Robust Common Rail Pressure Control for Diesel Engines using a Quantitative Feedback Theory

Jaewook Shin,Seungwoo Hong,Inseok Park,Minkwang Lee,Myoungho Sunwoo 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11

This paper proposes a common rail pressure controller for passenger car diesel engines. The common rail system of diesel engine has some difficulties to control rail pressure. The rail pressure is influenced by interaction between a metering unit (MeUn) and a pressure control valve (PCV). The interaction increases complexity of control algorithm. In order to solve this problem, we present a common rail pressure controller based on the quantitative feedback theory (QFT). For the controller design, a plant model of the common rail system is approximated by a first order transfer function, and the PCV driving current and the rail pressure are used as input/output variables of this model. The rail pressure variation by MeUn is represented as parametric uncertainty. Then, requirement specifications for stability and reference tracking are defined, and the control algorithm is designed to satisfy these requirements using the QFT method. In order to validate the proposed controller, engine experiments are performed. The QFT based rail pressure controller successfully satisfies the tracking performance. Furthermore, the control robustness is evaluated when the MeUn driving current is abruptly changed.

전자제어 디젤엔진의 연료압력 레귤레이터 고장에 따른 진단 및 성능 연구

김태중(Kim, Tae-Jung),조홍현(Cho, Hong-Hyun) 한국산학기술학회 2015 한국산학기술학회논문지 Vol.16 No.3

배출가스 규제강화에 대응하기 위해 전자제어 디젤엔진의 적용으로 연료 분사량과 연료 분사시기를 정밀하게 제어하 여 연료소비율과 출력 향상 및 소음과 진동이 감소되었다. 전자제어 디젤엔진 시스템의 성능을 유지하기 위해서는 연료압력 을 정밀하게 제어하는 중요한 부품이 연료압력 레귤레이터이며 제어불량이 발생할 경우 연료압력이 정밀하게 제어되지 않아 시동불량, 시동지연, 가속불량, 엔진부조 등 이상 현상이 초래된다. 본 실험에서는 연료압력 레귤레이터의 고장에 따른 성능 변화를 고찰하기 위하여 연료압력 레귤레이터 제어율에 변화를 주어 연료압력, 회수된 연료유량과 엔진회전수에 미치는 영 향을 실험적으로 고찰하였다. 실험결과, 연료압력 레귤레이터의 제어율이 기준에서 4-6% 정도 낮아지면 엔진회전수, 회수되 는 연료유량의 변화가 크게 나타났으며 이 때 이상현상이 발생함을 확인하였다. 또한 이를 통하여 연료압력 레귤레이터의 고장 유무을 판단할 수 있다. To cope with exhaust gas regulation, Diesel engine applied to electronic control system. As it accurately regulated the injected fuel mass and the fuel efficiency and the output are increased but the noise and the vibration are decreased. In order to keep the performance of Electronic Diesel Control System, it is important to accurately control the fuel pressure. However, when the regulator of fuel pressure is not controlled properly, the failure phenomenons(starting failure, staring delay, accelerated failure, engine mismatch et al.) occur because the fuel pressure is not stabilize. In this study, effects on a fuel pressure, engine rotating speed according to the control rate of fuel-pressure regulator are investigated in order to analyzed the performance variation with failure of fuel-pressure regulator. As a result, when the control rate of a fuel-pressure regulator is 4%~6% lower than that of standard condition, the variation of engine's rpm and return fuel flow is increased, and the abnormal condition was occurred. Besides, it is possible to diagnose the failures on fuel-pressure regulator under these conditions.

