CN115949520A - Low-carbon-zero-carbon fuel engine combustion closed-loop control system and method based on cylinder pressure feedback - Google Patents

Abstract

The invention aims to provide a low-carbon-zero-carbon fuel engine combustion closed-loop control system and method based on cylinder pressure feedback. The invention is based on a combustion closed-loop control strategy based on the CA50 and IMEP dual-combustion characteristic parameters, thereby not only ensuring the dynamic demand of the low-carbon/zero-carbon fuel engine, but also improving the combustion rationality of the low-carbon/zero-carbon fuel engine. The invention realizes the dynamic control of the low-carbon/zero-carbon fuel engine at high rotating speed by identifying the pressure change condition in the cylinder efficiently and accurately at lower cost by the signal processing means of parallel acquisition and integrated amplification, and obviously improves the performance of the low-carbon/zero-carbon fuel engine under the lean-burn condition.

Description

Low-carbon-zero-carbon fuel engine combustion closed-loop control system and method based on cylinder pressure feedback

Technical Field

The invention relates to an engine control system and a control method.

Background

The rapid development of the world transportation industry is driven by the economic globalization, and the tail gas of the engine is also caused to be a main source of urban air pollutants. Strict emission regulations of domestic and foreign legislation agencies force engine manufacturers to adopt new strategies to reduce exhaust emission and develop clean and efficient low-carbon/zero-carbon engine technologies.

Lean combustion is an advanced combustion technology of a low-carbon/zero-carbon fuel engine, and is beneficial to improving the combustion efficiency and reducing NO _X And the like. However, the low-carbon/zero-carbon engine is abnormally sensitive to the change of the excess air coefficient during the lean combustion process, and particularly, abnormal combustion phenomena such as 'knocking' and 'misfire' generated near a combustion boundary cause the combustion stability of the engine to be poor, and cause the efficiency to be rapidly reduced and the emission to be rapidly increased. Therefore, the method has important practical significance for improving the dynamic property, the economical efficiency and the emission performance of the low-carbon/zero-carbon fuel engine by improving the lean combustion stability of the low-carbon/zero-carbon fuel engine. The invention patent CN109723537B discloses a lean combustion comprehensive control system and method, which judges the combustion state of an engine by detecting the signal of an exhaust main oxygen sensor, controls a throttle valve, a booster bypass valve, a fuel gas injection valve and the like in a closed loop mode, and ensures that the air, the fuel gas amount and the air-fuel ratio required by the whole lean combustion of the engine are kept in a preset range so as to improve the economy of the engine. However, under the lean combustion condition, the air-fuel ratio between cylinders always has fluctuation difference under the influence of resonance, air intake and flow loss, and the tiny change of the air-fuel ratio under the lean combustion condition can generate amplification influence on the combustion process, so that the difference between combustion cycles and between cylinders of the low-carbon/zero-carbon fuel engine is obvious, the engine is difficult to control, and the performance is deteriorated.

Disclosure of Invention

The invention aims to provide a low-carbon-zero-carbon fuel engine combustion closed-loop control system and a low-carbon-zero-carbon fuel engine combustion closed-loop control method based on cylinder pressure feedback, which can effectively improve the combustion stability of a low-carbon/zero-carbon fuel engine and improve the dynamic property and the thermal efficiency of the engine.

The purpose of the invention is realized as follows:

the invention relates to a low-carbon-zero-carbon fuel engine combustion closed-loop control system based on cylinder pressure feedback, which is characterized in that: the system comprises a low-carbon/zero-carbon fuel engine, a signal acquisition system, a combustion characteristic parameter identification system and an electronic control system ECS;

the signal acquisition system comprises a cylinder pressure sensor, a parallel signal receiving unit, an integrated charge amplification unit, an angle marking instrument, a pulse signal generator and a signal acquisition card; the combustion characteristic parameter identification system comprises a cylinder pressure signal filtering unit, a combustion characteristic parameter calculation unit and a signal alarm unit; the ECS comprises an electronic control unit ECU, an igniter, a power supply, an ignition coil or a pilot fuel supply unit and a fuel injection valve;

