The study of the effect of intake valve timing on engine using cylinder deactivation technique via simulation

There are many technologies that being developed to increase the efficiency of internal combustion engines as well as reducing their fuel consumption. In this paper, the main area of focus is on cylinder deactivation (CDA) technology. CDA is mostly being applied on multi cylinders engines. CDA has the advantage to improve fuel consumption by reducing pumping losses at part load engine conditions. Here, the application of CDA on 1.6L four cylinders gasoline engine is studied. One-dimensional (1D) engine modeling work is performed to investigate the effect of intake valve strategy on engine performance with CDA. 1D engine model is constructed based on the 1.6L actual engine geometries. The model is simulated at various engine speeds at full load conditions. The simulated results show that the constructed model is well correlated to measured data. This correlated model is then used to investigate the CDA application at part load conditions. Also, the effects on the in-cylinder combustion as well as pumping losses are presented. The study shows that the effect of intake valve strategy is very significant on engine performance. Pumping losses is found to be reduced, thus improve fuel consumption and engine efficiency

Simulation of fuel economy for Malaysian urban driving

By understanding the implications of real-world driving conditions, improved fuel economy via a strategy of key technologies can be implemented to assist fuel economy validation during development programs. Vehicles in real-world driving conditions regularly travel at idle, low and medium speeds, particularly for urban driving, and this has a crucial weight in overall vehicle fuel economy, given the residencies at the lower engine speed and load region. This paper presents the validation of the derived engine conditions representing Malaysian actual urban driving in an attempt to formulate representative fuel economy data. The measurements were conducted through on-road urban driving within Kuala Lumpur to establish representative driving conditions. The effectiveness of the proposed conditions was then validated in terms of fuel economy using a simulation. The discrepancy between the fuel economy in the proposed conditions and the real-world measurements has improved, falling to 11.9% compared to 43.1% reported by the NEDC

Discharge and flow coefficient analysis in internal combustion engine using computational fluid dynamics simulation

Intake system is one of the crucial sub-systems in engine which can inflict significant effect on the air-fuel mixing, combustion, fuel consumption, as well as exhaust gases formation. There are many parameters that will influence engine performances. Good engine breathing is required to get better air flow rate to the engine. One of the methods includes the improvement of intake system by modifying the intake port design. This paper presents the application of Computational Fluid Dynamics analysis on two engines with different intake port shapes. Dimensionless parameters like discharge coefficient and flow coefficient are used to quantify the changes in intake flow at different valve lifts variation. Results show that when valve lift increases, this inflicted the increase in discharge coefficient because of greater mass flow rate of induction air. Both flow and discharge coefficient is dependent on valve lift. Flow analysis proved the relationship by computing the increase of flow coefficient as valve opening increase. The computed analysis shows that different intake port shapes does bring significant effect on discharge coefficient and flow coefficient

Experimental study to identify common engine part load conditions between Malaysian city driving and NEDC test

This paper describes an experimental study conducted to identify the common engine part load conditions between Malaysian city driving and NEDC (New European Driving Cycle) test on a 4 cylinder gasoline fuelled engine, with multi-point fuel injection system, and continuous variable transmission vehicle. This is to pinpoint a regional area from the part load map in the attempt to strategize key technologies such as CDA (Cylinder Deactivation) or CNG (Compressed Natural Gas). Technologies such as CDA or CNG do not operate at all engine operations. Due to certain drawbacks, the operation of the technologies must be strategized to obtain most benefit from the engine. With the knowledge of the common part load region, these technologies could be integrated and strategized into the region to reduce overall fuel consumption. With improvements in fuel consumption respective to the identified common part load operations, the overall fuel consumption benefit does not only serve the legislation but also most importantly benefit the local consumers who travel on Malaysian roads. Copyright © 2009 Praise Worthy Prize S.r.l. - All rights reserved

Cold flow analysis on internal combustion engine with different piston bowl configurations

Development of engine in automotive industry is deemed critical in order to fulfil demands by passengers and also due to pressure bring forward by the fact of stringent government law for protecting noise and air quality. In order to improve engine quality, understanding on flow properties in engine cylinder is of major importance because flow condition significantly influences engine efficiency. Capabilities in providing optimum flow conditions which include high discharge coefficient, optimum swirl ratio, and optimum tumble ratio in respective engine can result in enhancement of engine power and comfort, along with reduction of fuel consumption, exhaust emission and noise. This research aims to investigate the effect of different piston bowl configurations on in-cylinder flow characteristics. Cold flow simulation is used to compare in-cylinder flow for engine with three different piston bowls during intake stroke and compression stroke. Simulation analysis represents the flow properties in term of swirl ratio and tumble ratio. Result computed from this analysis shows that piston bowl geometry has little influence on in-cylinder flow during intake stroke. However, piston bowls configurations inflicted significant effect on flow during compression stroke especially near top-dead-centre. This analysis defined that at the end of compression stroke, engine model with toroidal shape piston give 34.8% improvement in term of swirl ratio and 7% improvement of tumble ratio value compared to original piston bowl shapes

