scholarly journals Effect of Valve Timing and Excess Air Ratio on Torque in Hydrogen-Fueled Internal Combustion Engine for UAV

Energies ◽  
2019 ◽  
Vol 12 (5) ◽  
pp. 771 ◽  
Author(s):  
Cheolwoong Park ◽  
Wonah Park ◽  
Yongrae Kim ◽  
Young Choi ◽  
Byeungjun Lim
Keyword(s):  
Gasoline Engine ◽  
Combustion Engine ◽  
Control Unit ◽  
Operating Conditions ◽  
Exhaust Valve ◽  
Airflow Rate ◽  
Intake Valve ◽  
Hydrogen Fuel ◽  
Excess Air ◽  
Valve Opening

In this study, in order to convert a 2.4 L reciprocating gasoline engine into a hydrogen engine an experimental device for supplying hydrogen fuel was installed. Additionally, an injector that is capable of supplying the hydrogen fuel was installed. The basic combustion characteristics, including torque, were investigated by driving the engine with a universal engine control unit. To achieve stable combustion and maximize output, the intake and exhaust valve opening times were changed and the excess air ratio of the mixture was controlled. The changes in the torque, excess air ratio, hydrogen fuel, and intake airflow rate, were compared under low engine speed and high load (wide open throttle) operating conditions without throttling. As the intake valve opening time advanced at a certain excess air ratio, the intake air amount and torque increased. When the opening time of the exhaust valve was retarded, the intake airflow rate and torque decreased. The torque and thermal efficiency decreased when the opening time of the intake and exhaust valve advanced excessively. The change of the mixture condition’s excess air ratio did not influence the tendency of the torque variation when the exhaust valve opening time and torque increased, and when the mixture became richer and the intake valve opening time was fixed. Under a condition that was more retarded than the 332 CAD condition, the torque decreased by about 2 Nm with the 5 CAD of intake valve opening time retards. The maximum torque of 138.1 Nm was obtained at an optimized intake and the exhaust valve opening time was 327 crank angle degree (CAD) and 161 CAD, respectively, when the excess air ratio was 1.14 and the backfire was suppressed. Backfire occurred because of the temperature increase in the combustion chamber rather than because of the change in the fuel distribution under the rich mixture condition, where the other combustion control factors were constantly fixed from a three-dimensional (3D) computational fluid dynamics (CFD) code simulation.

Effects of passive pre-chamber jet ignition on combustion and emission at gasoline engine

2021 ◽  
Vol 13 (12) ◽  
pp. 168781402110671
Author(s):  
Wei Duan ◽  
Zhaoming Huang ◽  
Hong Chen ◽  
Ping Tang ◽  
Li Wang ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Gasoline Engine ◽  
Combustion Process ◽  
Pressure Rise ◽  
Spark Ignition ◽  
Combustion Stability ◽  
Intake Valve ◽  
Part Load ◽  
Significant Difference ◽  
Valve Opening

Pre-chamber jet ignition is a promising way to improve fuel consumption of gasoline engine. A small volume passive pre-chamber was tested at a 1.5L turbocharged GDI engine. Combustion and emission characteristics of passive pre-chamber at low-speed WOT and part load were studied. Besides, the combustion stability of the passive pre-chamber at idle operation has also been studied. The results show that at 1500 r/min WOT, compared with the traditional spark ignition, the combustion phase of pre-chamber is advanced by 7.1°CA, the effective fuel consumption is reduced by 24 g/kW h, and the maximum pressure rise rate is increased by 0.09 MPa/°CA. The knock tendency can be relieved by pre-chamber ignition. At part load of 2000 r/min, pre-chamber ignition can enhance the combustion process and improve the combustion stability. The fuel consumption of pre-chamber ignition increases slightly at low load, but decreases significantly at high load. Compared with the traditional spark ignition, the NOx emissions of pre-chamber increase significantly, with a maximum increase of about 15%; the HC emissions decrease, and the highest decrease is about 36%. But there is no significant difference in CO emissions between pre-chamber ignition and spark plug ignition. The intake valve opening timing has a significant influence on the pre-chamber combustion stability at idle operation. With the delay of the pre-chamber intake valve opening timing, the CoV is reduced and can be kept within the CoV limit.