the low-carbon/zero-carbon fuel engine is a spark-ignition or compression-ignition multi-cylinder engine and is provided with an angle indicator, and each cylinder is provided with an independent fuel injection valve, an igniter and a cylinder pressure sensor; the angle gauge is arranged on the end face of a crankshaft on one side of the low-carbon/zero-carbon fuel engine, a shell of the angle gauge is fixed on a cylinder body of the low-carbon/zero-carbon fuel engine through a transition structure, and a central shaft of the angle gauge synchronously rotates along with the crankshaft and is used for generating a top dead center signal and a crankshaft rotation angle signal; the fuel injection valve is arranged on an intake manifold of the low-carbon/zero-carbon fuel engine; the igniter is vertically arranged on a cylinder cover of the low-carbon/zero-carbon fuel engine, and the central axis of the igniter is superposed with the central axis of the cylinder cover; the cylinder pressure sensor is a piezoelectric sensor and is arranged on a cylinder cover of the low-carbon/zero-carbon fuel engine;

the signal acquisition system simultaneously acquires cylinder pressure signals of each cylinder of the low-carbon/zero-carbon fuel multi-cylinder engine; the combustion characteristic parameter identification system calculates an average effective indicated pressure IMEP, a combustion starting point CA5, a combustion center CA50, a combustion duration CA90 and a cyclic variation coefficient COV combustion characteristic parameter according to the cylinder pressure signal of each cylinder; after receiving the characteristic parameters extracted by the combustion characteristic parameter identification system, the ECS controls an ignition device, a fuel injection rule and an equivalence ratio condition of the low-carbon/zero-carbon fuel engine based on the actual value and the target value of the combustion characteristic parameters, optimizes a combustion phase and a heat release rule based on a single-cylinder combustion state, improves the combustion stability and efficiency of the low-carbon/zero-carbon fuel engine, and improves the dynamic property, the economical efficiency and the emission property of the engine.

The low-carbon-zero-carbon fuel engine combustion closed-loop control system based on cylinder pressure feedback can further comprise:

1. the signal acquisition system is used for independently and parallelly acquiring and integrally amplifying cylinder pressure signals of all cylinders of the low-carbon/zero-carbon fuel multi-cylinder engine; the integrated charge amplification unit is provided with a plurality of input and output channels, the input end of the integrated charge amplification unit is sequentially connected with the cylinder pressure sensors of all cylinders, and weak charge signals are converted into voltage signals in direct proportion to the weak charge signals; the parallel signal receiving unit is a multi-channel input analog-to-digital conversion circuit and converts voltage into a digital signal in direct proportion to the voltage.

2. The signal acquisition frequency of the signal acquisition system is determined by the pulse signal output by the angle marking instrument; the pulse signal comprises a top dead center and a crank angle signal, and a trigger pulse signal is generated once after each fixed time step by taking the top dead center of the first cylinder as an initial phase; the data acquisition card acquires cylinder pressure signals according to the triggering intervals of the pulse signals and synchronously completes phase encoding.

3. And a cylinder pressure signal filtering unit of the combustion characteristic parameter identification system performs filtering processing on a time sequence of the cylinder pressure signal by using a non-sampling wavelet transform method to eliminate noise interference.

4. The combustion characteristic parameters calculated and extracted by the combustion characteristic parameter identification system include an average indicated effective pressure IMEP, a combustion start point CA5, a combustion center of gravity CA50, a combustion duration CA90, and a coefficient of cyclic variation COV parameter.

5. The ECS is provided with a plurality of paths of D/A channels, and a single-cylinder fuel injection rule and an ignition rule are independently controlled according to actual combustion conditions of different cylinders, so that combined control and comprehensive optimization of multiple feedback parameters are realized.

6. The timing of the ECS output control signal is affected by the shape of the crankshaft and the firing order of the low/zero carbon fueled engine; when the engine is a six-cylinder natural gas engine, the ignition sequence of each cylinder is 1-5-3-6-2-4,1 cylinder and 6 cylinder crank throws are on the same side, 5 cylinder and 2 cylinder crank throws are on the same side, 3 cylinder and 4 cylinder crank throws are on the same side, after ECS synchronously outputs 1 cylinder control signals and 6 cylinder control signals, after 120 ℃ A crank angle, synchronously outputs 5 cylinder control signals and 2 cylinder control signals, and after 240 ℃ A crank angle, synchronously outputs 3 cylinder control signals and 4 cylinder control signals, which are sequentially reciprocated.

