Four-cylinder Gasoline Engine Research Articles

STUDY OF THE INFLUENCE OF MISFIRES ON THE UNEVEN ROTATION OF THE CRANKSHAFT OF A GASOLINE ENGINE

Purpose. Investigate the effect of misfires on the unevenness of the torque on the crankshaft of gasoline internal combustion engine with spark ignition.
 Research methods. The results of the thermodynamic calculation of the operating cycle, the dynamic calculation of the engine parameters at the nominal operating mode of an well engine and an engine with misfiring in one cylinder are presented. The computer program Engine Calculation and Microsoft Office program package were used to perform the research. The object of the study is the MeMZ-245 four-stroke, four-cylinder gasoline engine. The subject of the study is the torque unevenness coefficient of the internal combustion engine μ.
 Results. The topical issue of investigating the impact of misfires on the indicators of unevenness of rotation of the crankshaft of a spark-ignition internal combustion engine has been solved. The torque unevenness coefficient μ = 6.164 for the MeMZ-245 4-stroke 4-cylinder engine when operating at the nominal mode was calculated. It was established that as a result of a malfunction (disabling one cylinder), the average effective torque of the engine decreases by 29.4%. The value of the torque unevenness coefficient of the faulty engine was calculated as μ = 12.165, which is twice the value for the well-worked engine. It was established that level of torque unevenness of MeMZ-245 4-cylinder in-line engine with misfiring approaches to single-cylinder engines.
 Scientific novelty. For the first time, it was theoretically proven that due to the lack of ignition in one of the cylinders of a 4-stroke 4-cylinder engine, the average effective torque of the engine decreases by 29.4% when operating at the nominal mode. The value of the torque unevenness coefficient μ of an engine with misfiring is twice the value for a well-worked engine, which is close to similar values of single-cylinder engines.
 Practical value. The method of calculating the torque unevenness coefficient of an internal combustion engine can be used in the design of new and modernization of existing internal combustion engines.

Dynamic cylinder deactivation: Thermodynamic mapping for the case of stoichiometric SI ICE

Conventional cylinder deactivation has been improving internal combustion efficiency for decades. It provides benefits for any internal combustion engine, particularly engines with high number of cylinders. The level of engine displacement reduction depends on the number of cylinders that may be deactivated during operation. This limits the potential benefit. Theoretically, maximum benefit of cylinder deactivation would require assignment of specific displacement reduction to each engine operating point. Dynamic cylinder deactivation is a new approach, which does not continuously deactivate cylinders, but deactivates selected engine cycles. This allows to dynamically reduce engine displacement and to assign optimum displacement reduction to each operating point. The paper deals with the one-dimensional thermodynamic simulation of the dynamic cylinder deactivation applied to a small displacement four-cylinder gasoline engine, points out crucial attributes of this new approach and compares it with baseline engine layouts and with the conventional cylinder deactivation as well. The research concludes that the dynamic cylinder deactivation improves the fuel consumption for engines loads BMEP < 5 bar. Deactivation strategy with the lowest trapped mass value in the deactivated cycle shows the most benefit.

Optimal design and analysis of a novel variable-length intake manifold on a four-cylinder gasoline engine

