The two development ways of turbocharger technology to solve the problem of matching performance with diesel were presented. The ways of waste valve gate turbocharger and variable geometry turbocharger can solve the p...The two development ways of turbocharger technology to solve the problem of matching performance with diesel were presented. The ways of waste valve gate turbocharger and variable geometry turbocharger can solve the problem of engine’s low speed torque and achieve lower smoke level. Especially for variable geometry turbocharger, it covers all conditions of engine. It can not only improve the low engine’s speed torque and keep the power performance at high engine speed, but also cover wide engine speed performance that keeps lower fuel consumption and exhaust gas temperature in full load and part load matching. The results of theory analysis and experiment research showed that it’s the ideal solution to solve the matching problem of diesel engines.展开更多
The critical speed and unbalance response of a small vehicle gasoline turbocharger in semi-floating bearing are analyzed.The dynamical characters of semi-floating bush bearing used in small vehicle gasoline turbocharg...The critical speed and unbalance response of a small vehicle gasoline turbocharger in semi-floating bearing are analyzed.The dynamical characters of semi-floating bush bearing used in small vehicle gasoline turbocharger were summarized by comparing the structure and shaft rigid mode of semi-floating bush bearings with those of floating bush bearings.The rotor model was built.The first,second and third mode of critical speeds of rotor system were computed,and the changes in the compressor or turbine bushing bearing clearances were analyzed.Compared with the experiment data,the accuracy and the rationality of computation model were verified.The unbalance response and time transient rotor response were also computed.展开更多
The critical speeds for a vehicle turbocharger with hybrid ceramic ball bearing are researched. The ball bearing-rotor system produces resonance when it working in critical speed and that makes the turbocharger injury...The critical speeds for a vehicle turbocharger with hybrid ceramic ball bearing are researched. The ball bearing-rotor system produces resonance when it working in critical speed and that makes the turbocharger injury working for a long time. The calculation and analysis methods of the critical speed for the vehicle turbocharger are described. The critical speed is computed by two methods including Riccati transfer matrix and DyRoBeS finite element method for a vehicle turbocharger with hybrid ceramic ball bearing. The vibration experiment had been taken to validate the calculating result, Comparison between the results by two calculation methods and the test results show that the first critical speed differences are 6.47 % and 5.66 %, the second critical speed differences are 2.87 % and 2.94 % respectively. And then, the primary factors which influence the critical speed are analyzed, the conclusions will be helpful for the vehicle turbocharger bearing-rotor system design.展开更多
A variable nozzle turbocharger （VNT） was applied to a 2.2-liter L4 natural gas engine,and a VNT control system was designed to operate it.Based on VNT matching test results,a VNT control strategy was studied,in whic...A variable nozzle turbocharger （VNT） was applied to a 2.2-liter L4 natural gas engine,and a VNT control system was designed to operate it.Based on VNT matching test results,a VNT control strategy was studied,in which VNT adjustment is carried out through pre-calibrated VNT handling rod position,combined with a closed-loop target boost pressure feedback using proportional-integral-derivative（PID） algorithm.Experimental results showed that the VNT control system presented in this thesis can lead to optimized performance of VNT,increase engine volumetric efficiency over a wide speed range,improve engine dynamic characteristics and upgrade economic performance.展开更多
To compute the matching performance of diesel engine with variable geometry turboeharger（VGT）, the formerly used program is improved through adjustment of turbine mass flow rate and efficiency characteristics. The c...To compute the matching performance of diesel engine with variable geometry turboeharger（VGT）, the formerly used program is improved through adjustment of turbine mass flow rate and efficiency characteristics. The calculation result is applied to forecast the performance of J6110Z diesel engine with rotary-vaned VGT70, and to guide the improvement of engine fuel supply. The computed engine performance curve coincides with the experiment result well： the low-speed torque, fuel economy, exhaust temperature and boost pressure of the VGT engine are all improved.展开更多