FUEL RAIL PRESSURE CONTROL CHARACTERISTICS OF A GDI HIGH-PRESSURE FUEL PUMP USING A NEWLY DEVELOPED EXPERIMENTAL SYSTEM CONTROLLED WITH A MICROCONTROLLER

이병진,이충훈 한국자동차공학회 2021 International journal of automotive technology Vol.22 No.2

An experimental system was developed to evaluate the fuel injection parts of a gasoline direct injection engine. An AC motor and an inverter were used to rotate the camshaft in the engine cylinder head. A single plunger high-pressure fuel pump (HPFP) driven by a square cam at the end of the camshaft was used in the gasoline direct injection engine. The rotation position of the square cam was measured by a rotary encoder. The developed system allows control of the camshaft rotation speed, the HPFP pressure control valve (PCV) opening and closing timing, and the fuel injection duration, which are three important factors affecting the fuel rail pressure (FRP). It is confirmed that the fuel rail pressure can be made to vary wit different combinations of these three factors. By using the experimental system developed in this study, the fuel rail pressure can be effectively controlled in the range of 3 MPa to 20 MPa. The most influential factor for control of the fuel rail pressure was the HPFP PCV opening and closing timings. With the proposed using the experimental system, the rail pressure, fuel rail pressure wave characteristics, and the injector drive characteristics can all be assessed under various fuel injection conditions.

QFT 를 이용한 디젤엔진의 커먼레일 압력 제어알고리즘 설계 연구

신재욱(Jaewook Shin),홍승우(Seungwoo Hong),박인석(Inseok Park),선우명호(Myoungho Sunwoo) 대한기계학회 2014 大韓機械學會論文集B Vol.38 No.2

이 연구에서는 Quantitative Feedback Theory(QFT) 기법을 이용한 승용디젤엔진의 커먼레일 압력제어 알고리즘을 제안하였다. 커먼레일 압력모델의 입력과 출력은 각각 Pressure Control Valve(PCV) 구동전류와 커먼레일 압력으로 정의하였고, Metering Unit(MeUn)이 커먼레일 압력에 미치는 영향은 모델 파라미터 불확실성으로 정의하였다. QFT 기법은 이러한 모델의 불확실성에 대하여 강건하면서도 정량적 요구사항을 만족할 수 있는 제어알고리즘 설계방법을 제시한다. 제안된 커먼레일 압력제어기는 목표 레일압력 추종성능과 안정성능이 확보되었으며, 인젝터에 의한 연료분사가 커먼레일 압력에 미치는 영향을 줄이기 위하여 외란제거성능(Disturbance Rejection)이 고려되었다. 설계된 제어 알고리즘은 엔진 동력계 실험을 통하여 검증하였으며, MeUn 구동전류와 연료분사량의 급격한 변화에 따른 제어알고리즘의 강건성과 외란제거성능을 검증하였다. This paper proposes a common rail pressure control algorithm for passenger car diesel engines. For handling the parameter-varying characteristics of common rail systems, the quantitative feedback theory (QFT) is applied to the design of a robust rail pressure control algorithm. The driving current of the pressure control valve and the common rail pressure are used as the input/output variables for the common rail system model. The model parameter uncertainty ranges are identified through experiments. Rail pressure controller requirements in terms of tracking performance, robust stability, and disturbance rejection are defined on a Nichols chart, and these requirements are fulfilled by designing a compensator and a prefilter in the QFT framework. The proposed common rail pressure control algorithm is validated through engine experiments. The experimental results show that the proposed rail pressure controller has a good degree of consistency under various operating conditions, and it successfully satisfies the requirements for reference tracking and disturbance rejection.

CONTROL STRATEGY BASED ON FLOW CONSERVATION EQUATION FOR HIGH-PRESSURE COMMON RAIL SYSTEM

Guo-Xiu Li 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.3

As the most advanced fuel injection system, the common rail system can achieve the flexible control of injection pressure, injection timing and injection rate. Thus, the pressure control strategy of high-pressure common rail system (HPCRS) will be critical for the performance of the diesel engine, as it affects its injection characteristics. In this paper, model in loop (MIL) simulation studies were carried out, a high-precision common rail hydraulic model and analytical rail pressure control strategy based on flow continuity equation were established. The delay of the high-pressure pump was accounted for and included in the proposed strategy, making it more targeted for HPCRS. The delay can be extremely important for high-pressure common rail overshoot especially in variable working condition. Next, the proposed strategy was compared to the traditional PI-based control strategy in both the start-up and transient conditions. Results indicated that the proposed strategy performs better regarding the overshoot, notably improving the control effect (compared to traditional PI-based strategy). The advances of using the proposed strategy primarily include improvements in working conditions with the obvious change in cycle injection quantity and engine speed. Both the proposed control strategy and PI-based strategy can track pressure effectively in various working conditions.