Research on Variable Cylinders of the Tandem 4-Cylinder Gasoline Engine for Fuel Economy

2008 ◽  
Vol 20 (1) ◽  
pp. 75-81 ◽  
Author(s):  
Kouki Yamaji ◽  
◽  
Hirokazu Suzuki ◽  
Keyword(s):  
Fuel Consumption ◽  
Fuel Economy ◽  
Gasoline Engine ◽  
Combustion Engine ◽  
Electronic Control Unit ◽  
Control Unit ◽  
Engine Fuel ◽  
Electronic Control ◽  
The Difference ◽  
Predetermined Time

With progress in internal combustion engine fuel economy, variable cylinder systems have attracted attention. We measured fuel consumption in cylinder cutoff by stopping the injector alone, collected data changing the location and number of cutoff cylinders and when varying the cutoff cylinder, and compared the difference in fuel cost reduction. A transistor is inserted serially into the injector control circuit of the electronic control unit (ECU). By controlling the transistor via microcomputer, the injector is turned on or off independently from ECU control in obtain cylinder cutoff. The amount of fuel consumption is measured using enhancement mode of a failure diagnostic device based on the OBD II standard to collect injection time and rotational speed of the injector for a predetermined time and calculated based on this data. We confirmed that by stopping the injector alone, fuel consumption was reduced 6 to 22% and is reduced when the cutoff cylinder is varied.

Model-Based Design and Hardware-in-the-Loop Simulation of Engine Lean Operation

2014 ◽  
Author(s):  
Pushkar Agashe ◽  
Yang Li ◽  
Bo Chen
Keyword(s):  
Gasoline Engine ◽  
Control Strategies ◽  
Electronic Control Unit ◽  
Control Unit ◽  
Simulation Models ◽  
Operating Conditions ◽  
Hardware In The Loop ◽  
Vehicle Performance ◽  
Model Based ◽  
Hil Simulation

This paper presents model-based design and hardware-in-the-loop (HIL) simulation of engine lean operation. The functionalities of the homogeneous combustion subsystem in engine Electronic Control Unit (ECU) in dSPACE Automotive Simulation Models (ASM) are first analyzed. To control the gasoline engine in lean operation without the drop of output torque, the combustion subsystem in engine ECU is modified by introducing two control loops, torque modifier and fuel multiplier. The performance of these two controllers is evaluated by HIL simulation using a dSPACE HIL simulator. The HIL simulation models, including vehicle plant model and softECUs in HIL simulator and engine lean control model in hardware engine ECU are modeled using model-based design. With HIL simulation, the designed engine control strategies can be immediately tested to evaluate the overall vehicle performance. The HIL simulation results show that the designed lean combustion control strategy can reduce fuel consumption and is able to meet the torque requirement at lean engine operating conditions.

Engine Control Unit Testing by Hardware-in-the-Loop Simulation

2014 ◽  
Vol 214 ◽  
pp. 67-74
Author(s):  
Jarosław Mamala ◽  
Sebastian Brol ◽  
Mariusz Graba
Keyword(s):  
Combustion Engine ◽  
Can Bus ◽  
Diagnostic System ◽  
Control Unit ◽  
Operating Conditions ◽  
Unit Testing ◽  
Hardware In The Loop ◽  
Ignition System ◽  
Input Signals ◽  
Instantaneous Position

The article presents simulator of injection-ignition system of internal combustion engine with spark ignition developed at the Technical University of Opole. This system is based on Bosch series engine ECU with software 7.5. It allows to analyze of motor parameters using both on-board diagnostic system, and data network CAN BUS under different operating conditions of the system. For this purpose, the simulator is equipped with a number of additional devices enable to generate repetitive input signals for the ECU, allowing to open the actual working conditions. Crucial for the simulator was to generate the signals informing ECU about the instantaneous position of the crankshaft and camshaft. For this purpose, the module Arduino was used. This type of solution allows, to recreate momentary engine operating conditions. This article also presents the concept of development with new features and sentences feasible for this type of device and simulation mode.