The structure parameters in an actual industrial production have a great influence on the coefficient of supercharger floating bearing dynamic characteristics,but there has been little systematic study so far.In this ...The structure parameters in an actual industrial production have a great influence on the coefficient of supercharger floating bearing dynamic characteristics,but there has been little systematic study so far.In this paper,the influence of structural parameters of the turbocharger floating bearing on its dynamic characteristic coefficientsis systematically investigated based on the theories of hydrodynamic lubrication and tribology.The influence of clearance ratio on eccentricity and the influence of internal to external radius ratios,and Sommerfeld number were analyzed.A new formula of responding characteristics of the oil film force caused by the displacement or velocity disturbance was deduced near an equilibrium in the steady state.Applying the newly developed formula,the dynamic characteristic was studied for floating bearings.Regularity for change of oil film stiffness and damping was analyzed with the structural parameters of floating bearing such as radius ratios and eccentricity.It has been found that the clearance ratio increases with eccentricity when the radius ratio is unchanged.The eccentricity decreases with the internal to external radius ratio of floating rings when the clearance ratio is constant.The absolute value of total principal stiffness and total main damping decrease with the clearance ratio and radius ratio of floating rings when the total cross damping is stable.The results and findings in this paper can contribute to nonlinear dynamics designs of turbocharger rotor-bearing systems.展开更多
The noise prediction of the turbocharger is studied.The broadband noise source model is employed to predict the near-field noise of the turbocharger.The 3D software Solidworks is adopted to establish the model blades ...The noise prediction of the turbocharger is studied.The broadband noise source model is employed to predict the near-field noise of the turbocharger.The 3D software Solidworks is adopted to establish the model blades and inlet of turbocharger compressor,then this 3D model is introduced into the software CFD to calculate the flow-field under different inlet shapes,different blades shapes and different clearances between casing and impeller.On the base of the above simulation,the broadband noise source model is employed to calculate and analyze the near-field noise.The calculation shows that compressor static pressure values and the sound power values near the impeller outlet are the largest.Through the noise calculation by using broadband noise source model under different inlet shapes and blade shapes,we find that the noise level of the inlet of cylindrical and cone types are smaller.Compared with the current widespread used backward skewed or radial blades,there is little difference of the noise value of the inlet of the forward skewed blades.展开更多
A spatial motion mechanism was designed which could make all the nozzle vanes rotate a- round the center of ball with the same radius synchronously to realize control of the variable nozzle mixed-flow turbocharger （V...A spatial motion mechanism was designed which could make all the nozzle vanes rotate a- round the center of ball with the same radius synchronously to realize control of the variable nozzle mixed-flow turbocharger （VN-MT）. The back and abdomen of the nozzle vane was designed as arc- shaped. A variable nozzle ring perfectly combined with the mixed-flow turbine was made available. The turbine geometric model of VN-MT was established through the computational fluid dynamics （CFD）. Compared with nozzleless mixed-flow turbine, the flow range of variable nozzle mixed-flow turbine was broadened tremendously while the peak turbine efficiency point was lower slightly. Flow field analysis in turbine stage showed that the energy was larger and the blade load of rotor was lower than loss of the VN-MT under designed condition the nozzleless mixed-flow turbocharger.展开更多
