WO2017013393A1

WO2017013393A1 - A control method and device for rf ignition of internal combustion engines

Info

Publication number: WO2017013393A1
Application number: PCT/GB2016/052047
Authority: WO
Inventors: Fang Sun
Original assignee: Sunimex Ltd
Priority date: 2015-07-20
Filing date: 2016-07-07
Publication date: 2017-01-26
Also published as: CN105003376B; CN105003376A

Abstract

An RF engine ignition control device and method are disclosed. The method includes the steps of: acquiring values of operating parameters at a time of ignition(101), wherein said operating parameters include: engine speed, ignition advance angle, air/fuel mixture ratio, air-fuel mixing degree, fuel quality, compression ratio, cylinder internal temperature and/or cylinder internal pressure; determining, based on said acquired values of the operating parameters, a resonance frequency of a cylinder corresponding to said values of the operating parameters(102); and emitting an RF signal corresponding to said resonance frequency of the cylinder(103).The RF engine ignition control device and method according to the present invention each provide an engine with improved fuel efficiency and reliability.

Description

A CONTROL METHOD AND DEVICE FOR RF IGNITION OF INTERNAL COMBUSTION ENGINES

Field of the Invention

The embodiment of the present invention relates to the field of automotive and electronic technology and, more particularly, to a radio frequency (RF) ignition control method and device for internal combustion engine (ICE). Background of the Invention

The concept of RF ignition was first proposed by Ward in his patents in 1974 and 1979. The original concept was an idea of using engine cylinders as resonators to generate high electromagnetic energy to breakdown air-fuel mixture in cylinders. The idea was used to improve the existing spark ignition. There was no practically applicable method described in patents in terms of realisation of an RF ignition system on modern vehicles.

Since the concept was published many studies have considered introducing RF and electromagnetic wave ignition and ignition system into the automotive ICEs. Many research institutions and companies have been trying to bring the idea of RF ignition into reality. Several more patents with respect to RF ignition have been published. Kimura suggested an ignition system that utilised engine cylinders as resonant cavities where resonance occurs and causes a plasma discharge to ignite the air-fuel mixture in patent US4446826. In order to ensure the occurrence of the resonance the patent shaped the engine cylinder in a manner which resulted in a change of structure of the engine cylinders. This method has been proven impractical for modern vehicles.

In patent JP2000230426A Kimura proposed a method to adjust the resonance frequency of a combustion chamber using a stub on the top of piston so the piston movement does not affect the resonance frequency of the engine cylinders. The method aims to stabilise the resonance frequency of the engine cylinder so that the frequency of injected microwave pulse matches it. However, the piston movement is not the only factor that affects the resonance frequency of the engine cylinders. Therefore, the method and device described in this patent cannot solve the problem of the realisation of the RF ignition.

Patent CN102278252A published an ignition method based on the resonance frequency of an electromagnetic wave. The method adjusts the frequency of an electromagnetic wave source to match the resonance frequency of the ignition chamber with a certain dimension. When the dimension of the ignition chamber changes, the frequency of electromagnetic wave source will be continuously adjusted to find the shifted resonance frequency of the ignition chamber so as to match it. This method cannot provide a stable ignition as a resonance cannot be always guaranteed at the desired ignition time even when the speed of the frequency adjustment of the electromagnetic wave source is greater than the speed of the piston movement. Besides the dimension of the ignition chamber is not the only factor that affects the resonance frequency of engine cylinders. Therefore, this method cannot effectively solve the practical problem of the RF ignition.

Patent CN103470427A published a microwave plasma ignition system that uses engine cylinders as resonant cavities. This patent described the idea of the ignition system, which is the same as the concept in Ward's patent. However, the patent did not provide any practical solutions to the problems encountered in realisation of the RF ignition system on modern vehicles.

The above patents and research of RF ignition using the engine cylinder as a resonant cavity describe the ignition method based on the resonance frequency of the electromagnetic wave, of which ignition occurs mainly by adjusting the frequency of electromagnetic wave source, or dimensions of resonant cavity. The RF ignition using the engine cylinder as a resonant cavity has been proven to be more fuel efficient and has less exhaust pollutants. There are other approaches to the application of RF ignition, which either use an independent coaxial cavity resonator as the resonant cavity to generate high power electromagnetic energy or use direct microwave energy. In patents US6357426, US6918366, US7204220, and US5361737A, the RF resonance occurs in an independent coaxial cavity resonator and the high power

electromagnetic energy generated in the coaxial cavity resonator is then emitted into engine cylinders to ignite air-fuel mixture. Because the resonance does not occur in engine cylinders this method or device cannot produce volume ignition as much as Ward's original concept may achieve, which limits its efficiency.

Patent US7770551 B2 suggested a process of ignition, which included injecting high microwave energy into cylinders to ignite air-fuel mixture. The process uses multi-pulse microwaves to prevent the formation of plasma so that a large volume of fuel can be ignited. The patent does not use either engine cylinders as a resonator or an independent cavity resonator and it may not be able to guarantee a stable volume ignition since the process relies on the absorption of microwave pulses, which is not instantaneous. These patents described different types of RF ignition than the present invention. The present invention is to overcome the problem of the RF ignition employing engine cylinders as resonant cavities.

Summary of the Invention Technical Problem The existing electromagnetic wave or RF ignition system that uses engine cylinders as resonant cavities employs an ignition method based on the resonance frequency of the electromagnetic wave or RF signal, of which the ignition occurs mainly by adjusting the frequency of electromagnetic wave or RF signal source, or dimensions of the resonant cavity.

In the process of implementing the present invention, the inventor found in the analysis of existing electromagnetic wave and RF engine ignition technology that: since the resonance frequency of the resonator for ignition is continuously changing when a vehicle is in the course of the campaign it is difficult to monitor the resonance frequency of the resonator for ignition in real time and then by adjusting the frequency of the electromagnetic wave source to adapt to the resonance frequency of the resonator for ignition, or it is difficult to adjust the dimensions of resonator for ignition to match the frequency of electromagnetic wave source, not to mention that the dimensions of resonator for ignition is not the only factors influencing resonator frequency for ignition, and thus, it is likely to result in missing the time of ignition due to aforementioned these difficulties. Therefore, the existing electromagnetic wave and RF engine ignition technology has problems such as poor reliability and high misfire or ignition failure rate etc, and cannot succeed in its practical application.

