ADS), especially for world model perceptions and ego vehicle trajectory planning in an ADS, contributing to the safety for the occupies and surrounding traffics. The performance of an ADS depends on the level of absence for functional insufficiency and performance limitation of the components and algorithms including AI in known and unknown scenarios. In this paper, we propose using System Theoretic Process Analysis, STPA, to characterize those known and unknown scenarios for SAE automation Levels 3 and 4. A key challenge of STPA is the identification of an appropriate dynamic control structure that is efficient for the purpose at hand. An ideal control structure should be able to include all causes of failure. What “all” really implies here is one of the central challenges.

Developed control algorithm for series hybrid electric power train is presented systematically, which keeps engine operation points on the locus of highest efficiency torque/speed points using a lookup table defined by engine power and speed. The off-line simulation model of series hybrid power train is developed which includes sub-models of control system and controlled objective (such as engine, motor, battery pack and so on). The debug and validation of control algorithm is performed on developed modular test facility. The results show that developed control algorithm can effectively keep engine operating on the locus of high efficiency points and much more fuel economy can be achieved than that of conventional ICE power train, meanwhile battery SOC can be maintained within reasonable level without charging outside during cycles.

Three thermo-wires with amplifying circuits have been developed to measure the time-resolved concentration of the exhaust gas recirculated into the intake manifold by a rotary valve-based exhaust gas recirculation (EGR) system of a diesel engine. Good agreement was found between the EGR rates measured by the temperature based system and a conventional CO2 tracing system. The developed EGR measuring system was used to investigate the EGR transient response in a turbo-charged and after-cooled diesel engine with a real-time measure and control system. The EGR response under EGR valve step change and engine transient operating conditions are discussed. At first, the engine was running under a certain steady condition with zero recirculated exhaust gas, then the rotary valve opened to maximum within 0.1s to demonstrate the EGR step change behavior. EGR rate and air intake stabilized in 0.5s.

In order to study and evaluate the effect of sulfated ash in different diesel engine lubricants on the performance and durability of diesel particulate filter (DPF), the two engine oils of API CI-4 and CJ-4 with different sulfated ash levels are used respectively in the durability tests of two DPF systems. Moreover, the pressure drop, ash loading and filtration efficiency of the two DPFs, deposits in the inlets and outlets of the DPFs, intake flow rate and fuel consumption rates of engine are measured and compared. The test results show that: Compared to the API CI-4 which has more ash in the formulation than the API CJ-4, the API CJ-4 shows a markedly excellent performance on the lower ash loading and longer service interval and life for DPF, as well as lower fuel consumption rate for the diesel engine with DPF.

This paper introduces the concept of separation of two-phase flow in condenser as a way to improve condenser efficiency. The benefits of vapor-liquid refrigerant separation and the reason why it will improve the condenser performance are explained. Numerical studies are presented on the effects of separation on performance of an R134a microchannel condenser, with the comparison to experiment data. Model predicts that at the same mass flow rate, the exit temperature is lower by 2.2 K in the separation condenser compared with that in the baseline. Up to 9% more flow rate of condensate is also predicted by the model in the separation condenser. Experiment results confirm the same trend. In addition, the reason why a certain circuiting of passes with pre-assumed separation results in the header improves the condenser is investigated by the model and results are presented.

This paper presents the results of an experimental study to determine the effect of vapor-liquid refrigerant separation in a microchannel condenser of a MAC system. R134a is used as the working fluid. A condenser with separation and a baseline condenser identical on the air side have been tested to evaluate the difference in the performance due to separation. Two categories of experiments have been conducted: the heat exchanger-level test and the system-level test. In the heat exchanger-level test it is found that the separation condenser condenses from 1.6% to 7.4% more mass flow than the baseline at the same inlet and outlet temperature (enthalpy); the separation condenser condenses the same mass flow to a lower temperature than the baseline condenser does. In the system-level test, COP is compared under the same superheat, subcooling and refrigerating capacity. Separation condenser shows up to 6.6% a higher COP than the baseline condenser.

