Engine Start-up Research Articles

Study on Activation System of Thermostatic Preheating Engine

Innovatively addressing the challenge of difficult winter starts for vehicles in northern regions, this study has developed a Thermally Controlled Preheating Engine Activation System. This system ingeniously integrates a thermal insulation kettle, an efficient water pump, precision valves, and temperature sensors, all closely linked with the engine’s coolant circulation system. In cold environments, the system automatically initiates a preheating mechanism by circulating and heating the coolant, significantly enhancing engine startup efficiency and reducing wear caused by cold starts. The anticipated outcome of this research is to substantially improve the operational reliability of vehicles in cold climates, extend their lifespan, promote energy conservation and emissions reduction, and drive the automotive industry towards greener, more efficient, and intelligent technologies, thus laying a solid foundation for industry upgrades and transformation.

A switched model predictive control with parametric weights-based mode transition strategy for a novel parallel hybrid electric vehicle

In a novel parallel hybrid electric vehicle (HEV) configuration, the transition from pure electric mode to hybrid mode encompasses critical operations such as engine startup, coordinated control of motor and engine torque, and engagement of the clutch. Addressing the intricate challenges associated with enhancing speed tracking performance during and after mode transition, mitigating jerk during mode transition, and minimizing mode transition time, this paper conducts a meticulous analysis of the vehicle configuration and mode transition process. The mode transition process is systematically delineated into four stages, with each stage characterized by the establishment of dynamic models. Subsequently, a mode transition strategy is proposed, leveraging switched model predictive control with parametric weights (SMPC-PW). This controller framework includes the design of two model predictive controllers (MPC) tailored for two pivotal stages, the formulation of a parametric weights pattern based on pre-transition acceleration, and the development of a stage switching strategy to ensure seamless switches between controllers. The efficacy of the proposed strategy is validated through co-simulations in the Simulink and GT-Power environment. The fine-tuning of MPC parameters is grounded in multiple sets of prediction horizons and sampling time simulation results. In comparison to strategies based on MPC and PID under various acceleration scenarios, the SMPC-PW strategy consistently maintains acceleration control below 10 m/s3. It not only achieves superior speed tracking during and after mode transition but also reduces mode switch time by 0.1 s-0.3 s. These compelling results unequivocally demonstrate that the proposed mode transition strategy significantly elevates the quality of mode transition for this specific parallel HEV configuration.

Addressing the challenge of ammonia slip and nitrous oxide emissions from zero-carbon fuelled engines through catalytic aftertreatment solutions

Addressing climate change demands, energy security and resilience has necessitated replacing conventional fossil-based fuels with zero and carbon-neutral fuels/energy carriers. The most immediate solution is the partial and progressive substitution of conventional fuels in transportation. The effects of partially substituting gasoline with ammonia/hydrogen (NH3/H2) mixtures in a spark ignition (SI) engine are investigated in this paper. The utilization of NH3/H2 mixtures is a promising avenue of research since they can be produced from on-board NH3 reforming, utilising heat energy that is recovered from hot exhaust gases. Experimental results indicate that adding NH3/H2 enabled stable engine operation at lean conditions (λ = 1.4), resulting in reduced carbon-based emissions due to the non-carbon nature of NH3/H2. Utilising an integrated approach that combined a hemispherical flame geometry model with a thermodynamic model, has revealed that the introduction of NH3/H2 significantly enhanced the combustion speed during the initial phase and further improved combustion efficiency. However, nitrogen-based emissions such as NO and NO2 increased. This work also assessed the performance of a conventional three-way catalyst (TWC) and a double-function ammonia slip catalyst (ASC) in mitigating emissions. The TWC effectively controlled carbon-based emissions and NO under stoichiometric conditions but exhibited reduced efficiency under lean conditions, especially with NH3 present. The ASC demonstrated high NH3 conversion efficiency even at low temperatures, making it suitable for engine start-up and warm-up phases. Under steady-state conditions with artificially increased NH3/NOX ratios, a significant reduction in NOx emission was achieved with the ASC. However, high NH3/NOX ratios increased nitrous oxide (N2O) formation and NH3 slip.