Solution to Problem

The embodiment of the present invention provides an RF ignition control method and device for ICE to overcome the problems of existing electromagnetic wave and RF ignition technology developed for modern ICE, such as poor reliability and high misfire or ignition failure rate etc. from a software angle.

The embodiment of the present invention provides an RF ignition control method for ICE, including: acquiring the values of the operating parameters at the time of ignition, wherein said operating parameters include engine speed, ignition advance angle, air/fuel mixture ratio, air-fuel mixing degree, fuel quality, compression ratio, cylinder internal temperature and/or cylinder internal pressure; determining, based on said acquired values of the operating parameters at the time of ignition, the resonance frequency of the cylinder corresponding to said values of the operating parameters at the time of ignition; emitting, based on said resonance frequency of the cylinder, an RF signal corresponding to said resonance frequency of the cylinder.

Alternatively, if said operating parameters include one of engine speed, ignition advance angle, air/fuel mixture ratio, air-fuel mixing degree, fuel quality, compression ratio, cylinder internal temperature or cylinder internal pressure, before determining the resonance frequency of the cylinder corresponding to said values of the operating parameters at the time of ignition, it includes: acquiring, according to the preset accuracy of parameters, through engine running experiments and simulations, the corresponding resonance frequency of the cylinder for any parameter's dynamic operational value for said operating parameters for different operating states of the engine; and creating a value mapping relationship for the cylinder resonance frequency corresponding to any dynamic operational value of said operating parameters for different operating states of the engine.

Alternatively, if said operating parameters include at least two of engine speed, ignition advance angle, air/fuel mixture ratio, air-fuel mixing degree, fuel quality, compression ratio, cylinder internal temperature or cylinder internal pressure, before determining the resonance frequency of the cylinder corresponding to said values of the operating parameters at the time of ignition, it includes: setting one of said operating parameters as a variable parameter and setting the other parameters as fixed parameters; acquiring, according to the preset accuracy of parameters, through engine running experiments and simulations, where the values of said fixed parameters are unchanged, the dynamic operational value of said variable parameter and the corresponding resonance frequency of the cylinder; and creating a mapping relationship between said fixed parameters, the dynamic operational value of said variable parameters and the corresponding resonance frequency of the cylinder.

Alternatively, said method further comprises: storing said value mapping relationship for the cylinder resonance frequency corresponding to any dynamic operational value of said operating parameters for different engine working conditions in an operating parameters database; or creating a mapping relationship between said fixed parameters, the dynamic operational value of said variable parameters and the corresponding resonance frequency of the cylinder and storing it in said operating parameters database. Alternatively, said accuracy of parameter values is used to ensure that, for said various cylinder resonance frequencies, the volume of simultaneous ignition within said cylinder is greater than a preset percentage. Alternatively, based on said acquired values of the operating parameters at the time of ignition, determining the resonance frequency of the cylinder

corresponding to said values of the operating parameters at the time of ignition, it includes: based on the acquired values of the operating parameters at the time of ignition, querying the operating parameters database; if the values of the operating parameters at the time of ignition are identical to those in said operating parameters database, based on said values of the operating

parameters, determining the resonance frequency of the cylinder corresponding to said values of the operating parameters;

and if the values of the operating parameters at the time of ignition are not identical to those of said operating parameters database, based on the accuracy of said parameters, determining the values of the operating parameters closest to the values of the operating parameters at the time of ignition, and, based on said closest values of the operating parameters from the values of the operating parameters stored in the operating parameters database, through pre- calculation, determining the corresponding resonance frequency of the cylinder for said closest values of the operating parameters.

The embodiment of the present invention further provides an RF engine ignition control device, characterized in that it includes: a retrieval module, used to acquire the values of operating parameters at the time of ignition, wherein said operating parameters include engine speed, ignition advance angle, air/fuel mixture ratio, air-fuel mixing degree, fuel quality, compression ratio, cylinder internal temperature and/or cylinder internal pressure; a determination module, used to determine the resonance frequency of the cylinder corresponding to said values of the operating parameters at the time of ignition based on said acquired values of the operating parameters at the time of ignition; and an emission module, used to emit an RF signal corresponding to said resonance frequency of the cylinder based on said resonance frequency of the cylinder. Alternatively, said device further comprises: a saving module, used to store said value mapping relationship for the cylinder resonance frequency corresponding to any dynamic operational value of said operating parameters for different engine working conditions in an operating parameters database; wherein said value mapping relationship for the cylinder resonance frequency corresponding to any dynamic operational values of said operating parameters for different operating states of the engine is based on preset accuracy of parameters, through engine running experiments and simulations, acquiring the

corresponding resonance frequency of the cylinder for any parameter's dynamic operational value for said operating parameters for different operating states of the engine, and creating a value mapping relationship for the cylinder resonance frequency corresponding to any dynamic operational value of said operating parameters for different operating states of the engine; or storing the mapping relationship between said fixed parameters, the dynamic operational value of said variable parameters and the corresponding resonance frequency of the cylinder in said operating parameters database; wherein the mapping

relationship between said fixed parameters, the dynamic operational value of said variable parameters and the corresponding resonance frequency of the cylinder is stored as a variable parameter in said operating parameters database, when the other parameters are set as fixed parameters; according to the accuracy of parameters, through engine running experiments and simulations, where the values of said fixed parameters are unchanged, acquiring the dynamic operational value of said variable parameter and the corresponding resonance frequency of the cylinder, and creating a mapping relationship between said fixed parameters, the dynamic operational value of said variable parameters and the corresponding resonance frequency of the cylinder.

Alternatively, said accuracy of parameter values are used to ensure that, for various cylinder resonance frequencies, the volume of simultaneous ignition within said cylinder is greater than a preset percentage. Alternatively, said determination module specifically is used to: based on the acquired values of the operating parameters at the time of ignition, querying the operating parameters database; if the values of the operating parameters at the time of ignition are identical to those in said operating parameters database, based on said values of the operating parameters, determine the resonance frequency of the cylinder corresponding to said values of the operating parameters; and if the values of the operating parameters at the time of ignition are not identical to those of said operating parameters database, based on said accuracy of parameters, among the values of the operating parameters stored in the operating parameters database, determine the values of the operating parameters closest to the values of the operating parameters at the time of ignition, then based on said closest values of the operating parameters, determine the corresponding resonance frequency of the cylinder for said closest values of the operating parameters.