7. The control signals for controlling the low-carbon/zero-carbon fuel engine to realize the combustion closed loop by the ECS comprise ignition rule signals and fuel injection rule signals; the ignition law signal is influenced by the combustion characteristic parameters related to the phase, such as the combustion starting point CA5, the combustion gravity center CA50, the combustion duration CA90 and the like, and the fuel injection law signal is influenced by the mean effective indicated pressure IMEP and the highest explosion pressure P _max Etc. relating to the performance of work.

8. Under the lean-burn condition, the actual combustion states of the low-carbon/zero-carbon fuel engine among combustion cycles and cylinders are dynamically different, the ECS performs closed-loop control according to single-cylinder combustion characteristic parameters of the low-carbon/zero-carbon fuel engine, control signals input among the cylinders are mutually independent and do not interfere with each other, namely control signals such as ignition timing, fuel injection quantity, fuel injection timing and the like corresponding to each cylinder are inconsistent and are determined only by the actual combustion state of the corresponding cylinder.

The invention relates to a low-carbon/zero-carbon fuel engine combustion closed-loop control method based on cylinder pressure feedback, which is characterized by comprising the following steps of:

(1) Setting the working condition of the low-carbon/zero-carbon fuel during the pre-starting period of the engine, specifically, inquiring an open-loop map by an ECS (electronic control system) according to the rotating speed and the load of the low-carbon/zero-carbon fuel engine, and setting initial values of control signals, including a throttle angle, ignition energy, ignition timing, fuel injection pulse width and fuel injection rate;

(2) The signal acquisition system acquires pressure information of all cylinders by using the piezoelectric cylinder pressure sensors and the parallel signal receiving units, and encodes crankshaft phases of cylinder pressure signals by using an angle marking instrument and pulse signals;

(3) The combustion characteristic parameter identification system carries out filtering processing on the cylinder pressure time sequence, and the cylinder pressure time sequence after noise removal enters a combustion characteristic parameter calculation unit;

(4) The combustion characteristic parameter calculation unit assigns a task calculation sequence, and defines N =0 as a spacer;

(5) Defining N =1, calculating IMEP and P for the 1 st and 6 th cylinders simultaneously _max If IMEP and P _max Are all within the range of the target,the ignition law class control signal is not modified if IMEP and P _max If the number of the compensation algorithms is larger than or equal to 1, judging whether the possibility of fire exists in the target range, if no fire danger exists, selecting a first class compensation algorithm for calculation, and if the danger of fire exists, selecting a second class compensation algorithm for calculation;

(6) The ECS respectively controls the fuel injection valves of the 1 st cylinder and the 6 th cylinder, and fuel supply of the 1 st cylinder and the 6 th cylinder is completed according to the corrected fuel injection rule;

(7) Defining N =2, simultaneously calculating combustion characteristic parameters of CA5, CA50 and CA90 of the 1 st cylinder and the 6 th cylinder, and selecting a compensation algorithm according to the combustion characteristic parameters needing to be corrected;

(8) The ECS respectively controls the ignition devices of the 1 st cylinder and the 6 th cylinder, and completes the ignition of the igniters of the 1 st cylinder and the 6 th cylinder according to the corrected ignition rule;

(9) Defining N =3, after the 1 and 6 cylinders signal processing is finished, starting the 5 and 2 cylinders closed-loop control, and calculating according to the task sequence.

The invention has the advantages that: natural gas, ammonia gas, alcohol ether fuel and the like are clean fuels and generally have the characteristics of rich resources, high efficiency, cleanness and the like, but a low-carbon/zero-carbon fuel engine is limited by low flame propagation speed and narrow air-fuel ratio range and needs to improve the heat release condition of in-cylinder combustion.

The cylinder pressure signal is rich in rich combustion information, so that negative feedback control is performed on the engine aiming at the cylinder pressure signal, and the method is an effective means for improving efficiency, improving emission and enhancing combustion stability in the field of the internal combustion engine at present. The invention is based on a combustion closed-loop control strategy based on the CA50 and IMEP dual-combustion characteristic parameters, thereby not only ensuring the dynamic demand of the low-carbon/zero-carbon fuel engine, but also improving the combustion rationality of the low-carbon/zero-carbon fuel engine. The invention realizes the dynamic control of the low-carbon/zero-carbon fuel engine at high rotating speed by identifying the pressure change condition in the cylinder efficiently and accurately at lower cost by the signal processing means of parallel acquisition and integrated amplification, and obviously improves the performance of the low-carbon/zero-carbon fuel engine under the lean-burn condition.

