scholarly journals The tuning of a small four-stroke spark ignition engine for flexible valve timings through numerical approach

2019 ◽  
Vol 255 ◽  
pp. 04004
Author(s):  
M. Haziq Adham Rosli ◽  
M. Razali Hanipah ◽  
Maurice Kettner
Keyword(s):  
Combustion Engine ◽  
Engine Performance ◽  
Numerical Approach ◽  
Spark Ignition Engine ◽  
Variable Valve Timing ◽  
Intake Valve ◽  
Valve Timing ◽  
Engineering Research ◽  
Numerical Assessment ◽  
Variable Valve

Variable valve timing has been implemented by various manufacturers to improve internal combustion engine performance while operating at wide speed and load ranges. A novel flexible valve timing system for a small four-stroke engine is currently under development by Automotive Engineering Research Group (AERG) in Universiti Malaysia Pahang (UMP). In this paper, a comprehensive intake and exhaust tuning for the flexible variable valve timing is presented. A numerical assessment has been conducted through one dimensional engine modelling and simulation using validated model. There are eight valve timing configurations investigated for the tuning for three main speed regions. The simulation shows a positive and significant impact to the engine performance in three approaches; namely late intake valve closing, early intake valve closing and late exhaust valve closing. These approaches sufficiently covered the whole range of engine speeds for optimum engine operational performance.

Numerical Calibration of Diesel Engine Variable Valve Timing

2012 ◽  
Vol 516-517 ◽  
pp. 628-633
Author(s):  
Sheng Ou Hu ◽  
Ren Xian Li
Keyword(s):  
Diesel Engine ◽  
Working Conditions ◽  
Combustion Engine ◽  
Engine Performance ◽  
Simulation Method ◽  
Calibration Method ◽  
Operating Conditions ◽  
Variable Valve Timing ◽  
Valve Timing ◽  
Variable Valve

The performance of internal combustion engine can be improved by using variable valve timing technology. but how to get the optimal inlet/export valve open or close angles under various operating conditions still relies mainly on testing calibration method. By means of one-dimensional working process simulation method, the performance of a four cylinder diesel engine was simulated, and the influences of diffrent inlet/export valve timing on engine performances were compared. Optimum valve timing values and engine performances under thirty kinds of working conditions were gotton. After that, the engine performances compared with that without variable valve timing. Simulation results show that the engine performance, especially the emission performance, can be improved at all simulation working conditions. The method used in this paper may be a new way for calibration of optimal valve timing.

scholarly journals PENCAPAIAN PERFORMA PADA KATUP VARIABEL TIMING FIXED TIMING UNTUK MESIN YANG OPTIMAL

2012 ◽  
Vol 11 (1) ◽  
pp. 68
Author(s):  
KETUT ASTAWA
Keyword(s):  
Engine Performance ◽  
Variable Valve Timing ◽  
Intake Valve ◽  
Valve Timing ◽  
Static Test ◽  
Load Transmission ◽  
Valve Opening ◽  
Efficient Machine ◽  
Hc Emissions ◽  
Variable Valve

Problems will be discussed in this research is how differences in exhaust emissions generatedby engine with variable valve timing and valve timing on a fixed volume of motor vehiclecylinder 1300 cc. Variable valve timing technology, which is set when opening and closingthe intake valve (intake valve) electronic fuel according to engine conditions. This will makemixing air and fuel that enters into an efficient machine that will produce great power, fueleconomy and low emissions. Research emissions (CO, CO2, HC, O2) was performedwith dynamictesting, where the vehicle in a state of the load lifted and given transmission. Unlikethe testing generally performed with a static test, in which the vehicle is at rest and without aload. This test is performed to determine how the condition of exhaust gases when the vehicledynamic (analogous to the vehicle running). In general, machines with variable valve timingto produce better emissions than engines with fixed valve timing. The higher the spin machineand load transmission system will result in CO and HC emissions are decreased and O2 andCO2 increased. Engine with variable valve timing control the suction valve opening times toachieve optimum engine performance at various driving conditions. And set out the engineoutput as needed.

