Common Rail Fuel Injection Technology in Diesel Engines

Guangyao Ouyang, Shijie An, Zhenming Liu, Yuxue Li

• Publisher: Wiley
• Year: 2019
• ISBN:
  9781119107262
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Automotive Transportation & Engineering
• Index: Technology & Engineering

A wide-ranging and practical handbook that offers comprehensive treatment of high-pressure common rail technology for students and professionals

In this volume, Dr. Ouyang and his colleagues answer the need for a comprehensive examination of high-pressure common rail systems for electronic fuel injection technology, a crucial element in the optimization of diesel engine efficiency and emissions. The text begins with an overview of common rail systems today, including a look back at their progress since the 1970s and an examination of recent advances in the field. It then provides a thorough grounding in the design and assembly of common rail systems with an emphasis on key aspects of their design and assembly as well as notable technological innovations. This includes discussion of advancements in dual pressure common rail systems and the increasingly influential role of Electronic Control Unit (ECU) technology in fuel injector systems. The authors conclude with a look towards the development of a new type of common rail system. Throughout the volume, concepts are illustrated using extensive research, experimental studies and simulations. Topics covered include:

• Comprehensive detailing of common rail system elements, elementary enough for newcomers and thorough enough to act as a useful reference for professionals
• Basic and simulation models of common rail systems, including extensive instruction on performing simulations and analyzing key performance parameters
• Examination of the design and testing of next-generation twin common rail systems, including applications for marine diesel engines
• Discussion of current trends in industry research as well as areas requiring further study

Common Rail Fuel Injection Technology is the ideal handbook for students and professionals working in advanced automotive engineering, particularly researchers and engineers focused on the design of internal combustion engines and advanced fuel injection technology. Wide-ranging research and ample examples of practical applications will make this a valuable resource both in education and private industry.

1
Introduction

Today, the diesel engine is being developed and perfected; with its advantages of high efficiency and a wide range of power, it has been widely used in industry, agriculture, national defense, and other fields. Predictably, the diesel engine will still occupy an important position in the field of engines for a long time in the future. With increasingly serious energy and environmental problems, people pay more and more attention to fuel economy and emissions of the diesel engine, especially putting emission issues at the top of considerations. Governments have developed increasingly stringent emission regulations since the 1970s, and internal combustion engine researchers and related companies have constantly committed to improve the performance of the diesel engine, in order to obtain better noise emissions and a more economic performance.

There are many factors that influence diesel engine exhaust emissions and fuel economy, which are quite complicated. The most important means of improving the emissions and economic performance of diesel engine performance is to improve its combustion performance. Therefore, transformation of the fuel injection system has become an object of primary concern since it has the greatest influence on the combustion performance. The parameters that impact the performance of the diesel fuel injection system mainly include injection pressure, injection quantity, fuel injection advance angle, etc. Traditional methods are not able to make these parameters in the diesel engine achieve optimal results in the broad scope of work carried out on the diesel engine, but the development of modern electronic technology has provided a broad space in which to improve the performance of the diesel engine.

The biggest impact of the diesel engine fuel injection system on combustion concerns three factors: injection timing, injection duration, and the fuel injection law. The main purpose of an electric controlled diesel engine fuel injection system is to realize the flexible adjustment of the above three factors, which ensure that the diesel engine is running in optimal working conditions.

The diesel engine electronic control injection system is usually composed of sensors, controllers, and actuators, as shown in Figure 1.1. The combustion process in the cylinder of the diesel engine is very complex, and is affected by many factors. The method of setting up a mathematical model, with the aid of all kinds of sensors, to realize the closed‐loop control of the burning process is difficult. The basic method that most diesel engine electronic control fuel injection systems now adopt is: adopting engine speed and load as a basic signal reflecting the actual working conditions of the diesel engine; then referring to the fuel injection quantity obtained by experiment in the optimum working condition and the injection timing MAP graph in order to determine the basic fuel injection quantity and injection timing; then carrying on the various compensation schemes (such as engine speed, load, water temperature, oil temperature, atmospheric pressure, etc.) in order to determine the cycle fuel injection quantity and injection timing; and then taking the closed‐loop feedback control to actuators in the process of working.

Figure 1.1 The basic compositions of the fuel injection system on an electronic controlled diesel engine.

After the diesel engine fuel system adopts the electric control system, it has the following features:

1. (1) The degree of control freedom increases. The electronic control fuel injection system can optimize comprehensive control on the injection parameters in accordance with the different operating conditions.
2. (2) The control precision improves. For instance, the injection timing control accuracy (CA) is higher than 0.5° CA and the accuracy is four times higher than with mechanical control.
3. (3) Since the diesel engine fuel injection system has the characteristics of high voltage and high frequency and pulse, it will be able to achieve these objectives and will certainly bring about the complexity of actuator and control and strict requirements on reliability and duration of system that are required.

1.1 The Development of an Electronic Control Fuel Injection System

After decades of development, the diesel engine electronic control fuel injection system has experienced three progressive stages, namely, position type control, time control, and pressure time control.

1.1.1 Position Type Electronic Control Fuel Injection System

A position type electronic control fuel injection system retains the basic structure of a traditional injection system and only replaces the original mechanical control mechanism with electronic components. On the basis of the original mechanical control loop fuel injection quantity and injection timing, the electromagnetic actuator of linear displacement or angular displacement has been adapted to realize electrically controlled fuel injection timing and to improve control accuracy and the mechanical control response speed. Its products involve an array plunger pump electronic control system and a rotor pump distribution electric control system. Typical representative types are shown in Table 1.1.

Table 1.1 Typical representatives of a position type electronic control fuel injection system.

Form	System name	Control characteristics
S T
	Pump Zexel (Japan) COPEC	High‐speed solenoid valve control injection time, variable inductance displacement control fuel injection quantity
R A	BOSCH (Germany company) EDR	High‐speed solenoid valve control gear lever displacement, adjustable CAM phase
I G	(American Caterpillar company) PEEC – ECD‐P3	Brushless torque motor control gear lever displacement, linear potentiometer control injection time
H	(Japan Toyota) ECD‐p	High‐speed solenoid valve control injection time, adjustable CAM phase
T	BOSCH (Germany company) TICS	High‐speed solenoid valve control plunger sleeve and gear lever position, the variable stroke
C	(Japan Toyota) ECD‐p	High‐speed solenoid valve control injection time, adjustable CAM phase
O	(British Lucas) EPIC	The phase of the CAM ring to control injection timing, control the distribution of rotor axial displacement control of oil
L U	(Stanadyne companies in the United States) PCF	Control CAM follower body axial displacement control of oil, the control of fuel injection advance unit control injection time
M N	BOSCH (Germany company) ECD – COVEC	Rotating magnet control sliding sleeve position, solenoid valve control injection time

A position type electronic control injection system adapts electronic control components to replace the original mechanical adjusting mechanism, while the use of electronic control mechanical actuators is to control the process of injection indirectly; thus the control accuracy, response time, is comparatively lower than in other electronic control systems. Since the basic structure of the injection system has not changed, the injection characteristics cannot be greatly changed and so the injection rate is not likely to achieve flexible control.

1.1.2 Time Type Electronic Control Fuel Injection System

As the performance of the diesel engine has further requirements on fuel injection process control, the first generation of fuel injection systems that installed an electronic control device with the original mechanical injector could not meet demand and thus the second generation of electronic control fuel injection system arises at the historic moment to use the electronic control unit (ECU) to control the injection starting point and end point directly...