A novel non-destroy repeatable-use impact theory based total cylinder sampling system has been established. This system is mainly composed of a knocking body and a sampling valve. The knocking body impacts the sampling valve with certain velocity resulting in huge force to open the sampling valve and most of the in-cylinder gas has been dumped to one sampling bag for after-treatment. The feasibility and sampling response characteristics of this impact theory based total cylinder sampling system were investigated by engine bench testing. Within 0 to 35°CA ATDC (Crank Angle After Top Dead Center) sample timing 50 percent to 80 percent of in-cylinder mass would be sampled, which was a little less compared with the traditional system. The half decay period of pressure drop was 10 to 20 degrees crank angle within 0 to 60°CA ATDC sample timing, which was about 2-3 times of the traditional system.

The incomplete combustion and misfire of diesel engine during starting result in unwanted white smoke. The histories of combustion and emission in different phases under different start conditions were studied in this paper. The optimization of the fuel injection control strategy under start conditions was performed. When the diesel engine is started under low temperature, the control strategy adapted to start the engine with a certain constant fuel mass injected per cycle, there may be misfire cycles in the initial period or in the transitional process, which is mainly caused by the mismatch between the fuel mass injected per cycle and the instantaneous engine speed. Therefore, an optimized control strategy was put forward, namely, the engine starts with high fuel mass injection in the first several cycles and then decreases step by step during the transitional period until it operates at idle condition. This strategy was validated to decrease significantly the misfire cycles.

In order to improve the vehicle economy of electric vehicles, this paper first analyzes the energy-saving mechanism of electric vehicles. Taking the energy consumption of the deceleration process as a starting point, this paper deeply analyzes the energy consumption of the deceleration process under several different control modes by the test data, so as to obtain two principles that should be followed in energy-saving control strategy. Then, an intelligent deceleration energy-saving control strategy by getting the forward vehicle information is developed. The overall architecture of the control strategy consists of three parts: information processing, target calculation and torque control. The first part is mainly to obtain the forward vehicle information from the perception systems, and the user's habits information from big data, and this information is processed for the next part.

Phase separation circuiting have been proved in the past to effectively improve the performance of mobile air conditioning (MAC) condensers. In the vertical second header of the condenser, liquid separates from vapor mainly due to gravity, leaving vapor-rich flow with higher heat transfer coefficient to go into the upper passes. The condenser effectiveness is improved in this way. However, separation is usually not perfect, expressed through the separation efficiency (ηl and ηv). This paper presents the numerical study of phase separation phenomena in the second header. The Euler-Euler method of Computational Fluid Dynamics (CFD) is used. Simulations are conducted for two-phase refrigerant R-134a for MAC application. Inlet mass flow rate is simulated at values of 16 g∙s-1, 20 g∙s-1, and 30 g∙s-1 for 21 inlet microchannel tubes, which is the same 1st-pass tube number as of a real separation condenser. Corresponding mass fluxes are 166 kg∙m-2∙s-1, 207 kg∙m-2∙s-1, and 311 kg∙m-2∙s-1.

When manufacturing the stators in EV motors, stator wires are first coated with a layer of resin to provide primary insulation. After winding, impregnating varnish fills all voids within the windings and between the windings and lamination. In addition to electrically insulating the copper wires, another function of the varnish fill is to mechanically secure the copper wires from movement. The process is not complicated in terms of physics. In essence, the mechanics of the varnish flow is the balance of inertia force, viscous force, gravity and surface tension. However, understanding the fluid dynamics of the varnish flow is critical to predicting the quality of the varnish fill, which has a tremendous impact on motor performance. With the advancement of computational fluid dynamics (CFD), the industry can benefit greatly if the varnish trickling process can be tuned, without physical tryouts, to achieve optimal fill.

In concept design and prototype development of hybrid power train with ISG (Integration of Starter and Generator) for transit bus one of the main concerns is to determine the appropriate parameters of power train components. Utilizing the developed off-line simulation model of hybrid power train with ISG the study on the influence of components' parameters on acceleration performance and fuel economy of transit bus is completed. Based on these the guideline strategies of parametric design of parallel hybrid power train for transit bus are brought forward in this paper. Given the condition of propulsion requirement the parametric design for this transit bus is performed targeting minimizing fuel consumption. It is conclusion that the appropriate components' parameters determined by means of parametric design can make hybrid transit bus with ISG achieve much better acceleration performance and much lower fuel equivalent consumption than that of baseline transit bus.

