A control method and control system for performance of a methanol engine

Abstract

The application relates to the engine technical field and discloses a control method and a control system for the performance of a methanol engine, wherein when the engine is in a steady state condition, the current rotating speed and the current load of the engine are acquired, the corresponding set air-fuel ratio is acquired according to the current rotating speed and the current load, the corresponding steady state correction factor is obtained according to the set air-fuel ratio and the current load, the charging time is calculated by using the formula: charging time = current charging time * steady state correction factor, the charging time is transmitted to an ignition module to control the ignition coil. It can be seen that the application sets different charging times of the ignition coil according to different set air-fuel ratios according to the combustion demand of the methanol engine under different steady state conditions, so that higher energy is output by the ignition system under high air-fuel ratio to stabilize the engine combustion, and the energy input by the ignition system is reduced under lower air-fuel ratio to prolong the service life of the ignition coil and the spark plug.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and in particular to a method and control system for controlling the performance of a methanol engine. Background Technology

[0002] Spark-ignition methanol engines monitor the air-fuel ratio using a wide-range oxygen sensor and employ closed-loop air-fuel ratio control to ensure optimal engine operation. To maintain engine emissions performance, a higher air-fuel ratio is required under partial load to reduce nitrogen oxide emissions. However, an excessively lean air-fuel ratio can lead to engine instability. Therefore, it is necessary to increase the ignition energy to ensure stable combustion.

[0003] Currently, spark-ignition methanol engines typically employ wide-range oxygen sensors to monitor the oxygen concentration in the exhaust gas in real time and control the injection pulse width through closed-loop feedback to maintain engine operation at the target air-fuel ratio. To meet increasingly stringent emission regulations, especially in the partial load range commonly used in urban driving conditions, engineers tend to increase the air-fuel ratio (lean combustion) to lower the combustion temperature and thus significantly reduce the formation of nitrogen oxides (NOx).

[0004] However, the existing technology has the following problems:

[0005] Lean combustion results in poor stability: When the air-fuel ratio is too high (too lean), the distance between combustible methanol molecules in the mixture increases, significantly slowing down the flame propagation speed. This easily leads to increased fluctuations in the combustion cycle, and even misfire. This not only causes engine vibration and power interruption, but also leads to a surge in unburned methanol and formaldehyde emissions, thus worsening emission performance.

[0006] Insufficient ignition energy adaptability: When combustion instability is detected, it is usually improved by delaying the ignition advance angle or adjusting the exhaust gas recirculation rate, or by directly increasing the charging time of the ignition coil. However, under partial load and high air-fuel ratio, the ignition energy was not increased in time and in sufficient quantity to match the lean-burn demand; while under low load and rich-burn conditions, the ignition energy was not actively reduced, resulting in long-term overload operation of the ignition system.

[0007] Transient response lag: When the engine is under transient conditions such as rapid acceleration or deceleration, sudden changes in intake pressure cause the air-fuel ratio to deviate from the target value instantaneously. Due to the hysteresis of the oxygen sensor signal, the existing feedback control cannot provide sufficient ignition energy to support the combustion of the unstable mixture in the first instance, resulting in transient misfire or backfire.

[0008] Therefore, those skilled in the art urgently need to design a control method for an ignition-fired methanol engine that can actively and precisely adjust the ignition coil energization time according to real-time operating conditions and changes in air-fuel ratio, ensuring lean combustion to reduce emissions while ensuring absolute engine stability and taking into account the service life of the ignition system. Summary of the Invention

[0009] To address the aforementioned shortcomings, the technical problem to be solved by this invention is to provide a method and control system for controlling the performance of a methanol engine. By setting different air-fuel ratios, different charging times for the ignition coils are set to ensure that the ignition system outputs higher energy at high air-fuel ratios to stabilize engine combustion; and at lower air-fuel ratios, the energy input to the ignition system is reduced to extend the service life of the ignition coils and spark plugs.

[0010] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0011] A method for controlling the performance of a methanol engine includes the following steps:

[0012] S10. Determine whether the engine is in a steady-state operating condition;

[0013] S20. If the engine is in a steady-state condition, obtain the engine's current speed and current load;

[0014] S30. Obtain the corresponding set air-fuel ratio based on the current speed and current load;

[0015] S40. Obtain the corresponding steady-state correction factor based on the set air-fuel ratio and the current load;

[0016] S50. Calculate the power-on time using the formula: Power-on time = Current power-on time * Steady-state correction factor;

[0017] S60 transmits the power-on time to the ignition module to control the ignition coil.

