Different Rule-based Control Schemes for a Series Hydraulic Hybrid Vehicle

In a hybrid hydraulic vehicle, the hydraulic accumulator is used as the secondary power source in addition to the engine to propel the vehicle. Since the accumulator is a passive power source, it will be only used to compensate the difference between the power demand and the power delivery by the engine. Obviously, the main energy consumption is the engine. Hence a straightforward strategy to improve the fuel economy is to reduce the engine operating period. In contrast, because of the low energy density characteristic, the accumulator can only afford the required power in a short period. As a consequence, the hydraulic hybrid vehicle has been concluded only suitable for start-stop-and-go driving pattern. This paper present different rule-based control schemes for a 3.5- ton series hydraulic hybrid truck. The simulation results indicate that by applying suitable control scheme, the proposed series hydraulic hybrid system offers improvements of fuel economy for both urban and highway driving condition. The improvement is of 42.67% and 36.56% for urban and highway driving conditions, respectively in comparison with the corresponding conventional vehicle

Multilayer phosphor-in-glass packaging for the development in WLED color uniformity

When mentioning the remote phosphor structure, the most noticeable advantage is its higher luminous flux than any other structure’s. However, there are existing flaws in their color uniformity and color rendering index (CRI). Thus, the improvements in these two optic factors must be improved for the better usage of remote phosphor geometry in modern WLED devices. Many researchers have drawn their attention to this idea, and then it has become the primary objective for their studies. In this paper, we also try to accomplish the same result by adjusting the distances between the phosphor layers and through that enhance the optical properties of WLEDs. The mie-scattering theory is applied in our calculations to ensure the reliability and accuracy of experimental results. In our research, with distance d = 0.64 mm, the luminous flux grew 9.7% in comparison to the original value. At 0.84 mm, the distance d enhanced the color uniformity by two times. In the meantime, the CRI remained static during the course of experiment. With suitable application, these results can bring valuable contributions to the development of next WELDs generation

Using flat phosphor layer in dual-layer remote phosphor configuration to improve luminous efficacy

The phosphor layer shape and components distances are the subjects proposed to advance the quality of WLEDs in this article. The two distances, between phosphor layers (d1) and between the phosphor layer and the LED chip (d2) in Flat dual-remote phosphor (FDRP) and Concave dual-remote phosphor (CDRP) were examined by experiments to determine their impacts on WLEDs lighting performances. The results suggest that FDRP is a better option than CDRP for lighting performance. In each respective structure, the distances influence the lighting capacity and color output whenever they fluctuate. Therefore, to effectively control and study this phenomenon, the correlated color temperature is maintained at 8500 K, and the concentration of phosphor material is altered while the distances are changing. When d1 and d2 are at the starting value of 0, the recorded lumen output and chromatic performance of lighting devices are the lowest and begin to increase as d1 and d2 expand. Bigger d1 and d2 mean bigger scattering area and better chromatic light integration, which leads to higher color quality. Detailed results present that optimal values of d1 or d2 for the highest lumen output of 1020 lm are 0.08 mm or 0.63 mm, respectively. Meanwhile the lowest color deviation is accomplished with d1=0.64 mm or d2=1.35 mm

Using SiO2 nano-particles for better color uniformity and lumen output in 8500 K conformal and in-cup white LEDs

In the effort of improving the performance of white light LEDs devices (WLEDs), the SiO2 nano-particles were applied and have shown a significant impact on the optical properties. Specifically, the light output of the lighting devices is enhanced when a mixture of SiO2 particles and silicone gel is diffused on the encapsulation layer surface. This enhancement is the result of light scattering from SiO2 that strengthens the emitted blue light at further angles and reduces the color discrepancy. The evidence is that CCT deviation in SiO2-doped structure decline from 1000 K to 420 K in -70° to 70°. In addition, the SiO2 with refractive index in between the phosphor material and outside environment allows light to be emitted outward more effectively. This lighting enhancement of SiO2-doped structure increases the lumen output by 2.25% at 120 mA power source in comparison to structure without SiO2. These experimental outcomes suggest that SiO2 is an effective material to add in WLEDs structure for better lighting efficiency

