Diesel engine oil injection timing angle determination method
By using a general MCU timer and counter in diesel engines and combining crankshaft coded signals, the accurate identification of the injection timing angle of the diesel engine is achieved, solving the problem of large identification errors in the prior art and reducing the design and development costs.
Patent Information
- Application Number
- CN202510302269.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-14
- Publication Date
- 2025-06-20
AI Technical Summary
The prior art has large errors in identifying the fuel injection timing angle of diesel engines, which leads to the inability to operate normally and stably. The electronic control unit has high requirements for MCU hardware, which increases the design and development cost and difficulty.
By using a general-purpose timer integrated inside the MCU, the generation of micro pulses of the diesel engine fuel injection timing calculation is realized, and the period of the correction micro pulses is calculated through the combination of counter and timer, thereby achieving accurate identification of the fuel injection timing angle.
It realizes accurate identification of the fuel injection timing angle of the diesel engine, reduces the requirements for MCU hardware, and reduces the design and development cost and difficulty of the diesel engine control unit.
Smart Images
Figure CN120175504A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method for determining the fuel injection timing angle in the technical field of engine electronic control, and particularly to a method for determining the fuel injection timing angle of a diesel engine with a crankshaft coding signal sensor and a square wave pulse for angle determination as the coding signal. Background Art
[0002] Due to its advantages in efficiency and reliability, the diesel engine is one of the main power sources for large ships and large commercial vehicles at present. The electronic control fuel injection technology has been widely applied to engines, and the electronic control unit has become a key component to ensure the reliable operation of diesel engines. In the electronic control unit, accurately identifying the fuel injection timing is the key to ensuring the normal operation of the diesel engine.
[0003] The crankshaft rotation angle position of a diesel engine is usually judged according to the signal of a crankshaft position sensor installed at the flywheel end of the crankshaft. Since the diesel engine rotates one circle, the number of corresponding position pulse signals emitted by the actually applied crankshaft position sensor is relatively small, usually ranging from 60 pulses to 120 pulses. If the original signal of the crankshaft position sensor is directly used to identify the fuel injection timing, there will be a large error. For example, when the number of pulses per revolution of the crankshaft position sensor is 60, the maximum possible error can reach 5° crankshaft rotation angle, which cannot ensure the normal and stable operation of the diesel engine. Generally, in order to accurately calculate the fuel injection timing angle of the diesel engine, the electronic control unit uses its own software and hardware logic to process the actually sampled crankshaft position sensor signal, and inserts micro-pulses with higher angle recognition accuracy in the pulse interval of the original signal of the crankshaft position sensor. Using this micro-pulse to calculate the current actual crankshaft position can greatly improve the calculation accuracy of the crankshaft rotation angle position of the diesel engine.
[0004] Currently, the generation of the fuel injection timing calculation micro-pulses of the actually applied electronic control unit is usually realized by special function timers integrated inside the main control MCU. Moreover, the programming operations for these special function timers usually require their own special instructions. This greatly narrows the selection range of the main control MCU of the electronic control unit, and thus greatly increases the design and development cost of the electronic control unit. Summary of the Invention
[0005] In order to solve the deficiencies of the prior art, the present invention provides a method for determining the fuel injection timing angle of a diesel engine, which uses a general timer integrated inside a general MCU to realize the generation of the fuel injection timing calculation micro-pulses of the diesel engine, realizes the accurate identification of the fuel injection timing angle of the diesel engine, and greatly reduces the requirements for the MCU hardware, thereby greatly reducing the design and development cost and difficulty of the diesel engine control unit.