Multisensing Fuel Injector in Turbocharged Gasoline Direct Injection Engines

2014 ◽  
Vol 136 (11) ◽  
Author(s):  
Fadi Estefanous ◽  
Shenouda Mekhael ◽  
Tamer Badawy ◽  
Naeim Henein ◽  
Akram Zahdeh
Keyword(s):  
Combustion Engine ◽  
Direct Injection ◽  
Control Unit ◽  
Electric Circuit ◽  
Operating Conditions ◽  
Gasoline Direct Injection ◽  
Feedback Signal ◽  
Injection Timing ◽  
Fuel Injector ◽  
Spark Plug

With the increasingly stringent emissions and fuel economy standards, there is a need to develop new advanced in-cylinder sensing techniques to optimize the operation of the internal combustion engine. In addition, reducing the number of on-board sensors needed for proper engine monitoring over the lifetime of the vehicle would reduce the cost and complexity of the electronic system. This paper presents a new technique to enable one engine component, the fuel injector, to perform multiple sensing tasks in addition to its primary task of delivering the fuel into the cylinder. The injector is instrumented within an electric circuit to produce a signal indicative of some injection and combustion parameters in electronically controlled spark ignition direct injection (SIDI) engines. The output of the multisensing fuel injector (MSFI) system can be used as a feedback signal to the engine control unit (ECU) for injection timing control and diagnosis of the injection and combustion processes. A comparison between sensing capabilities of the multisensing fuel injector and the spark plug-ion sensor under different engine operating conditions is also included in this study. In addition, the combined use of the ion current signals produced by the MSFI and the spark plug for combustion sensing and control is demonstrated.

Design, Development, and Evaluation of a Control Framework for an Atkinson Cycle Engine

2017 ◽  
Vol 140 (5) ◽  
Author(s):  
G. Murtaza ◽  
A. I. Bhatti ◽  
Q. Ahmed
Keyword(s):  
Fuel Economy ◽  
Gasoline Engine ◽  
Thermodynamic Cycle ◽  
Mean Value ◽  
Operating Conditions ◽  
Intake Valve ◽  
Design Development ◽  
Engine Model ◽  
Atkinson Cycle ◽  
Control Framework

The efficiency of the spark ignition (SI) engine degrades while working at part loads. It can be optimally dealt with a slightly different thermodynamic cycle termed as an Atkinson cycle. It can be implemented in the conventional SI engines by incorporating advanced mechanisms as variable valve timing (VVT) and variable compression ratio (VCR). In this research, a control framework for the Atkinson cycle engine with flexible intake valve load control strategy is designed and developed. The control framework based on the extended mean value engine model (EMVEM) of the Atkinson cycle engine is evaluated in the view of fuel economy at the medium and higher load operating conditions for the standard new European driving cycle (NEDC), federal urban driving schedule (FUDS), and federal highway driving schedule (FHDS) cycles. In this context, the authors have already proposed a control-oriented EMVEM model of the Atkinson cycle engine with variable intake valve actuation. To demonstrate the potential benefits of the VCR Atkinson cycle VVT engine, for the various driving cycles, in the presence of auxiliary loads and uncertain road loads, its EMVEM model is simulated by using a controller having similar specifications as that of the conventional gasoline engine. The simulation results point toward the significant reduction in engine part load losses and improvement in the thermal efficiency. Consequently, considerable enhancement in the fuel economy of the VCR Atkinson cycle VVT engine is achieved over conventional Otto cycle engine during the NEDC, FUDS, and FHDS cycles.

Application of Variable Valve Actuation Strategies and Direct Gasoline Injection Schemes to Reduce Combustion Harshness and Emissions of Boosted HCCI Engine

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Jacek Hunicz ◽  
Maciej Mikulski
Keyword(s):  
Pressure Rise ◽  
Operating Conditions ◽  
Exhaust Valve ◽  
Boost Pressure ◽  
Pressure Reduction ◽  
Intake Valve ◽  
Valve Timing ◽  
Hcci Engine ◽  
Auto Ignition ◽  
The Impact

The present study investigates various measures to reduce pressure rise rates (PRRs) in a residual-affected homogeneous charge compression ignition (HCCI) engine. At the same time, the impact of those measures on efficiency and emissions is assessed. Experimental research was performed on a single cylinder engine equipped with a fully flexible valve train mechanism and direct gasoline injection. The HCCI combustion mode with exhaust gas trapping was realized using negative valve overlap (NVO) and fuel reforming, achieved via the injection of a portion of fuel during exhaust recompression. Three measures are investigated for the PRR control under the same reference operating conditions, namely: (i) variable intake and exhaust valve timing, (ii) boost pressure adjustment, and (iii) split fuel injection to control the amount of fuel injected for reforming. Variable exhaust valve timing enabled control of the amount of trapped residuals, and thus of the compression temperature. The reduction in the amount of trapped residuals, at elevated engine load, delays auto-ignition, which results in a simultaneous reduction of pressure rise rates and nitrogen oxides emissions. The effects of intake valve timing are much more complex because they include the variability in the amount of intake air, the thermodynamic compression ratio, as well as the in-cylinder fluid flow. It was found, however, that both early and late intake valve openings (IVOs) delay auto-ignition and prolong combustion. Additionally, the reduction of the amount of fuel injected during exhaust recompression further delays combustion and reduces combustion rates. Intake pressure reduction has by far the largest effect on peak pressure reduction yet is connected with excessive NOX emissions. The research successfully identifies air-path and injection techniques, which allow for the control of combustion rates and emissions under elevated load regime.