Advantageous Effects of Invention

The embodiment of the present invention in this patent acquires the values of operating parameters at the time of ignition; determines, based on said acquired values of the operating parameters at the time of ignition, the resonance frequency of the cylinder corresponding to said values of the operating parameters at the time of ignition; emits, based on said resonance frequency of the cylinder, an RF signal corresponding to said resonance frequency of the cylinder. Since the embodiment of the present invention considers the influence of the operating parameters at the time of ignition (such as ignition advance angle, air/fuel mixture ratio, air-fuel mixing degree, fuel quality, cylinder internal temperature, cylinder internal pressure and compression ratio etc.) in the process of determining the resonance frequency of the cylinder it reduces the influence of the sensitivity of the resonance frequency of the cylinder to operating parameters on the RF resonance in the cylinder, thereby improving the adaptability of the frequency of RF signal to the resonance frequency of the cylinder, and therefore the reliability of existing electromagnetic wave or RF engine ignition technologies is improved or the misfire or ignition failure rate of existing electromagnetic wave or RF engine ignition technology is reduced and the problems such as poor reliability and high rate of ignition misfire or ignition failure of existing

electromagnetic wave or RF engine ignition technology in practical application are solved.

Brief Description of Drawings

In order to illustrate the technical solution of the embodiments of the present invention or the existing technologies more clearly, drawings used in the description of the embodiments or the existing technologies are briefly described. Obviously, drawings described below are some embodiments of the present invention. For ordinary technique personnel in relevant area other drawings can be obtained based on these drawings under the premise of no creative efforts. Figure 1 is the flow chart of an implementation example of an RF engine ignition control method in the present invention;

Figure 2 is the flow chart of another implementation example of an RF engine ignition control method in the present invention;

Figure 3 is the illustration of the corresponding relationship between the accuracy of air/fuel mixture ratio and the resonance frequency of the cylinder;

Figure 4 is the illustration of the corresponding relationship between ignition advance angle and the resonance frequency of the cylinder;

Figure 5 is yet another illustration of the corresponding relations between ignition advance angle and the resonance frequency of the cylinder;

Figure 6 is the structural diagram of an implementation example of an RF engine ignition control device in the present invention; and

Figure 7 is the structural diagram of an implementation example of an RF engine ignition control system in the present invention.

Description of Embodiments

In order to clearly illustrate the purpose, the technical solution, and the

advantages of the embodiments of the present invention, along with drawings of the implementation examples of the present invention, a clear and complete description of the technical solution of the present invention is made. Obviously, the described implementation examples are some of embodiments of the present invention, rather than all of them. Based on the described implementation examples in the present invention, all other implementation examples obtained by ordinary technique personnel in relevant area under the premise of no creative efforts are within the scope of the protection of the present invention.

A study of existing technologies found: the resonance frequency of the cylinder is influenced by many factors including: ignition advance angle (also may be referred to as the piston position), air/fuel mixture ratio and air-fuel mixing degree, fuel quality, cylinder internal temperature, cylinder internal pressure, compression ratio etc. when automotive gasoline engines and natural gas engines are in the course of a cycle. Therefore, realising the RF resonance ignition on automotive gasoline engines and natural gas engines will cause problems such as high misfire rate, high ignition failure rate and poor ignition reliability due to the over-sensitivity of the resonance frequency of the cylinder to engine states caused by aforementioned factors.

The RF ignition control method for ICE proposed in the present invention can effectively solve the problems in existing technologies, such as misfire and unreliable ignition etc.

It should be noted here, in the embodiment of the present invention, the parameter ignition advance angle is the same argument as the parameter piston position. Therefore, in the patent the term ignition advance angle can be replaced by piston position.

Figure 1 is the flow chart of an implementation example of an RF engine ignition control method in the present invention. As shown in Figure 1 , the method of the implementation example includes: acquiring the values of the operating parameters at the time of ignition (step 101). In practical implementation, for example, an automotive engine control system sends a sequence of instructions of parameters such as an amount of fuel injection, air/fuel mixture ratio, and ignition advance angle etc. to control ignition at an ignition time. Meanwhile the automotive engine control system also monitors the operating parameters of the engine in real-time. Therefore, multi- dimension parameters describing engine states at a specific ignition time can be obtained through the automotive engine control system.

The operating parameters may include multi-dimension parameters, including engine speed, ignition advance angle, air/fuel mixture ratio, air-fuel mixing degree, fuel quality, compression ratio, cylinder internal temperature, and cylinder internal pressure. For example, when the engine speed is 3505 rpm, the ignition advance angle is 3 degree to TDC (in order to determine piston position at the time of ignition); the measured pressure in the cylinder is 1400 kPa; the measured temperature in the cylinder is 1000 Kelvin; the air/fuel mixture ratio at this time is 23:1 ; the compression ratio is 10: 1 ; the air-fuel mixing degree is 1 , indicating air-fuel mixture is well mixed; and the fuel quality is 95.

It should be noted that said multi-dimension operating parameters in the present invention include, but not limited to, ignition advance angle, air/fuel mixture ratio, air-fuel mixing degree, fuel quality, cylinder internal temperature, cylinder internal pressure, and compression ratio.

The method further includes determining, based on said acquired values of the operating parameters at the time of ignition, the resonance frequency of the cylinder corresponding to said values of the operating parameters at the time of ignition (step 102).

In an alternative embodiment, before the step 102, it includes: acquiring, according to the preset accuracy of parameters, through engine running experiments and simulations, the corresponding resonance frequency of the cylinder for any parameter's dynamic operational value for said operating parameters for different operating states of the engine; creating a value mapping relationship for the cylinder resonance frequency corresponding to any dynamic operational value of said operating parameters for different operating states of the engine; and then, storing said value mapping relationship for the cylinder resonance frequency corresponding to any dynamic operational value of said operating parameters for different engine working conditions in an operating parameters database.

