Common Rail Fuel Injection Technology in Diesel Engines

Preface xiii Introduction xv 1 Introduction 1 1.1 The Development of an Electronic Control Fuel Injection System 2 1.1.1 Position Type Electronic Control Fuel Injection System 3 1.1.2 Time Type Electronic Control Fuel Injection System 4 1.1.3 Pressure–Time Controlled (Common Rail) Type Electronic Control Fuel Injection System 4 1.1.3.1 Medium-Pressure Common Rail System 5 1.1.3.2 High-Pressure Common Rail System 6 1.2 High-Pressure Common Rail System: Present Situation and Development 7 1.2.1 For a Common Rail System 7 1.2.1.1 Germany BOSCH Company of the High-Pressure Common Rail System 8 1.2.1.2 The Delphi DCR System of the Company 10 1.2.1.3 Denso High-Pressure Common Rail Injection System of the Company 10 1.2.2 High-Power Marine Diesel Common Rail System 11 1.2.2.1 System Structure 11 1.2.2.2 High-Pressure Oil Pump 12 1.2.2.3 Accumulator 13 1.2.2.4 Electronically Controlled Injector 13 2 Common Rail System Simulation and Overall Design Technology 15 2.1 Common Rail System Basic Model 15 2.1.1 The Common Rail System Required to Simulate a Typical Module HYDSIM 16 2.1.1.1 Container Class 16 2.1.1.2 Valves 17 2.1.1.3 Runner Class Module 19 2.1.1.4 Annular Gap Class Module Physical Model Shown in Figure 2.6 20 2.1.2 The Relevant Parameters During the Simulation Calculations 21 2.1.2.1 Fuel Physical Parameters 21 2.1.2.2 Fuel Flow Resistance 21 2.1.2.3 Partial Loss of Fuel Flow 22 2.1.2.4 Rigid Elastic Volume Expansion and Elastic Compression 22 2.2 Common Rail System Simulation Model 23 2.2.1 High-Pressure Pump Simulation Model 23 2.2.2 Injector Flow Restrictor Simulation Model 24 2.2.3 Simulation Model Electronic Fuel Injector 25 2.2.4 Overall Model Common Rail System 25 2.3 Influence Analysis of the High-Pressure Common Rail System Parameters 26 2.3.1 Influence Analysis of the High-Pressure Fuel Pump Structure Parameters 26 2.3.1.1 Frequency of the Fuel Supply Pump 27 2.3.1.2 Quantity of the Fuel Supply by the High-Pressure Supply Pump 27 2.3.1.3 Diameter of the Oil Outlet Valve Hole of the High-Pressure Pump 29 2.3.1.4 Influence of the Pre-tightening Force of the Oil Outlet Valve 31 2.3.2 Analysis of the Influence of the High-Pressure Rail Volume 33 2.3.3 Influence of the Injector Structure Parameters 34 2.3.3.1 Control Orifice Diameter 34 2.3.3.2 Influence of the Control Chamber Volume 36 2.3.3.3 Influence of the Control Piston Assembly on the Fuel Injector Response Characteristics 36 2.3.3.4 Influence of the Needle Valve Chamber Volume 38 2.3.3.5 Influence of the Pressure Chamber Volume 38 2.3.3.6 Influence of the Nozzle Orifice Diameter on the Response Characteristics of the Injector 39 2.3.4 Influence of the Flow Limiter 40 2.3.4.1 Influence of the Plunger Diameter 40 2.3.4.2 Influence of the Flow Limiter Orifice Diameter 41 2.3.5 Common Rail System Design Principle 42 3 Electronically Controlled Injector Design Technologies 43 3.1 Electric Control Fuel Injector Control Solenoid Valve Design Technology 43 3.1.1 Solenoid Valve 33 Mathematical Analysis Model 43 3.1.1.1 Circuit Subsystem 43 3.1.1.2 Magnetic Circuit Subsystem 46 3.1.1.3 Mechanical Circuit Subsystem 47 3.1.1.4 Hydraulic Subsystem 48 3.1.1.5 Thermodynamic Subsystem 48 