scholarly journals Throttleless control of SI engine load by fully flexible inlet valve actuation system

2016 ◽  
Vol 164 (1) ◽  
pp. 44-48
Author(s):  
Zbigniew ŻMUDKA ◽  
Stefan POSTRZEDNIK ◽  
Grzegorz PRZYBYŁA
Keyword(s):  
Charge Exchange ◽  
Spark Ignition Engine ◽  
Inlet Valve ◽  
Inlet System ◽  
Engine Load ◽  
Actuation System ◽  
Partial Load ◽  
Effective Efficiency ◽  
Cycle Efficiency ◽  
Valve Actuation

A system with independent, early inlet valve closure (EIVC) has been analysed. The open, theoretical cycle has been assumed as a model of processes proceeding in the engine with variable inlet valve actuation. The system has been analysed individually and comparatively with open Seiliger-Sabathe cycle which is theoretical cycle for the classic throttle governing of engine load. The influence of EIVC on fuel economy, cycle work, relative charge exchange work and cycle efficiency has been theoretically investigated. The use of the analysed system to governing of an engine load will enable to eliminate a throttling valve from inlet system and reduce the charge exchange work, especially within the range of partial load. The decrease of the charge exchange work leads to an increase of the internal and effective works, which results in an increase of the effective efficiency of the spark ignition engine.

scholarly journals Improving the effective efficiency of a spark ignition engine through the use of a fully independent valve control system

2021 ◽  
Author(s):  
Zbigniew Żmudka ◽  
Stefan Postrzednik
Keyword(s):  
Charge Exchange ◽  
Spark Ignition Engine ◽  
Theoretical Research ◽  
Si Engine ◽  
Load Range ◽  
Engine Operation ◽  
Engine Load ◽  
Effective Work ◽  
Partial Load ◽  
Valve Control

The article presents theoretical research of the proposed system of fully independent valve control (FIVC) of the SI engine. The analysis included controlling the movement of the intake valves, which results in adjusting the mass of the fresh charge to the current engine load, as well as the movement of the exhaust valves, where the main aim is to keep the rest of the exhaust gas in the cylinder, i.e. implementation of internal EGR. The open theoretical Seiliger-Sabathe cycle with the classic throttle regulation of load is the reference cycle for assessment of benefits and study of the effectiveness of obtaining work as a result of application of the FIVC system. A comparative analysis of the effectiveness of application of the proposed system was carried out based on the selected quantities: fuel dose, cycle work, relative work of charge exchange and cycle efficiency. The use of the FIVC to regulate the SI engine load makes it possible to eliminate the throttle and thus reduce the charge exchange work, especially in the partial load range. And this then leads to an increase in internal and effective work, which in turn results in an increase in the effective energy efficiency of an engine operation.

scholarly journals Realization of the Atkinson-Miller cycle in spark-ignition engine by means of the fully variable inlet valve control system

2014 ◽  
Vol 35 (3) ◽  
pp. 191-205 ◽  
Author(s):  
Zbigniew Żmudka ◽  
Stefan Postrzednik ◽  
Grzegorz Przybyła
Keyword(s):  
Charge Exchange ◽  
Flow Resistance ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Miller Cycle ◽  
Inlet Valve ◽  
Engine Operation ◽  
Engine Load ◽  
Part Load ◽  
Valve Control

Abstract The theoretical analysis of the charge exchange process in a spark ignition engine has been presented. This process has significant impact on the effectiveness of engine operation because it is related to the necessity of overcoming the flow resistance, followed by the necessity of doing a work, so-called the charge exchange work. The flow resistance caused by the throttling valve is especially high during the part load operation. The open Atkinson-Miller cycle has been assumed as a model of processes taking place in the engine. Using fully variable inlet valve timing the A-M cycle can be realized according to two systems: system with late inlet valve closing and system with early inlet valve closing. The systems have been analysed individually and comparatively with the open Seiliger-Sabathe cycle which is a theoretical cycle for the classical throttle governing of the engine load. Benefits resulting from application of the systems with independent inlet valve control have been assessed on the basis of the selected parameters: fuel dose, cycle work, charge exchange work and a cycle efficiency. The use of the analysed systems to governing of the SI engine load will enable to eliminate a throttling valve from the system inlet and reduce the charge exchange work, especially within the range of part load operation.