• A genetic algorithm is used to optimize the nonlinear behavior of variable-length manifold. • Variable-length manifolds are proposed through the analysis of optimal length and diameter. • Thermal, fluid-flow, heat and mass transfer criteria are defined to evaluate the proposal. • Results improved the thermal efficiency, fuel consumption and heat release rate of the engine. In this study, a novel variable-length intake manifold is designed to increase the volumetric efficiency of a four-cylinder gasoline engine. The proposed intake manifold is designed with four independent throttle bodies on its inlet duct, which are separately connected to the atmosphere. By opening and closing each one of these throttle bodies, a different length of the intake manifold is obtained. The novelty of this study lies in the fact that in addition to the variable-length system at each engine speed, it uses a different combination of opened throttle bodies to further increase volumetric efficiency. To demonstrate the efficiency of the novel design, a one-dimensional model of the Stock engine is developed using the GT-Power software in wide-open throttle steady-state condition and then validated with experimental results. Five vital criteria are defined for evaluating all of the thermo-fluid, heat, and mass transfer characteristics of the engine. The result of using the novel proposed design indicates that the volumetric efficiency, brake torque, brake specific fuel consumption, brake thermal efficiency, and heat release rate of the engine compared to the stock intake manifold were improved by 6.33%, 7.23%, 0.83%, 1.77%, and 11.79% respectively. Based on the obtained results, the best performance is achieved at 3500 rpm almost in all conditions. At this condition, the air and fuel mass flow rates and brake power are 0.0574 kg/s, 0.0041 kg/s, and 56.42 kW, respectively.

Effect of Vibration and Noise on Spark Ignition Engines of Methanol Fuel Blended with Gasoline

Nowadays, various types of engines are manufactured by the automotive industry, especially for cars that have huge demand all over the world in general, and Malaysia in particular. The vibration and noise continue to be a significant problem among the various issues that exist in the engine to date. In this research, tests were performed on a four-cylinder gasoline engine of methanol fuel blended with gasoline fuel at distinct quantities (between 5% and 10%) and motor speeds of 1000, 1200, and 1400 rpm. The findings indicate that the methanol gasoline combination has the highest vibration and noise between 1200 and 1400 rpm, while gasoline has the lowest vibration and noise between 1000 and 1400 rpm. The modifications in the combustion system owing to the characteristics of the fuel mixture used have an essential impact on the engine’s vibration and noise.

Analysis of fatigue crack growth in cylinder head bolts of gasoline engine based on experimental data

Engines cylinder head bolts failure from the thread location in cylinder block causes the problems during repairing time. Exact prediction of fatigue crack growth in bolts by experimental analysis and finite element method modeling can affect the Maintenance Planning and Scheduling Implementation. In this study, the fatigue analysis of cylinder head bolts of a four-cylinder gasoline engine imposed by premature failure is investigated. The bolts suffer a mechanical seizure on the threads about 2 × 108 cycles in service. For such aim, standard specimens are cut off from the bolts and examined to evaluate the mechanical properties and material chemical composition. Optical microscopes and scanning electron microscopy are employed to consider the microstructures, defects, fracture surface and failure cause. The morphology of the fracture surface shows the fatigue crack growth marks, including the beachmarks, the ratchet marks and the river cracks. The finite element analysis model is presented applying the elastic–plastic finite element analysis for the bolts under variable combustion pressure. The stress history is then used to calculate stress intensity factors and fatigue life of bolts. Numerical results show that crack existence to depth of 0.35 mm is the source of failure of premature fracture.

Experimental Analysis and Optimization of Timing Belt Guide Plate Material on Engine Operational Friction Loss

We focus on the friction loss measurement and reduction of the timing belt guide plates of a fourcylinder gasoline engine. To minimize the friction loss caused by the dynamic friction of the guide plates during timing belt motion and improve the efficiency of the internal combustion engine (ICE), we adopt four different plastic materials in fabricating the guide plates. With controlled engine boundary conditions and operational modes, an AVL electric dynamometer is used to measure the output of the engine. The results indicate that selecting polytetrafluoroethylene (PTFE) as the additive in fabricating the guide plates can effectively reduce the friction loss, so that the output torque and output power of the engine can be improved, thus reducing fuel consumptions. This work also has positive impact on the efficiency optimization of similar ICEs.