3.1.1.6 Dynamic Characteristic Synthetic Mathematical Model of the Solenoid Valve 49 3.1.2 Solenoid Magnetic Field Finite Element Analysis 49 3.1.2.1 Model Establishment and Mesh Creation 50 3.1.2.2 Loading Analysis 51 3.1.2.3 Result Display After ANSYS 53 3.1.3 Solenoid Valve Response Characteristic Analysis 53 3.1.3.1 The Influence of Spring Pre-load on the Dynamic Response Time of the Solenoid Valve 57 3.1.3.2 The Influence of Spring Stiffness on the Dynamic Response Time of the Solenoid Valve 60 3.1.3.3 The Influence of Driving Voltage on the Dynamic Response Time of the Solenoid Valve 60 3.1.3.4 Influence of Capacitance on the Dynamic Response Time of the Solenoid Valve 62 3.1.3.5 Influence of Structure of the Iron Core on the Response Characteristics of the Solenoid Valve 63 3.1.3.6 Influence of Coil Structure Parameters on the Response Characteristics of the Solenoid Valve 67 3.1.3.7 The Influence of Working Air Gap (Electromagnetic Valve Lift) of the Solenoid Valve 68 3.1.3.8 Material Selection of the Electromagnetic Valve 69 3.1.4 What Should Be of Concern When Designing the Solenoid Valve 71 3.2 Nozzle Design Technology 72 3.2.1 Mathematical Model and Spray Model Analysis of the Nozzle Internal Flow Field 72 3.2.1.1 CFD Simulation of the Nozzle Flow Field 73 3.2.1.1.1 Description of the Computational Model 73 3.2.1.2 Determination of the Calculation Area and Establishment of the Calculation Model 78 3.2.1.3 Discrete Computational Model of the Finite Volume Method 81 3.2.1.3.1 Computational Mesh Generation 81 3.2.1.3.2 Definition of Boundary and Initial Conditions 82 3.2.1.3.3 Numerical Solution 83 3.2.1.4 Spray Model of the Nozzle 84 3.2.1.4.1 Hole Type Flow Nozzle Model 85 3.2.1.4.2 WAVE Model 86 3.2.1.4.3 KH-RT Model 88 3.2.1.4.4 Primary Breakup Model of Diesel Engine 89 3.2.2 Analysis of the Influence of Injection on the Electronically Controlled Injector 90 3.2.2.1 The Effect of Injector Orifices 91 3.2.2.2 The Influence of the Ratio of the Length to the Diameter of the Orifice 95 3.2.2.3 The Influence of the Round Angle at the Inlet of the Orifice 101 3.2.2.4 The Influence of the Shape of the Needle Valve Head 106 3.2.2.5 Effect of the Injection Angle 110 3.2.2.6 The Influence of the Number of Orifices 116 3.2.3 Simulation and Experimental Study of Spray 119 3.2.3.1 Test Scheme 119 3.2.3.2 Simulation Calculation of the Nozzle Flow Field 119 3.2.3.3 Simulation and Test Verification of Spray 123 4 High-Pressure Fuel Pump Design Technology 127 4.1 Leakage Control Technique for the Plunger and Barrel Assembly 127 4.1.1 Finite Element Analysis of the Fluid Physical Field in the Plunger and Barrel Assembly Gap 130 4.1.1.1 Similarity Principle 130 4.1.1.2 Similarity Criterion 131 4.1.1.3 Dimensional Analysis and the Pion Theorem 132 4.1.1.4 Similarity Model and Finite Element Analysis of the Clearance Flow Field 133 4.1.2 Finite Element Analysis of the Plunger and Barrel Assembly Structure 138 4.1.2.1 Three-dimensional Solid Finite Element Model 138 4.1.2.2 Constraint Condition of Structure Field 139 4.1.2.3 Structural Field Solution 140 4.1.3 Structural Optimization of the Plunger and Barrel Assembly 140 4.1.3.1 Analysis of the Preliminary Simulation Result 140 4.1.3.2 Deformation Compensation