Non-repeatability of the WLTP vehicle test results

The paper presents results of considerations on the repeatability of the passenger car test results obtained in the WLTP procedure on a chassis dynamometer. The research concerned the aspects of exhaust emissions and fuel consumption. Measurements were carried out in the WLTC test with a cold engine start and then in four WLTC (Worldwide harmonized Light vehicles Test Cycle) tests with a hot engine start. The following values were measured: average specific distance emissions of hydrocarbons, non-methane hydrocarbons, carbon monoxide, nitrogen oxides, particulate matter and carbon dioxide, specific distance particulate number, and operational fuel consumption. Thus, it was possible to assess the impact of the engine's thermal state at start-up on the test results and the nature of test results repeatability with the start-up of a hot engine. The repeatability of the test results was assessed based on the coefficient of variation obtained in the individual tests and the relationship of the maximum difference between measurement results values in the individual tests for a hot engine start. The obtained test results turned out to be very diverse for the considered parameters and indicated low repeatability. Values of carbon dioxide emissions and operational fuel consumption were definitely the least varied in individual hot engine start tests. The exhaust emission of particulate matter varied the most in individual test iterations. However, the specific distance particulate number was relatively similar between individual tests, less so than the exhaust emission of other pollutants. In the case of different engine thermal state at start-up, the emitted particulate number varied the most in the test results, while the emission of carbon dioxide and operational fuel consumption varied the least. The repeatability of executing the velocity process in WLTC tests at hot engine and cold engine start-up was also examined as processes determining exhaust emissions and fuel consumption. These tests were much more repeatable than the exhaust emission and fuel consumption.

Analysis of unstable combustion caused by the Gas–Liquid two-phase flow in small hypergolic propellant engines

Hypergolic bipropellant engines are extensively used in spacecraft operations. In these engines, the combustion reaction is initiated by the impinging jets of the oxidizer and fuel in the liquid phase. The most commonly used hypergolic fuels, hydrazine and monomethylhydrazine, as well as the oxidizer, nitrogen tetroxide, are all in liquid state under room temperature and atmospheric pressure conditions. However, as these engines are operated in a space vacuum, a portion of the propellant inevitably evaporates because of low-pressure boiling immediately after engine start-up. The mixing of gas with liquid propellant results in unstable combustion, and minimizing this effect is critical for the engine design. Particularly, preventing high-frequency combustion instability is essential as it can be detrimental to the engine. This paper presents a mechanism that activates high-frequency combustion instability, realized by analyzing the pressure within the combustion chamber during artificially induced unstable combustion. Furthermore, the methodology for establishing operational constraints based on the proposed mechanism is clarified, along with the method for collecting test data. The study findings provide important indicators for the design criteria of bipropellant engines, contributing to the diversification and complexity of space development programs.

A new real-time optimal energy management strategy for range extended electric vehicles considering battery degradation and engine start-up

Range extended electric vehicles (REEVs) offer a solution to the limited range of pure electric vehicles by incorporating an additional energy source. Effectively managing the output power among these energy sources is the key to reduce operating cost. To enhance the economy of REEVs, this paper proposes a multi-objective optimal energy management strategy (MOEMS) that considers battery degradation. The powertrain of the REEV is comprehensively modeled by integrating the efficiency of the range extender, battery, and driving motor. MOEMS is designed to instantaneously minimize the total operating cost of the vehicle, including factors such as fuel consumption, electricity consumption, and battery degradation. To minimize the frequency of engine starts and stops, the cost associated with engine startup is integrated into the objective function. Two control coefficients are introduced into the objective function to regulate the battery state of charge. Additionally, another coefficient is employed to restrict variations of engine output power, thereby avoiding significant fluctuations of engine load. Simulation results show that compared to the adaptive equivalent consumption minimization strategy (AECMS) and rule-based energy management strategy (REMS), the total cost of MOEMS is reduced by 9.1% and 32.3% in WLTC driving cycles, and by 7.9% and 31.7% in CLTC driving cycles.

