Simulation And Experimental Investigation Of Cylinder Deactivation Technology On Diesel Engine

The cylinder deactivation technology is used for it can effectively reduce the fuel consumption of the gasoline engine.Cylinder deactivation is gradually being applied from 8-cylinder,6-cylinder gasoline engine to 4-cylinder or even 3-gasoline engine to address fuel shortage pressures and new emission regulations for carbon emissions restrictions.After deactivating the cylinder,the throttle opening has to be increased to provide more mixed gas to ensure that the engine provide the same power,and in this case,throttling loss is reduced and the charging efficiency is improved.Also,the higher combustion quality of the fuel mixture and the better fuel consumption performance are achieved.Diesel engine does not have a throttle,the efficiency,combustion quality and the cycle of thermal efficiency of the working cylinder are improved and the fuel consumption is reduced after deactivating the cylinder.In addition,the heat transfer loss,the mechanical loss and the fuel consumption are reduced when deactivating the cylinder of the diesel engine by stopping fuel and airflow injection into the cylinder.The cylinder deactivation has been applied to the 4-cylinder diesel engine at abroad.Meanwhile,the current study about cylinder deactivation of diesel engine is less and mostly on the 8-cylinder,6-cylinder diesel engine cylinder deactivation simulation study due to the less application of diesel engine in the passenger car as a result that it lacks the comprehensive experimental study of cylinder deactivation in the application of small diesel engine about fuel consumption,emissions and vibration in the country.Therefore,the study of cylinder deactivation in the application of small 4-cylinder diesel engine has a high practical value.In this paper,a 4 cylinder diesel engine was taken as the research object,based on which,the simulation and experimental study of the cylinder deactivation in the application of small displacement diesel engine was performed.Firstly,set up the experimental bench,completed the selection of dynamometer and verified the performance of external characteristic for the original engine.Secondly,based on the GT-power software,the model of the diesel engine was established,then we selected the simulation point which was of the same load rate torque but range in engine speed from low,medium to high speed and simulated how cylinder deactivation position influence the fuel consumption when 1 or 2 cylinder was deactivated.After that,the influence of deactivation position on engine vibration was also measured.Taking the vibration,fuel consumption,heat loss and other factors into consideration,we decided deactivation position when 1 or 2 cylinder stop working.And then we deactivated the cylinder by stopping fuel injection or stopping fuel injection and at the same time,stopping the airflow into the cylinder respectively.The numerical simulation and experiment showed that:(1)The deactivation position had little influence on fuel consumption when only 1 cylinder was deactivated,but when two cylinders were deactivated,deactivating cylinder 1 and 4 had better fuel consumption performance than deactivating cylinder 2 and 3;When the cylinder was deactivated by stopping fuel injection into the cylinder,the fuel consumption increased because cylinder isovolumetric degree decreased,the fuel consumption was more or less compared with the original engine when deactivating 1 cylinder by stopping fuel and airflow injection into the cylinder,but the fuel consumption when deactivate 2 cylinder was more than the original engine at the same condition.(2)The NOx emission was higher after deactivating cylinder by stopping fuel injection into the cylinder,but the carbon emissions was lower.The NOx and the carbon emission are higher when deactivating cylinder by stopping fuel injection and airflow into the cylinder compared with deactivating cylinder by stopping fuel injection into the cylinder.But compared with the original engine,the carbon emission increased or decreased.(3)The vibration was higher when deactivating cylinder compared with original engine,but the vibration increased or decreased at different deactivating cylinder mode.The noise was higher when deactivating cylinder compared with original engine.This paper provided the research basis for the cylinder deactivation in the application of the small diesel engine.Detail works were as follows:deactivating cylinder by stopping fuel injection into the cylinder was not applicable to the diesel engine in the practical application:Deactivate cylinder by stopping fuel and airflow injection into the cylinder in the application of diesel engine can reduce diesel engine only when 1 cylinder was deactivated.We should solve the problem of speed and improving the degree caused by the cylinder mixed gas after deactivating the cylinder of the diesel engine.