Finite element analysis for engine crankshaft torsional stiffness

Accurate crankshaft torsional stiffness is important to build the lumped parameter model (LPM) for crankshaft torsional vibration analysis. For the crankshaft system of a four-cylinder in-line gasoline engine, a procedure to build the finite element model (FEM) is presented. And the applicability of two ways to set the equivalent mass or equivalent moment of inertia for piston-rod in FEM is declared. When building a lumped parameter model, the concept of rigid-rotation of the crank pin central section around the central line of the crankshaft is proposed, and a method to obtain the torsional angle of the central section is declared. What is more, three post-processing methods are presented to obtain the torsional stiffness coefficients. According to three load cases of no-load, half load and full load, the tests are carried out. The simulation results of FEM and LPM, and the test results have good agreement with each other.

Study on Valve Strategy of Variable Cylinder Deactivation Based on Electromagnetic Intake Valve Train

The camless electromagnetic valve train (EMVT), as a fully flexible variable valve train, has enormous potential for improving engine performances. In this paper, a new valve strategy based on the electromagnetic intake valve train (EMIV) is proposed to achieve variable cylinder deactivation (VCD) on a four-cylinder gasoline engine. The 1D engine model was constructed in GT-Power according to test data. In order to analyze the VCD operation with the proposed valve strategy, the 1D model was validated using a 3D code. The effects of the proposed valve strategy were investigated from the perspective of energy loss of the transition period, the mass fraction of oxygen in the exhaust pipe, and the minimum in-cylinder pressure of the active cycle. On the premise of avoiding high exhaust oxygen and oil suction, the intake valve timing can be determined with the variation features of energy losses. It was found that at 1200 and 1600 rpm, fuel economy was improved by 12.5–16.6% and 9.7–14.6%, respectively, under VCD in conjunction with the early intake valve closing (EIVC) strategy when the brake mean effective pressure (BMEP) ranged from 0.3 MPa to 0.2 MPa.

Influence of numerous start-ups and stops on tribological performance evolution of engine main bearings

For main bearings of internal combustion engines, most of the wear occurs during the start-ups and stops. The popularity of the start–stop system in automobile engines, which is used to save fuel consumption during idling stage, makes the working condition of main bearings severer because more frequent starts and stops will be generated. Changes in the bearing surface caused by wear will directly affect the bearing’s working performance. So in this study a transient mixed lubrication model and a wear model are coupled to analyze the influence of numerous start-ups and stops on the tribological performance evolution of engine main bearings. Starved lubrication of bearings before the oil supply is considered. The wear process is studied on the scale of surface topography and geometry. A main bearing in a four-stroke four-cylinder gasoline engine is studied under engine start–stop cycle conditions. The effects of temperature and lubricant grade on the transient tribodynamic behavior during the start-ups and stops are first investigated. Then the evolutions of surface characteristics and tribological performance of main bearings after numerous engine start-ups and stops are simulated. Results show that the temperature and lubricant grade can significantly affect the friction and wear of bearings. Hot start–stop condition leads to more serious asperity contact friction in the early stage of start-up, while cold start–stop condition generates more friction loss. The wear process of bearing surface is faster when applying oil with lower viscosity. And the impacts of engine start-ups and stops on bearing working performance are mainly seen in contact friction.

Trade-off on fuel economy, knock, and combustion stability for a stratified flame-ignited gasoline engine

A combination of port fuel injection (PFI) and direct injection (DI), called P-DI strategy, was used in a four-cylinder gasoline engine. The aim was to achieve a stratified flame ignition (SFI) hybrid combustion and manage the trade-off among fuel economy, knock, and combustion stability (EKS) in a gasoline engine. In the proposed P-DI strategy, DI was used to enrich the local mixture around the spark plug to enhance the early spark-ignition combustion. On the other hand, PFI was used to form a largely lean homogeneous mixture to achieve a moderately controlled auto-ignition combustion in the outer region of the cylinder. The effects of DI fraction (RDI) and start of injection (SOI) timing of DI on the SFI hybrid combustion were investigated experimentally. It was found that an increased RDI resulted in a parabolic-like effect on the combustion phasing and combustion stability. The earliest combustion phasing was achieved with an RDI of approximately 35%. The fuel economy deteriorated monotonously with increasing RDI. In comparison, the effect of SOI on the SFI hybrid combustion was more complicated. It was found that an SOI between 50°CA before top-dead-center (BTDC) and 90°CA BTDC showed a potential to achieve a satisfactory trade-off among EKS. Based on the above findings, a cost function (J) was proposed to represent the EKS trade-off and reduce the calibration burden for optimal SOI at different engine operating conditions. An extremum-seeking algorithm was adopted to search for the maximum value of J and obtain the optimal SOI timing at each operating point. The proposed algorithm was then validated by experimental results.

