Design of Cam Profile Based on Miller-Cycle

2010 ◽  
Vol 43 ◽  
pp. 588-593
Author(s):  
Sheng Li Wei ◽  
Wu Qiang Long ◽  
Zhong Wang ◽  
Xian Yin Leng
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Optimization Design ◽  
Valve Train ◽  
Miller Cycle ◽  
Intake Valve ◽  
Closing Time ◽  
Order Polynomial ◽  
Cam Profile ◽  
General Method

The necessity which high-order polynomials are used for optimization design of cam profile is analyzed in valve train of high-speed engines. Basing on the basic idea of Miller-cycle delayed intake valve closing time to reduce the compression ratio, this method is used for re-optimize design of the cam profile in CY4D47 diesel engine. The general method is given by the five-order polynomial. So, the improved cam profile equations can be obtained, then, the lift, velocity, acceleration and Jerk curves are got, lastly, the cam profile are drew by AutoCAD soft.

Improving the NOx-BSFC Trade Off of a Turbocharged Large Diesel Engine Using Performance Simulation

2002 ◽  
Author(s):  
Ki-Doo Kim ◽  
Dong-Hun Kim
Keyword(s):  
Experimental Data ◽  
Diesel Engine ◽  
Fuel Consumption ◽  
Fuel Injection ◽  
Nox Emission ◽  
Injection System ◽  
Miller Cycle ◽  
Intake Valve ◽  
Closing Time ◽  
Performance Simulation

The purpose of this study is to determine the optimum intake valve closing time of a large diesel engine having lower fuel consumption and lower NOx emission. The performance simulation has been conducted for this purpose, and a phenomenological combustion model is verified by experimental data of heat release rate and NOx emission in order to enhance the prediction quality of the performance simulation. The results of performance simulation are compared with measured data to confirm the modeling method and results. The fuel injection system simulation has been also performed to get fuel injection rate, and the results is also verified by experimental data of fuel injection pump pressure and injected fuel mass. The performance simulation investigate the application of Miller cycle to a large diesel engine, and so, the intake valve closing time is determined at the condition of reducing NOx emission and fuel consumption at the same time. As that result, Miller cycle has a feature that the maximum reduction of NOx emission is 15.7% while the improvement of specific fuel oil consumption is 1.7g/kWh.

Analysis and Optimization of High-Speed Gasoline Engine Cam Profile

2013 ◽  
Vol 278-280 ◽  
pp. 184-188
Author(s):  
Yuan Li ◽  
Jing Yang ◽  
Ke Li
Keyword(s):  
Contact Stress ◽  
High Speed ◽  
Gasoline Engine ◽  
Simulation Software ◽  
Valve Train ◽  
Intake Valve ◽  
Abnormal Sound ◽  
Cam Profile ◽  
Overall Performance ◽  
Train Simulation

In this paper, to solve the problems of tappet damaged seriously and mechanisms abnormal sound that existed in a high-speed gasoline engine, the valve train simulation software AVL-TYCON was applied to perform both kinematic and dynamic analysis. The results show that the original speed and acceleration curves of intake valve train are not smooth enough and the contact stress is excessive high. The intake cam was then redesign to improve the overall performance of the engine, and results are verified through experiments

Nonlinear Transient Response of a High Speed Driven Valve System and Stresses in Valve Springs for Internal Combustion Engines

1989 ◽  
Vol 111 (3) ◽  
pp. 264-271 ◽  
Author(s):  
K. Nagaya
Keyword(s):  
High Speed ◽  
Internal Combustion Engines ◽  
Three Dimensional ◽  
Beam Theory ◽  
Internal Combustion ◽  
Valve Train ◽  
Combination Method ◽  
Combustion Engines ◽  
Valve System ◽  
Cam Profile

This paper presents a method for solving the dynamic response problems of a driven valve system and the stress problem of valve springs for internal combustion engines. In this system there is hysteresis behavior in the spring constants during the rotation of the cam shaft. To treat this nonlinearity, the rigidity of each section is assumed to be one of a partly linear spring. For the valve trains, the cam profile is complex in general. To treat a general cam profile, this paper applies a combination method of the Fourier expansion, the Laplace transform and the analytical connection methods, and gives a response of valve trains. This paper also presents a theoretical result for the stresses in the valve spring due to the motion of the valve train based on the three dimensional curved beam theory.