Simulation of intake and exhaust valve timing on internal combustion engine

Internal combustion engine in automotive industry is widely researched to increase its efficiency and power output. Valve system in modern internal combustion engine controls the opening and closing timing of intake and exhaust stroke. Its duration affects the performance of the engine at both power output and fuel efficiency. Therefore, this study discusses about the Miller cycle concept that alters the duration of both intake and exhaust valve opening and closing characteristics. The study focuses mainly on finding the optimum timing characteristics on Proton Iriz gasoline engine. A 1-dimensional model has been built using a commercial software called GT-POWER for engine simulation purpose. The engine is then calibrated with the simulation model. The optimization was run in this software to find the best optimum timing of intake and exhaust valve for two categories which are targeting performance and fuel consumption. The results show positive trends in the BSFC results with the maximum percentage difference of 26.27% at 6,250 rpm. The average percentage difference in the BSFC results is 14.12%. For targeting performance, the overall results show an increasing trend in the brake torque curves with maximum percentage difference is 9.83%. The average percentage difference in brake torque is found to be 3.12%. Therefore, this paper concludes that Miller cycle implementation gives minimal performance increment. The targeting performance and fuel consumption optimization can also be implemented for changing mode of driving. However, the increase compression ratio would also give adverse effects on engine performance and endurance. The Miller cycle is also more suitable to be implemented on force induction system

Simulation of fuel economy for Malaysian urban driving

By understanding the implications of real-world driving conditions, improved fuel economy via a strategy of key technologies can be implemented to assist fuel economy validation during development programs. Vehicles in real-world driving conditions regularly travel at idle, low and medium speeds, particularly for urban driving, and this has a crucial weight in overall vehicle fuel economy, given the residencies at the lower engine speed and load region. This paper presents the validation of the derived engine conditions representing Malaysian actual urban driving in an attempt to formulate representative fuel economy data. The measurements were conducted through on-road urban driving within Kuala Lumpur to establish representative driving conditions. The effectiveness of the proposed conditions was then validated in terms of fuel economy using a simulation. The discrepancy between the fuel economy in the proposed conditions and the real-world measurements has improved, falling to 11.9% compared to 43.1% reported by the NEDC

COLD FLOW ANALYSIS ON INTERNAL COMBUSTION ENGINE WITH DIFFERENT PISTON BOWL CONFIGURATIONS

Development of engine in automotive industry is deemed critical in order to fulfil demands by passengers and also due to pressure bring forward by the fact of stringent government law for protecting noise and air quality. In order to improve engine quality, understanding on flow properties in engine cylinder is of major importance because flow condition significantly influences engine efficiency. Capabilities in providing optimum flow conditions which include high discharge coefficient, optimum swirl ratio, and optimum tumble ratio in respective engine can result in enhancement of engine power and comfort, along with reduction of fuel consumption, exhaust emission and noise. This research aims to investigate the effect of different piston bowl configurations on in-cylinder flow characteristics. Cold flow simulation is used to compare incylinder flow for engine with three different piston bowls during intake stroke and compression stroke. Simulation analysis represents the flow properties in term of swirl ratio and tumble ratio. Result computed from this analysis shows that piston bowl geometry has little influence on in-cylinder flow during intake stroke. However, piston bowls configurations inflicted significant effect on flow during compression stroke especially near top-dead-centre. This analysis defined that at the end of compression stroke, engine model with toroidal shape piston give 34.8% improvement in term of swirl ratio and 7% improvement of tumble ratio value compared to original piston bowl shapes

Comparative analysis of different engine operating parameters for on-board fuel octane number classification

The comparative analysis on combustion of commercial gasoline with research octane number (RON) 95, 97, and 100 was carried out on a spark ignition (SI) engine under different engine speeds, loads and spark advances. The RON classification procedure was investigated using regression analysis and artificial neural network (ANN) by executing the combustion properties derived from the in-cylinder pressure signal and engine rotational speed signal. The results showed a special pattern for each fuel RON; these patterns were obtained using the peak in-cylinder pressure, maximum rate of pressure rise, and maximum amplitude of pressure oscillations. In addition, a pre-defined threshold or formula is necessary to restrict the implementation of these parameters for on-board fuel identification. Lastly, the confusion matrix that provided the ANN model efficiency for RON classification had the highest accuracy when the pressure signal was employed as the network input for all spark advance timing. However, the ANN model with rotational speed signal input could only identify the fuel octane number after a specific advance timing that was detected at the beginning of noisy combustion because of knock. The confusion matrix for the ANN with speed signal input increased from 68.1% to 100% when ignition advanced from −10° to −30° before top dead center. The results established the feasibility of use of the rotational speed signal as the input for an ANN model to identify different fuel octane number patterns