[0018] In a preferred embodiment, S10 further includes: determining whether the engine is in a transient operating condition;

[0019] S20 further includes: if the engine is in a transient operating condition, acquiring the real-time air-fuel ratio and the corresponding set air-fuel ratio;

[0020] S30 further includes: calculating the air-fuel ratio deviation between the real-time air-fuel ratio and the set air-fuel ratio;

[0021] The S40 further includes: obtaining the corresponding transient correction factor based on the air-fuel ratio deviation;

[0022] S50 further includes: calculating the power-on time using the formula: power-on time = current power-on time * transient correction factor, and then executing S60.

[0023] In a preferred embodiment, S10 further includes:

[0024] After the engine starts, the intake manifold pressure of the engine is obtained;

[0025] Calculate the intake manifold pressure change rate based on the intake manifold pressure.

[0026] Determine whether the intake manifold pressure change rate is greater than a preset pressure change rate threshold.

[0027] If the intake manifold pressure change rate is greater than the pressure change rate threshold, the current operating condition is a transient condition.

[0028] If the intake manifold pressure change rate is not greater than the pressure change rate threshold, then the current operating condition is a steady-state condition.

[0029] The preferred method is to obtain the set air-fuel ratio from a preset set air-fuel ratio MAP, which is calibrated using engine speed and load.

[0030] The preferred method is to obtain the steady-state correction factor from the preset steady-state correction factor MAP, which is calibrated using the set air-fuel ratio and load.

[0031] The preferred method is that the transient correction factor is obtained from the preset transient correction factor MAP, and the transient correction factor MAP is calibrated using the air-fuel ratio deviation.

[0032] The preferred method is to calculate the real-time air-fuel ratio by measuring the oxygen concentration in the exhaust gas using an oxygen sensor and a preset air-fuel ratio model.

[0033] The preferred method further includes the following steps:

[0034] When starting the engine, determine whether the engine is a cold start;

[0035] If the engine is cold-started, find the preset cold-start correction factor;

[0036] The energizing time of the ignition coil is corrected using a cold start correction factor.

[0037] If the engine is not cold-started, then discontinue the ignition coil energizing time correction.

[0038] The preferred method is that the step of determining whether the engine is a cold start includes:

[0039] When the engine starts, the real-time coolant temperature of the engine is obtained;

[0040] Determine if the real-time water temperature is lower than the preset water temperature threshold;

[0041] If the real-time water temperature is lower than the water temperature threshold, the engine is cold-started;

[0042] If the real-time water temperature is not lower than the water temperature threshold, then the engine is not cold-started.

[0043] A control system for methanol engine performance includes an electronic control unit (ECU) and a parameter detection unit, a condition detection unit, a correction factor acquisition unit, an ignition time correction unit, and an ignition module, all electrically connected to the ECU. The parameter detection unit detects the engine's current coolant temperature, current engine speed, and intake manifold pressure, and transmits the corresponding parameter signals to the ECU. The ECU then transmits the parameter signals to the condition detection unit and the correction factor acquisition unit. The condition detection unit determines whether the engine is cold-started based on the received current coolant temperature and transmits a corresponding cold-start determination signal to the ECU. The condition detection unit also determines the engine's current condition based on the received intake manifold pressure and transmits a corresponding current condition determination signal to the ECU. The ECU then transmits both the cold-start determination signal and the current condition determination signal to the correction factor acquisition unit. The correction factor acquisition unit is used to find the corresponding cold start correction factor when the engine is cold-started and transmit it to the power-on time correction unit. The correction factor acquisition unit is used to obtain the corresponding steady-state correction factor based on the current speed and current load when the engine is in steady-state operation and transmit the steady-state correction factor to the power-on time correction unit. The correction factor acquisition unit is used to obtain the corresponding transient correction factor based on the air-fuel ratio deviation between the real-time air-fuel ratio and the set air-fuel ratio when the engine is in transient operation and transmit the transient correction factor to the power-on time correction unit. The power-on time correction unit uses the cold start correction factor, steady-state correction factor, or transient correction factor to correct the current power-on time of the ignition coil and transmits the corrected power-on time to the electronic control unit. The electronic control unit then transmits the power-on time to the ignition module, and the ignition module controls the ignition coil.