Due to increasingly stricter emissions on particulate matter(PM)emissions,diesel particulate filter(DPF)regeneration has become the most widely used and effective technology to reduce PM emissions.However,using incyli...Due to increasingly stricter emissions on particulate matter(PM)emissions,diesel particulate filter(DPF)regeneration has become the most widely used and effective technology to reduce PM emissions.However,using incylinder post-injection-based active DPF regeneration can increase engine oil dilution,thus affecting engine lubrication.Using a 4-cylinder turbocharged direct-injection diesel engine,this study analyzed the effect of lubricating oil on the formation and properties of turbocharger compressor soot deposits associated with engine oil dilution.Three diesel engine lubricating oils(CJ-4,CK-4,and CJ-4*)were selected,with each subjected to 200 hours of engine bench testing at 8%oil dilution.The composition of CJ-4*was the same as that of CJ-4 but with reduced amount of additives.Soot deposits were collected and analyzed.A merit calculation method was established to rate turbocharger deposits.Transmission electron microscopy,Raman spectroscopy,Fourier transform infrared spectroscopy,and thermogravimetric analysis(TGA)were used to characterize the morphology and composition of soot samples.The results showed that turbocharger deposits from CJ-4 and CK-4 were less than that from CJ-4*.The deposits from CJ-4*showed a more disordered morphology,whereas those from CJ-4 and CK-4 exhibited a higher degree of order.TGA results showed that the soluble organic fraction content in the deposit derived from CJ-4*was much higher than that obtained from CJ-4 and CK-4.展开更多
Nowadays alternative and innovative energy recovery solutions are adopted on board ships to reduce fuel consumption and harmful emissions.According to this,the present work compares the engine exhaust gas waste heat r...Nowadays alternative and innovative energy recovery solutions are adopted on board ships to reduce fuel consumption and harmful emissions.According to this,the present work compares the engine exhaust gas waste heat recovery and hybrid turbocharger technologies,which are used to improve the efficiency of a dual-fuel four-stroke(DF)marine engine.Both solutions aim to satisfy partly or entirely the ship’s electrical and/or thermal loads.For the engine exhaust gas waste heat recovery,two steam plant schemes are considered:the single steam pressure and the variable layout(single or dual steam pressure plant).In both cases,a heat recovery steam generator is used for the electric power energy generation through a steam turbine.The hybrid turbocharger is used to provide a part of the ship’s electric loads as well.The thermodynamic mathematical models of DF engines,integrated with the energy recovery systems,are developed in a Matlab-Simulink environment,allowing the comparison in terms of performance at different engine loads and fuels,which are Natural Gas(NG)and High Fuel Oil(HFO).The use of NG always involves better efficiency of the system for all the engine working conditions.It results that the highest efficiency value achievable is 56%at 50%maximum continuous rating(MCR)engine load.展开更多
In order to improve performance of the DA465Q gasoline engine, a substantial amount of research was done to optimize its turbocharging system. The research led to the GT12 turbocharger being selected and its turbochar...In order to improve performance of the DA465Q gasoline engine, a substantial amount of research was done to optimize its turbocharging system. The research led to the GT12 turbocharger being selected and its turbocharging parameters being settled. Based on these tests, rational matching was worked out for respective components of the turbocharging system. Results show that this turbocharger allows the engine to easily meet the proposed requirements for power and economic performance, giving insight into further performance improvements for gasoline engines.展开更多
A two stage turbocharging control system was proposed,in which the pressure regulator valve with a close-loop pressure adjusting function instead of a high speed on-off solenoid valve,is used as a driving mechanism of...A two stage turbocharging control system was proposed,in which the pressure regulator valve with a close-loop pressure adjusting function instead of a high speed on-off solenoid valve,is used as a driving mechanism of waste gate.A digital-analog（DA）conversion circuit based on pulse width modulation（PWM）generates one analog voltage signal required by the pressure regulating valve control.The principle of the DA conversion circuit was analyzed,meanwhile,the performance of the conversion circuit was improved by adopting a speed-up capacitor,which helps to increase the stability and responsiveness of the control voltage generated by the conversion circuit;the structure parameters of the circuit was optimized by simulation.After the optimization,the ripple wave of circuit output voltage was kept within16mV under the 12bit conversion accuracy,the conversion time of the circuit could be reduced to 4ms.The engine bench test show that the turbocharging boost pressure control system which adopted the circuit had a rather good stable control accuracy（the steady state within 0.8%）and dynamic response（the regulation time is less than 4s）.展开更多