scholarly journals Analysis of scavenge port designs and exhaust valve profiles on the in-cylinder flow and scavenging performance in a two-stroke boosted uniflow scavenged direct injection gasoline engine

2017 ◽  
Vol 19 (5) ◽  
pp. 509-527 ◽  
Author(s):  
Xinyan Wang ◽  
Jun Ma ◽  
Hua Zhao
Keyword(s):  
Gasoline Engine ◽  
Direct Injection ◽  
Orientation Angle ◽  
Exhaust Valve ◽  
Direct Injection Gasoline Engine ◽  
Valve Opening ◽  
The Difference ◽  
Cylinder Flow ◽  
Exhaust Valves ◽  
Scavenging Efficiency

In this study, effects of intake scavenge port designs and exhaust valve opening profiles were studied on the scavenging process in a newly proposed two-stroke boosted uniflow scavenged direct injection gasoline engine by detailed three-dimensional engine simulations. As the most important geometric parameters, the axis inclination angle and swirl orientation angle of scavenge ports, as shown in Figure 1, were investigated and optimized for best scavenging performances at first. With the optimal axis inclination angle of 90° and swirl orientation angle of 20°, various combinations of scavenge port opening timing, exhaust valve opening duration and exhaust valve opening timing were then analysed. Four distinct scavenging periods, that is, early backflow period, backflow scavenging period, main scavenging period and post backflow period, were identified and their impacts on the in-cylinder flow motions and scavenging performances were investigated. The results show that the optimal scavenging performance can be achieved with a higher delivery ratio, charging efficiency and scavenging efficiency when the post backflow is just avoided by tuning the difference between the closing timings of scavenge ports and exhaust valves (Δ close) and the overlap between the opening profiles of scavenge ports and exhaust valves (Δ overlap) for a specific exhaust valve opening duration. A longer exhaust valve opening duration can be used to further improve the scavenging performances. In addition, the difference between the opening timings of scavenge ports and exhaust valves (Δ open) can be increased to improve scavenging efficiency. The Δ close also shows strong positive correlation with in-cylinder swirl ratio and negative correlation with tumble ratio. The results presented in this study provide the fundamental knowledge of the scavenging process in the uniflow scavenged two-stroke engine and assist the design of scavenge ports and valve strategies to optimize in-cylinder flow motion and scavenge performances in the two-stroke boosted uniflow scavenged direct injection gasoline engine with a variable valve actuation system for exhaust valves.

The Influence of Valve Port Design on the Volumetric Efficiency of the Compression-Ignition Engine

1948 ◽  
Vol 2 (1) ◽  
pp. 63-79
Author(s):  
C B. Dicksee
Keyword(s):  
Combustion Engine ◽  
Operating Conditions ◽  
Volumetric Efficiency ◽  
Valve Lift ◽  
Essential Difference ◽  
Compression Ignition ◽  
Fuel Injector ◽  
Compression Ignition Engine ◽  
Port Design ◽  
Valve Opening

In the paper the author discusses the cause of the loss of pressure in the induction system of an internal combustion engine, and also the essential difference between the breathing conditions of a carburetting engine and those of a compression-ignition engine, and the features which are peculiar to the latter. He gives particulars of some experiments on the influence of valve ports of different shapes upon the breathing of a given compression-ignition engine cylinder. The experiments cover the measurement of the pressure loss under a steady air flow as well as the effect upon the volumetric efficiency under actual operating conditions. The effect of a change in valve lift is discussed also. The results of the experiments show that the governing factor in volumetric efficiency is the velocity of the air at the actual valve opening, and that a Venturi form of port provides much needed room for the accommodation of the fuel injector, without any sacrifice in volumetric efficiency, by allowing a material reduction in diameter of the port at a short distance ahead of the valve opening. It does not, however, possess any other great advantage over a parallel port with an equal diameter of valve seat.

Sign in / Sign up

Export Citation Format

Share Document