Development of a variable mode valve actuation system for a heavy-duty engine

2020 ◽  
Vol 234 (10-11) ◽  
pp. 2618-2633
Author(s):  
Yang Wang ◽  
Wuqiang Long ◽  
Jingchen Cui ◽  
Hua Tian ◽  
Xiangyu Meng ◽  
...  
Keyword(s):  
Solenoid Valve ◽  
Valve Lift ◽  
Heavy Duty ◽  
Driving Mode ◽  
Actuation System ◽  
Failure State ◽  
Body Dynamics ◽  
Variable Mode ◽  
Multi Body ◽  
Valve Actuation

A new variable mode valve actuation system for a heavy-duty engine was proposed and designed in this paper. The variable mode valve actuation system can significantly enhance braking safety and improve fuel economy and emission of heavy-duty engines through flexible switching among four-stroke driving mode, two-stroke compression-release braking mode, and cylinder deactivation mode on a conventional four-stroke engine. The switching was controlled by four-stroke driving modules and two-stroke braking modules, both of which have two operation states: effective state and failure state. For the control of the multi-cylinder engine, all cylinders can be divided into several groups, and all the four-stroke driving modules in the same group were controlled by one solenoid valve, as well as all the two-stroke braking modules were controlled by another solenoid valve. A hydraulic-mechanical multi-body dynamics model was established to investigate the switching response of the variable mode valve actuation system. The results indicated that when the engine operated at 2000 r/min, the switching of the four-stroke driving module and the two-stroke braking module required 30 °CA and 101 °CA at most, respectively. In addition, to avoid the conflict between the four-stroke driving valve lift and the two-stroke braking valve lift, the switching between the four-stroke driving mode and the two-stroke compression-release braking mode must have a reasonable sequence. The variable mode valve actuation system has an excellent switching response and it is convenient for the control of the multi-cylinder engine. Therefore, the variable mode valve actuation system has a good application prospect for heavy-duty engines.

Analysis and optimization of a variable mode valve actuation system

2020 ◽  
pp. 146808742090599
Author(s):  
Yang Wang ◽  
Jingchen Cui ◽  
Xiangyu Meng ◽  
Jiangping Tian ◽  
Hua Tian ◽  
...  
Keyword(s):  
Thermal Management ◽  
Flow Rate ◽  
Outlet Temperature ◽  
Brake Specific Fuel Consumption ◽  
Cylinder Pressure ◽  
Heavy Duty ◽  
Cylinder Deactivation ◽  
Actuation System ◽  
Variable Mode ◽  
Valve Actuation

Braking safety of heavy-duty engines has always been the focus of the research, and the fuel economy and after-treatment thermal management during low-load operation of heavy-duty engines have also received much attention in recent years. A variable mode valve actuation system which can realize switching between four-stroke driving, two-stroke compression release braking and cylinder deactivation modes on a traditional four-stroke engine was proposed in this article. Two-stroke compression release braking mode of the variable mode valve actuation system can greatly enhance the braking safety, while the overload of valve train was a great challenge, especially during the release event. The effects of different release opening timing on cylinder pressure and the braking performance were studied. The results indicated that a higher cylinder pressure does not always lead to higher braking power. When the release opening timing was advanced by 6 °CA, the braking power reduced by only 9 kW (2.65%) at 1900 r/min compared with the initial value, while the maximum cylinder pressure reduced by 11.4 bar (20.8%). Besides, the variable mode valve actuation system can realize alternate three-cylinder cylinder deactivation mode on a six-cylinder turbocharged engine, which can improve the brake-specific fuel consumption by 14.67% and increase the turbine outlet temperature by 63.6 °C and reduce the exhaust flow rate by 50.66% at lightly load idle. Meanwhile, when the engine load is less than 50% at the rated speed, the three-cylinder cylinder deactivation mode can improve the brake-specific fuel consumption, increase the turbine outlet temperature and reduce the exhaust flow rate. The increase of the turbine outlet temperature and the decrease of the exhaust flow rate are very beneficial to improve the efficiency of the after-treatment thermal management of heavy-duty engines.

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