[0044] After adopting the above technical solution, the beneficial effects of the present invention are:

[0045] The methanol engine performance control method and control system of this invention, when the engine is in steady-state operation, acquires the current engine speed and current load; obtains the corresponding set air-fuel ratio based on the current speed and current load; obtains the corresponding steady-state correction factor based on the set air-fuel ratio and current load; calculates the energizing time using the formula: energizing time = current energizing time * steady-state correction factor; and transmits the energizing time to the ignition module to control the ignition coil. Therefore, this invention, in response to the combustion requirements of the methanol engine under different steady-state operating conditions, achieves on-demand distribution of ignition energy by dynamically adjusting the energizing time of the ignition coil; it ensures sufficient ignition energy to prevent misfire under high load or lean combustion (high air-fuel ratio), and reduces ignition energy under low load or rich combustion (low air-fuel ratio), avoiding energy waste and ignition system overheating, extending the service life of spark plugs and ignition coils, while optimizing combustion efficiency and ensuring engine load responsiveness. Attached Figure Description

[0046] Figure 1 This is a flowchart illustrating the method for controlling the performance of a methanol engine in this invention.

[0047] Figure 2 This is a schematic diagram of the process when the engine is cold-started in this invention;

[0048] Figure 3 This is a schematic diagram of the control system for the performance of the methanol engine in this invention. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0050] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0051] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0052] Example 1:

[0053] like Figure 1 As shown, a method for controlling the performance of a methanol engine includes the following steps:

[0054] Step S10: Determine whether the engine is in a steady-state operating condition;

[0055] Step S20: If the engine is in steady-state operation, obtain the current engine speed and current load;

[0056] It should be noted that in this invention, the engine electronic control unit collects engine speed and intake manifold pressure, and then uses a calibrated torque model to find the current load of the engine.

[0057] Step S30: Obtain the corresponding set air-fuel ratio based on the current speed and current load;

[0058] It should be noted that the air-fuel ratio can be set to, but is not limited to, the rated value.

[0059] Step S40: Obtain the corresponding steady-state correction factor based on the set air-fuel ratio and the current load;

[0060] It should be noted that the steady-state correction factor can be, but is not limited to, the calibration value.

[0061] Step S50: Calculate the power-on time using the formula: Power-on time = Current power-on time * Steady-state correction factor;

[0062] Step S60: Transmit the power-on time (specifically, transmit the corresponding ignition energy command) to the ignition module to control the ignition coil.

[0063] The method for controlling the performance of a spark-ignition methanol engine of this invention establishes a precise mapping relationship between engine speed, load, air-fuel ratio, and ignition energy. By dynamically adjusting the energizing time (i.e., charging time) of the ignition coil to meet the combustion requirements of the methanol engine under different steady-state operating conditions, it achieves on-demand distribution of ignition energy. Therefore, the control method of this invention can ensure sufficient ignition energy to prevent misfire under high load or lean combustion, while reducing ignition energy under low load or rich combustion, avoiding energy waste and overheating of the ignition system, extending the service life of spark plugs and ignition coils, and optimizing combustion efficiency.

[0064] In this invention, the set air-fuel ratio is obtained from a preset set air-fuel ratio MAP, which is calibrated using engine speed and load; the steady-state correction factor is obtained from a preset steady-state correction factor MAP, which is calibrated using the set air-fuel ratio and load; see the table below for details:

[0065] Set the air-fuel ratio MAP table:

[0066]

[0067] Steady-state correction factor (MAP) table:

[0068]

[0069] In the table, lambda means air-fuel ratio, and Fac1 to Fac… are all steady-state correction factors.

[0070] When the engine is operating under steady-state conditions, the set air-fuel ratio (MAP) is determined based on the current engine speed and load. Then, a steady-state correction factor for the ignition coil's energizing time is calculated based on the MAP and the current load. A higher load results in a higher air-fuel ratio and a larger ignition coil energizing time correction factor, thus increasing the spark plug discharge energy and optimizing engine combustion. Conversely, a lower load results in a lower air-fuel ratio and a smaller ignition coil energizing time correction factor, reducing ignition energy while ensuring stable engine operation and extending the lifespan of the ignition coil and spark plugs.

[0071] The MAP (Maximum Amount of Air-Fuel Ratio) of this invention calibrates the set air-fuel ratio, ensuring that the engine can operate in the optimal combustion state within the steady-state operating range.

[0072] This invention utilizes the steady-state correction factor (MAP) to identify the specific requirements of methanol under certain load and air-fuel ratio combinations, achieving a refined analysis of the correction factor, avoiding the incomplete combustion problem caused by a one-size-fits-all ignition control, and reducing HC and formaldehyde emissions.