Study on Non-Axisymmetric 3D Curved Surface Turning by Driven-Type Rotary Tool Synchronized With Spindle

2021 ◽  
Author(s):  
Akane Ishizuka ◽  
Narimasa Ueda ◽  
Yoshitaka Morimoto ◽  
Akio Hayashi ◽  
Yoshiyuki Kaneko ◽  
...  
Keyword(s):  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Curved Surface ◽  
Variable Valve Timing ◽  
Valve Timing ◽  
Cam Mechanism ◽  
Rotary Tool ◽  
Variable Valve ◽  
New System

Abstract Since shifting to electric vehicles as a countermeasure against global warming is not always easy to complete, the hybrid car has been considered as another possible solution. However, based on the calculation of total CO2 emissions, all hybrid cars which will constitute 90% of all cars are expected to be equipped with an internal combustion engine even after 2030. Therefore, further efficiency improvement of the internal combustion engine is necessary. One of the key factors is the variable valve timing and variable lift with the 3D cam mechanism. Since conventional technology uses a complicated link mechanism and servo motor control, this leads a problem to set into small cars or motorcycles because they cannot afford to install the variable valve timing and variable lift with cam mechanism. To solve this problem, a cam shape with a three-dimensional curved surface has been proposed. In order to create this shape, the machining method for non-axisymmetric curved surface turning (NACS-Turning) is required. To build the new system, our research group has proposed a new machining method using a driven type rotary tool and a linear motor driven moving table to enable to achieve NACS-Turning. In this new system, a new tool rotation axis (B axis) is adopted to synchronize its rotational position with the rotational position of the spindle (C axis) holding the workpiece, the X1-, X2-, and Z-Axis positions in total. In this paper, the new hardware configuration is proposed to overcome the present machining accuracy.

scholarly journals FEASIBILITY OF BACKFIRE CONTROL AND PERFORMANCE USING CHANGES OF VALVE OVERLAP PERIOD FOR A HYDROGEN-FUELED ENGINE WITH EXTERNAL MIXTURE

2009 ◽  
Vol 12 (14) ◽  
pp. 77-85
Author(s):  
Cong Thanh Huynh ◽  
Kang Joon-Kyoung ◽  
Noh Ki-Cholo ◽  
Lee Jong-Tai ◽  
Mai Xuan Pham
Keyword(s):  
High Efficiency ◽  
Engine Performance ◽  
Continuous Variable ◽  
Variable Valve Timing ◽  
Valve Timing ◽  
Performance Loss ◽  
Wide Range ◽  
And Performance ◽  
Variable Valve ◽  
Valve Overlap

The development of a hydrogen-fueled engine using an external mixture (e.g., using port injection) with high efficiency and high power is dependent on the control of backfire. This work has developed a method to control backfire by reducing the valve overlap period. For this goal, a single-cylinder hydrogen-fueled research engine with a mechanical continuous variable valve timing (MCVVT) system was developed. This facility provides a wide range of valve overlap periods that can be continuously and independently varied during firing operation. In experiments, the behavior of backfire occurrence and engine performance are determined as functions of the valve overlap period for fuel-air equivalence ratios between 0.25 and 1.2. The results showed that the research engine with the MCVVT system has similar performance to a conventional engine, and is especially effective in controlling the valve overlap period. The obtained results demonstrate that decreasing the valve overlap period may be one of the methods for controlling backfire in a H engine. Also, a method for compensating performance loss due to shortened valve overlap period is recommended.

Factors influencing the burn rate characteristics of a spark ignition engine with variable valve timing

2008 ◽  
Vol 222 (11) ◽  
pp. 2147-2158 ◽  
Author(s):  
F Bonatesta ◽  
P J Shayler
Keyword(s):  
Mass Fraction ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Variable Valve Timing ◽  
Valve Timing ◽  
Spark Timing ◽  
Piston Speed ◽  
Flame Development ◽  
Variable Valve ◽  
Valve Overlap

The charge burn characteristics of a four-cylinder port-fuel-injected spark ignition engine fitted with a dual independent variable-valve-timing system have been investigated experimentally. The influence of valve timings on the flame development angle and the rapid burn angle is primarily associated with valve overlap values and internal gas recirculation. Conditions examined cover light to medium loads and engine speeds up to 3500r/min. As engine loads and speeds exceeded about 6bar net indicated mean effective pressure and 3000r/min respectively, combustion duration was virtually independent of the valve timing setting. At lower speeds and work output conditions, valve timing influenced burn angles through changes in dilution mass fraction, charge density, and charge temperature. Of these, changes in dilution mass fraction had the greatest influence. Increasing the dilution by increasing the valve overlap produced an increase in both burn angles. The effects of mean piston speed and spark timing have also been examined, and empirical expressions for the flame development and the rapid burn angles are presented.

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