[0006] The present invention is implemented through the following technical solutions. The present invention includes the following steps: Step S1, the main control system determines four rising edges Pn-3, Pn-2, Pn-1, Pn of the crankshaft encoding signal pulses before the target injection angle Cs; Step S2, when the first encoding signal pulse rising edge Pn-3 appears, trigger the first counter to count the system clock Fsys, and end the count at the pulse falling edge Dn-3 to obtain the count value Q1; Step S3, when the second encoding signal pulse rising edge Pn-2 appears, trigger the second counter to count the system clock Fsys, and end the count at the pulse falling edge Dn-2 to obtain the count value Q2; Step S4, in the low-level stage Tn-3 after the pulse falling edge Dn-2, the system calculates the period Tx of the correction micro-pulse according to Q1, Q2, the period Tsys of the system clock Fsys, the crankshaft rotation angle DAng corresponding to the high level of the encoding signal pulse, and the angle resolution D0 set by the system; Step S5, when the third encoding signal pulse rising edge Pn-1 appears, trigger the first timer to send out a correction micro-pulse according to the correction micro-pulse period Tx, and trigger the third counter to count the correction micro-pulse, and end the count at the pulse falling edge Dn-1 to obtain the correction micro-pulse count value Q3; Step S6, in the low-level stage Tn-1 after the pulse falling edge Dn-1, the system calculates the micro-pulse angle Dpx in the Tn-2 stage according to Q3, compares it with the crankshaft rotation angle DAng corresponding to the high level of the pulse to obtain the correction micro-pulse rotation angle error Derr, and calculates the period error Terr of the correction micro-pulse and the corrected micro-pulse period Tp; Step S7, when the fourth encoding signal pulse rising edge Pn appears, trigger the second timer to send out an injection count micro-pulse according to the corrected micro-pulse period Tp, and trigger the fourth counter to count the correction micro-pulse, and when the count value Q4 reaches the set injection angle count value, trigger the injection action.
[0007] Further, in the above step S1, the crankshaft encoding signal is a continuous square wave signal sent by an encoding signal sensor installed at the flywheel end of the diesel engine. The crankshaft rotation angle DAng corresponding to the high level stage of any square wave pulse of this signal is equal, and the rising edge and falling edge of any square wave pulse correspond to their respective fixed crankshaft rotation angle values; the target injection angle is the crankshaft rotation angle corresponding to the start of fuel injection by the injector at the end of the compression stroke of the working cylinder of the diesel engine calculated by the main control system according to the current state of the diesel engine.
[0008] Furthermore, in the above step S2, the counting interval of the first counter is the pulse high-level stage Tn-6 from the first rising edge Pn-3 to the first falling edge Dn-3. The counting pulse input of the first counter is the system clock Fsys of the main control system, and this clock has a fixed period Tsys.
[0009] Further, in the above step S3, the counting range of the second counter is the pulse high-level stage Tn-4 from the first rising edge Pn-2 to the first falling edge Dn-2. Similarly, the counting pulse input of the second counter is the system clock Fsys of the main control system.
[0010] Further, in the above step S4, in the low-level stage Tn-3 after the pulse falling edge Dn-2, the main control system calculates the period Tx of the correction micro-pulse. The system clock count value Qe corresponding to the high-level stage Tn-2 of the encoded signal is linearly extrapolated from the count value Q1 of the first counter and the count value Q2 of the second counter, i.e., Qe = 2×Q2 - Q1. According to the system clock period Tsys, the time estimate value Te corresponding to Tn-2 is calculated as Te = Qe×Tsys. According to the actual crankshaft angle DAng corresponding to Tn-2 and the angle resolution D0 set by the system, the period Tx of the correction micro-pulse is calculated as Tx = Te×D0 / DAng.
[0011] Further, in the above step S5, the first timer starts to send correction micro-pulses with a period of Tx at the third encoded signal pulse rising edge Pn-1, which is used as the counting pulse input of the third counter, and stops sending correction micro-pulses at the third encoded signal pulse falling edge Dn-1; the third counter starts to count the correction micro-pulses at the pulse rising edge Pn-1 and stops counting at the pulse falling edge Dn-1.
[0012] Further, in the above step S6, in the low-level stage Tn-1 after the pulse falling edge Dn-1, according to the count value Q3 of the third counter and the angle resolution D0 set by the system, the correction micro-pulse angle Dpx corresponding to the Tn-2 stage is calculated as Dpx = Q3×D0, and it is compared with the actual crankshaft angle D corresponding to the Tn-2 stage Ang to obtain the correction micro-pulse angle error Derr = Dpx - DAng, calculate the correction micro-pulse period error Terr = Tx×Q3×D0 / DAng - Tx, and calculate the corrected fuel injection counting micro-pulse period Tp = Tx×Q3×D0 / DAng.
[0013] Further, in the above step S7, the second timer starts to send fuel injection counting micro-pulses with a period of Tp at the fourth encoded signal pulse rising edge Pn, which is used as the counting pulse input of the fourth counter; the fourth counter starts to count the fuel injection counting micro-pulses at the pulse rising edge Pn. When the fourth counter reaches the set fuel injection angle count value, it triggers the fuel injection action and stops the fourth counter from counting and stops the second timer from sending fuel injection counting micro-pulses; according to the crankshaft angle DPn corresponding to the pulse rising edge Pn, the target fuel injection angle Cs and the angle resolution D0 set by the system, the count value Qs of the fourth counter corresponding to triggering the fuel injection action is Qs = (Cs - DPn) / D0.