[0073] like Figure 1As shown, the methanol engine performance control method of the present invention further includes transient operating conditions, specifically:

[0074] Step S10 also includes: determining whether the engine is in a transient operating condition;

[0075] Step S20 also includes: if the engine is in a transient operating condition, obtaining the real-time air-fuel ratio and the corresponding set air-fuel ratio;

[0076] It should be noted that the real-time air-fuel ratio is calculated by measuring the oxygen concentration in the exhaust gas using an oxygen sensor and a preset air-fuel ratio model. Through real-time feedback from the oxygen sensor and calculation via the air-fuel ratio model, true closed-loop control is achieved, ensuring the accuracy and real-time nature of the air-fuel ratio deviation data.

[0077] Step S30 further includes: calculating the air-fuel ratio deviation between the real-time air-fuel ratio and the set air-fuel ratio; specifically, air-fuel ratio deviation = real-time air-fuel ratio - set air-fuel ratio;

[0078] Step S40 further includes: obtaining the corresponding transient correction factor based on the air-fuel ratio deviation;

[0079] It should be noted that the transient correction factor can be, but is not limited to, the calibration value.

[0080] Step S50 further includes: calculating the power-on time using the formula: Power-on time = Current power-on time * Transient correction factor;

[0081] Step S60: Transmit the power-on time (specifically, transmit the corresponding ignition energy command) to the ignition module to control the ignition coil.

[0082] When the electric motor is under sudden load conditions (a type of transient condition), the air-fuel ratio of the engine will increase due to the lag in methanol injection. Based on the deviation between the real-time air-fuel ratio measured by the oxygen sensor and the set air-fuel ratio, different ignition coil energizing time correction factors are set to improve the spark plug discharge energy, thereby optimizing engine combustion and improving the engine's responsiveness under transient load.

[0083] Through the above steps, this invention solves the combustion instability problem caused by fuel response lag in methanol engines under sudden operating conditions (such as sudden load increase); by introducing air-fuel ratio deviation as a correction basis, millisecond-level dynamic response is achieved. When the actual air-fuel ratio deviates from the set air-fuel ratio, the ignition time is immediately adjusted through a transient correction factor before combustion deterioration (misfire) occurs; this effectively suppresses speed fluctuations and jerking during transient processes, improving the driving smoothness and transient response speed of the methanol engine.

[0084] In this invention, the transient correction factor is obtained from a preset transient correction factor MAP, which is calibrated using the air-fuel ratio deviation; see the table below for details:

[0085] Transient correction factor MAP:

[0086]

[0087] In the table, Fac1, Fac2, Fac… are all transient correction factors.

[0088] This invention transforms the abstract air-fuel ratio deviation into a specific ignition energy correction. The establishment of the transient correction factor MAP can linearly or non-linearly adjust the ignition intensity according to the degree of deviation from the target (the magnitude of the deviation), ensuring that the engine can maintain optimal combustion stability and prevent stalling under various extreme transient conditions.

[0089] like Figure 1 As shown, the determination of the current operating condition of the engine in this invention, i.e., step S10, specifically includes the following steps:

[0090] After the engine starts, the intake manifold pressure of the engine is obtained;

[0091] Calculate the intake manifold pressure change rate based on the intake manifold pressure.

[0092] Determine whether the intake manifold pressure change rate is greater than a preset pressure change rate threshold.

[0093] If the intake manifold pressure change rate is greater than the pressure change rate threshold, the current operating condition is a transient condition.

[0094] If the intake manifold pressure change rate is not greater than the pressure change rate threshold, then the current operating condition is a steady-state condition.

[0095] This invention, by calculating the intake manifold pressure change rate (dp / dt), can detect the driver's sudden acceleration faster than simply monitoring the engine speed. Through the above steps, transient correction can be triggered earlier, thereby strengthening ignition in advance before the air-fuel mixture concentration is fully established. This effectively prevents the acceleration backfire and instantaneous misfire phenomena common in methanol engines. Moreover, this operating condition determination method has the advantages of high sensitivity and low cost.

[0096] like Figure 2 As shown, the methanol engine performance control method of the present invention further includes the following steps:

[0097] When starting the engine, determine whether the engine is a cold start;

[0098] If the engine is cold-started, find the preset cold-start correction factor;

[0099] The energizing time of the ignition coil is corrected using a cold start correction factor.

