Combustion Analysis on a Variable Valve Actuation Spark Ignition Engine Operating With E22 and E100

2017 ◽  
Author(s):  
Igor Trevas ◽  
Adm José baeta ◽  
Charles Pimenta ◽  
Heder Fernandes ◽  
Matheus Carvalho ◽  
...  
Keyword(s):  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Combustion Analysis ◽  
Variable Valve Actuation ◽  
Variable Valve ◽  
Valve Actuation

Experimental Investigation of Internal Exhaust Gas Recirculation on a Variable Valve Actuation Spark Ignition Engine Operating with Gasoline and Ethanol

2016 ◽  
Author(s):  
Heder Fernandes ◽  
Charles Quirino Pimenta ◽  
Wanderson Navegantes Rodrigues ◽  
Raphael Bezerra de Souza Montemor ◽  
José Eduardo Mautone Barros
Keyword(s):  
Experimental Investigation ◽  
Exhaust Gas Recirculation ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Exhaust Gas ◽  
Variable Valve Actuation ◽  
Variable Valve ◽  
Gas Recirculation ◽  
Valve Actuation

A numerical procedure for the calibration of a turbocharged spark-ignition variable valve actuation engine at part load

2016 ◽  
Vol 18 (8) ◽  
pp. 810-823 ◽  
Author(s):  
Fabio Bozza ◽  
Vincenzo De Bellis ◽  
Luigi Teodosio
Keyword(s):  
Fuel Consumption ◽  
Spark Ignition ◽  
Specific Fuel Consumption ◽  
Brake Specific Fuel Consumption ◽  
Valve Closure ◽  
Intake Valve ◽  
Part Load ◽  
Variable Valve Actuation ◽  
Variable Valve ◽  
Valve Actuation

Referring to spark-ignition engines, the downsizing, coupled to turbocharging and variable valve actuation systems are very common solutions to reduce the brake-specific fuel consumption at low-medium brake mean effective pressure. However, the adoption of such solutions increases the complexity of engine control and management because of the additional degrees of freedom, and hence results in a longer calibration time and higher experimental efforts. In this work, a twin-cylinder turbocharged variable valve actuation spark-ignition engine is numerically investigated by a one-dimensional model (GT-Power™). The considered engine is equipped with a fully flexible variable valve actuation system, realizing both a common full-lift strategy and a more advanced early intake valve closure strategy. Refined sub-models are used to describe turbulence and combustion processes. In the first stage, one-dimensional engine model is validated against the experimental data at full and part load. The validated model is then integrated in a multipurpose commercial optimizer (modeFRONTIER™) with the aim to identify the engine calibration that minimizes brake-specific fuel consumption at part load. In particular, the decision parameters of the optimization process are the early intake valve closure angle, the throttle valve opening, the turbocharger setting and the spark timing. Proper constraints are posed for intake pressure in order to limit the gas-dynamic noise radiated at the intake mouth. The adopted optimization approach shows the capability to reproduce with good accuracy the experimentally identified calibration. The latter corresponds to the numerically derived Pareto frontier in brake mean effective pressure–brake specific fuel consumption plane. The optimization also underlines the advantages of an engine calibration based on a combination of early intake valve closure strategy and intake throttling rather than a purely throttle-based calibration. The developed automatic procedure allows for a ‘virtual’ calibration of the considered engine on completely theoretical basis and proves to be very helpful in reducing the experimental costs and the engine time-to-market.

Potential of the Variable Valve Actuation (VVA) Strategy on a Heavy Duty CNG Engine

2014 ◽  
Author(s):  
Mirko Baratta ◽  
Roberto Finesso ◽  
Daniela Misul ◽  
Ezio Spessa ◽  
Yifei Tong ◽  
...  
Keyword(s):  
Fuel Consumption ◽  
Operating Conditions ◽  
Intake Valve ◽  
Heavy Duty ◽  
Engine Emissions ◽  
Variable Valve Actuation ◽  
Cng Engine ◽  
Variable Valve ◽  
Working Point ◽  
Valve Actuation