Optimization Strategy 144 4.1.3.3 ANSYS Optimization Analysis 144 4.1.3.4 Evaluation of the Optimization Result 147 4.1.4 Experimental Study on the Deformation Compensation Performance of the Plunger and Barrel Assembly 148 4.1.4.1 Test for the Sealing Performance of the Plunger and Barrel Assembly 148 4.1.4.2 Plunger and Barrel Assembly Deformation Test 151 4.2 Strength Analysis of the Cam Transmission System for a High-pressure Fuel Pump 154 4.2.1 Dynamic Simulation of the Cam Mechanism of a High-Pressure Pump 155 4.2.1.1 Solid Modeling 155 4.2.1.2 Rigid–Flexible Hybrid Modeling and Simulation of the Camshaft Mechanism 156 4.2.2 Stress Analysis of the Cam and Roller Contact Surface 158 4.2.2.1 Contact Stress Calculation Method 159 4.2.2.2 Calculation of Contact Stress under the Combined Action of Normal and Tangential Loads 162 4.2.2.3 Analysis of the CamWorking State 164 4.2.3 Experimental Study on Stress and Strain of the High-Pressure Fuel Pump 169 4.2.3.1 Test and Analysis of the Pressure of the Plunger Cavity 169 4.2.3.2 Stress Test and Analysis of the Camshaft 174 4.3 Research on Common Rail Pressure Control Technology Based on Pump Flow Control 176 4.3.1 Design Study of a High-Pressure Pump Flow Control Device 177 4.3.1.1 Overview of a High-Pressure Pump Flow Control Device 177 4.3.1.2 Structure andWorking Principle of the High-Speed Solenoid Valve 181 4.3.1.3 Simulation of the Static Characteristic of the Solenoid Valve 183 4.3.1.4 Simulation of Dynamic Characteristics of the Solenoid Valve 188 4.3.1.5 Design and Optimization of the One-Way Valve 191 4.3.2 Conjoint Simulation Analysis of a Flow Control Device and the Common Rail System 194 4.3.2.1 Simulation of the Flow Control Device 194 4.3.3 Analysis of Simulation Results 196 4.3.4 Experimental Study on the Regulation of Common Rail Pressure by the Flow Control Device 200 4.3.4.1 Test Device 200 4.3.4.2 Sealing Performance Test of the One-Way Valve 201 4.3.4.3 Experimental Study on the Dynamic Response Characteristics of the Electromagnet 202 4.3.4.4 Test of Pressure Control in the Common Rail Chamber 204 4.3.4.5 Test Results 205 4.3.4.6 Experimental Study of the Influence of the Duty Ratio of the Solenoid Valve on the Pressure Fluctuation of the Common Rail 208 5 ECU Design Technique 211 5.1 An Overview of Diesel Engine Electronically Controlled Technology 211 5.1.1 The Development of ECU 212 5.1.1.1 The Application of Control Theory in the Research of an Electronically Controlled Unit 212 5.1.1.1.1 Adaptive Control and Robust Control 212 5.1.1.1.2 Neural Network and Fuzzy Control 213 5.1.1.2 Function Expansion of the Engine Management System 213 5.1.1.2.1 Fault Diagnosis Function for an Electronically Controlled Engine 214 5.1.1.2.2 Field Bus Technology 214 5.1.1.2.3 Sensor Technology 214 5.1.1.3 Development of Computer Hardware Technology 215 5.1.2 Development of Electronically Controlled System Development Tools and Design Methods 215 5.1.2.1 Application of Computer Simulation Technology 215 5.1.2.2 Computer-Aided Control System Design Technology 216 5.2 Overall Design of the Controller 217 5.2.1 Controller Development Process 217 5.2.2 Hierarchical Function Design and Technical Indicators of the Controller 219 5.2.3 Input