[0014] The present invention provides a method for determining the fuel injection timing of a diesel engine. According to the rising edges Pn-3, Pn-2, Pn-1, Pn of four crankshaft encoding signal pulses before the target injection angle Cs determined by the main control system, when the rising edge Pn-3 of the first encoding signal pulse appears, trigger the first counter to count the system clock Fsys, and end the counting at the falling edge Dn-3 of the pulse, and the count value is Q1; when the rising edge Pn-2 of the second encoding signal pulse appears, trigger the second counter to count the system clock Fsys, and end the counting at the falling edge Dn-2 of the pulse, and the count value is Q2. In the low-level stage Tn-3 after the falling edge Dn-2 of the pulse, the system calculates the period Tx of the correction micro-pulse according to Q1, Q2, and the period Tsys of the system clock Fsys. When the rising edge Pn-1 of the third encoding signal pulse appears, trigger the first timer to issue a correction micro-pulse according to the period Tx, and at the same time trigger the third counter to count the correction micro-pulse, and end the counting at the falling edge Dn-1 of the pulse, and the count value is Q3. In the low-level stage Tn-1 after the falling edge Dn-1 of the pulse, the system calculates the micro-pulse angle Dpx in the Tn-2 stage according to Q3, compares it with the crankshaft angle DAng corresponding to the high level of the pulse to obtain the correction micro-pulse angle error Derr, and calculates the period error Terr of the correction micro-pulse and the corrected period Tp of the correction micro-pulse. When the rising edge Pn of the fourth encoding signal pulse appears, trigger the second timer to issue an injection counting micro-pulse according to the period Tp, and at the same time trigger the fourth counter to count the injection counting micro-pulse. When the count value Q4 reaches the set injection angle count value, trigger the fuel injection action.
[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses the general timer integrated in the general MCU to realize the generation of the calculation micro-pulse for the fuel injection timing of the diesel engine, realizes the accurate identification of the fuel injection timing angle of the diesel engine, and greatly reduces the requirements for the MCU hardware, thereby greatly reducing the design and development cost and difficulty of the diesel engine control unit. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 is a schematic diagram of a method for determining the fuel injection timing angle of a diesel engine in an embodiment of the present invention;
[0017] Figure 2 is a flowchart of a method for determining the fuel injection timing angle of a diesel engine in an embodiment of the present invention;
[0018] Figure 3 is a flowchart of calculating the period Tx of the correction micro-pulse in an embodiment of the present invention;
[0019] Among them, 11 is the first counter, 12 is the second counter, 13 is the first timer, 14 is the third counter, 15 is the second timer, and 16 is the fourth counter. Detailed implementation manners
[0020] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the present invention, rather than limiting the present invention. In addition, it should be noted that, for the sake of convenience of description, only a part related to the present invention rather than all the structures are shown in the accompanying drawings.
[0021] The schematic diagram of a method for determining the fuel injection timing angle of a diesel engine applicable to the embodiments of the present invention is as Figure 1 shown, including four counters, namely the first counter 11, the second counter 12, the third counter 14, and the fourth counter 16, and two timers, namely the first timer 13 and the second timer 15. The main control system determines the rising edges Pn-3, Pn-2, Pn-1, and Pn of four crankshaft encoding signal pulses before the target fuel injection angle Cs. When the rising edge Pn-3 of the pulse appears, the first counter 11 is triggered to count the system clock Fsys, and the counting ends at the falling edge Dn-3 of the pulse, and the count value is Q1; when the rising edge Pn-2 of the pulse appears, the second counter 12 is triggered to count the system clock Fsys, and the counting ends at the falling edge Dn-2 of the pulse, and the count value is Q2; in the low-level stage Tn-3 after the falling edge Dn-2 of the pulse, the system calculates the period Tx of the correction micro-pulse according to Q1, Q2, and the period Tsys of the system clock Fsys; when the rising edge Pn-1 of the pulse appears, the first timer 13 is triggered to issue a correction micro-pulse according to the period Tx, and at the same time, the third counter 14 is triggered to count the correction micro-pulse, and the counting ends at the falling edge Dn-1 of the pulse, and the count value is Q3; in the low-level stage Tn-1 after the falling edge Dn-1 of the pulse, the system calculates the micro-pulse angle Dpx in the Tn-2 stage according to Q3, and further calculates the correction micro-pulse rotation angle error Derr and the period error Terr of the correction micro-pulse, so as to calculate the period Tp of the corrected fuel injection counting micro-pulse; when the rising edge Pn of the pulse appears, the second timer 5 is triggered to issue a fuel injection counting micro-pulse according to the period Tp, and at the same time, the fourth counter 16 is triggered to count the fuel injection counting micro-pulse. When the count value Q4 reaches the set fuel injection angle count value, the fuel injection action is triggered.