The environmental concerns officially aroused in 1970s made the control of the engine emissions a major issue for the automotive industry. The corresponding reduction in fuel consumption has become a challenge so as to meet the current and future emission legislations. Given the increasing interest retained by the optimal use of a Variable Valve Actuation (VVA) technology, the present paper investigates into the potentials of combining the VVA solution to CNG fuelling. Experiments and simulations were carried out on a heavy duty 6-cylinders CNG engine equipped with a turbocharger displaying a twin-entry waste-gate-controlled turbine. The analysis aimed at exploring the potentials of the Early Intake Valve Closure (EIVC) mode and to identify advanced solutions for the combustion management as well as for the turbo-matching. The engine model was developed within the GT-Power environment and was finely tuned to reproduce the experimental readings under steady state operations. The 0D-1D model was hence run to reproduce the engine operating conditions at different speeds and loads and to highlight the effect of the VVA on the engine performance as well as on the fuel consumption and engine emissions. Pumping losses proved to reduce to a great extent, thus decreasing the brake specific fuel consumption (BSFC) with respect to the throttled engine. The exhaust temperature at the turbine inlet was kept to an almost constant value and minor variations were allowed. This was meant to avoid an excessive worsening in the TWC working conditions, as well as deterioration in the turbocharger performance during load transients. The numerical results also proved that full load torque increases can be achieved by reducing the spark advance so that a higher enthalpy is delivered to the turbocharger. Similar torque levels were also obtained by means of Early Intake Valve Closing strategy. For the latter case, negligible penalties in the fuel consumption were detected. Moreover, for a given combustion phasing, the IVC angle directly controls the mass-flow rate and thus the torque. On the other hand, a slight dependence on the combustion phasing can be detected at part load. Finally, the simulations assessed for almost constant fuel consumption for a wide range of IVC and SA values. Specific attention was also paid to the turbocharger group functioning and to its correct matching to the engine working point. The simulations showed that the working point on the compressor map can be optimized by properly setting the spark advance (SA) as referred to the adopted intake-valve closing angle. It is anyhow worth observing that the engine high loads set a constraint deriving from the need to meet the limits on the peak firing pressure (PFP), thus limiting the possibility to optimize the working point once the turbo-matching is defined.

Experimental research on pumping losses and combustion performance in an unthrottled spark ignition engine

2018 ◽  
Vol 232 (7) ◽  
pp. 888-897 ◽  
Author(s):  
Tingting Sun ◽  
Yingjie Chang ◽  
Zongfa Xie ◽  
Kaiyu Zhang ◽  
Fei Chen ◽  
...  
Keyword(s):  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Valve Lift ◽  
Combustion Characteristic ◽  
Spark Ignition Engines ◽  
Intake Valve ◽  
Valve System ◽  
Combustion Performance ◽  
Intake Swirl ◽  
Variable Valve

A novel fully hydraulic variable valve system is described in this paper, which achieves continuous variations in maximum valve lift, valve opening duration, and the timing of valve closing. The load of the unthrottled spark ignition engine with fully hydraulic variable valve system is controlled by using an early intake valve closing rather than the conventional throttle valve. The experiments were carried out on BJ486EQ spark ignition engine with fully hydraulic variable valve system. Pumping losses of the throttled and unthrottled spark ignition engines at low-to-medium loads are compared and the reason of it decreasing significantly in the unthrottled spark igntion engine is analyzed. The combustion characteristic parameters, such as cyclic variation, CA50, and heat release rate, were analyzed. The primary reasons for the lower combustion rate in the unthrottled spark ignition engines are discussed. In order to improve the evaporation of fuel and mix with air in an unthrottled spark ignition engine, the in-cylinder swirl is organized with a helical intake valve, which can generate a strong intake swirl at low intake valve lifts. The effects of the intake swirl on combustion performance are investigated. Compared with the throttled spark ignition engine, the brake specific fuel consumption of the improved unthrottled spark ignition engine is reduced by 4.1% to 11.2%.

Sign in / Sign up

Export Citation Format

Share Document