For example, to acquire, based on the preset accuracy of the engine speed, the values of the engine speed under different engine states and the resonance frequencies of the cylinder corresponding to the different values of the engine speed through experiments or simulations; to acquire, based on the preset accuracy of the air/fuel mixture ratio, the values of the air/fuel mixture ratio under different engine states and the resonance frequencies of the cylinder

corresponding to the different values of the air/fuel mixture ratio through experiments or simulations; to acquire, based on the preset accuracy of the ignition advance angle, the values of the ignition advance angle under different engine states and the resonance frequencies of the cylinder corresponding to the different values of the ignition advance angle through experiments or simulations; to acquire, based on the preset accuracy of the air-fuel mixing degree, the values of the air-fuel mixing degree under different engine states and the resonance frequencies of the cylinder corresponding to the different values of the air-fuel mixing degree through experiments or simulations; to acquire, based on the preset accuracy of the fuel quality, the values of the fuel quality under different engine states and the resonance frequencies of the cylinder corresponding to the different values of the fuel quality through experiments or simulations; to acquire, based on the preset accuracy of the cylinder internal temperature, the values of the cylinder internal temperature under different engine states and the resonance frequencies of the cylinder corresponding to the different values of the cylinder internal temperature through experiments or simulations; to acquire, based on the preset accuracy of the cylinder internal pressure, the values of the cylinder internal pressure under different engine states and the resonance frequencies of the cylinder corresponding to the different values of the cylinder internal pressure through experiments or simulations; or to acquire, based on the preset accuracy of the compression ratio, the values of the compression ratio under different engine states and the resonance frequencies of the cylinder corresponding to the different values of the compression ratio through experiments or simulations. Table 1 shows an example of the database storing mapping relationship between the operating parameters and the resonance frequency of the cylinder:

In an alternative embodiment, before the step 102, it also includes: setting one of said operating parameters as a variable parameter and setting the other parameters as fixed parameters; acquiring, according to the preset accuracy of parameters, through engine running experiments and simulations, where the values of said fixed parameters are unchanged, the dynamic operational value of said variable parameter and the corresponding resonance frequency of the cylinder; creating a mapping relationship between said fixed parameters, the dynamic operational value of said variable parameters and the corresponding resonance frequency of the cylinder; 1 and then, creating a mapping relationship between said fixed parameters, the dynamic operational value of said variable parameters and the corresponding resonance frequency of the cylinder and storing it in said operating parameters database.

Table 2 shows another example of the database storing the mapping relationship between the operating parameters and the resonance frequency of the cylinder: Ignition Air/fuel Air-fuel Fuel Cylinder internal Cylinder Compression Engine Cylinder advance mixture mixing quality temperature 1 internal ratio 1 Speed resonance angle 1 ratio 1 degree 1 1 pressure 1 frequency

1 1 1 1 1 1 1 1 1

Ignition Air/fuel Air-fuel Fuel Cylinder internal Cylinder Compression Engine Cylinder advance mixture mixing quality temperature 1 internal ratio 1 Speed resonance angle 1 ratio 1 degree 1 1 pressure 2 frequency

1 1 1 1 1 1 1 12

Ignition Air/fuel Air-fuel Fuel Cylinder internal Cylinder Compression Engine Cylinder advance mixture mixing quality temperature 1 internal ratio 1 Speed resonance angle 1 ratio 1 degree 1 1 pressure M frequency

1 1 1 1 1 1 1 1 M

Ignition Air/fuel Air-fuel Fuel Cylinder internal Cylinder Compression Engine Cylinder advance mixture mixing quality temperature 1 internal ratio 2 Speed resonance angle 1 ratio 1 degree 1 1 pressure 1 frequency

1 1 1 1 1 1 121

Ignition Air/fuel Air-fuel Fuel Cylinder internal Cylinder Compression Engine Cylinder advance mixture mixing quality temperature 1 internal ratio P Speed resonance angle 1 ratio 1 degree 1 1 pressure 1 frequency

1 1 1 1 1 1 1 P1

Ignition Air/fuel Air-fuel Fuel Cylinder internal Cylinder Compression Engine Cylinder advance mixture mixing quality temperature 1 internal ratio 2 Speed resonance angle 1 ratio 1 degree 1 1 pressure 2 frequency

1 1 1 1 1 1 122

Ignition Air/fuel Air-fuel Fuel Cylinder internal Cylinder Compression Engine Cylinder advance mixture mixing quality temperature 1 internal ratio P Speed resonance angle 1 ratio 1 degree 1 1 pressure 2 frequency

1 1 1 1 1 1 1 P2

Ignition Air/fuel Air-fuel Fuel Cylinder internal Cylinder Compression Engine Cylinder advance mixture mixing quality temperature 1 internal ratio 2 Speed resonance angle 1 ratio 1 degree 1 1 pressure M frequency

1 1 1 1 1 1 12M

Ignition Air/fuel Air-fuel Fuel Cylinder internal Cylinder Compression Engine Cylinder advance mixture mixing quality temperature 1 internal ratio P Speed resonance angle 1 ratio 1 degree 1 1 pressure M frequency

1 1 1 1 1 1 1 PM

Ignition Air/fuel Air-fuel Fuel Cylinder internal Cylinder Compression Engine Cylinder advance mixture mixing quality temperature L internal ratio P Speed resonance angle 2 ratio E degree F G pressure M frequency

N 2EFGLNP

M

Ignition Air/fuel Air-fuel Fuel Cylinder internal Cylinder Compression Engine Cylinder advance mixture mixing quality temperature L internal ratio P Speed resonance angle X ratio E degree F G pressure M frequency

N XEFGLNP

M For example, in the simulation and experiment measurements, when measuring a dimension of the database it is required to fix other remaining dimensions of it in order to measure this dimension. For an example, it is required to fix parameters engine speed, air/fuel mixture ratio, air-fuel mixing degree, fuel quality, compression ratio, cylinder internal temperature, and cylinder internal pressure in order to measure the resonance frequencies of the cylinder corresponding to different ignition advance angles. The accuracy of the ignition advance angle can be determined through simulation and experiment studies and the accuracy of ignition advance angle decides the number of unit of the ignition advance angle required to be measured. When measuring the ignition advance angle, the accuracy of the ignition advance angle determines the number of ignition advance angle to be measured. For all measuring of the ignition advance angle all other parameters are required to be set as fixed parameters. The accuracy of the ignition advance angle is used to ensure that, for various cylinder resonance frequencies, the volume of simultaneous ignition within the cylinder is greater than a preset percentage, wherein, e.g., the preset percentage includes 70%, 80%, or 90%, or the preset percentage includes any percentage value between 70% and 90%; or the accuracy of the ignition advance angle is used to ensure that the accuracy of each resonance frequency of the cylinder reaches 0.1 MHz. Typically, the accuracy of the resonance frequency of the cylinder depends on engine and cylinder model. Said simultaneous means when resonance generates the preset percentage volume of air-fuel mixture is broken down at the same time if the volume in the cylinder that the electrical field strength is great than the ignition threshold of the electrical field strength is greater than the preset percentage. Once the air-fuel mixture is broken down (no matter how much volume of the air-fuel mixture is broken down, even 1 %) the resonant conditions will change, which results in off-resonance and the remaining air-fuel mixture will be ignited through combustion propagation. For spark ignition, roughly the simultaneous ignition volume of air-fuel mixture is less than 1 %. RF ignition aims to enable the largest possible volume of air-fuel mixture to be ignited simultaneously.