[0100] If the engine is not cold-started, then discontinue the ignition coil energizing time correction.

[0101] When the engine is cold-started, the ignition coil energizing time is corrected to increase ignition energy and improve combustion stability. If the engine is not cold-started, the ignition coil energizing time correction is not required and can be discontinued.

[0102] like Figure 2 As shown, the step of determining whether the engine is cold-started in this invention includes:

[0103] When the engine starts, the real-time coolant temperature of the engine is obtained;

[0104] Determine if the real-time water temperature is lower than the preset water temperature threshold;

[0105] If the real-time water temperature is lower than the water temperature threshold, the engine is cold-started;

[0106] If the real-time water temperature is not lower than the water temperature threshold, then the engine is not cold-started.

[0107] This invention utilizes a simple, reliable, and low-cost cold start determination method, which can accurately distinguish between cold and hot machine states without the need for additional hardware.

[0108] The methanol engine performance control method of the present invention sets different charging times for ignition coils by setting different air-fuel ratios. This ensures that at high air-fuel ratios, the ignition system outputs higher energy to stabilize engine combustion; at lower air-fuel ratios, it reduces the energy input to the ignition system to extend the service life of the ignition coils and spark plugs; under transient conditions, it increases ignition energy by measuring the air-fuel ratio using a wide-range oxygen sensor to ensure engine load responsiveness; and during cold starts, when methanol atomization is poor at low temperatures, it improves combustion stability by increasing ignition energy.

[0109] In summary, the methanol engine performance control method of the present invention adjusts the ignition coil charging time in stages according to the set air-fuel ratio under steady-state engine conditions to achieve stable combustion at high air-fuel ratios and extend the life of ignition coils and spark plugs at low air-fuel ratios; establishes a transient condition prediction mechanism to identify operating conditions in advance by the intake manifold pressure change rate, and increases ignition energy before the mixture becomes lean, thus solving the problems of loading lag and combustion fluctuations in methanol engines; and improves the cold start stability of the engine.

[0110] Example 2:

[0111] like Figure 3As shown, a control system for the performance of a methanol engine includes an electronic control unit (ECU) and a parameter detection unit, a working condition detection unit, a correction factor acquisition unit, an ignition time correction unit, an ignition module, and a preset unit, all electrically connected to the ECU.

[0112] The parameter detection unit is used to detect the engine's current coolant temperature, current speed, and intake manifold pressure, and transmits the corresponding parameter signals to the electronic control unit (ECU). The ECU then transmits the parameter signals to the operating condition detection unit and the correction factor acquisition unit. In this embodiment, the parameter detection unit includes a speed sensor, an intake manifold pressure sensor, and an oxygen sensor. The ECU determines the current load based on the current speed using a torque model calibrated on a test bench.

[0113] The operating condition detection unit is used to determine whether the engine is cold-started based on the received current water temperature, and transmits the corresponding cold-start determination signal to the electronic control unit. The operating condition detection unit is used to determine the current operating condition of the engine based on the received intake manifold pressure, and transmits the corresponding current operating condition determination signal to the electronic control unit. The electronic control unit then transmits the cold-start determination signal and the current operating condition determination signal to the correction factor acquisition unit, and the determination is made in accordance with the method described in Embodiment 1.

[0114] The correction factor acquisition unit is used to find the corresponding cold start correction factor when the engine is cold-started and transmit it to the power-on time correction unit. The correction factor acquisition unit is used to obtain the corresponding steady-state correction factor based on the current speed and current load when the engine is in steady-state operating condition and transmit the steady-state correction factor to the power-on time correction unit. The correction factor acquisition unit is used to obtain the corresponding transient correction factor based on the air-fuel ratio deviation between the real-time air-fuel ratio and the set air-fuel ratio when the engine is in transient operating condition and transmit the transient correction factor to the power-on time correction unit. The cold start correction factor, steady-state correction factor and transient correction factor can be obtained according to the method described in Embodiment 1.

[0115] The power-on time correction unit uses a cold start correction factor, a steady-state correction factor, or a transient correction factor to correct the current power-on time of the ignition coil, and transmits the corrected power-on time to the electronic control unit (ECU). The ECU then transmits the power-on time (corresponding ignition energy command) to the ignition module, which controls the ignition coil. The cold start correction factor, steady-state correction factor, and transient correction factor can correct the power-on time of the ignition coil according to the correction method described in Example 1.