Design and Research of a Certain Type of Automatic Alarm Equipment

Rapid detection of oxygen leaks in pipelines is crucial to prevent catastrophic accidents. This paper presents the design of an oxygen leakage detection and alarm instrument that converts ultrasonic signals, generated by gas escaping through small holes, into audible frequencies for headset use. This instrument is particularly suitable for ensuring the airtightness of oxygen supply systems for flight crews, engine startup supplemental oxygen systems, and four-station oxygen supply equipment. The design integrates ultrasonic principles, signal processing, computer control, and anti-jamming technologies to detect even minor leaks from a distance. The modular design includes components such as ultrasonic sensors, preamplifiers, filtering circuits, and microcontrollers, ensuring high detection sensitivity and reliability. The alarm system features light and sound alerts, enhancing maintenance efficiency and safety. This modern precision testing instrument significantly improves upon traditional leak detection methods like soapy water tests.

Jerusalem Artichoke as a Raw Material for Manufacturing Alternative Fuels for Gasoline Internal Combustion Engines

The Jerusalem artichoke (Helianthus tuberosus) is a high-yield crop, and a great source of fermentable sugars, which gives the plant the potential to be used as raw material for economical fuel alcohol production. In this article, the authors focus on the technological aspect of the biofuel manufacturing process and its properties. First, the fuel alcohol manufacturing process is described, afterwards assessing its characteristics such as kinematic viscosity, density and octane number. The amount of fuel alcohol obtained from 10 kg of biomass equals to 0.85 L. Afterwards, the mixtures of gasoline and obtained fuel alcohol are prepared and studied. Optimal alcohol and gasoline mixtures are determined to obtain biofuels with octane ratings of 92, 95 and 98. The kinematic viscosity of obtained mixtures does not differ significantly from its values for pure gasoline. The obtained biofuel mixture with 25% alcohol content yielded a decrease of sulfur content by 38%, an increase of vaporized fuel amount by 17.5% at 70 °C and by 10.5% at a temperature of 100 °C, which improves engine startup time and ensures its stable operation in comparison to pure gasoline. The alcohol obtained can be successfully used as a high-octane additive for gasolines.

Experimental study on the coupled flow field and thrust characteristics of tail cavity and jet

During the launch process of underwater vehicles, a tail cavity is formed at the bottom, which plays a crucial role in the engine ignition stage. The flow state within this tail cavity significantly impacts the engine's operational efficiency. Moreover, the evolution of the tail cavity and jet coupling, along with hydrodynamic characteristics, influences the motion attitude of the vehicle. This article delves into the effects of initial tail cavity length, Froude number, and pressure ratio on cavity morphology and hydrodynamic characteristics, utilizing water tunnel experiments to explore these dynamics at the vehicle's bottom. The experimental findings suggest that while the length of the initial tail cavity influences the jet's coupling mode, it does not significantly affect the cavity's ultimate morphological evolution. A larger initial cavity scale correlates with a lower initial pressure peak following nozzle activation; similarly, an increase in the Froude number leads to a decrease in the initial pressure peak. When the cavity morphology remains intact, the pressure pulsation amplitude and frequency are relatively low. In contrast, partially broken cavities and pulsating foam cavities differ in morphological structure and peak internal pressure oscillations, though their pressure pulsation frequencies are similar. During the initial phase of nozzle activation, the thrust produced by the nozzle plays a more significant role than the bottom thrust. Notably, in the initial phase of nozzle activation, the nozzle-generated thrust is more influential than the bottom thrust. The thrust pulsations from pulsating foam cavities are especially strong, with peak values surpassing the initial peak thrust. These insights offer a new insight on the dynamic behavior of underwater vehicles, crucial for refining engine startup strategies.

