Wide Range Of Engine Speeds Research Articles

Misfire Detection of Spark Ignition Engines Using a New Technique Based on Mean Output Power

Control and detection of misfire are an essential part of on-board diagnosis (OBD) of modern spark ignition (SI) engines. This study proposes a novel model-based technique for misfire detection for a multicylinder SI engine. The new technique uses a dynamic engine model to determine mean output power, which is then used to calculate a new parameter for misfire detection. The new parameter directly relates to combustion period and is sensitive to engine speed fluctuations caused by misfire. The new technique requires only measured engine speed data and is computationally viable for use in a typical engine control unit (ECU). The new technique is evaluated experimentally on a four-cylinder 1.6-l SI engine. Three types of misfire are studied including single, continuous, and multiple-event. The steady-state and transient experiments were done for a wide range of engine speeds and engine loads, using a vehicle chassis dynamometer and on-road vehicle testing. The validation results show that the new technique is able to detect all three types of misfire with up to 94% accuracy during steady-state conditions. The new technique is augmented with a compensation factor to improve the accuracy of the technique for transient operations. The resulting technique is shown to be capable of detecting misfire during both transient and steady-state engine conditions.

The potential of RCCI concept to meet EURO VI NOx limitation and ultra-low soot emissions in a heavy-duty engine over the whole engine map

This work investigates the potential of RCCI concept to achieve ultra-low NOx and soot emissions over a wide range of engine speed and loads. For this purpose, a detailed experimental methodology has been defined and applied in a heavy-duty single-cylinder engine fueled with diesel and gasoline. In addition, to assess the influence of the engine compression ratio on RCCI capabilities two different compression ratios, 14.4:1 and 11:1, have been tested.Results suggest that a low compression ratio allows to fulfill all the self-imposed constraints (maximum cylinder pressure rise rate of 25bar/CAD, NOx<0.4g/kWh and soot∗<0.01g/kWh) from idle to full load and engine speeds from 900 to 1800rpm. However, the use of higher compression ratio requires a delayed injection strategy to avoid excessive knocking levels, which results in unacceptable soot emissions at loads higher than 50%, even when gasoline fractions around 90% are used.

Biodiesels: Oxidizing enhancers to improve CI engine performance and emission quality

Biodiesels, renewable fuels derived from biomass, animal fat, algae, wastes or residues, are amongst potential candidates to improve energy security and to reduce greenhouse gas emissions. Different from fossil diesel which mainly consists of hydrocarbons, biodiesels are oxygenated fuels. Oxygen contained in biodiesels, as an oxidizing enhancer, plays a crucial role in improving the auto-ignition quality. The oxygen enrichment coming from biodiesels causes the fuel–air mixture in the auto-ignition zone where the mixture is quite rich to become leaner, consequently improving combustion and emission quality. As such, a quantitative analysis of the impact of oxygen content in biodiesel–diesel blends in engine combustion and emission concentrations is crucial in giving key clues to fuel manufacturing as well as to internal combustion engine modeling. This study aims to establish a link between the oxygen content and engine performance as well as emission concentrations when using biodiesel blends B0, B10 and B20 (0%, 10% and 20% of biodiesel by volume in biodiesel–diesel mixtures, respectively). The biodiesel was derived from residues of the manufacturing process of palm cooking oil using methanol transesterification with the aid of a high hardness solid ceramic metal catalyst. The engine used in this test is a modern common-rail, single-cylinder engine operating under a fixed injection condition (injection timing, pressure and duration) but with a wide range of engine speeds. The results show that the oxygen enrichment coming from the fuel blends tested in this study lowers the engine power which is attributable to lower heating values of the biodiesel blends compared with that of the fossil diesel. However, the oxygen contained in the blends suppresses particle formation and decreases hydrocarbon and carbon monoxide concentrations.

G0700703 天然ガスエンジンを用いたドーム形フランジ付き点火プラグの点火特性

CO_2 in exhaust gas from automobile is brought about global warming. In a spark ignition engine, lean combustion brings high thermal efficiency. It becomes difficult to ignite successfully on the other hand. There is a risk of shortening the longevity of the igniter though in it, there is a method of increasing the spark energy as measures. In the study, we proposed the spark plug that installed the flange of dome shaped as the risk measures. This spark plug has aimed at the collection of the shock wave energy generated at the spark discharge and the control of the flow around the spark discharge path. We made dome flanged spark plugs of 3 types. The effect of dome flanged spark plug on the ignition probability using a single cylinder natural gas engine was examined. As a result, it has been understood that the dome flanged spark plug with three holes was effective for the ignition characteristics for wide range of engine speed. (162 words)