Signal 221 5.2.3.1 Man–Machine Interactive Interface Input Signal 222 5.2.3.1.1 Switching Signal 222 5.2.3.1.2 Continuous Signal 222 5.2.3.2 Sensor Input Signal 222 5.2.3.2.1 Temperature Input Signal 222 5.2.3.2.2 Pressure Input Signal 223 5.2.3.2.3 Pulse Input Signal 223 5.2.4 Output Signal 223 5.2.4.1 Starting Motor Control Switch Signal 225 5.2.4.2 Drive Signal of the Electronically Controlled Injector 225 5.2.4.2.1 Time Precision Requirements 225 5.2.4.2.2 Current Waveform Requirements 226 5.2.4.2.3 Power Requirements 226 5.2.4.3 The Driving Signal of the Solenoid Valve Controlled by the Common Rail Chamber Pressure 227 5.3 Design of the Diesel Engine Control Strategy Based on the Finite State Machine 228 5.3.1 Brief Introduction of the Finite State Machine 228 5.3.1.1 Finite State Machine Definition 228 5.3.1.2 State Transition Diagram 229 5.3.2 Design of the Operation State Conversion Module 229 5.3.3 Design of the Self-Inspection State Control Strategy 232 5.3.4 Design of the Starting State Control Strategy 232 5.3.5 Design of a State Control Strategy for Acceleration and Deceleration 233 5.3.6 Design of a Stable Speed Control Strategy 234 5.3.7 Principle of the Oil Supply Pulse 234 5.4 Design of the ECU Hardware Circuit 235 5.4.1 Selection of Core Controller Parts 235 5.4.1.1 Characteristics of FPGA 236 5.4.1.2 Selection of Core Auxiliary Devices 237 5.4.2 Control Core Circuit Design 238 5.4.2.1 FPGA Circuit Design 238 5.4.2.1.1 Power Supply Design 239 5.4.2.1.2 Configuration Circuit Design 239 5.4.2.1.3 Logic Voltage Matching Circuit 239 5.4.2.2 Circuit Design of SCM 240 5.4.3 Design of the Sensor Signal Conditioning Circuit 242 5.4.3.1 Design of the Signal Conditioning Circuit for the Temperature Sensor 242 5.4.3.2 Design of the Signal Conditioning Circuit for the Pressure Sensor 244 5.4.3.3 Design of the Pulse Signal Conditioning Circuit 245 5.4.4 Design of the Power Drive Circuit 248 5.4.4.1 Design of the Power Drive Circuit of the Pressure Controlled Solenoid Overflow Valve in the Common Rail Chamber 248 5.4.4.2 Design of the Power Drive Circuit for the Solenoid Valve of the Injector 249 5.5 Soft Core Development of the Field Programmable Gate Array (FPGA) 255 5.5.1 EDA Technology and VHDL Language 256 5.5.1.1 Introduction of EDA Technology and VHDL Language 256 5.5.1.2 Introduction of EDA Tools 257 5.5.2 Module Division of the FPGA Internal Function 258 5.5.3 Design of the Rotational Speed Measurement Module 261 5.5.3.1 Measuring Principle 261 5.5.3.2 Structure Design 263 5.5.4 Design of the Control Pulse Generation Module for the Injector 266 5.5.4.1 The Function, Input, and Output of the Injector Control Pulse Generation Module 266 5.5.4.1.1 Shortening Timing Compensation Method 268 5.5.4.1.2 Increasing the Advance Angle Compensation Method 269 5.5.4.2 The Realization of the Control Pulse Generation Module of the Injector 271 6 Research on Matching Technology 273 6.1 Component Matching Technology of the Common Rail System 273 6.1.1 Matching Design of the High-Pressure Fuel Pump 273 6.1.2 Matching Design of the Rail Chamber 274 6.1.3 Matching Design of the Injector 274 6.1.3.1 Modeling and Verification of Diesel Engine Spray and the Combustion Simulation Model 276 6.1.3.2 Optimal