Electromagnetic Valve Actuation System With Two Configurations

2009 ◽  
Author(s):  
Rudolf Seethaler ◽  
Konrad Duerr
Keyword(s):  
High Speed ◽  
Digital Simulation ◽  
Valve Train ◽  
Electromagnetic Valve ◽  
High Speed Engine ◽  
Actuation System ◽  
Control Scheme ◽  
Cam Profile ◽  
Actuation Devices ◽  
Valve Actuation

Electromagnetic valve actuation systems for automotive combustion engines must provide extremely fast valve motion when the engine speed is high, but they also need to ensure low valve seating velocities during engine idle. These two constraints are difficult to combine in conventional spring assisted electromagnetic valve actuation devices that operate at a fixed resonance frequency. This paper focuses on a mechanism with two distinct configurations for low and high speed engine operations respectively. The mechanism is based on two pivoting cams. The synthesis of the cam profile ultimately determines the performance of the actuation system. An algorithm is presented that provides a time optimum cam profile for the high speed cam. The low speed cam is designed to allow for servo control of the valve system. A control scheme that aims to minimize electric losses in the drive system is also introduced. Both the cam synthesis algorithms and the control algorithm are applied to a typical automotive valve train and a digital simulation is used to validate the effectiveness of the mechanical cam design and control scheme.

Study on the Intake Valve Close Timing Misalignment Between the Maximum Volume Efficiency and the None Backflow on a Single Cylinder Diesel Engine

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Fushui Liu ◽  
Zhongjie Shi ◽  
Yang Hua ◽  
Ning Kang ◽  
Yikai Li ◽  
...  
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Three Dimensional ◽  
Intake Valve ◽  
Maximum Volume ◽  
Single Cylinder ◽  
Gradual Process ◽  
The Mean ◽  
The Relationship ◽  
Volume Efficiency

Since the intake valve close timing (IVC) directly determines the amount of displacement backflow and the amount of fresh charge trapped in the cylinder, optimizing the IVC is important to improve the performance of the diesel engine. In this paper, the relationship between the IVC and the displacement backflow of the cylinder at the high-speed condition was studied by establishing a one-dimensional (1D) gas dynamic model of a single-cylinder diesel engine. The results show that the forward airflow mass of intake and the backflow increase as the IVC retards, and the airflow mass trapped in cylinder increases at first and then decreases. It is interesting to find that the backflow does not equal zero when the air mass trapped in cylinder is the largest, which is different from the traditional optimizing strategy on the IVC. That is to say, there exists a misalignment between the maximum-volume-efficiency IVC and the none-backflow IVC. To further verify this interesting misalignment, the airflow characteristics at the optimized IVC condition are studied by establishing a three-dimensional (3D) simulation. It is found that the appearance of backflow is a gradual process, and there exists an overall backflow when the engine volume efficiency reaches its maximum value. In addition, the misalignment is reduced as the mean valve-closing velocity increases. The misalignment equals to 0 only if the mean valve-closing velocity approaches infinity.

Dynamics Analysis and Cam Profile Optimal Design of the Valve Train in the Diesel Engine with High Specific Power

2011 ◽  
Vol 308-310 ◽  
pp. 1636-1640 ◽  
Author(s):  
Li Wei Sun ◽  
Tie Xiong Su ◽  
Jun Feng Xu ◽  
Qiang Wang ◽  
Chun Long Xu ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Optimal Design ◽  
Dynamic Analysis ◽  
Process Simulation ◽  
Valve Train ◽  
Specific Power ◽  
Intake Port ◽  
Working Process ◽  
High Specific Power ◽  
Cam Profile

The study carries out optimal design for the cam profile of the valve train in a high-specific-power diesel engine. The dynamic analysis on the original cam reveals that the original one, which leads to adequate fullness coefficient, is designed far from the material margins. The fullness coefficient and time area value are selected as the optimization objective, and the piecewise fucntion method is utilized to optimally design the cam profile. The restrictive contidons are applied to each section on the cam. Thus the function and the optimal coeficients are obtained. Then the dynamic analysis and working process simulation on the optimal valve train are carried out, and it proves that the dynamic and intake port performaces of the optimized one are greatly impoved.