Modeling a complete Stirling engine

The assumptions of second order Stirling engine models were reviewed. An ideal adiabatic plus simple heat exchanger model was developed. The model included the external components such as the fan, combustor, and preheater. The external heat transfer to the engine heater was modeled using a log-mean-temperature difference for a constant tube surface temperature. The performance of the model of the external components compared reasonably well to experimental data. The performance of the complete engine model was also compared to experimental data of the GPU-3. By adjusting the flow dissipation to better account for unsteady flow conditions and compressibility effects, the complete engine model was able to predict engine power and brake specific fuel consumption to within ±14% over a wide range of engine speeds and mean pressures. This analysis and others suggest that second order models of Stirling engines need to account for the gradient of the divergence of velocity term in the compressible momentum equation if the mean engine pressure is low enough (less than 3.0 MPa) and the engine speed is high enough (above 30 Hz).

Optimum utilization of recovered heat of a gas engine heat pump used for water heating at low air temperature

Abstract Engine waste heat recovery represents one of the main advantages of gas engine heat pump (GEHP) as compared to conventional heat pump. At lower air ambient temperature, engine waste heat can be used either to evaporate the refrigerant in the refrigerant circuit (mode-I) or to heat the supply water (mode-II). In this paper, the performance of a gas engine heat pump integrated with heat recovery subsystem for both modes are experimentally investigated. In order to achieve this objective, a test facility was developed and experiments were performed over a wide range of engine speed (1300:2200 rpm), ambient air temperature (−3.3:22 °C) and condenser water inlet temperature (27:48 °C). Performance characteristics of the gas engine heat pump were characterized by outlet water temperature, heating capacity and primary energy ratio. The results showed that the effect of condenser water inlet temperature on the system performance is more significant than the effects of ambient air temperature and engine speed. Maximum primary energy ratio has been estimated with a value of 1.83 when the recovered engine heat is transferred to water while it is limited to 1.25 as the recovered engine heat is transferred to refrigerant circuit.

Integration of meanline and one-dimensional methods for prediction of pulsating performance of a turbocharger turbine

Stringent emission regulations are driving engine manufacturers to increase investment into enabling technologies to achieve better specific fuel consumption, thermal efficiency and most importantly carbon reduction. Engine downsizing is seen as a key enabler to successfully achieve all of these requirements. Boosting through turbocharging is widely regarded as one of the most promising technologies for engine downsizing. However, the wide range of engine speeds and loads requires enhanced quality of engine-turbocharger matching, compared to the conventional approach which considers only the full load condition. Thus, development of computational models capable of predicting the unsteady behaviour of a turbocharger turbine is crucial to the overall matching process. A purely one-dimensional (1D) turbine model is capable of good unsteady swallowing capacity predictions, however it has not been fully exploited to predict instantaneous turbine power. On the contrary, meanline models (zero-dimensional) are regarded as a good tool to determine turbine efficiency in steady state but they do not include any information about the pressure wave action occurring within the turbine.This paper explores an alternative methodology to predict instantaneous turbine power and swallowing capacity by integrating one-dimensional and meanline models. A single entry mixed-flow turbine is modelled using a 1D gas dynamic code to solve the unsteady flow state in the volute, consequently used as the input for a meanline model to evaluate the instantaneous turbine power. The key in the effectiveness of this methodology relies on the synchronisation of the flow information of different time scales. The model is validated against experimental data generated at Imperial College London under steady and pulsating flow conditions. Three rotational speeds (27.0, 43.0, and 53.7rps/K) and four pulse flow frequencies (20 to 80Hz) are considered for performance validation. In addition to the turbine performance, the common level of unsteadiness is also compared based on Strouhal number evaluations. Furthermore, comparisons are made with the quasi-steady assumption in order to understand the strengths and weaknesses of the current method for effective unsteady turbine performance prediction.