Table 3 shows a specific example of the database storing the mapping relationship between engine operating parameters and the resonance frequency of the cylinder, wherein all remaining parameters are fixed when the ignition advance angle is measured: Engine Air/fuel Fuel Cylinder Cylinder Compression Air-fuel Ignition Cylinder Speed mixture quality internal internal ratio mixing advance resonance ratio temperature pressure degree angle frequency

3505 23:1 95 1000 Kelvin 1400 kPa 10 1 Ignition Cylinder

(indicating advance resonance the air- angle 1 frequency 1 fuel Ignition Cylinder mixture is advance resonance mixed angle 2 frequency 2 well)

Ignition Cylinder advance resonance angle X frequency

X

In an alternative embodiment, step 102 includes: based on the acquired values of the operating parameters at the time of ignition, querying the operating parameters database; if the values of the operating parameters at the time of ignition are

5 identical to those in said operating parameters database, based on said values of the

operating parameters, determining the resonance frequency of the cylinder

corresponding to said values of the operating parameters; if the values of the

operating parameters at the time of ignition are not identical to those of said

operating parameters database, based on the accuracy of said parameters,

10 determining the values of the operating parameters closest to the values of the

operating parameters at the time of ignition; and based on said closest values of the operating parameters from the values of the operating parameters stored in the

operating parameters database, through pre-calculation, determining the

corresponding resonance frequency of the cylinder for said closest values of the

15 operating parameters.

The method further includes emitting, based on said resonance frequency of the

cylinder, an RF signal corresponding to said resonance frequency of the cylinder

(step 103).

20

In practical implementation, for example, the control signal is sent to the RF signal generator through the RF signal generation control unit to instruct the RF signal

generator to generate the RF signal at the frequency corresponding to said resonance frequency of the cylinder. Further, the RF signal at the frequency corresponding to said resonance frequency of the cylinder is transmitted through an amplifier, a transmission line, and a coupler, and coupled into the cylinder. If the frequency of RF the signal coupled into the cylinder is identical to the resonance frequency of the cylinder at the time of ignition and then the resonance is generated in the cylinder which result in the formation of a high strength electrical field used to breakdown air-fuel mixture in the cylinder.

The embodiment of the present invention in this patent acquires the values of operating parameters at the time of ignition; determines, based on said acquired values of the operating parameters at the time of ignition, the resonance frequency of the cylinder corresponding to said values of the operating parameters at the time of ignition; emits, based on said resonance frequency of the cylinder, an RF signal corresponding to said resonance frequency of the cylinder. Since the embodiment of the present invention considers the influence of the operating parameters at the time of ignition (such as ignition advance angle, air/fuel mixture ratio, air-fuel mixing degree, fuel quality, cylinder internal temperature, cylinder internal pressure and compression ratio etc.) in the process of determining the resonance frequency of the cylinder it can reduce the sensitivity of the resonance frequency of the cylinder to the operating parameters, thereby improving the adaptability of the frequency of RF signal to the resonance frequency of the cylinder, and thus it can realise the high reliability and the low misfire rate or low ignition failure rate of the RF engine ignition technology and the problems of poor reliability or high rate of ignition misfire and ignition failure of existing electromagnetic wave or RF engine ignition technology in practical application are solved.

Figure 2 is the flow chart of another implementation example of an RF engine ignition control method in the present invention. As shown in Figure 2, the method of the implementation example includes: acquiring the values of the operating parameters at the time of ignition (step 201); wherein, said operating parameters of the present implementation example include, but not limited to, ignition advance angle, air/fuel mixture ratio, air-fuel mixing degree, fuel quality, cylinder internal temperature, cylinder internal pressure, and compression ratio. The procedure of the implementation of Step 201 can be referred to the Step 101 of the implementation example shown in Figure 1 , and will not be restated in detail.

The method further includes querying the operating parameters database (step 202).

The establishment of the database of the operating parameters in the present implementation example can be referred to the procedure of Step 102 of the implementation example shown in Figure 1 , and will not be restated in detail. For example, the mapping relationship of the operating parameters in database can be illustrated by the schematic diagram. Assuming the condition of engine speed, ignition advance angle, air-fuel mixing degree, fuel quality, cylinder internal temperature, cylinder internal pressure, and compression ratio remaining

unchanged, the database of the operating parameters stores mapping relationship between air/fuel mixture ratio and the resonance frequency of the cylinder. Figure 3 is the illustration of the corresponding relationship between the accuracy of air/fuel mixture ratio and the resonance frequency of the cylinder.

Step 203, whether the values of the operating parameters at the time of ignition are identical to those in said operating parameters database. If they are, then going to Step 204, otherwise, Step 205.

The method further includes based on said values of the operating parameters, determining the resonance frequency of the cylinder corresponding to said values of the operating parameters (step 204).

When the values of the operating parameters at the time of ignition are identical to those in said operating parameters database, in which case, based on said values of the operating parameters, the resonance frequency of the cylinder corresponding to said values of the operating parameters can be determined.

The method further includes based on said accuracy of parameters, among the values of the operating parameters stored in the operating parameters database, determining the values of the operating parameters closest to the values of the operating parameters at the time of ignition, then based on said closest values of the operating parameters, determining the corresponding resonance frequency of the cylinder for said closest values of the operating parameters (step 205).