The Effect of Ethanol Fuel-Diluted Lubricants on the Friction of Oil Control Ring Conjunction: A Combined Analytical and Experimental Investigation

This paper presents an investigation of the frictional behaviour of three-piece piston oil control rings. A bespoke tribometer replicates the kinematics of the contact between a full oil control ring and the cylinder liner. The three-piece oil control ring is composed of two segments, separated by a waveform-type expander. The experimental results indicate the dominance of a mixed regime of lubrication throughout the stroke. This is particularly the case when the experiments are conducted at 80 °C, a typical engine sump temperature, when compared with those at 20 °C (a typical engine start-up temperature in the UK in the summer). A mixed hydrodynamic analytical model of the oil control ring–cylinder liner tribological interface is employed to apportion frictional contributions with their physical underlying mechanisms. Therefore, combined numerical and experimental investigations are extended to lubricant contamination/dilution by ethanol-based fuels. This study shows that the transition from E10 to E85 would have an insignificant effect on the friction generated in the oil control ring conjunction. This holistic approach, using a detailed predictive l mixed regime of lubrication model and a representative bespoke tribometry, has not hitherto been reported in the open literature.

КОМП'ЮТЕРНЕ МОДЕЛЮВАННЯ НЕСТАЦІОНАРНОГО ПРОЦЕСУ РОЗВИТКУ НАДЗВУКОВОГО ПЕРЕРОЗШИРЕНОГО СТРУМЕНЮ

Questions of numerical simulation of non-stationary process of the development of a supersonic overexpanded jet are considered. Unsteady Reynolds-averaged Navier-Stokes equations (URANS) of compressible flows, written in an arbitrary coordinate system, along with the Spalart-Allmaras one-equation differential turbulence model are applied. The calculations of non-stationary formation of an air cold supersonic jet during the blowing through a conical Laval nozzle (simulation of engine start-up) were made. The physical features of the shock and acoustic waves generation and propagation are discussed. In the stationary phase an overexpanded free supersonic turbulent jet is formed, which includes a Mach disc in its structure. The obtained results were compared with experimental data and calculations by other authors based on the ANSYS Fluent and FloEFD CFD tools.

Electromechanical and mechanical starter characteristics in the car engine start mode

When designing electric starter start systems for new automotive engines, it is necessary to coordinate the characteristics of the battery, starter and starting engine in order to determine the point of their joint operation under specified conditions. The starter is a converter of electrical energy into mechanical energy, that is, a matching link between the battery and the engine with its characteristic electromechanical and mechanical characteristics. This article discusses the issues of obtaining these characteristics for the conditions of low-temperature start-up of automobile engines. Keywords discharge current, voltage, resistance and volt-ampere characteristic of the battery, torque and frequency of rotation of the anchor, power and efficiency of the starter, electromechanical and mechanical characteristics of the starter

IM-TD3: A Reinforcement Learning Approach for Liquid Rocket Engine Start-Up Optimization

IM-TD3: A Reinforcement Learning Approach for Liquid Rocket Engine Start-Up Optimization

An assessment of the application of catalyst preheating prior to engine cold start to improve the filtration performance of CDPF on particulate emissions