Effects of H2 Addition to Compressed Natural Gas Blends on Cycle-to-Cycle and Cylinder-to-Cylinder Combustion Variation in a Spark-Ignition Engine

An experimental investigation and a burning-rate analysis have been performed on a production 1.4 liter compressed natural gas (CNG) engine fueled with methane-hydrogen blends. The engine features a pent-roof combustion chamber, four valves per cylinder, and a centrally located spark plug. The experimental tests have been carried out in order to quantify the cycle-to-cycle and the cylinder-to-cylinder combustion variation. Therefore, the engine has been equipped with four dedicated piezoelectric pressure transducers placed on each cylinder and located by the spark plug. At each test point, in-cylinder pressure, fuel consumption, induced air mass flow rate, pressure, and temperature at different locations on the engine intake and exhaust systems as well as “engine-out” pollutant emissions have been measured. The signals related to engine operation have been acquired by means of a National Instruments PXI-DAQ system and software developed in house. The acquired data have then been processed through a combustion diagnostic tool resulting from the integration of an original multizone thermodynamic model with a computer-aided design (CAD) procedure for the evaluation of the burned-gas front geometry. The diagnostic tool allows the burning velocities to be computed. The tests have been performed over a wide range of engine speeds, loads, and relative air-fuel ratios (up to the lean operation limit (LOL)). For stoichiometric operation, the addition of hydrogen to CNG has produced a brake-specific fuel combustion (bsfc) reduction ranging between 2% and 7% and a brake-specific total unburned hydrocarbons (bsTHCs) decrease up to 40%. These benefits have appeared to be even higher for lean mixtures. Hydrogen has shown to significantly enhance the combustion process, thus leading to a sensibly lower cycle-to-cycle variability. Hydrogen addition has generally resulted in extended operation up to relative air-to-fuel ratio (RAFR) = 1.8. Still, the LOL consistently varies depending on the considered cylinder.

The heat release analysis of bio-butanol/gasoline blends on a high speed SI (spark ignition) engine

In this study, experiments were conducted on a single-cylinder high speed SI (spark ignition) engine fueled with 30 and 35%vol butanol/gasoline blends and compared to the pure gasoline. This research is trying to find out the common principles about the influence on combustion heat release of SI engine for variables such as ignition timing, engine load, and butanol blend ratio in a wide engine speed range (3000–8500 rpm). The results showed that butanol provides higher knocking resistance by allowing advance the ignition timing in SI engines, leading to more efficient combustion. The laminar burning velocity of butanol is higher than that of gasoline, but that doesn't guarantee a faster burning speed in a real engine unless the combustion process is more reasonably organized, such as using the optimum ignition timing. In the overall trend, as the butanol blend ratio increasing, one can achieve a more efficient combustion process with using the optimum operating parameters. Obviously, the rate of heat release became slower and declined in peak value as the engine load decreases, accompanied by a shift of peak value to later for both pure gasoline and butanol/gasoline blends. In the aspect of fuel oxidation rate, the fuel–air ratio is the dominated factor rather than fuel type.

Effect of design and operating parameters on the ion current in a single-cylinder diesel engine

Ion current has been the subject of extensive research in gasoline engines forin-cylinder combustion sensing and as a feedback signal for closed-loop engine control. The sources of the ion current in gasoline engines have been identified. Such identification is not the case in diesel engines. This paper presents experimental data and analysis of the ion current produced in a single-cylinder diesel engine equipped with an electronically controlled common-rail-injection system using an accessible engine control unit. The experiments cover a wide range of engine speeds, loads, injection pressures, and injection timings. The effect of each operating parameter on the shape of the ion current signal, as well as its amplitude, timing, and phase shift relative to the rate of heat release, are determined.

Load Expansion of Stoichiometric HCCI Using Spark Assist and Hydraulic Valve Actuation

A spark-assist homogeneous charge compression ignition (SA-HCCI) operating strategy is presented here that allows for stoichiometric combustion from 1000-3000 rpm, and at loads as high as 750 kPa net IMEP. A single cylinder gasoline engine equipped with direct fuel injection and fully variable hydraulic valve actuation (HVA) is used for this experimental study. The HVA system enables negative valve overlap (NVO) valve timing for hot internal EGR. Spark-assist stabilizes combustion over a wide range of engine speeds and loads, and allows for stoichiometric operation at all conditions. Characteristics of both spark-ignited combustion and HCCI are present, with combustion analysis showing a distinctive spark ignited phase of combustion, followed by a much more rapid HCCI combustion phase. At high load, the maximum pressure rise rate is controlled by a combination of spark timing and retarding the intake valve closing angle. The latter reduces the effective compression ratio, and therefore the compressive temperatures, allowing the high load limit of the operating range to be expanded. The SA-HCCI operating strategy exhibits improved thermal efficiency at most operating conditions, with fuel consumption improvements up to 9% realized at light engine loads. The SA-HCCI operating strategy presented here does not provide an efficiency advantage atmore » all operating points compared to SI combustion; a decrease was observed at the highest speed and at loads above 500 kPa net IMEP. At light engine loads the majority of the heat release takes place during the HCCI phase of the heat release, and as such the NOx emissions are very low and are similar to levels observed in pure HCCI. At higher loads, a larger portion of the heat release takes place during the spark ignited phase of combustion, which produces NOx emissions that are much higher than is typically associated with HCCI, but still represent a decrease from conventional SI combustion. By limiting the fuel/air mixture to stoichiometric conditions, the higher NOx emissions do not represent an implementation barrier to this strategy because compatibility is maintained with very effective conventional 3-way catalysts.« less