In addition, the invention has universal applicability, when a single fuel engine is applied, the ignition unit is adopted to control the ignition timing, and the concentration and the combustion rule of the mixed gas are controlled by controlling the injection quantity and the injection rule of the fuel; when the fuel is popularized to a dual-fuel engine, the activity and concentration coupling layering of the mixed gas can be realized by controlling the injection of the high-reactivity fuel, and the ignition timing and the combustion rate of the mixed gas are controlled.

Drawings

FIG. 1 is a block diagram of the present invention;

FIG. 2 is a view showing the positions of mounting of a fuel injection valve, an igniter and a cylinder pressure sensor according to the present invention;

FIG. 3 is a filtering schematic of the present invention;

FIG. 4 is a schematic diagram of the compensation algorithm of the present invention;

FIG. 5 is a control strategy of the present invention.

Detailed Description

The invention is described in more detail below by way of example with reference to the accompanying drawings:

with reference to fig. 1-5, the closed-loop control system for combustion of the low-carbon/zero-carbon fuel engine of the present invention comprises a low-carbon/zero-carbon fuel engine, a signal acquisition system, a combustion characteristic parameter identification system, an Electronic Control System (ECS), and the like.

The low-carbon/zero-carbon fuel engine is provided with an angle indicator 6, the number of cylinders is more than 1, and each cylinder is provided with an independent fuel injection valve 1, an igniter 5 and a cylinder pressure sensor 3; the mounting position of the angle indicator 6 is shown in the attached figure 2, the angle indicator is mounted on the end face of a crankshaft on one side of a low-carbon/zero-carbon fuel engine, a shell of the angle indicator 6 is fixed on a cylinder body of the low-carbon/zero-carbon fuel engine through a transition structure, and the center of the angle indicator 6 synchronously rotates along with a crankshaft 7 and is used for generating top dead center and crankshaft rotation angle signals; the installation position of the fuel injection valve 1 is shown in FIG. 3, and the fuel injection valve is installed on an intake manifold 2 of a low-carbon/zero-carbon fuel engine; the igniter 5 is vertically arranged on the cylinder cover 4 of the low-carbon/zero-carbon fuel engine as shown in figure 3, and the central axis of the igniter is superposed with the central axis of the cylinder cover 4; the cylinder pressure sensor 3 is a piezoelectric sensor and is arranged on a cylinder cover 4 of the low-carbon/zero-carbon fuel engine, as shown in fig. 3, the end surface of the sensor 3 is close to the lower surface of the cylinder cover 4, and the channel effect can be effectively avoided;

the signal acquisition system consists of a cylinder pressure sensor, a parallel signal receiving unit, an integrated charge amplification unit, an angle marking instrument, a pulse signal generator and a signal acquisition card; the combustion characteristic parameter identification system consists of a cylinder pressure signal filtering unit, a combustion characteristic parameter calculation unit and a signal alarm unit; the ECS is composed of an Electronic Control Unit (ECU), an igniter, a power supply, an ignition coil or pilot fuel supply unit, a fuel injection valve, a wire harness and the like;

the signal acquisition system is used for simultaneously acquiring cylinder pressure signals of each cylinder of the low-carbon/zero-carbon fuel multi-cylinder engine; the combustion characteristic parameter identification system calculates combustion characteristic parameters such as average effective indicated pressure IMEP, combustion starting point CA5, combustion gravity center CA50, combustion duration CA90, cyclic variation coefficient COV and the like according to cylinder pressure signals of each cylinder; after receiving the characteristic parameters extracted by the combustion characteristic parameter identification system, the ECS controls an ignition device, a fuel injection rule and an equivalence ratio condition of the low-carbon/zero-carbon fuel engine based on an actual value and a target value of the combustion characteristic parameters, optimizes a combustion phase and a heat release rule based on a single-cylinder combustion state, improves the combustion stability and efficiency of the low-carbon/zero-carbon fuel engine, and improves the dynamic property, the economical property and the emission property of the engine;

the signal acquisition system can independently and parallelly acquire and integrally amplify cylinder pressure signals of all cylinders of the low-carbon/zero-carbon fuel multi-cylinder engine; the integrated charge amplification unit is provided with a plurality of input channels and a plurality of output channels, the input end of the integrated charge amplification unit is sequentially connected with the cylinder pressure sensors of all cylinders, and weak charge signals are converted into voltage signals in direct proportion to the weak charge signals; the parallel signal receiving unit is a multi-channel input analog-to-digital conversion circuit and converts voltage into a digital signal in direct proportion to the voltage;

