Torque Allocation of Hybrid Electric Trucks for Drivability and Transient Emissions Reduction

This paper aims at investigating powertrain behaviour, especially in transient dynamic responses, using a nonlinear truck vehicle dynamic model with a parallel hybrid configuration. A power split control was designed to achieve the desired drivability performance, with a focus on NOx emissions. The controller was characterized by high-level model-based logic used to elaborate the total powertrain torque required, and a low-level allocation strategy for splitting power between the engine and the electric motor. The final task was to enhance vehicle drivability based on driver requests, with the goal of reducing-in a hybrid configuration-transient diesel engine emissions when compared to a conventional pure thermal engine powertrain. Different parameters were investigated for the assessment of powertrain performance, in terms of external input disturbance rejection and NOx emissions reduction. The investigation of torque allocation performance was limited to the simulation of a Tip-in manoeuvre, which showed a satisfying trade-off between vehicle drivability and transient emissions

Analysis of an Integrated Agro-waste Gasification and 120 kW SOFC CHP System: Modeling and Experimental Investigation

Abstract Renewable sources of hydrogen are of major interest in the context of energy production through fuel cells. The technical feasibility of CHP system composed by orange peels steam/air gasification unit coupled with a solid oxide fuel cell (SOFC) was investigated in this study. To this purpose, a zero-dimensional process simulation model of the CHP system using Aspen Plus was developed. Mathematical model was experimentally validated in a lab scale apparatus. Moreover, optimal operative conditions and integration options were investigated, as well as the system maximum theoretical overall efficiency. Results showed that in order to obtain 120 kW of DC power from the specific SOFC, 65 kg/h of biomass with 20% of moisture and 173 kg/h of raw biomass with 70% of water needed to be fed in the CHP system. It was theoretically proved that 120 kW of DC power and 135 kW of heat could be produced from SOFC unit at the selected operative conditions, with a net CHP maximum efficiency equal to 74%

Passenger car active braking system: Pressure control design and experimental results (part II)

This paper deals with the design of a brake caliper pressure controller for a conventional anti-lock braking system/electronic stability control system and the experimental validation of its tracking performances. The analysis of the hydraulic plant, carried out in part I of this two-part study, is here utilized to develop the control algorithm. The control strategy is based on a feed-forward and a proportional integral controller through pulse width modulation with a constant frequency and variable duty cycle. The feed-forward contribution requires modeling of the nonlinear openloop system behavior which has been experimentally identified and described through two-dimensional maps: the inputs are the duty cycle applied to the electrovalves and the pressure drop across their orifice, while the output is the pressure gradient in the brake caliper. These maps, obtained for inlet and outlet valves, are used to set the feed-forward term. Finally a proportional integral controller is designed to reject external disturbances and compensate for model uncertainties. A brake system test rig, described in part I, is used for building inverse maps and validating the proposed control logic. Different reference pressure profiles are used to experimentally verify the control tracking performances

Test Bench Characterisation and Frequency Domain Torsional Model Validation of Transmission Systems and Components

The article presents an experimental methodology used to characterize the torsional dynamic behaviour of automotive transmission systems and components and the analytical methods for simulating them in the frequency domain. A general description of the test bench is given in the paper: it is composed of an induction motor for the torsional excitation of the system and of torque and angular position sensors. The tests were carried out by keeping one end of the transmission locked. Two case study are discussed: a Dual Mass Flywheel (DMF) and a complete Automated Manual Transmission (AMT). In the first example the experimental data from sine sweep tests are used to estimate the damping factor of the DMF. In the second case the dependency of the frequency response function (FRF) on the engaged gear ratio for a 5-speed AMT is investigated. A torsional model for each test rig configuration is proposed and the corresponding equations of motion derived. The compliance FRFs of the torsional systems are then numerically evaluated and compared with the results from the experiments. A good match between simulated and measured data is shown

Passenger Car Active Braking System: Model and experimental validation (Part I)