Hereby, take the variable parameter ignition advance angle (piston position) as an example to illustrate the procedure, while setting remaining parameters as fixed parameters. Figure 4 is the illustration of the corresponding relationship between ignition advance angle and the resonance frequency of the cylinder. As shown in Figure 4, when fixing all other parameters and measuring various ignition advance angles, the resonance frequency of the cylinder at each ignition advance angle can be acquired. The acquired resonance frequencies of the cylinder are stored in the database and are corresponding to measured the ignition advance angle and other parameters. Figure 4 show the total measured 10 ignition advance angles from 10 degree before top dead centre (TDC) to 1 degree before TDC. The measurement accuracy of ignition advance angle is preset to 1 degree. As seen from Figure 4 the electric field strength of the overlapping portion between two adjacent ignition advance angle drops below the required minimum ignition electric field strength 106 V/m. Therefore, the accuracy of ignition advance angle cannot meet the desired requirement of the RF ignition. Figure 5 is yet another illustration of the corresponding relations between ignition advance angle and the resonance frequency of the cylinder. From Figure 5, which illustrates the result from increasing the measurement accuracy of the ignition advance angle, it can be seen that when the accuracy of ignition advance angle is greater than 7.2 arc seconds the electric field strength of the overlapping portion between two adjacent ignition advance angles 1 degree before TDC and 1 degree 7.2 arc seconds before TDC is above required minimum ignition of electric field strength. Therefore, the measurement accuracy meets the desired requirement of the RF ignition and the accuracy of the corresponding resonance frequency of the cylinder is 105 Hz. If it is calculated in accordance with the measurement accuracy of 7.2 arc seconds of the ignition advance angle it is calculated based on the accuracy of 7.2 arc seconds of ignition advance angle, then 5001 ignition advance angles need to be measured between 10 degrees before TDC and TDC position, so on so forth, 10001 ignition advance angles need to be measured between 20 degrees before TDC and TDC position. The initial ignition advance angle to be measured is determined by the maximum ignition advance angle of the engine, while the maximum ignition advance angle will be determined based on engine experiments.

For example, when the ignition advance angle at the time of ignition is not identical to any measured ignition advance angles, e.g. the operating parameters database does not exist the resonance frequency of the cylinder that corresponds to the ignition advance angle at the time of ignition, the resonance frequency of the cylinder corresponding to the ignition advance angle at the time of ignition needs to be approximated based on measured ignition advance angles using the pre-defined algorithm. Take Figure 5 as an example: various ignition advance angles have been measured; positions of 1 degree before TDC and 1 degree 7.2 arc seconds before TDC and corresponding resonance frequencies of the cylinder have been stored in the operating parameters database, assuming other remaining operating parameters are fixed. From Figure 5 it can be seen that when the piston moves to the position of 1 degree 5 arc seconds before TDC, if using resonance frequency of the cylinder measured at 1 degree 7.2 arc seconds before TDC to approximate the resonance frequency of the cylinder at 1 degree 5 arc seconds before TDC and emitting the RF signal at the resonance frequency of the cylinder measured at 1 degree 7.2 arc seconds before TDC then the electric field strength can reach 4.5 x 106V/m, or if using the resonance frequency of the cylinder measured at 1 degree before TDC to approximate the resonance frequency of the cylinder at 1 degree 5 arc seconds before TDC and emitting the RF signal at the resonance frequency of the cylinder measured at 1 degree before TDC then the electric field strength can reach 3.5 x 106V/m, of which both electric field strength can meet the requirement of ignition. According to the optimisation principle the resonance frequency of the cylinder measured at 1 degree 7.2 arc seconds before TDC is a better choice. Therefore, through an optimisation algorithm, the resonance frequency of the cylinder corresponding to the position of 1 degree 7.2 arc seconds before TDC is used to approximate the resonance frequency of the cylinder corresponding to the position of 1 degree 5 arc seconds before TDC.

The method further includes emitting, based on said resonance frequency of the cylinder, an RF signal corresponding to said resonance frequency of the cylinder (step 206). Optionally, step 206 may be executed after either step 204 or step 205.

The embodiment of the present invention in this patent acquires the values of operating parameters at the time of ignition; determines, based on said acquired values of the operating parameters at the time of ignition, the resonance frequency of the cylinder corresponding to said values of the operating parameters at the time of ignition; emits, based on said resonance frequency of the cylinder, an RF signal corresponding to said resonance frequency of the cylinder. Since the embodiment of the present invention considers the influence of the operating parameters at the time of ignition (such as ignition advance angle, air/fuel mixture ratio, air-fuel mixing degree, fuel quality, cylinder internal temperature, cylinder internal pressure and compression ratio etc.) in the process of determining the resonance frequency of the cylinder it can reduce the influence of the sensitivity of the resonance frequency of the cylinder to operating parameters on the RF resonance in the cylinder, and greatly improve the adaptability of the frequency of RF signal to the resonance frequency of the ignition at the time of ignition.

Further, the embodiments of the present invention establish the database of the operating parameters according to the accuracy of parameters. Said accuracy of parameter values are used to ensure that, for various cylinder resonance

frequencies, the volume of simultaneous ignition within said cylinder is greater than a preset percentage, and therefore, if the values of the operating parameters at the time of ignition are not identical to those of said operating parameters database, based on said accuracy of parameters, among the values of the operating parameters stored in the operating parameters database, determine the values of the operating parameters closest to the values of the operating parameters at the time of ignition according to optimisation rules, then based on said closest values of the operating parameters, determine the corresponding resonance frequency of the cylinder for said closest values of the operating parameters, so as to realise the high reliability and low misfire and ignition failure rate of the RF engine ignition

technology, and to solve the problems of the existing electromagnetic wave or RF engine ignition technology such as poor reliability, high misfire and ignition failure rate etc. Figure 6 is the structural diagram of an implementation example of an RF engine ignition control device in the present invention. As shown in Figure 6 the device in the implementation example includes: a retrieval module 61 , used to acquire the values of the operating parameters at the time of ignition, wherein said operating parameters include engine speed, ignition advance angle, air/fuel mixture ratio, air- fuel mixing degree, fuel quality, compression ratio, cylinder internal temperature and/or cylinder internal pressure; a determination module 62, used to determine the resonance frequency of the cylinder corresponding to said values of the operating parameters at the time of ignition based on said acquired values of the operating parameters at the time of ignition; and an emission module 63, used to emit an RF signal corresponding to said resonance frequency of the cylinder based on said resonance frequency of the cylinder.