the signal acquisition frequency of the signal acquisition system is determined by the pulse signal output by the angle marking instrument; the pulse signals comprise top dead center signals and crank angle signals, the top dead center of the first cylinder is taken as an initial phase, and one-time trigger pulse signals are generated through each fixed time step; the data acquisition card acquires cylinder pressure signals according to the triggering intervals of the pulse signals and synchronously completes phase encoding;

a cylinder pressure signal filtering unit of the combustion characteristic parameter identification system performs filtering processing on a time sequence of a cylinder pressure signal by using a non-sampling wavelet transform method to eliminate noise interference;

the combustion characteristic parameters calculated and extracted by the combustion characteristic parameter identification system comprise but are not limited to parameters such as mean effective indicated pressure IMEP, combustion starting point CA5, combustion gravity center CA50, combustion duration CA90, cyclic variation coefficient COV and the like;

the ECS is provided with a plurality of paths of D/A channels, and can independently control single-cylinder fuel injection rules and ignition rules according to actual combustion conditions of different cylinders, so that combined control and comprehensive optimization of multiple feedback parameters are realized;

the timing of the ECS output control signal is affected by the shape of the crankshaft and the firing order of the low/zero carbon fueled engine; taking a laboratory six-cylinder natural gas engine as an example (the ignition sequence of each cylinder is 1-5-3-6-2-4, the same side of the crank throw of 1 cylinder and 6 cylinders, the same side of the crank throw of 5 cylinder and 2 cylinder, and the same side of the crank throw of 3 cylinder and 4 cylinder), after synchronously outputting the control signals of 1 cylinder and 6 cylinders by an ECS, synchronously outputting the control signals of 5 cylinder and 2 cylinders after a crank angle of 120 ℃ A, and synchronously outputting the control signals of 3 cylinder and 4 cylinder after a crank angle of 240 ℃ A, and sequentially reciprocating;

the ECS controls the low-carbon/zero-carbon fuel engine to realize that a control signal of a combustion closed loop is divided into an ignition rule signal and a fuel injection rule signal; the ignition law type signal is influenced by combustion characteristic parameters related to phases such as a combustion starting point CA5, a combustion gravity center CA50 and a combustion duration CA90, and the fuel injection law type signal is influenced by an average effective indicated pressure IMEP and a highest explosion pressure P _max The influence of the combustion characteristic parameters related to work doing;

under the lean-burn condition, because of the influence of resonance, air intake and flow loss, the actual combustion states among combustion cycles and cylinders of the low-carbon/zero-carbon fuel engine have dynamic difference, the ECS performs closed-loop control according to single-cylinder combustion characteristic parameters of the low-carbon/zero-carbon fuel engine, and control signals input among the cylinders are independent and do not interfere with each other, namely the control signals such as ignition timing, fuel injection quantity, fuel injection timing and the like corresponding to each cylinder are inconsistent and are determined only by the actual combustion state of the corresponding cylinder;

in the process of realizing combustion closed loop by controlling a low-carbon/zero-carbon fuel engine by an ECS (electronically controlled fuel system), pressure signals and phase signals are adopted for double closed loop control, for example: based on a closed loop of dual combustion characteristic parameter parameters of CA50 and IMEP; the control core of the ignition law signal is a CA50 combustion state parameter closed loop, and CA5, CA90 and phi are realized on the basis of the CA50 combustion state parameter closed loop _Pmax Closed loop with equal combustion state parameters; the control core of the fuel injection law signal is an IMEP combustion state parameter closed loop, and P is realized on the basis of a CA50 combustion state parameter closed loop _max And closing a loop by the combustion state parameters.