ADAPTATION STRATEGY FOR EXHAUST GAS RECIRCULATION AND COMMON RAIL PRESSURE TO IMPROVE TRANSIENT TORQUE RESPONSE IN DIESEL ENGINES

Seungwoo Hong,Donghyuk Jung,선우명호 한국자동차공학회 2018 International journal of automotive technology Vol.19 No.4

Fuel injection limitation algorithms are widely used to reduce particulate matter (PM) emissions under transient states in diesel engines. However, the limited injection quantity leads to a decrease in the engine torque response under transient states. To overcome this issue, this study proposes an adaptation strategy for exhaust gas recirculation (EGR) and common rail pressure combined with a fuel injection limitation algorithm. The proposed control algorithm consists of three parts: fuel injection limitation, EGR adaptation, and rail pressure adaptation. The fuel injection quantity is limited by adjusting the exhaust burned gas rate, which is predicted based on various intake air states like air mass flow and EGR mass flow. The control algorithm for EGR and rail pressure was designed to manipulate the set-points of the EGR and rail pressure when the fuel injection limitation is activated. The EGR controller decreases the EGR gas flow rate to rapidly supply fresh air under transient states. The rail pressure controller increases the rail pressure set-point to generate a well-mixed air-fuel mixture, resulting in an enhancement in engine torque under transient states. The proposed adaptation strategy was validated through engine experiments. These experiments showed that PM emissions were reduced by up to 11.2 %, and the engine torque was enhanced by 5.4 % under transient states compared to the injection limitation strategy without adaptation.

GPIO BASED SLIDING MODE CONTROL FOR DIESEL ENGINE HIGH PRESSURE COMMON RAIL SYSTEM

Zheng Yuan,Chen Dai,Hao Sun,Shihua Li,Bifeng Yin 한국자동차공학회 2023 International journal of automotive technology Vol.24 No.1

With the rapid development of diesel engines, reducing the pressure fluctuation of the common rail has become a key factor to improve the performance of the high pressure common rail (HPCR) system. Among traditional rail pressure control approaches, the influence of time-varying disturbances on the HPCR system is not fully considered and is not well dealt with. To this end, a nonlinear model of the HPCR system is firstly established based on fluid dynamics and mechanics laws. And a composite controller based on the nonlinear model is proposed. It consists of two parts: 1) A sliding mode feedback part; 2) A disturbance feedforward compensation part based on a generalized proportional integral observer. Finally, a group of test is simulated in the AMESim simulation environment and the results are shown to demonstrate the effectiveness of the proposed method.

코먼 레일 시스템의 압력 제어기 설계

전윤식 한국기계기술학회 2001 한국기계기술학회 학술대회논문집 Vol.2001 No.4

디젤차량용 연료압력 제어밸브

윤소남(S. N. Yun),윤동원(D. W. Youn),정용현(Y. H. Jung),이현철(H. C. Lee) 한국동력기계공학회 2006 한국동력기계공학회 학술대회 논문집 Vol.- No.-

Generally, diesel vehicles emit the toxic gases including nitrogen and produce noise during operation. these problems deteriorate the comport of passangers, environmental pollutions and energy saving. As the solution for the above-mentioned problems, the method, which involves the injection of high pressure and atomization of fuel, is needed to improve the combution process of diesel engine. In this study, researches for performance improvement of the high pressure control valve with solenoid actuator used in Common Rail System of diesel vehicle were accomplished. Also, the results of numerical analysis from the FEM and effects of the design parameters were discussed.

코먼 레일의 압력 제어 시뮬레이션

전윤식 한국기계항공기술학회(구 한국기계기술학회) 2002 한국기계기술학회지 Vol.4 No.2