This paper introduces a method to characterize the dynamic behavior of a normal production hydraulic brake system through experiments on a hardware-in-the-loop test bench for both modeling (part I) and control (part II) tasks. The activity is relative to the analysis, modeling, and control of anti-lock braking system and electronic stability control digital valves, and is aimed at obtaining reference tracking and disturbance-rejection performance similar to that achievable when using pressure proportional valves. The first part of this two-part study is focused on the development of a mathematical model that emulates the pressure dynamics inside a brake caliper when the inlet valve, outlet valve, and motor pump are controlled by digital or pulse width modulated signals. The model takes into account some inherent nonlinearities of these systems, e.g. the variation of fluid bulk modulus with pressure, while inlet and outlet valves together with the relay box are modeled as second-order systems with variable gains. The hardware-in-the-loop test rig is used for both parameter estimation and model validation; the parameters and model will be used for the control strategy development presented in the second part of this study

Effects of low-grade gas composition on the energy/exergy performance of a polygeneration system (CH2HP) based on biomass gasification and ICE

Bio-hydrogen from sustainable biomass (i.e. agro-industrial residues) gasification can play a relevant role in the hydrogen economy, providing constant hydrogen from renewable sources. Nowadays, most hydrogen production systems integrate one or more water-gas shift (WGS) units to maximize the hydrogen yield that, however, needs additional syngas treatments, investment and operational costs. Besides, different electricity inputs are needed along the process to power the compression of raw syngas, shifted syngas, and pure hydrogen to the desired pressure. This common process integration with WGS generates a kind of off-gas from the hydrogen separation unit whose composition may or may not be suitable for power production, depending on the operating conditions of the gasification unit. In this regard, this work proposes a different approach in which no WGS reactors are involved and the off-gas is used to generate heat and power to provide the energy input needed by the system. In particular, the authors tested the bio-syngas and the corresponding off-gas in a 4-cylinders, spark ignition natural gas internal combustion engine operated in cogeneration mode with the aim to analyse the effect of removing the hydrogen from the original bio-syngas on mechanical/electric and thermal power, on fuel efficiency and CO2 specific emission

A Simulation Tool to Evaluate the Feasibility of a gasification-I.C.E. System to Produce Heat and Power for Industrial Applications☆

Abstract Combined heat and power (CHP) systems fed by renewable sources are of great interest for efficient and greener energy production in industrial applications. In order to reduce fossil fuel consumption, biomass gasification coupled with I.C.E. is a viable way for ensure constant and accurately predictable renewable energy production. The aim of this work is to evaluate the integration in an industrial context of a CHP system fed by syngas produced from woody biomass gasification in a downdraft reactor. The feasibility study was developed thorough the combination of two simulation programs. Aspen Plus was used for simulating the biomass gasification unit and was exploited in order to determine the syngas composition and flow rate. Results have been employed in TRNSYS, that has instead been chosen for the modeling of the complete CHP system

performance analysis of biofuel fed gas turbine

Abstract The present paper deals with the study of the performance of a heavy-duty gas turbine running on biofuels. In particular, synthesis gas from glycerol steam reforming was used to feed the combustion turbine. Engine performances were compared with methane fed ones. Therefore, a mathematical model of the gas turbine was implemented using GateCycle software. Model calibration was made using gas turbine on-design parameters, while performance test results were compared with experimental running data. The resulting analysis highlighted that the mathematical model is able to correctly simulate engine behaviour in different combustion turbine running conditions thus validating the mathematical model. The combustion turbine studied was integrated with a syngas generator plant and overall efficiency was evaluated. The analysis of the results confirms that using biofuels a reduction in engine performance occurs. On the contrary, integrating the gas turbine and syngas generator plant an overall efficiency increase was registered

Steam gasification of waste tyre: Influence of process temperature on yield and product composition

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on the wind turbine wake mathematical modelling

Abstract The present paper deals with a study on the wind turbine wake mathematical modelling as well as experimental validation by means of wind tunnel experiments. In particular, different wind turbine wake's equations were implemented and results compared with experimental data. Therefore, an experimental setup was implemented in the wind tunnel test section with a small-scale wind turbine, while velocity deficit was measured. A design of experiment based on three parameters variation was defined: wind velocity, turbine rotational speed and distance from the wind turbine rotor. In the same experimental conditions simulations were carried out by means of three 1D equations. In particular, Jensen, Larsen and Frandsen equations were studied. Comparing theoretical and experimental results, it is evident that Larsen mathematical model is in good agreement with experimental data, while Jensen and Frandsen mathematical models are able to identify only mean and peak velocity deficit, respectively