A turbocharged diesel engine model was built with the GT-Power software,and experimentally verified.Then two different control variables for the control of the variable geometry turbocharger（VGT）were described,and t...A turbocharged diesel engine model was built with the GT-Power software,and experimentally verified.Then two different control variables for the control of the variable geometry turbocharger（VGT）were described,and their distinct effects on engine performance,i.e.NOxand soot emissions and fuel consumption,were simulated and compared on the basis of this model.The results showed that NOxemissions decreased obviously with the increase of exhaust gas recirculation（EGR）rate at constant boost pressure condition,but soot emissions and fuel consumption considerably increased.It was a good way to reduce NOxemissions without increasing fuel consumption and soot emissions when VGT was controlled to maintain the excess oxygen ratio unchanged as EGR rate increases.展开更多
文摘The two development ways of turbocharger technology to solve the problem of matching performance with diesel were presented. The ways of waste valve gate turbocharger and variable geometry turbocharger can solve the problem of engine’s low speed torque and achieve lower smoke level. Especially for variable geometry turbocharger, it covers all conditions of engine. It can not only improve the low engine’s speed torque and keep the power performance at high engine speed, but also cover wide engine speed performance that keeps lower fuel consumption and exhaust gas temperature in full load and part load matching. The results of theory analysis and experiment research showed that it’s the ideal solution to solve the matching problem of diesel engines.
基金Supported by Turbocharging Laboratory of Beijing Institute of Technology(1030040610016)
文摘The critical speed and unbalance response of a small vehicle gasoline turbocharger in semi-floating bearing are analyzed.The dynamical characters of semi-floating bush bearing used in small vehicle gasoline turbocharger were summarized by comparing the structure and shaft rigid mode of semi-floating bush bearings with those of floating bush bearings.The rotor model was built.The first,second and third mode of critical speeds of rotor system were computed,and the changes in the compressor or turbine bushing bearing clearances were analyzed.Compared with the experiment data,the accuracy and the rationality of computation model were verified.The unbalance response and time transient rotor response were also computed.
文摘The critical speeds for a vehicle turbocharger with hybrid ceramic ball bearing are researched. The ball bearing-rotor system produces resonance when it working in critical speed and that makes the turbocharger injury working for a long time. The calculation and analysis methods of the critical speed for the vehicle turbocharger are described. The critical speed is computed by two methods including Riccati transfer matrix and DyRoBeS finite element method for a vehicle turbocharger with hybrid ceramic ball bearing. The vibration experiment had been taken to validate the calculating result, Comparison between the results by two calculation methods and the test results show that the first critical speed differences are 6.47 % and 5.66 %, the second critical speed differences are 2.87 % and 2.94 % respectively. And then, the primary factors which influence the critical speed are analyzed, the conclusions will be helpful for the vehicle turbocharger bearing-rotor system design.
基金Sponsored by the Ministerial Advanced Research Foundation (C2002AA002)
文摘A variable nozzle turbocharger （VNT） was applied to a 2.2-liter L4 natural gas engine,and a VNT control system was designed to operate it.Based on VNT matching test results,a VNT control strategy was studied,in which VNT adjustment is carried out through pre-calibrated VNT handling rod position,combined with a closed-loop target boost pressure feedback using proportional-integral-derivative（PID） algorithm.Experimental results showed that the VNT control system presented in this thesis can lead to optimized performance of VNT,increase engine volumetric efficiency over a wide speed range,improve engine dynamic characteristics and upgrade economic performance.
基金the Ministerial Level Advanced Research Foundation (37256)
文摘To compute the matching performance of diesel engine with variable geometry turboeharger（VGT）, the formerly used program is improved through adjustment of turbine mass flow rate and efficiency characteristics. The calculation result is applied to forecast the performance of J6110Z diesel engine with rotary-vaned VGT70, and to guide the improvement of engine fuel supply. The computed engine performance curve coincides with the experiment result well： the low-speed torque, fuel economy, exhaust temperature and boost pressure of the VGT engine are all improved.