In an alternative embodiment of the present invention, before the determination module 62 determines the resonance frequency of the cylinder corresponding to said values of the operating parameters at the time of ignition, it is required to acquire, according to the preset accuracy of parameters, through engine running experiments and simulations, the corresponding resonance frequency of the cylinder for any parameter's operational value for said operating parameters for different operating states of the engine and then to create a value mapping relationship for the cylinder resonance frequency corresponding to any operational values of said operating parameters for different operating states of the engine.

In an alternative embodiment of the present invention, before the determination module 62 determines the resonance frequency of the cylinder corresponding to said values of the operating parameters at the time of ignition, it sets one of said operating parameters as a variable parameter and setting the other parameters as fixed parameters; and then it acquires, according to the preset accuracy of parameters, through engine running experiments and simulations, where the values of said fixed parameters are unchanged, the dynamic operational value of said variable parameter and the corresponding resonance frequency of the cylinder and creates a mapping relationship between said fixed parameters, the operating value of said variable parameters and the corresponding resonance frequency of the cylinder. Correspondingly, the device of the present invention further includes: a saving module 64, used to store said value mapping relationship for the cylinder resonance frequency corresponding to any dynamic operational value of said operating parameters for different engine working conditions in an operating parameters database; or storing the mapping relationship between said fixed parameters, said variable parameters and the corresponding resonance frequency of the cylinder in said operating parameters database.

Alternatively, said accuracy of parameter values are used to ensure that, for various cylinder resonance frequencies, the volume of simultaneous ignition within said cylinder is greater than a preset percentage.

Alternatively, said determination module specifically is used to: based on the acquired values of the operating parameters at the time of ignition, querying the operating parameters database; if the values of the operating parameters at the time of ignition are identical to those in said operating parameters database, based on said values of the operating parameters, determine the resonance frequency of the cylinder corresponding to said values of the operating parameters; and if the values of the operating parameters at the time of ignition are not identical to those of said operating parameters database, based on said accuracy of parameters, among the values of the operating parameters stored in the operating parameters database, determine the values of the operating parameters closest to the values of the operating parameters at the time of ignition, then based on said closest values of the operating parameters, determine the corresponding resonance frequency of the cylinder for said closest values of the operating parameters.

The device in the implementation example can be used to execute the technical solution of the implementation example shown in Figure 1 or Figure 2, their realisation principle and technical effects are likewise, and will not be restated in detail.

The detailed implementation example is used below to describe the technical solution of the embodiments shown in Figure 1 or Figure 2. Figure 7 is the structural diagram of an implementation example of an RF engine ignition control system in the present invention. As shown in Figure 7, it includes: a RF signal source, a RF signal transmission line, a RF signal coupler and emitter, and the control unit of the RF ignition system.

The RF signal source comprises an RF signal generator, a RF signal amplifier and a RF signal generator

The RF signal generator needs to be able to adjust the RF signal frequency in range of 300MHz-6GHz and the RF signal frequency is adjustable within the range of ±20% of the centre frequency of the cylinder. The centre frequency of the cylinder is the median frequency of the frequency range for ignition in the cylinder.

The RF signal generator needs to generate a minimum input power of 5-10 watts required for the RF signal amplifier. The RF signal amplifier needs to be a wide-band and high power RF amplifier. The bandwidth needs to cover ±20% of the centre frequency of the cylinder. The output power of the RF amplifier is required to reach 100-260 watts. The RF signal transmission line needs to be a wide-band transmission line, of which the bandwidth is required to match the bandwidth of the RF signal generator. RF signal coupler and emitter needs to be a wide-band coupler and emitter, of which the bandwidth is required to match the bandwidth of the RF signal generator and the RF signal transmission line.

The control unit of the RF ignition system comprises the RF resonant ignition control software and hardware. The software includes a resonance frequency database for RF resonance ignition (equivalent to said operating parameters database in the implementation examples shown in Figure 1 or Figure 2), the signal of the cylinder status analysis program and the control program of the generation time and pulse length of the RF signal. The hardware includes the receiver of the engine operating state parameters, the centre control unit, and the RF control signal transmitting unit. For example, when realising said system of the implementation example, the receiver of the engine operating state parameters F receives the values of the operating parameters. These operating parameters are analysed using the parameter signal analysis unit G. The resonance frequency of the cylinder is determined by comparing these operating parameters against the database of the operating parameter. The control signal is then sent to the RF signal generator A through the RF signal generator control unit H to instruct the RF signal generator A to generate the RF signal at the determined frequency. The generated RF signal is amplified B, transmitted C, coupled and emitted D into the cylinder E, at the time of the frequency of the RF signal emitted into the cylinder E matching the frequency of the cylinder under the present state. The resonance is generated in the cylinder to breakdown air-fuel mixture inside the cylinder.

Correspondingly, said system in the implementation example may implement any technical solution of the embodiment shown in Figure 1 or Figure 2. Their realisation principle and technical effects are likewise. The frequency control method in said system of the embodiment of the present invention can be applied on RF resonant ignition systems, microwave (resonant) ignition systems, plasma ignition systems for automotive petrol and/or natural gas internal combustion engine or automotive hybrid engine to improve their reliability and fuel efficiency. The frequency control method in said system of the embodiment of the present invention can be applied on modern automotive petrol and/or natural gas internal combustion engines or automotive hybrid engines directly under the premise of no modifications to the cylinder and the engine structure.

The ordinary technique personnel in relevant area can understand: the realisation of above-described all or part steps of any implementation example can be

accomplished using relevant hardware with the instruction of program. The aforementioned program can be stored in a computational readable memory media. When executing the program, the execution comprises the steps included in each above-described implementation example; said memory media may include: ROM, RAM, CD-ROM, DVD-ROM or any memory media that can be used to store program codes.

Finally, it should be noted that: the above embodiments are merely provided for describing the technical solutions of the present invention but not to restrict it.

Although the present invention has been described in detail using aforementioned embodiments, the ordinary technique personnel should understand: they can still modify aforementioned technical solutions described in any embodiment or replace all of part of technical features; and such modifications or replacements do not make the essence of the corresponding technical solutions out of the application range of the technical solutions of various embodiments of the present invention.