[0022] The flowchart of a method for determining the fuel injection timing angle of a diesel engine implemented by the present invention is as Figure 2 shown, and this method is executed through the Figure 1 principle shown, and specifically includes the following steps:
[0023] Step S1: The main control system determines the rising edges Pn-3, Pn-2, Pn-1, and Pn of the four crankshaft encoder signals before the target injection angle Cs.
[0024] Among them, the crankshaft encoder signal is the main input signal for the main control system to determine the injection angle timing of the diesel engine and is an indispensable input signal. This signal is a continuous square wave signal emitted by the encoder signal sensor installed at the flywheel end of the diesel engine. The crankshaft angle DAng corresponding to the high-level stage of any square wave pulse of this signal is equal, and the rising edge and falling edge of any square wave pulse correspond to their respective fixed crankshaft angle values; the target injection angle Cs is the crankshaft angle corresponding to the start of fuel injection by the injector at the end of the compression stroke of the working cylinder of the diesel engine calculated by the main control system according to the current state of the diesel engine; the relevant calculation method of the main control system is the calculation program preset in the main control system.
[0025] Step S2: When the rising edge Pn-3 of the first encoder signal pulse appears, trigger the first counter to count the system clock Fsys and end the count at the falling edge Dn-3 of the pulse to obtain the count value Q1.
[0026] Among them, the counting interval of the first counter is the pulse high-level stage Tn-6 from the first rising edge Pn-3 to the first falling edge Dn-3. The counting pulse input of the first counter is the system clock Fsys of the main control system, and this clock has a fixed period Tsys.
[0027] Step S3: When the rising edge Pn-2 of the second encoder signal pulse appears, trigger the second counter to count the system clock Fsys and end the count at the falling edge Dn-2 of the pulse to obtain the count value Q2.
[0028] Among them, the counting interval of the second counter is the pulse high-level stage Tn-4 from the first rising edge Pn-2 to the first falling edge Dn-2. Similarly, the counting pulse input of the second counter is the system clock Fsys of the main control system.
[0029] Step S4: In the low-level stage Tn-3 after the falling edge Dn-2 of the pulse, the system calculates the period Tx of the correction micro-pulse according to Q1, Q2, the period Tsys of the system clock Fsys, the crankshaft angle DAng corresponding to the high level of the encoder signal pulse, and the angle resolution D0 set by the system.
[0030] Among them, the period Tx of the correction micro-pulse is calculated by the main control system in the low-level stage Tn-3 after the falling edge Dn-2 of the pulse. For example Figure 3As shown, the system clock count value Qe = 2×Q2 - Q1 corresponding to the high-level stage Tn-2 of the encoded signal is linearly extrapolated from the count value Q1 of the first counter and the count value Q2 of the second counter. The time estimate value Te = Qe×Tsys corresponding to Tn-2 is calculated according to the system clock period Tsys. According to Te, the actual crankshaft angle DAng corresponding to the high-level stage, and the angle resolution D0 set by the system, the period Tx of the correction micro-pulse is calculated as Tx = Te×D0 / DAng.
[0031] Step S5: When the rising edge Pn-1 of the third encoded signal pulse appears, trigger the first timer to issue a correction micro-pulse according to the correction micro-pulse period Tx, trigger the third counter to count the correction micro-pulse, and end the counting at the falling edge Dn-1 of the pulse to obtain the correction micro-pulse count value Q3.
[0032] Among them, the first timer starts to issue a correction micro-pulse with a period of Tx at the rising edge Pn-1 of the third encoded signal pulse, which is input as the counting pulse of the third counter, and stops issuing the correction micro-pulse at the falling edge Dn-1 of the third encoded signal pulse; the third counter starts to count the correction micro-pulse at the rising edge Pn-1 of the pulse and stops counting at the falling edge Dn-1 of the pulse.