The low-carbon/zero-carbon fuel engine combustion closed-loop control system and method based on cylinder pressure feedback realize combustion closed-loop control through the following steps:

1. setting the working condition of the low-carbon/zero-carbon fuel during the pre-starting period of the engine, specifically, inquiring an open-loop map by an ECS (electronic control system) according to the rotating speed and the load of the low-carbon/zero-carbon fuel engine, and setting initial values of control signals, including a throttle angle, ignition energy, ignition timing, fuel injection pulse width, fuel injection rate and the like;

2. the signal acquisition system acquires pressure information of all cylinders by using the piezoelectric cylinder pressure sensors and the parallel signal receiving units, and encodes crankshaft phases of cylinder pressure signals by using an angle marking instrument and pulse signals;

3. the combustion characteristic parameter identification system carries out filtering processing on the cylinder pressure time sequence according to the principle shown in FIG. 5, and the cylinder pressure time sequence after noise removal enters a combustion characteristic parameter calculation unit;

4. the combustion characteristic parameter calculation unit assigns a task calculation sequence, and defines N =0 as a spacer;

5. defining N =1, calculating IMEP and P for the 1 st and 6 th cylinders simultaneously _max If IMEP and P _max If both are within the target range, the ignition law class control signal is not corrected, and if IMEP and P are within the target range, the ignition law class control signal is not corrected _max More than or equal to 1 of the fire door is not in the target range, whether the fire door possibility exists is judged, if no fire door danger exists, the I-type compensation algorithm is selected for calculation, and if the fire door possibility exists, the fire door is selectedCalculating a danger selection class II compensation algorithm;

the principle of the compensation-type algorithm is shown in fig. 4, where R represents the combustion characteristic parameter target value; r is an actual value of the combustion characteristic parameter; e is an error; t is a cyclic variation coefficient gain factor which is influenced by the cyclic variation coefficient of each combustion characteristic parameter; o is a compensation coefficient and is influenced by parameters needing to be corrected of the low-carbon/zero-carbon fuel engine; PID and BP-PID are respectively a controller and a self-adaptive controller, wherein the PID is responsible for enabling the actual value to quickly approach the target value, and the BP-PID is responsible for enabling the error between the actual value and the target value to be reduced as much as possible;

ECS controls the fuel injection valves of the 1 st cylinder and the 6 th cylinder respectively, and fuel supply of the 1 st cylinder and the 6 th cylinder is completed according to the corrected fuel injection rule;

7. defining N =2, simultaneously calculating combustion characteristic parameters of the 1 st cylinder and the 6 th cylinder, such as CA5, CA50, CA90 and the like, and selecting a compensation algorithm according to the combustion characteristic parameters needing to be corrected;

the ECS respectively controls the ignition devices of the 1 st cylinder and the 6 th cylinder, and the igniters of the 1 st cylinder and the 6 th cylinder are ignited according to the corrected ignition rule;

9. defining N =3, starting closed-loop control of 5 th and 2 nd cylinders after signal processing of 1 and 6 th cylinders is finished, and calculating according to a task sequence;

it is worth emphasizing that when the single-fuel ignition engine is applied, the ignition unit is adopted to control the ignition timing, and the concentration and the combustion law of the mixed gas are regulated and controlled by controlling the fuel injection quantity and the injection law. When the method is applied to the dual-fuel engine, the closed loop of the single-cylinder CA50 combustion characteristic parameters and the closed loop of other phase combustion characteristic parameters can be realized by only converting the control of single-cylinder ignition timing, ignition energy and the like into the control of the single-cylinder high-reaction active fuel substitution rate, the high-reaction active fuel injection timing and the like; the control of single-cylinder fuel injection timing, injection pulse width, injection rate and the like is converted into the control of single-cylinder low-reaction active fuel injection timing, injection pulse width, injection rate and the like, so that single-cylinder IMEP combustion characteristic parameter closed loops and other work-doing combustion characteristic parameter closed loops can be realized.

Claims (10)

1. Low carbon-zero carbon fuel engine combustion closed-loop control system based on cylinder pressure feedback is characterized in that: the system comprises a low-carbon/zero-carbon fuel engine, a signal acquisition system, a combustion characteristic parameter identification system and an electronic control system ECS;

the signal acquisition system comprises a cylinder pressure sensor, a parallel signal receiving unit, an integrated charge amplification unit, an angle marking instrument, a pulse signal generator and a signal acquisition card; the combustion characteristic parameter identification system comprises a cylinder pressure signal filtering unit, a combustion characteristic parameter calculation unit and a signal alarm unit; the ECS comprises an electronic control unit ECU, an igniter, a power supply, an ignition coil or a pilot fuel supply unit and a fuel injection valve;