The optimization of on-board H2 generator control strategy and fuel consumption of an engine under the NEDC condition with start-stop system and H2 start

The addition of hydrogen has been proven to be an effective way for improving the engine efficiency and lowering carbon-related emissions. However, difficulties in the hydrogen onboard storage and production are barriers for its practical applications in the automobiles. This paper first conducted a series of experiments to optimize the control strategy of the on-board hydrogen generator and then proposed a start-stop system and pure hydrogen start strategy for the engine to improve overall fuel economy. Bench tests for optimizing the control strategy of on-board hydrogen generator was conducted on a four-cylinder gasoline engine equipped with an electronically controlled hydrogen port-injection system at engine speeds of 1000, 1500, 2000 and 2600 rpm, respectively. For a given engine speed, the intake manifolds absolute pressure (MAP) was increased from 25 to 100 kPa. The test results showed that the production of hydrogen could be started when the engine speed was greater than 1300 rpm and MAP was higher than 48 kPa to gain better fuel economy. A simulation model was built based on AVL CRUISE code to investigate the overall fuel consumption of vehicle equipped with on-board hydrogen generator and adopted the start-stop system-and-hydrogen start strategy under the New European Driving Cycle (NEDC). The numerical results demonstrated that the adoption of start-stop system could reduce the fuel consumption by 5.09% when the hydrogen generator was continuously worked within the whole NEDC. By further adopting the optimal working range acquired from this test, the vehicle fuel consumption could be reduced by 8.43%.

Targeted Efficiency Optimisation for Gasoline Engines

The European Union’s mandatory CO2 standards for new passenger cars in 2009 set a 2015 target of 130 g/km for the fleet average of all manufacturers combined, which was met in 2013, with average EU fleet emissions amounting to 129 g/km. Individual manufacturers are allowed a higher CO2 emission value, depending on the average vehicle weight of their fleet. The heavier the average weight of the cars sold by a manufacturer, the higher the CO2 level allowed. Figure 1 shows that in order to meet the future EU emissions regulations, significant increases in gasoline engine efficiency will have to be realised. Open image in new window FIGURE 1 European CO2 targets and the derived average fuel consumptions resulting from efficiency improvements for the C- and D- vehicle segments for European passenger car markets for the intervals 2015-2021 and 2021-2025 (© FEV) Based on two representative vehicles from the C- and D-segment, which meet the present day CO2 targets, it can be demonstrated that there is a need to improve efficiency for the intervals 2015 to 2021 and 2021 to 2025. The CO2 targets of the two vehicles have been converted to specific fuel consumption targets for each of comparison. The common reduction measures — reduction in vehicle mass, reduction of rolling resistance — and electrification of the powertrain (Micro-HEV, Mild-HEV, HEV) are already considered. — In a C-Segment vehicle, the engine is allowed a maximum average fuel consumption of 256 g/kWh in 2021 and for 2025 it should be 223 g/kWh (Micro-HEV). — In a D-Segment vehicle, the engine is allowed a maximum average fuel consumption of 238 g/kWh in 2021 and for 2025 it should be 213 g/kWh (Micro-HEV). The specification of such an average fuel consumption map is readily comparable across different driving cycles and therefore provides a simple way of evaluating the various technologies in a wide scope. In contradiction, the use of micro-hybridisation to advance electrification of the gasoline engine, allows a slight increase in the maximum allowable average Brake Specific Fuel Consumption (BSFC); but the Micro-HEV must be increasingly used in the new fleet of vehicles [3]. In the analysis presented here, a three-cylinder and a four-cylinder gasoline engine are considered: — 1.0-l three-cylinder turbocharged gasoline engine with direct injection, capable of 200 Nm and 90 kW — 1.6-l four-cylinder turbocharged gasoline engine with direct injection, capable of 250 Nm and 115 kW. Both engines are turbocharged and equipped with direct fuel injection and have intake and exhaust cam phasers. Figure 2 shows the full engine operating range of the 1.0-l- and 1.6-l engines with focus on fuel consumption in the New European Drive Cycle (NEDC) and Worldwide Harmonized Light-Duty Vehicles Test Procedure (WLTP) driving cycles for the C- and D-segment vehicles. Open image in new window FIGURE 2 Engine operating range of the 1.0-l and 1.6-l engines with focus on fuel consumption (marked with red/gray outline) on the NEDC and WLTP driving cycles for the C- and D-segment vehicles (© FEV) Comparing the individual engine maps in Figure 2, it is clear to see that the average fuel consumption would be highly influenced by the different driving cycles and target vehicles. Especially when considering the high load WLTP-H (WLTP with highest vehicle mass) cycle, extended areas of the engine map will also need to be optimised. Technologies with efficacy in broad regions of the engine map will definitively have an advantage. To this effect, the next section will analyse the effectiveness of the individual fuel consumption reduction technologies.