[0033] Step S6: In the low-level stage Tn-1 after the falling edge Dn-1 of the pulse, the system calculates the correction micro-pulse angle Dpx of the Tn-2 stage according to Q3, compares it with the crankshaft angle DAng corresponding to the high level of the pulse to obtain the correction micro-pulse angle error Derr, and calculates the period error Terr of the correction micro-pulse and the corrected micro-pulse period Tp.
[0034] Among them, in the low-level stage Tn-1, the system calculates the correction micro-pulse angle Dpx = Q3×D0 of the Tn-2 stage according to Q3 and the angle resolution D0 set by the system, compares it with the actual crankshaft angle DAng corresponding to the Tn-2 stage to obtain the correction micro-pulse angle error Derr = Dpx - DAng, and further calculates the period error Terr of the correction micro-pulse as Terr = Tx×Q3×D0 / DAng - Tx, so as to calculate the corrected fuel injection counting micro-pulse period Tp.
[0035] Step S7: When the rising edge Pn of the fourth encoded signal pulse appears, trigger the second timer to issue a fuel injection counting micro-pulse according to the corrected micro-pulse period Tp, trigger the fourth counter to count the fuel injection counting micro-pulse, and when the count value Q4 reaches the set fuel injection angle count value, trigger the fuel injection action.
[0036] Among them, the second timer starts to emit fuel injection counting micro-pulses with a period of Tp at the rising edge Pn of the fourth coding signal pulse, which are input as the counting pulses of the fourth counter; the fourth counter starts to count the fuel injection counting micro-pulses at the rising edge Pn of the pulse, and triggers the fuel injection action when the fuel injection angle count value set by the main control system is reached. At the same time, the main control system stops the fourth counter from counting and the second timer from emitting fuel injection counting micro-pulses; according to the crankshaft rotation angle DPn corresponding to the rising edge Pn of the pulse, the target fuel injection angle Cs, and the angle resolution D0 set by the system, the count value Qs of the fourth counter corresponding to the triggered fuel injection action is Qs=(Cs - D Pn ) / D0.
[0037] A method for determining the fuel injection timing angle of a diesel engine provided in this embodiment uses a general timer integrated inside a general MCU to generate fuel injection timing calculation micro-pulses for a diesel engine, realizes the accurate identification of the fuel injection timing angle of the diesel engine, greatly reduces the requirements for the MCU hardware, and thus greatly reduces the design and development cost and difficulty of the diesel engine control unit.
[0038] Note that the above is only the preferred embodiment of the present invention and the technical principles applied. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described above, and various obvious re-adjustments, changes, and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments. Without departing from the concept of the present invention, more other equivalent embodiments can be included, and the scope of the present invention is determined by the scope of the appended claims.
Claims
1. A method for determining the injection timing angle of a diesel engine, characterized in that: The following steps are involved: Step S1, the main control system determines the four crankshaft encoding signal pulse rising edges Pn-3, Pn-2, Pn-1, and Pn before the target injection angle according to the target injection angle Cs; Step S2, when the rising edge Pn-3 of the first encoding signal pulse appears, the first counter is triggered to count the system clock Fsys, and the counting ends at the falling edge Dn-3 of the pulse to obtain the count value Q1; Step S3, when the rising edge Pn-2 of the second encoding signal pulse appears, the second counter is triggered to count the system clock Fsys, and the counting ends at the falling edge Dn-2 of the pulse to obtain the count value Q2; Step S4, in the low level stage Tn-3 after the falling edge Dn-2 of the pulse, the system calculates the period Tx of the correction micro pulse according to Q1, Q2, the period Tsys of the system clock Fsys, the crankshaft angle DAng corresponding to the high level of the encoding signal pulse and the angle resolution D0 set by the system; Step S5, when the third coded signal pulse rising edge Pn-1 appears, the first timer is triggered to send a correction micropulse according to the correction micropulse period Tx, and the third counter is triggered to count the correction micropulses, and the counting ends at the pulse falling edge Dn-1 to obtain the correction micropulse count value Q3; Step S6, in the low level stage Tn-1 after the falling edge Dn-1 of the pulse, the system calculates the corrected micropulse angle Dpx of the Tn-2 stage according to Q3, compares it with the crankshaft angle DAng corresponding to the high level of the pulse to obtain the corrected micropulse angle error Derr, and calculates the corrected micropulse period error Terr and the corrected micropulse period Tp; Step S7, when the rising edge Pn of the fourth coded signal pulse appears, the second timer is triggered to send an injection counting micro-pulse according to the corrected micro-pulse period Tp, and the fourth counter is triggered to count the injection counting micro-pulses, and when the count value Q4 reaches the set injection angle count value, the injection action is triggered.