In concept design and prototype development of parallel hybrid power train for transit bus one of the main concerns is to determine the appropriate parameters of power train components. Utilizing the developed off-line simulation model of parallel hybrid power train the study on the influence of components' parameters on acceleration performance and fuel economy of transit bus is completed. Based on these the guideline strategies of parametric design of parallel hybrid power train for transit bus are brought forward in this paper. Given the condition of propulsion requirement the parametric design for this transit bus are performed targeting minimizing fuel consumption. It is conclusion that the appropriate components' parameters determined by means of parametric design can make parallel hybrid transit bus achieve much better acceleration performance and much lower fuel equivalent consumption than that of baseline transit bus.

Utilizing the developed off-line simulation model of series hybrid power train the study on the influence of components' parameters on acceleration performance and fuel economy of transit bus is completed. Based on these the guideline strategies of parametric design of series hybrid power train for transit bus are brought forward in this paper. Given the condition of propulsion requirement the parametric design for this transit bus are performed targeting minimizing fuel consumption. It is conclusion that the appropriate components' parameters determined by means of parametric design can make series hybrid transit bus achieve much better acceleration performance and much lower fuel equivalent consumption than that of baseline transit bus.

Utilizing the developed off-line simulation model of series power train for fuel cell transit bus, the study on the influence of components' parameters on acceleration performance and fuel economy of transit bus is completed. Based on these the guideline strategies of parametric design of series power train for fuel cell transit bus are brought forward in this paper. Given the condition of propulsion requirement the parametric design for this transit bus is performed targeting minimizing fuel consumption. It is conclusion that the appropriate components' parameters determined by means of parametric design can make fuel cell transit bus achieve much better acceleration performance and much lower fuel equivalent consumption than that of baseline transit bus.

This paper provides an analysis of how communication performance between vehicles using Dedicated Short-range Communication (DSRC) devices varies by antenna mounting, vehicle relative positions and orientations, and between receiving devices. DSRC is a wireless technology developed especially for vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communications. A frequency band near 5.9 GHz has been set aside in the US and other countries for exploring safety and other uses for road vehicles. DSRC devices installed onboard vehicles broadcast their location using global navigation space systems (GNSS), speed, heading, and other information. This can be used to study communication performance in many scenarios including: car-following situations, rear-end crash avoidance, oncoming traffic situations, left turn advisory, head-on crash avoidance and do-not-pass warnings.

This paper presents results of the visualization of the separation in the vertical header of the automotive condenser. A prototype of a heat exchanger was made that has inlet in the middle of the header, with 21 microchannel tubes as the first pass. In the second header liquid separates and leaves through 4 microchannel tubes beneath while mostly vapor leaves through 11 microchannel tubes on the top as another exit. That way the 2nd pass has liquid below first pass and vapor above it. R134a was used in the tests. Mass flow at the inlet to the header was in the range 8.4 - 30 g/s (mass flux of 54 kg/m2·s-193 kg/m2·s) and quality at the inlet to second header was varied over a range of 0.05 to 0.25, to see their impact on the separation of two-phase flow inside the transparent header. Visualization was performed to better understand and define the physical parameters that dominate the separation phenomena.

Classification of diagnosis knowledge for Common Rail System(CRS) was investigated in this paper. Main fault modes and judgement regulations of CRS were confirmed throng principle of expert system. A scan tool was designed to communicate with vehicle Electronic Control Unit(ECU), and data link between scanner and ECU was realized through K-line communication, moreover, diagnosis program was accomplished based on Key Word Protocol 2000(KWP2000). This study focused on methods to validate faults of CRS based on expert system. Method advanced was effective on fault diagnosis because expert system had capability of intellectual faculties. Finally, experiments were carried out on a six-cylinder diesel.