The catalytic diesel particulate filter (CDPF) is an effective technology for reducing particle emissions. However, during engine startup, especially in cold start conditions, notable particle emissions are observed at the CDPF outlet. These emissions are attributed to combustion deterioration during startup and the low temperature of the aftertreatment catalyst. Addressing this challenge, this study investigated the effectiveness of rapidly preheating the diesel oxidation catalyst (DOC) and CDPF substrate temperatures before engine start to enhance particle removal during cold starts. Experimental results indicated that CDPF filtration efficiency during cold start was lower compared to hot start conditions, with a clean CDPF exhibiting very low efficiency due to minimal particle deposition. Substrate temperature preheating of either the DOC or CDPF was found to improve CDPF filtration efficiency for particles during cold start, albeit with a concurrent increase in emissions of particles smaller than 50 nm. Notably, a combination of a 250 °C DOC with a 22 °C CDPF yielded the most significant reduction in particle emissions, particularly for particles under 50 nm. Given that the DOC shares the same material composition as the CDPF but has a smaller volume that requires less energy for heating, preheating the DOC emerges as a more energy-efficient strategy. These findings underscore the need for more comprehensive studies on catalyst preheating to further the commercialization of technologies that effectively reduce cold start particle emissions, aligning with increasingly stringent future emission regulations.

Experimental study on flow control system of an electric pump-fed cycle for thrust control

An electric pump-fed cycle can enable the electrical control of pump revolutions and rapidly vary the propellant flow rate. This paper proposes the pump control method as a flow control system of an electric pump-fed cycle. In order to evaluate the applicability of the designed flow control system, the test equipment that simulates an electric pump-fed cycle was constructed, including the Li-ion battery power system and communication instruments. The designed PID controller demonstrated rapid flow stabilization and robustness compared to the system without a controller. Meanwhile, under the initial pressurized condition in the run tank that simulated an engine start-up sequence, the controller response delay occurred was more than 500 ms. In addition, the dynamic loads, such as the water hammer effects and overshoot, were identified. The start-up sequence of an EP cycle was adjusted to alleviate those issues. Consequently, the supply stabilizing time and overshoot were adjusted to 400 ms and 1.7 %, respectively. This study can be the first step in utilizing an electric pump-fed cycle for the thrust control technology in the upper stage of a mission.

Explore Electrical Insights: Evaluation of the Tektronix THS3024 Handheld Oscilloscope for Engine Analysis

The Tektronix THS3024 handheld oscilloscope is explored in this study by examining its efficiency in electrical measurements.In this study, the potential of the instrument is used to evaluate its performance in both unloaded and loaded engines. The THS3024 isequipped with 8 channels and allows the measurement of current and voltage. For this work, 6 channels were enabled due to the deltaconfiguration of the engine, providing 3 voltage channels and 3 current channels. Using a 60 volt supply, the channels were configuredto measure voltage and current parameters with appropriate attenuations. Through rigorous analysis, this study examines the behavior ofthe engine at startup and steady state, both with and without load. The plots showing the current waveforms during startup and steadystate with and without load highlight the ability of the device to automatically adjust its scale to capture even subtle variations. Thestudy acknowledges that while intrinsic factors have hindered the analysis of harmonics, the THS3024 still provides the ability to displayharmonic spectra. By examining the voltage and current response during engine startup, this study demonstrates the value of the THS3024in capturing essential transient characteristics and precise parameter changes. The negligible differences between loaded and unloadedengines underscore the reliability of the instrument in evaluating electrical behavior. This study thus demonstrates the potential of theTHS3024 for precise electrical measurements and promotes its applicability in electrical engineering research.

Effect of Operating Parameters on the Real-Time Torque Distribution of a Plug-In Electric Hybrid Vehicle

<div>This article presented a real-time torque distribution strategy for a single-shaft, plug-in hybrid electric vehicle (PHEV) and investigated the effect of multiple operating parameters by using three working conditions, namely, steady operating conditions, acceleration operating conditions, and brake operating conditions. The corresponding experiments were performed according to the earlier discussed three working conditions. The main conclusions of this study are given as follows: (1) Under steady operating conditions, the engine no longer offers torque to the motor for charging when the pedal degree is higher than 60%. (2) Under acceleration conditions, the engine startup is sensitive to the state of charge (SOC) decrement, maximum of 1%, and this decrement increases with an increase in the initial SOC. (3) Under brake operating conditions, the initial SOC may have a significant influence on the variation stability of motor torque, especially when the braking intensity is less than 0.1.</div>