the low-carbon/zero-carbon fuel engine is a spark-ignition or compression-ignition multi-cylinder engine and is provided with an angle indicator, and each cylinder is provided with an independent fuel injection valve, an igniter and a cylinder pressure sensor; the angle gauge is arranged on the end face of a crankshaft on one side of the low-carbon/zero-carbon fuel engine, the shell of the angle gauge is fixed on the cylinder body of the low-carbon/zero-carbon fuel engine through a transition structure, and the central shaft of the angle gauge synchronously rotates along with the crankshaft and is used for generating a top dead center signal and a crankshaft rotation angle signal; the fuel injection valve is arranged on an intake manifold of the low-carbon/zero-carbon fuel engine; the igniter is vertically arranged on a cylinder cover of the low-carbon/zero-carbon fuel engine, and the central axis of the igniter is superposed with the central axis of the cylinder cover; the cylinder pressure sensor is a piezoelectric sensor and is arranged on a cylinder cover of the low-carbon/zero-carbon fuel engine;

the signal acquisition system simultaneously acquires cylinder pressure signals of each cylinder of the low-carbon/zero-carbon fuel multi-cylinder engine; the combustion characteristic parameter identification system calculates an average effective indicated pressure IMEP, a combustion starting point CA5, a combustion gravity center CA50, a combustion duration CA90 and a cyclic variation coefficient COV combustion characteristic parameter according to the cylinder pressure signal of each cylinder; after receiving the characteristic parameters extracted by the combustion characteristic parameter identification system, the ECS controls an ignition device, a fuel injection rule and an equivalence ratio condition of the low-carbon/zero-carbon fuel engine based on the actual values and the target values of the combustion characteristic parameters, optimizes a combustion phase and a heat release rule based on a single-cylinder combustion state, improves the combustion stability and efficiency of the low-carbon/zero-carbon fuel engine, and improves the dynamic property, the economical property and the emission property of the engine.

2. The cylinder pressure feedback-based combustion closed-loop control system for a low-carbon-zero-carbon fuel engine as claimed in claim 1, wherein: the signal acquisition system is used for independently and parallelly acquiring and integrally amplifying cylinder pressure signals of all cylinders of the low-carbon/zero-carbon fuel multi-cylinder engine; the integrated charge amplification unit is provided with a plurality of input channels and a plurality of output channels, the input end of the integrated charge amplification unit is sequentially connected with the cylinder pressure sensors of each cylinder, and weak charge signals are converted into voltage signals in direct proportion to the weak charge signals; the parallel signal receiving unit is a multi-channel input analog-to-digital conversion circuit and converts voltage into a digital signal in direct proportion to the voltage.

3. The cylinder pressure feedback-based low-carbon-zero-carbon fuel engine combustion closed-loop control system as claimed in claim 1, wherein: the signal acquisition frequency of the signal acquisition system is determined by the pulse signal output by the angle marking instrument; the pulse signal comprises a top dead center and a crank angle signal, and a trigger pulse signal is generated once after each fixed time step by taking the top dead center of the first cylinder as an initial phase; the data acquisition card acquires cylinder pressure signals according to the triggering intervals of the pulse signals, and phase encoding is completed synchronously.

4. The cylinder pressure feedback-based low-carbon-zero-carbon fuel engine combustion closed-loop control system as claimed in claim 1, wherein: and a cylinder pressure signal filtering unit of the combustion characteristic parameter identification system performs filtering processing on a time sequence of the cylinder pressure signal by using a non-sampling wavelet transform method to eliminate noise interference.

5. The cylinder pressure feedback-based combustion closed-loop control system for a low-carbon-zero-carbon fuel engine as claimed in claim 1, wherein: the combustion characteristic parameters calculated and extracted by the combustion characteristic parameter identification system include an average indicated effective pressure IMEP, a combustion start point CA5, a combustion center of gravity CA50, a combustion duration CA90, and a coefficient of cyclic variation COV parameter.

6. The cylinder pressure feedback-based low-carbon-zero-carbon fuel engine combustion closed-loop control system as claimed in claim 1, wherein: the ECS is provided with a plurality of paths of D/A channels, and a single-cylinder fuel injection rule and an ignition rule are independently controlled according to actual combustion conditions of different cylinders, so that the combined control and comprehensive optimization of multiple feedback parameters are realized.