基金Supported by the Natural Science Foundation of Shanxi Province Project(2012011023-2)
文摘The structure parameters in an actual industrial production have a great influence on the coefficient of supercharger floating bearing dynamic characteristics,but there has been little systematic study so far.In this paper,the influence of structural parameters of the turbocharger floating bearing on its dynamic characteristic coefficientsis systematically investigated based on the theories of hydrodynamic lubrication and tribology.The influence of clearance ratio on eccentricity and the influence of internal to external radius ratios,and Sommerfeld number were analyzed.A new formula of responding characteristics of the oil film force caused by the displacement or velocity disturbance was deduced near an equilibrium in the steady state.Applying the newly developed formula,the dynamic characteristic was studied for floating bearings.Regularity for change of oil film stiffness and damping was analyzed with the structural parameters of floating bearing such as radius ratios and eccentricity.It has been found that the clearance ratio increases with eccentricity when the radius ratio is unchanged.The eccentricity decreases with the internal to external radius ratio of floating rings when the clearance ratio is constant.The absolute value of total principal stiffness and total main damping decrease with the clearance ratio and radius ratio of floating rings when the total cross damping is stable.The results and findings in this paper can contribute to nonlinear dynamics designs of turbocharger rotor-bearing systems.
基金Sponsored by the National Natural Science Foundation of China (50875022)Research Foundation of Beijing Institute of Technology(20070342012)
文摘The noise prediction of the turbocharger is studied.The broadband noise source model is employed to predict the near-field noise of the turbocharger.The 3D software Solidworks is adopted to establish the model blades and inlet of turbocharger compressor,then this 3D model is introduced into the software CFD to calculate the flow-field under different inlet shapes,different blades shapes and different clearances between casing and impeller.On the base of the above simulation,the broadband noise source model is employed to calculate and analyze the near-field noise.The calculation shows that compressor static pressure values and the sound power values near the impeller outlet are the largest.Through the noise calculation by using broadband noise source model under different inlet shapes and blade shapes,we find that the noise level of the inlet of cylindrical and cone types are smaller.Compared with the current widespread used backward skewed or radial blades,there is little difference of the noise value of the inlet of the forward skewed blades.
基金Supported by the National Natural Science Foundation of China(51009003)
文摘A spatial motion mechanism was designed which could make all the nozzle vanes rotate a- round the center of ball with the same radius synchronously to realize control of the variable nozzle mixed-flow turbocharger （VN-MT）. The back and abdomen of the nozzle vane was designed as arc- shaped. A variable nozzle ring perfectly combined with the mixed-flow turbine was made available. The turbine geometric model of VN-MT was established through the computational fluid dynamics （CFD）. Compared with nozzleless mixed-flow turbine, the flow range of variable nozzle mixed-flow turbine was broadened tremendously while the peak turbine efficiency point was lower slightly. Flow field analysis in turbine stage showed that the energy was larger and the blade load of rotor was lower than loss of the VN-MT under designed condition the nozzleless mixed-flow turbocharger.
基金financially supported by SINOPEC(Grant No.124015)。
文摘Due to increasingly stricter emissions on particulate matter(PM)emissions,diesel particulate filter(DPF)regeneration has become the most widely used and effective technology to reduce PM emissions.However,using incylinder post-injection-based active DPF regeneration can increase engine oil dilution,thus affecting engine lubrication.Using a 4-cylinder turbocharged direct-injection diesel engine,this study analyzed the effect of lubricating oil on the formation and properties of turbocharger compressor soot deposits associated with engine oil dilution.Three diesel engine lubricating oils(CJ-4,CK-4,and CJ-4*)were selected,with each subjected to 200 hours of engine bench testing at 8%oil dilution.The composition of CJ-4*was the same as that of CJ-4 but with reduced amount of additives.Soot deposits were collected and analyzed.A merit calculation method was established to rate turbocharger deposits.Transmission electron microscopy,Raman spectroscopy,Fourier transform infrared spectroscopy,and thermogravimetric analysis(TGA)were used to characterize the morphology and composition of soot samples.The results showed that turbocharger deposits from CJ-4 and CK-4 were less than that from CJ-4*.The deposits from CJ-4*showed a more disordered morphology,whereas those from CJ-4 and CK-4 exhibited a higher degree of order.TGA results showed that the soluble organic fraction content in the deposit derived from CJ-4*was much higher than that obtained from CJ-4 and CK-4.