Performance of a gas engine heat pump (GEHP) using R410A for heating and cooling applications

Abstract A gas engine heat pump (GEHP) represents one of the most practicable systems which improve the overall energy utilization efficiency and reduce the operating cost for heating and cooling applications. The present work aimed at evaluating the performance of a GEHP for air-conditioning and hot water supply. In order to achieve this objective, a test facility was developed and experiments were performed over a wide range of engine speed (1200 rpm–1750 rpm), ambient air temperature (24.1 °C–34.8 °C), evaporator water flow rate (1.99 m 3 /h–3.6 m 3 /h) and evaporator water inlet temperature (12.2 °C–23 °C). Performance characteristics of the GEHP were characterized by water outlet temperatures, cooling capacity, heating capacity and primary energy ratio (PER). The results showed that the effect of evaporator water inlet temperature on the system performance is more significant than the effects of ambient air temperature and evaporator water flow rate. PER of the considered system at evaporator water inlet temperature of 23 °C is higher than that one at evaporator water inlet temperature of 12.2 °C by about 22%. PER of the system decreases by 16% when engine speed changes from 1200 rpm to 1750 rpm.

Numerical analysis of Miller-premixed charge compression ignition combustion on a dynamic φ—T map

A variable valve timing mechanism has been applied in a high-speed direct injection diesel engine. The effective compression ratio ( εeff) is lowered by means of late intake valve closing, while keeping the expansion ratio constant. Premixed charge compression ignition (PCCI) combustion, adopting the Miller cycle, was experimentally realized and numerically analysed. Significant improvements in NO x (nitrogen oxides) and soot emissions were achieved for a wide range of engine speeds and loads frequently used in a transient mode test. The operating range of the Miller-PCCI combustion has been expanded up to an indicated mean effective pressure of 1.3 MPa.

Prediction of Combustion Parameters, Performance, and Emissions in Compressed Natural Gas and Gasoline SI Engines

The simulation of heat release, flame propagation speeds, and pollutant formation was carried out in both a turbocharged compressed natural gas (CNG) engine and a multivalve naturally aspirated bifuel engine running on either CNG or gasoline. The predictive tool used for investigation is based on an enhanced fractal geometry concept of the flame front, which is able to capture the modulation of turbulent to laminar burning speed ratio throughout the overall combustion phase without introducing flame kernel growth or burnout submodels. The prediction model was applied to a wide range of engine speeds, loads, relative air-fuel ratios, and spark advances, and the obtained results were compared to experimental data. These latter were extracted from measured in-cylinder pressure by an advanced diagnostics technique that was previously developed by the authors. The results confirmed a quite accurate prediction of burning speed even without any kind of tuning, with respect to different currently available fractal as well as nonfractal approaches for the simulation of flame-turbulence interaction. Furthermore, the computational code proved to be capable of capturing the effects of fuel composition, different combustion-chamber concepts, and operating conditions on engine performance and emissions.

Improving fuel efficiency with laser surface textured piston rings

An experimental study is presented to evaluate the effect of partially laser surface textured piston rings on the fuel consumption and exhaust gas composition of a compression–ignition IC engine. Dynamometer tests were performed with a Ford Transit naturally aspirated 2500 cm 3 engine at a wide range of engine speeds under near-half-load conditions. A comparison was made between the performance of reference non-textured conventional barrel-shaped rings and optimum partial laser surface texturing (LST) cylindrical-shape rings. It was found that the partial LST piston rings exhibited up to 4% lower fuel consumption, while no traceable change in the exhaust gas composition or smoke level was observed.

The New 1.6 | Diesel Engine

A new 1.6 | diesel engine has been launched to enhance the competitive power of Hyundai/Kia Motors’ C-segment vehicles. This engine provides 84.6 kW of maximum power, 255 Nm of torque over a wide engine speed range and has a homologated fuel consumption of 4.7 l/100 km. In parallel to these achievements, noise, vibration and harshness (NVH) characteristics were optimised by both collaborated structural analysis of the powertrain and refined calibration of the injection parameters.