2. A method for determining the injection timing angle of a diesel engine according to claim 1, characterized in that In step S1, the crankshaft encoding signal is a continuous square wave signal emitted by a coding signal sensor installed at the flywheel end of the diesel engine. The crankshaft angle DAng corresponding to the high level phase of any square wave pulse of the signal is equal, and the rising edge and falling edge of any square wave pulse correspond to respective fixed crankshaft angle values; the target injection angle is the crankshaft angle corresponding to the working cylinder of the diesel engine when the injector starts to inject fuel at the end of the compression stroke, calculated by the main control system according to the current diesel engine state.
3. A method for determining the injection timing angle of a diesel engine according to claim 1, characterized in that The counting interval of the first counter in step S2 is the pulse high level stage Tn-6 from the first rising edge Pn-3 to the first falling edge Dn-3. The counting pulse input of the first counter is the system clock Fsys of the main control system, which has a fixed period Tsys.
4. A method for determining the injection timing angle of a diesel engine according to claim 1, characterized in that The counting interval of the second counter in step S3 is the pulse high level stage Tn-4 from the first rising edge Pn-2 to the first falling edge Dn-2. Similarly, the counting pulse input of the second counter is the system clock Fsys of the main control system.
5. A method for determining the injection timing angle of a diesel engine according to claim 1, characterized in that In step S4, in the low level stage Tn-3 after the falling edge Dn-2 of the pulse, the main control system calculates the period Tx of the correction micropulse, and linearly extrapolates the count value Q1 of the first counter and the count value Q2 of the second counter to obtain the system clock count value Qe=2×Q2-Q1 corresponding to the high level stage Tn-2 of the encoding signal, and calculates the time estimation value Te=Qe×Tsys corresponding to Tn-2 according to the system clock period Tsys, and calculates the period Tx=Te×D0 / DAng of the correction micropulse according to the actual crankshaft angle DAng corresponding to Tn-2 and the angular resolution D0 set by the system.
6. A method for determining the injection timing angle of a diesel engine according to claim 1, characterized in that In step S5, the first timer starts to emit a correction micropulse with a period of Tx at the rising edge Pn-1 of the third coded signal pulse as the counting pulse input of the third counter, and stops emitting the correction micropulse at the falling edge Dn-1 of the third coded signal pulse; the third counter starts counting the correction micropulses at the rising edge Pn-1 of the pulse, and stops counting at the falling edge Dn-1 of the pulse.
7. A method for determining the injection timing angle of a diesel engine according to claim 1, characterized in that In step S6, in the low level stage Tn-1 after the falling edge Dn-1 of the pulse, the corrected micro-pulse angle Dpx=Q3×D0 of the Tn-2 stage is calculated according to the count value Q3 of the third counter and the angle resolution D0 set by the system, and compared with the actual crankshaft angle DAng corresponding to the Tn-2 stage, the corrected micro-pulse angle error Derr=Dpx-DAng is obtained, and the period error Terr=Tx×Q3×D0 / DAng-Tx of the corrected micro-pulse is calculated, and the corrected injection counting micro-pulse period Tp=Tx×Q3×D0 / DAng is calculated.
8. A method for determining the injection timing angle of a diesel engine according to claim 1, characterized in that In step S7, the second timer starts to emit injection counting micro-pulses with a period of Tp at the rising edge Pn of the fourth coding signal pulse, which serves as the counting pulse input of the fourth counter; the fourth counter starts to count the injection counting micro-pulses at the rising edge Pn of the pulse, and the fourth counter triggers the injection action when the set injection angle count value is reached, and stops the fourth counter counting and stops the second timer from emitting injection counting micro-pulses; according to the crankshaft angle DPn corresponding to the rising edge Pn of the pulse, the target injection angle Cs and the angle resolution D0 set by the system, the count value Qs=(Cs-DPn) / D0 of the fourth counter corresponding to the injection action is triggered.
9. A method for determining the injection timing angle of a diesel engine according to claim 1, characterized in that After the execution of steps S1 to S7, the system performs a reset operation on the first counter, the second counter, the third counter and the fourth counter, and the count values return to zero.