文摘Nowadays alternative and innovative energy recovery solutions are adopted on board ships to reduce fuel consumption and harmful emissions.According to this,the present work compares the engine exhaust gas waste heat recovery and hybrid turbocharger technologies,which are used to improve the efficiency of a dual-fuel four-stroke(DF)marine engine.Both solutions aim to satisfy partly or entirely the ship’s electrical and/or thermal loads.For the engine exhaust gas waste heat recovery,two steam plant schemes are considered:the single steam pressure and the variable layout(single or dual steam pressure plant).In both cases,a heat recovery steam generator is used for the electric power energy generation through a steam turbine.The hybrid turbocharger is used to provide a part of the ship’s electric loads as well.The thermodynamic mathematical models of DF engines,integrated with the energy recovery systems,are developed in a Matlab-Simulink environment,allowing the comparison in terms of performance at different engine loads and fuels,which are Natural Gas(NG)and High Fuel Oil(HFO).The use of NG always involves better efficiency of the system for all the engine working conditions.It results that the highest efficiency value achievable is 56%at 50%maximum continuous rating(MCR)engine load.
文摘In order to improve performance of the DA465Q gasoline engine, a substantial amount of research was done to optimize its turbocharging system. The research led to the GT12 turbocharger being selected and its turbocharging parameters being settled. Based on these tests, rational matching was worked out for respective components of the turbocharging system. Results show that this turbocharger allows the engine to easily meet the proposed requirements for power and economic performance, giving insight into further performance improvements for gasoline engines.
基金Supported by the Ministerial Level Research Project of China(D2220112901)
文摘A two stage turbocharging control system was proposed,in which the pressure regulator valve with a close-loop pressure adjusting function instead of a high speed on-off solenoid valve,is used as a driving mechanism of waste gate.A digital-analog（DA）conversion circuit based on pulse width modulation（PWM）generates one analog voltage signal required by the pressure regulating valve control.The principle of the DA conversion circuit was analyzed,meanwhile,the performance of the conversion circuit was improved by adopting a speed-up capacitor,which helps to increase the stability and responsiveness of the control voltage generated by the conversion circuit;the structure parameters of the circuit was optimized by simulation.After the optimization,the ripple wave of circuit output voltage was kept within16mV under the 12bit conversion accuracy,the conversion time of the circuit could be reduced to 4ms.The engine bench test show that the turbocharging boost pressure control system which adopted the circuit had a rather good stable control accuracy（the steady state within 0.8%）and dynamic response（the regulation time is less than 4s）.
基金Supported by Diesel Engine Development Program of MIIT(DEDP-1004)Natural Science Foundation of BIT(3030012211428)
文摘A turbocharged diesel engine model was built with the GT-Power software,and experimentally verified.Then two different control variables for the control of the variable geometry turbocharger（VGT）were described,and their distinct effects on engine performance,i.e.NOxand soot emissions and fuel consumption,were simulated and compared on the basis of this model.The results showed that NOxemissions decreased obviously with the increase of exhaust gas recirculation（EGR）rate at constant boost pressure condition,but soot emissions and fuel consumption considerably increased.It was a good way to reduce NOxemissions without increasing fuel consumption and soot emissions when VGT was controlled to maintain the excess oxygen ratio unchanged as EGR rate increases.