Parameters and Objective Functions 278 6.1.3.3 Simulation Experiment Design (DOE) 278 6.1.3.4 Establishment of an Approximate Model for the Response Surface 280 6.2 Parameter Optimization and Result Analysis of the Injection System 281 6.2.1 DoE Optimization 281 6.2.2 Global Optimization Based on the Approximate Model 282 6.2.3 Optimization Results Analysis 283 6.3 Optimization Calibration Technology of the Jet Control MAP 285 6.3.1 Summary 285 6.3.2 Optimal Calibration Method 285 6.3.3 Optimization of Target Analysis 286 6.4 Off-line Steady-State Optimization Calibration of the Common Rail Diesel Engine 286 6.4.1 Mathematical Model for Optimization of the Electric Control Parameters 287 6.4.2 Experimental Design 287 6.4.3 Establishment of the Performance Prediction Response Model 288 6.4.4 Optimal Calibration 289 6.4.5 Test Result 291 7 Development of the Dual Pressure Common Rail System 293 7.1 Structure Design and Simulation Modeling of the Dual Pressure Common Rail System 295 7.1.1 Design of the Dual Pressure Common Rail System Supercharger 295 7.1.2 Modeling of the Dual Pressure Common Rail System 299 7.2 Simulation Study of the Dual Pressure Common Rail System 299 7.2.1 Study of the Dynamic Characteristics of the System 299 7.2.1.1 Simulation of the Dynamic Characteristics of the System 300 7.2.1.2 Sensitivity Analysis of the Structural Parameters of the Supercharger 303 7.2.1.3 Study on Pressure Oscillation Elimination of the Supercharger Chamber in the Dual Pressure Common Rail System 308 7.2.1.3.1 Scheme I 309 7.2.1.3.2 Scheme II 311 7.2.2 Prototype Trial Production 312 7.3 Control Strategy and Implementation of the Dual Pressure Common Rail System 313 7.3.1 Control Strategy of the Dual Pressure Common Rail System 314 7.3.2 Hardware and Software Design of the Controller Based on the Single Chip Microcomputer 315 7.3.2.1 The Basic Composition of the Control System 315 7.3.2.2 Performance of Control Chip and Its Circuit Design 316 7.3.2.2.1 The Circuit Design of the Minimum System of the Single Chip Microcomputer 316 7.3.2.2.2 Design of the Serial Communication Circuit 316 7.3.2.2.3 Pulse Signal Conditioning Circuit 318 7.3.2.3 Programming of Control System 319 7.3.3 Drive Circuit Design 319 7.3.3.1 Design Requirements of the Driving Circuit 319 7.3.3.2 Design of the Power Drive Circuit 321 7.3.3.2.1 Power Drive Circuit of the GMM Actuator 321 7.3.3.2.2 Power Drive Circuit of the Solenoid Valve 323 7.4 Experimental Study on the Dual Pressure Common Rail System 325 7.4.1 Test of Pressurization Pressure and Injection Law 325 7.4.1.1 Test Platform for Pressurization Pressure and Fuel Injection 325 7.4.1.2 Simulation and Test 328 7.4.1.3 Effect of the Turbocharging Ratio on Pressure and Fuel Injection Law 329 7.4.1.4 Effect of the Control Time Series on Pressurization Pressure and Fuel Injection Law 334 7.4.1.5 Test of System High-Pressure Oil Consumption 334 7.4.2 Test on Spray Characteristics of the Dual Pressure Common Rail System 336 7.4.2.1 Spray Photography Test Platform 336 7.4.2.2 Effect of the Fuel Injection Law on Fuel Injection Quantity 338 7.4.2.3 Effect of the Injection Rate Shape on Spray Penetration and the Spray Cone Angle 338 7.4.3 Experimental Research Conclusions 340 Index 343