Claims

1. An RF engine ignition control method, characterized in that includes:

acquiring values of operating parameters at a time of ignition, wherein said operating parameters include: engine speed, ignition advance angle, air/fuel mixture ratio, air-fuel mixing degree, fuel quality, compression ratio, cylinder internal temperature and/or cylinder internal pressure;

determining, based on said acquired values of the operating parameters, a resonance frequency of a cylinder corresponding to said values of the operating parameters; and

emitting an RF signal corresponding to said resonance frequency of the cylinder.

2. The method described in claim 1 , characterized in that, if said operating parameters include one of engine speed, ignition advance angle, air/fuel mixture ratio, air-fuel mixing degree, fuel quality, compression ratio, cylinder internal temperature or cylinder internal pressure, before determining the resonance frequency of the cylinder corresponding to said values of the operating parameters at the time of ignition, the method includes:

acquiring, according to a preset accuracy of parameters, through engine running experiments and simulations, the corresponding resonance frequency of the cylinder for any parameter's dynamic operational value for said operating parameters for different operating states of the engine; and

creating a value mapping relationship for the cylinder resonance frequency corresponding to any dynamic operational value of said operating parameters for different operating states of the engine.

3. The method described in Claim 1 , characterized in that, if said operating parameters include: at least two of engine speed, ignition advance angle, air/fuel mixture ratio, air-fuel mixing degree, fuel quality, compression ratio, cylinder internal temperature or cylinder internal pressure, before determining the resonance frequency of the cylinder corresponding to said values of the operating parameters at the time of ignition, the method includes:

setting one of said operating parameters as a variable parameter and setting other operating parameters as fixed parameters;

acquiring, according to the preset accuracy of parameters, through engine running experiments and simulations, where values of said fixed parameters are unchanged, a dynamic operational value of said variable parameter and the corresponding resonance frequency of the cylinder; and

creating a mapping relationship between said fixed parameters, the dynamic operational value of said variable parameters and the corresponding resonance frequency of the cylinder.

4. The method described in Claim 2 or Claim 3, characterized in that, said method further comprises:

storing said value mapping relationship for the cylinder resonance frequency corresponding to any dynamic operational value of said operating parameters for different engine working conditions in an operating parameters database; or

creating a mapping relationship between said operating parameters, the dynamic operational value of said variable parameters and the corresponding resonance frequency of the cylinder and storing it in said operating parameters database.

5. The method described in Claim 2 or Claim 3, characterized in that, said preset accuracy of parameter values are used to ensure that, for said various cylinder resonance frequencies, a volume of simultaneous ignition within said cylinder is greater than a preset percentage.

6. The method described in Claim 4, characterized in that, based on said values of the operating parameters at the time of ignition, determining the resonance frequency of the cylinder corresponding to said values of the operating

parameters at the time of ignition, it includes:

based on the values of the operating parameters at the time of ignition, querying the operating parameters database;

if the values of the operating parameters at the time of ignition are identical to those in said operating parameters database, based on said values of the operating parameters, determining the resonance frequency of the cylinder corresponding to said values of the operating parameters;

if the values of the operating parameters at the time of ignition are not identical to those of said operating parameters database, based on the accuracy of said parameters, determining the values of the operating parameters closest to the values of the operating parameters at the time of ignition, and

based on said closest values of the operating parameters from the values of the operating parameters stored in the operating parameters database, through pre-calculation, determining the corresponding resonance frequency of the cylinder for said closest values of the operating parameters.

7. An RF engine ignition control device, characterized in that it includes:

a retrieval module, used to acquire values of operating parameters at a time of ignition, wherein said operating parameters include engine speed, ignition advance angle, air/fuel mixture ratio, air-fuel mixing degree, fuel quality, compression ratio, cylinder internal temperature and/or cylinder internal pressure; a determination module, used to determine a resonance frequency of a cylinder corresponding to said values of the operating parameters at the time of ignition based on said values of the operating parameters at the time of ignition; and

an emission module, used to emit an RF signal corresponding to said resonance frequency of the cylinder based on said resonance frequency of the cylinder.

8. The device described in Claim 7, characterized in that device further comprises:

a saving module, used to store a value mapping relationship for the cylinder resonance frequency corresponding to any dynamic operational value of said operating parameters for different engine working conditions in an operating parameters database;

wherein said value mapping relationship for the cylinder resonance frequency corresponding to any dynamic operational values of said operating parameters for different operating states of the engine is based on preset accuracy of parameters, through engine running experiments and simulations, acquiring the corresponding resonance frequency of the cylinder for any parameter's dynamic operational value for said operating parameters for different operating states of the engine, and creating the value mapping relationship for the cylinder resonance frequency corresponding to:

any dynamic operational value of said operating parameters for different operating states of the engine; or

storing the mapping relationship between said operating parameters, the dynamic operational value of said variable parameters and the corresponding resonance frequency of the cylinder in said operating parameters database; wherein the mapping relationship between said operating parameters, the dynamic operational value of said variable parameters and the corresponding resonance frequency of the cylinder is stored as a variable parameter in said operating parameters database, when other parameters are set as fixed parameters; according to the preset accuracy of parameters, through engine running experiments and simulations, where the values of said fixed parameters are unchanged, acquiring the dynamic operational value of said variable parameter and the corresponding resonance frequency of the cylinder, and creating a mapping relationship between said fixed parameters, the dynamic operational value of said variable parameters and the corresponding resonance frequency of the cylinder.

9. The device described in Claim 8, characterized in that said accuracy of parameter values are used to ensure that, for various cylinder resonance frequencies, a volume of simultaneous ignition within said cylinder is greater than a preset percentage.

10. The device described in Claim 8, characterized in that said determination module specifically is used to:

based on the acquired values of the operating parameters at the time of ignition, querying the operating parameters database;

if the values of the operating parameters at the time of ignition are identical to those in said operating parameters database, based on said values of the operating parameters, determine the resonance frequency of the cylinder corresponding to said values of the operating parameters; and

if the values of the operating parameters at the time of ignition are not identical to those of said operating parameters database, based on said accuracy of parameters, among the values of the operating parameters stored in the operating parameters database, determine closest values of the operating parameters closest to the values of the operating parameters at the time of ignition, then based on said closest values of the operating parameters, determine the corresponding resonance frequency of the cylinder for said closest values of the operating parameters.