Dynamics Optimization for the Valve Train of a Diesel Engine

2011 ◽  
Vol 117-119 ◽  
pp. 565-569
Author(s):  
Hai Yan Liu ◽  
Xiao Bo Wang ◽  
Wen Jie Qin
Keyword(s):  
Diesel Engine ◽  
Optimization Design ◽  
Response Surfaces ◽  
Valve Train ◽  
Dynamics Model ◽  
Valve Seat ◽  
Simulation Experiments ◽  
Maximum Acceleration ◽  
Spring Force ◽  
Multi Body

The parameterized multi-body system dynamics model of the valve train of a diesel engine is built in ADAMS. The spring stiffness, spring force, valve mass and valve stiffness are set as experimental factors, and valve seat force and maximum acceleration are set as responses. Dynamic simulation experiments are carried out using design of experiment (DOE) method, from which the notable factors are obtained. The functions of response surfaces on notable factors are gotten, and then optimization design is implemented based on response surfaces.

Design and Performance of a Variable Valve Timing System on a Highly Turbocharged Diesel Engine—Experimental and Predicted Results

1995 ◽  
Vol 209 (4) ◽  
pp. 297-311 ◽  
Author(s):  
C R Stone ◽  
H J Leonard ◽  
C Elliott ◽  
M J Newman ◽  
S J Charlton ◽  
...  
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Reverse Flow ◽  
Valve Train ◽  
Variable Valve Timing ◽  
Valve Timing ◽  
Single Cylinder ◽  
Cycle Simulation ◽  
Timing System ◽  
Variable Valve

A previous study using a cycle simulation program had identified the possibility that highly rated diesel engines might benefit from a variable valve timing (VVT) system. In particular, the study had shown that, by delaying the start of inlet valve opening at part load, it should be possible to eliminate the reverse flow that can lead to inlet port fouling. The work reported here encompasses the design and implementation of a variable valve timing system on a highly rated high-speed marine diesel engine. The principal topics addressed are the selection and design of a mechanism, a comparison between the predictions and results from mechanism testing on a single-cylinder valve-train rig and the engine performance predictions and results obtained when the mechanism was tested on the engine. The results from the single-cylinder test rig demonstrated that the mechanism performed satisfactorily, and this led to a design suitable for retro-fitting to the engine. The engine was comprehensively instrumented and the experimental results were in good agreement with the cycle simulation predictions.

scholarly journals Kinematic Analysis of Polydyne Cam Profile of A Diesel Engine

2020 ◽  
Vol 9 (6) ◽  
pp. 759-762
Keyword(s):  
Diesel Engine ◽  
Internal Combustion Engine ◽  
Kinematic Analysis ◽  
Combustion Engine ◽  
Gear Train ◽  
Order Polynomial ◽  
Cam Profile ◽  
Overall Efficiency ◽  
Insight Into ◽  
Valve Gear

This research paper tends to have an insight into the dynamics of cam and tappet of diesel engine which is supposed to work continuously for a longer period under huge variable loads to operate the valves of an internal combustion engine. The dynamics of valve gear train is so elemental in the due functioning of an engine. In this research, the analysis of five-order polynomial cam has been done to find the profile of displacement, velocity, acceleration and jerk for the suitability of diesel engines. The MATLAB software has been used as the vital aid in this analysis. This insight would sure be helpful in improving the mechanism of cam profile generation leading to betterment of camshaft design so as to increase the overall efficiency of the engine.

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