Utilization of Non-verbal Communication in the Engine Room Training – Basic Research on Hand Signals among Monocultural Crew on Board

Accidents are likely to occur in an environment where work is done with teamwork by multiple crew members due to lack of communication, especially in a multicultural environment. Therefore, if there are internationally common maritime hand signals, it would contribute to reduction of human error among multicultural crews on board. As basic research on utilization of hand signals among multicultural crew on board, we invented several common hand signals. Furthermore, as a first step in an experiment to verify the effectiveness of hand signals during teamwork operation in engine room, we conducted the experiment in a mono-cultural environment through onboard training on a training ship. Our target task was practical onboard training for main engine start-up procedure in engine room because it required a lot of multitasking and teamwork. We studied the effectiveness and improvement of use of hand signals through questionnaires and interviews conducted with cadets and onboard instructors.

3D-printed zeolite 13X-Strontium chloride units as ammonia carriers

The selective catalytic reduction (SCR) system in automobiles using urea solution as a source of NH3 suffers from solid deposit problems in pipelines and poor efficiency during engine startup. Although direct use of high pressure NH3 is restricted due to safety concerns, which can be overcome by using solid sorbents as NH3 carrier. Strontium chloride (SrCl2) is considered the best sorbent due to its high sorption capacity; however, challenges are associated with the processing of stable engineering structures due to extraordinary volume expansion during the NH3 sorption. This study reports the fabrication of a novel structure consisting of a zeolite cage enclosing the SrCl2 pellet (SPZC) through extrusion-based 3D printing (Direct Ink Writing). The printed SPZC structure demonstrated steady sorption of NH3 for 10 consecutive cycles without significant uptake capacity and structural integrity loss. Furthermore, the structure exhibited improved sorption and desorption kinetics than pure SrCl2. The synergistic effect of zeolite as physisorbent and SrCl2 as chemisorbent in the novel composite structure enabled the low-pressure (<0.4 bar) and high-pressure (>0.4 bar) NH3 sorption, compared to pure SrCl2, which absorbed NH3 at pressures above 0.4 bar. Regeneration of SPZC composite sorbent under evacuation showed that 87.5% percent of NH3 was desorbed at 20 °C. Thus, the results demonstrate that the rationally designed novel SPZC structure offers safe and efficient storage of NH3 in the SCR system and other applications.

Data-driven predictive energy consumption minimization strategy for connected plug-in hybrid electric vehicles

Powertrain electrification incorporating advanced combustion-based dedicated hybrid engines (DHEs) is an effective and affordable approach to automotive energy saving. To explore the concealed fuel-saving potential of connected plug-in hybrid electric vehicles (CPHEVs) and manage engine dynamics, a data-driven predictive energy consumption minimization strategy (D-PECMS) is proposed in a hierarchical framework. The strategy relies on multi-source trip information provided by advanced driving assistance systems (ADAS) combined with maps and realizes power demand prediction by designing a multivariable long-term and short-term memory (M-LSTM) network. The upper level adopts dynamic programming (DP) to realize SOC planning, while the bottom layer utilizes D-PECMS to achieve computationally-efficient energy management with the engine combustion process being regulated in transient. This strategy is featured with predictive SOC tracking ability with less computational burden and look-ahead engine start-stop control. To ensure the credibility of validation, bench test data are used from a high-efficiency spark-induced compression ignition (SICI) engine to model the CPHEV, and the real-world driving scenarios are reconstructed based on real-time traffic data collected in China. The proposed D-PECMS strategy is tested through comprehensive experiments and compared against both the adaptive ECMS and offline DP. The results demonstrate that the proposed strategy effectively reduces fuel consumption by 3.1% and 13.2% in contrast to the adaptive ECMS and rule-based control respectively. Moreover, the D-PECMS strategy successfully avoids frequent engine operation mode switching as well as engine startup and shutdown.