7. The cylinder pressure feedback-based combustion closed-loop control system for a low-carbon-zero-carbon fuel engine as claimed in claim 1, wherein: the timing of the ECS output control signal is affected by the shape of the crankshaft and the firing order of the low/zero carbon fueled engine; when the engine is a six-cylinder natural gas engine, the ignition sequence of each cylinder is 1-5-3-6-2-4,1 and 6 cylinder crank throws are on the same side, 5 and 2 cylinder crank throws are on the same side, 3 and 4 cylinder crank throws are on the same side, after ECS synchronously outputs 1 and 6 cylinder control signals, after 120 CA crank angle synchronously outputs 5 and 2 cylinder control signals, and after 240 CA crank angle synchronously outputs 3 and 4 cylinder control signals, the operation is repeated in sequence.

8. The cylinder pressure feedback-based combustion closed-loop control system for a low-carbon-zero-carbon fuel engine as claimed in claim 1, wherein: the control signals for controlling the low-carbon/zero-carbon fuel engine to realize the combustion closed loop by the ECS comprise ignition rule signals and fuel injection rule signals; the ignition law type signal is influenced by combustion characteristic parameters such as a combustion starting point CA5, a combustion gravity center CA50 and a combustion duration CA90 which are related to phases, and the fuel injection law type signal is influenced by an average effective indicated pressure IMEP and a highest explosion pressure P _max Etc. relating to the performance of work.

9. The cylinder pressure feedback-based combustion closed-loop control system for a low-carbon-zero-carbon fuel engine as claimed in claim 1, wherein: under the lean-burn condition, the actual combustion states of the low-carbon/zero-carbon fuel engine among combustion cycles and cylinders are dynamically different, the ECS performs closed-loop control according to single-cylinder combustion characteristic parameters of the low-carbon/zero-carbon fuel engine, control signals input among the cylinders are mutually independent and do not interfere with each other, namely control signals such as ignition timing, fuel injection quantity, fuel injection timing and the like corresponding to each cylinder are inconsistent and are determined only by the actual combustion state of the corresponding cylinder.

10. The low-carbon/zero-carbon fuel engine combustion closed-loop control method based on cylinder pressure feedback is characterized in that:

(1) Setting the working condition of the low-carbon/zero-carbon fuel during the pre-starting period of the engine, specifically, inquiring an open-loop map by an ECS (electronically controlled fuel system) according to the rotating speed and the load of the low-carbon/zero-carbon fuel engine, and setting initial values of a control signal, wherein the initial values comprise a throttle angle, ignition energy, ignition timing, fuel injection pulse width and fuel injection rate;

(2) The signal acquisition system acquires pressure information of all cylinders by using the piezoelectric cylinder pressure sensor and the parallel signal receiving unit, and encodes the crankshaft phase of the cylinder pressure signal by using the angle marking instrument and the pulse signal;

(3) The combustion characteristic parameter identification system carries out filtering processing on the cylinder pressure time sequence, and the cylinder pressure time sequence after noise removal enters a combustion characteristic parameter calculation unit;

(4) The combustion characteristic parameter calculation unit assigns a task calculation sequence, and defines N =0 as a spacer;

(5) Defining N =1, calculating IMEP and P for the 1 st and 6 th cylinders simultaneously _max If IMEP and P _max If both are within the target range, the ignition law class control signal is not corrected, and if IMEP and P are within the target range, the ignition law class control signal is not corrected _max If the number of the compensation algorithms is larger than or equal to 1, judging whether the possibility of fire exists in the target range, if no fire danger exists, selecting a first class compensation algorithm for calculation, and if the danger of fire exists, selecting a second class compensation algorithm for calculation;

(6) The ECS respectively controls the fuel injection valves of the 1 st cylinder and the 6 th cylinder, and fuel supply of the 1 st cylinder and the 6 th cylinder is completed according to the corrected fuel injection rule;

(7) Defining N =2, simultaneously calculating combustion characteristic parameters of CA5, CA50 and CA90 of the 1 st cylinder and the 6 th cylinder, and selecting a compensation algorithm according to the combustion characteristic parameters needing to be corrected;

(8) The ECS respectively controls the ignition devices of the 1 st cylinder and the 6 th cylinder, and completes ignition of the igniters of the 1 st cylinder and the 6 th cylinder according to the corrected ignition rule;

(9) Defining N =3, after the 1 and 6 cylinders signal processing is finished, starting the 5 and 2 cylinders closed-loop control, and calculating according to the task sequence.

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