Safety and efficacy of fluoxetine on functional outcome after acute stroke (AFFINITY): a randomised, double-blind, placebo-controlled trial

Background Trials of fluoxetine for recovery after stroke report conflicting results. The Assessment oF FluoxetINe In sTroke recoverY (AFFINITY) trial aimed to show if daily oral fluoxetine for 6 months after stroke improves functional outcome in an ethnically diverse population. Methods AFFINITY was a randomised, parallel-group, double-blind, placebo-controlled trial done in 43 hospital stroke units in Australia (n=29), New Zealand (four), and Vietnam (ten). Eligible patients were adults (aged ≥18 years) with a clinical diagnosis of acute stroke in the previous 2–15 days, brain imaging consistent with ischaemic or haemorrhagic stroke, and a persisting neurological deficit that produced a modified Rankin Scale (mRS) score of 1 or more. Patients were randomly assigned 1:1 via a web-based system using a minimisation algorithm to once daily, oral fluoxetine 20 mg capsules or matching placebo for 6 months. Patients, carers, investigators, and outcome assessors were masked to the treatment allocation. The primary outcome was functional status, measured by the mRS, at 6 months. The primary analysis was an ordinal logistic regression of the mRS at 6 months, adjusted for minimisation variables. Primary and safety analyses were done according to the patient's treatment allocation. The trial is registered with the Australian New Zealand Clinical Trials Registry, ACTRN12611000774921. Findings Between Jan 11, 2013, and June 30, 2019, 1280 patients were recruited in Australia (n=532), New Zealand (n=42), and Vietnam (n=706), of whom 642 were randomly assigned to fluoxetine and 638 were randomly assigned to placebo. Mean duration of trial treatment was 167 days (SD 48·1). At 6 months, mRS data were available in 624 (97%) patients in the fluoxetine group and 632 (99%) in the placebo group. The distribution of mRS categories was similar in the fluoxetine and placebo groups (adjusted common odds ratio 0·94, 95% CI 0·76–1·15; p=0·53). Compared with patients in the placebo group, patients in the fluoxetine group had more falls (20 [3%] vs seven [1%]; p=0·018), bone fractures (19 [3%] vs six [1%]; p=0·014), and epileptic seizures (ten [2%] vs two [<1%]; p=0·038) at 6 months. Interpretation Oral fluoxetine 20 mg daily for 6 months after acute stroke did not improve functional outcome and increased the risk of falls, bone fractures, and epileptic seizures. These results do not support the use of fluoxetine to improve functional outcome after stroke

A Model Predictive Control Approach for Fuel Economy Improvement of a Series Hydraulic Hybrid Vehicle

This study applied a model predictive control (MPC) framework to solve the cruising control problem of a series hydraulic hybrid vehicle (SHHV). The controller not only regulates vehicle velocity, but also engine torque, engine speed, and accumulator pressure to their corresponding reference values. At each time step, a quadratic programming problem is solved within a predictive horizon to obtain the optimal control inputs. The objective is to minimize the output error. This approach ensures that the components operate at high efficiency thereby improving the total efficiency of the system. The proposed SHHV control system was evaluated under urban and highway driving conditions. By handling constraints and input-output interactions, the MPC-based control system ensures that the system operates safely and efficiently. The fuel economy of the proposed control scheme shows a noticeable improvement in comparison with the PID-based system, in which three Proportional-Integral-Derivative (PID) controllers are used for cruising control

The Development of an Optimal Control Strategy for a Series Hydraulic Hybrid Vehicle

In this work, a Truck Class II series hydraulic hybrid model is established. Dynamic Programming (DP) methodology is applied to derive the optimal power-splitting factor for the hybrid system for preselected driving schedules. Implementable rules are derived by extracting the optimal trajectory features from a DP scheme. The system behaviors illustrate that the improved control strategy gives a highly effective operation region for the engine and high power density characteristics for the hydraulic components