S 字形状管内における自動車エンジン排気脈動流の 圧力挙動と流動場の相関

Pulsatile exhaust flow from an automotive engine is studied to investigate the correlation between the flow field and pressure characteristics. In our experiments, the exhaust flow is generated by a four-cylinder gasoline engine in a S-shaped duct, which consists of two bends and straight part, and time fluctuations of velocity and pressure of the flow are measured by hot wire anemometry and pressure sensor, respectively. Numerical simulations are also performed with RNG k-ε model. It is shown that time fluctuations of velocity and pressure are waves which have 8 peaks and we found that the fluctuation of velocity influences on differential pressure at both bends. In present work, the relation between velocity and wall pressure in S-shaped duct is discussed.

Composite Adaptive Internal Model Control and Its Application to Boost Pressure Control of a Turbocharged Gasoline Engine

Internal model control (IMC) explicitly incorporates the plant model and its approximate inverse and offers an intuitive controller structure and calibration procedure. In the presence of plant-model uncertainty, combining the IMC structure with parameter estimation through the certainty equivalence principle leads to adaptive IMC (AIMC), where either the plant model or its inverse is identified. This paper proposes a composite AIMC (CAIMC) that explores the IMC structure and simultaneous plant dynamics and inverse dynamics identification to achieve improved performance of AIMC. A toy plant is used to illustrate the feasibility and potential of CAIMC. The advantages of CAIMC are later demonstrated on the boost-pressure control problem of a turbocharged gasoline engine. The design of the CAIMC assumes that the plant model and its inverse are represented by the first-order linear dynamics. The unmodeled dynamics and uncertainties due to linearization and variations in operating conditions are compensated through adaptation. The resulting CAIMC is first applied to a physics-based high-order and nonlinear proprietary turbocharged gasoline engine model, and then validated on a turbocharged 2-L four-cylinder gasoline engine on a vehicle with vacuum-actuated wastegate. Both the simulation and experimental results show that the CAIMC cannot only effectively compensate for uncertainties but also auto-tune the IMC controller for the best performance.