Effect of Piston Friction on the Performance of SI Engine: A New Thermodynamic Approach

Abstract This paper presents thermodynamic analysis of piston friction in spark-ignition internal combustion engines. The general effect of piston friction on engine performance was examined during cold starting and normal working conditions. Considerations were made using temperature-dependent specific heat model in order to make the analysis more realistic. A parametric study was performed covering wide range of dependent variables such as engine speed, taking into consideration piston friction combined with the variation of the specific heat with temperature, and heat loss from the cylinder. The results are presented for skirt friction only, and then for total piston friction (skirt and rings). The effect of oil viscosity is investigated over a wide range of engine speeds and oil temperatures. In general, it is found that oils with higher viscosities result in lower efficiency values. Using high viscosity oil can reduce the efficiency by more than 50% at cold oil temperatures. The efficiency maps for SAE 10, SAE 30, and SAE 50 are reported. The results of this model can be practically utilized to obtain optimized efficiency results either by selecting the optimum operating speed for a given oil type (viscosity) and temperature or by selecting the optimum oil type for a given operating speed and temperature. The effect of different piston ring configurations on the efficiency is also presented. Finally, the oil film thickness on the engine performance is studied in this paper.

The Effects of High-Pressure Injection on a Compression–Ignition, Direct Injection of Natural Gas Engine

This study investigated the effects of injection pressure on the performance and emissions of a pilot-ignited, late-cycle direct-injected natural gas fueled heavy-duty engine. The experiments, conducted on a single-cylinder engine, covered a wide range of engine speeds, loads, and exhaust gas recirculation fractions. The injection pressure was varied at each operating condition while all other parameters were held constant. At high loads, increasing the injection pressure substantially reduced particulate matter and CO emissions, with small increases in NOx and no significant effect on hydrocarbon emissions or fuel consumption. At low loads, injection pressure had no significant impact on either emissions or performance. At high loads, higher injection pressures consistently reduced both the number density and the size of particles in the exhaust stream. Injection pressure had reduced effects at increased engine speeds.

Effects of N2 and CO2 mixing on ignition and combustion in a homogeneous charge compression ignition engine operated on dimethyl ether

The control of ignition timing and combustion duration over a wide range of engine speeds and loads in a homogeneous charge compression ignition (HCCI) engine is one of the barriers to the realization of this type of engine. Application of exhaust gas recirculation (EGR) is a promising option to control ignition timing, extend combustion duration, and suppress knock-like combustion. In this study, the effects of the mixing of N2 and CO2, major components of exhaust gas, with the fuel-air mixture on the heat release of the cool flames and the emission characteristics of CO were investigated by experiment and computation. The heat release of the cool flames was reduced with N2 mixing; however, it increased with CO2 mixing. From the systematic experiments and chemical kinetic computations, it was confirmed that the amount of heat release from the cool flames depends strongly on the concentration of O2 at the onset of cool flame. The dominant pathway for CO oxidation is the reaction of CO + OH = CO2 + H, where the H atoms produced react with O2 molecules and produce OH + O or HO2. The CO oxidation becomes active as the branching rate to OH + O is increasing. However, the branching rate to HO2 was increased with the addition of CO2 into the mixture, resulting in higher CO emission. Though the mixing of CO2 is effective in suppressing knock-like combustion owing to its small specific heat ratio and large heat capacity, it has an inferior effect on CO emission.

Analysis of the effect of variations in fuel line pressure in high-speed direct injection diesel engines, with high-pressure common rail fuel injection systems on heat release, cylinder pressure, performance, and NOx emissions

This paper is a further development of work previously reported on a wholly analytical approach to heat release modelling and is applicable to high-speed direct injection (HSDI) diesel engines operating with high-pressure common rail fuel injection systems under conditions of predominantly mixing-controlled combustion. The key variable in this treatment is the fuel preparation or combustion rate factor WH which, in conjunction with the primary injection variables, i.e. rail pressure, injection velocity and duration, defines the shape and amplitude of the heat release curve. It was shown in a previous paper that by expressing the fuel preparation rate factor WH as a function of time rather than crank angle, i.e. WHt instead of WHθ, the former can be presented as a nearly linear function of the square of injection velocity, i.e. WHt is directly proportional to the kinetic energy of the injected fuel spray, the latter evidently being the primary influence on the rate of the fuel-air mixing process. The analytical treatment developed in the authors' previous paper then allows heat release rates in the engine, dQ/dθ, to be calculated over a wide range of engine speeds and loads, with the aid of the existing engine simulation code ODES (Otto diesel engine simulation) to predict the associated engine performance and emissions, without resorting to further engine testing.