Combustion analysis and emissions characteristics of a hydrogen-blended methanol engine at various spark timings

This paper studied the effect of spark timing on combustion and emissions characteristics of a hydrogen-enriched methanol engine. The experiment was performed on a four-cylinder gasoline engine equipped with an electronic controlled hydrogen port-injection system. The engine speed was kept at 1400 rpm and the manifolds absolute pressure was kept at 61.5 kPa with an excess air ratio of 1.20. The hydrogen volume fractions in the total intake were kept at 0, 1.5% and 3%, respectively. The spark timings for each specified hydrogen addition level were varied from 18 to 46 °CA before top dead center with steps of 2 °CA. The test results showed that the indicated thermal efficiency was first increased and then decreased with the increase of spark advance. With increase of spark advance, flame development period was prolonged whereas the flame propagation period was shortened. The coefficient of variation in indicated mean effective pressure was first decreased and then slightly increased with the advance of spark timing. HC and CO emissions were decreased after hydrogen addition. NOx from the hydrogen-blended engines could be reduced through retarding the spark timing.

A Study on Estimating Gasoline Engine Radiated Noise Based on Surface Vibration Measurement

A study on the method of estimating gasoline engine radiated noise by measuring surface vibration is carried out. Firstly, the theoretical basis and test method is studied. Then an experiment is carried out on a four-cylinder gasoline engine. By measuring the engine surface vibration velocity, the sound power level of these engine parts and of the engine body is calculated. The result shows that the estimation of engine radiated noise is accurate. It shows the sound power level of gasoline engine can be predicted by surface vibration.

CFD Analysis for Cooling Water Cavity of a Four-Cylinder Gasoline Engine

s: The 3D model of cooling water cavity was set up, which was in a four cylinders gasoline engine, and the CFD analysis was done after setting the CFD calculation model and boundary conditions. The CFD analysis results shows that the structure design of engine’s cooling water cavity can meet the requirements basically, but there are some zone in which the water speed is lower than 0.5m/s, and there are some whirlpools in cylinder water jacket. In order to improve the cooling effect of the engine, the cooling water inlet channel and cylinder head should be improved.

Characterization of wear-debris group in on-line visual ferrographic images

Wear-debris characterization using ferrography, which is of importance in machine condition monitoring and fault diagnosis, remains a challenge. The newly developed on-line visual ferrograph can provide digital wear-debris images and perform on-line analysis during wear monitoring. In this article, image projection transformation was utilized for extracting the overall characteristics of the wear-debris chains according to the fundamental feature of wear-debris arraying along the horizontal direction. Moreover, Full Binary Tree Based Image Division was also proposed to analyse the regional features on different scales in on-line visual ferrographic images. Several descriptive parameters including thinning ratio, chain length and chain width were proposed. In the experiments, four types of images with different wear-debris groups were compared and a group of time-sequence on-line visual ferrographic images of an inline four-cylinder gasoline engine was studied. It is found that more comprehensive wear information can be acquired through the proposed multi-parameter description method. Meanwhile, the image projection transformation method extracts macrocharacteristics of images rapidly and efficiently and the thinning ratio measures wear-debris width in an intuitive way.

Investigation on the cold start characteristics of a hydrogen-enriched methanol engine

This paper experimentally investigated the effect of hydrogen addition on the cold start performance of a methanol engine. The test was conducted on a modified four-cylinder gasoline engine. An electronically controlled hydrogen injection system was applied to realize the hydrogen port injection. The engine was started at an ambient temperature of 25 °C with two hydrogen flow rates of 0 and 189 dm3/s, respectively. The results demonstrated that hydrogen addition availed elevating the peak engine speed and cylinder pressure during the cold start. Both flame development and propagation periods are shortened after the hydrogen addition. When the hydrogen volume flow rate was raised from 0 to 189 dm3/s, HC, CO and total number of particulate emissions within 19 s from the onset of cold start were reduced by 68.7%, 75.2% and 72.4%, respectively. However, because of the enhanced in-cylinder temperature, NOx emissions were increased after the addition of hydrogen.

The new BMW Three- and Four-Cylinder Gasoline Engines

The new BMW Three- and Four-Cylinder Gasoline Engines