[0116] The preset unit calibrates the cold start correction factor, steady-state correction factor, or transient correction factor according to the calibration method described in Example 1.

[0117] like Figure 3 As shown, the working principle of the methanol engine performance control system of the present invention is as follows:

[0118] When the engine is started, the electronic control unit identifies parameters such as the engine's current coolant temperature and intake air temperature. If the current coolant temperature T is less than the preset coolant temperature threshold Tx, the engine is determined to be cold-started. At this time, the ignition coil energizing time is corrected using a cold-start correction factor to increase ignition energy and improve combustion stability. When the current coolant temperature T is not less than the preset coolant temperature threshold Tx, the ignition coil energizing time correction is discontinued.

[0119] When the engine is operating under steady-state conditions, the electronic control unit (ECU) searches for the preset air-fuel ratio (MAP) based on the current engine speed and load. Based on the MAP and the current load, it then determines the steady-state correction factor for the ignition coil's energizing time. A higher load results in a higher air-fuel ratio and a larger ignition coil energizing time steady-state correction factor, thus increasing the spark plug discharge energy and optimizing engine combustion. Conversely, a lower load results in a lower air-fuel ratio and a smaller ignition coil energizing time steady-state correction factor, reducing ignition energy while ensuring stable engine operation and extending the lifespan of the ignition coil and spark plugs.

[0120] When the electronic control unit identifies the rate of change of intake manifold pressure and determines that the engine is in a transient condition, such as when the engine is under a sudden load, the air-fuel ratio of the engine will increase due to the lag of methanol injection. Based on the deviation between the real-time air-fuel ratio measured by the oxygen sensor and the set air-fuel ratio, different transient correction factors for the ignition coil energizing time are set to improve the discharge energy of the spark plug, thereby optimizing engine combustion and improving the engine's responsiveness under transient load.

[0121] As can be seen, the methanol engine performance control system of this invention sets different ignition coil charging times according to different air-fuel ratios. This ensures that at high air-fuel ratios, the ignition system outputs higher energy to stabilize engine combustion; at lower air-fuel ratios, it reduces the energy input to the ignition system to extend the service life of the ignition coils and spark plugs. In transient conditions, the real-time air-fuel ratio measured by a wide-range oxygen sensor is used to increase ignition energy and ensure engine load responsiveness. During cold starts, when methanol atomization is poor at low temperatures, increasing ignition energy improves combustion stability, and automatically reduces ignition energy after warm-up.

[0122] In addition, the electronic control unit (ECU) collects engine speed and intake manifold pressure, uses a bench-calibrated torque model to determine the current engine load, and calculates the engine air-fuel ratio by measuring the oxygen concentration in the exhaust gas using an oxygen sensor. Based on the current load and air-fuel ratio, the ignition system's ignition energy output is adjusted to achieve combustion control in the methanol engine.

[0123] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications made within the spirit and principles of the present invention, or improvements to the control method and control system of the same methanol engine performance, should be included within the protection scope of the present invention.

Claims

1. A method for controlling the performance of a methanol engine, characterized in that, Includes the following steps: S10. Determine whether the engine is in a steady-state operating condition; S20. If the engine is in a steady-state condition, obtain the engine's current speed and current load; S30. Obtain the corresponding set air-fuel ratio based on the current speed and current load; S40. Obtain the corresponding steady-state correction factor based on the set air-fuel ratio and the current load; S50. Calculate the power-on time using the formula: Power-on time = Current power-on time * Steady-state correction factor; S60 transmits the power-on time to the ignition module to control the ignition coil.

2. The method for controlling the performance of a methanol engine according to claim 1, characterized in that, S10 further includes: determining whether the engine is in a transient operating condition; S20 further includes: if the engine is in a transient operating condition, acquiring the real-time air-fuel ratio and the corresponding set air-fuel ratio; S30 further includes: calculating the air-fuel ratio deviation between the real-time air-fuel ratio and the set air-fuel ratio; The S40 further includes: obtaining the corresponding transient correction factor based on the air-fuel ratio deviation; S50 further includes: calculating the power-on time using the formula: power-on time = current power-on time * transient correction factor, and then executing S60.

3. The method for controlling the performance of a methanol engine according to claim 2, characterized in that, S10 further includes: After the engine starts, the intake manifold pressure of the engine is obtained; Calculate the intake manifold pressure change rate based on the intake manifold pressure. Determine whether the intake manifold pressure change rate is greater than a preset pressure change rate threshold. If the intake manifold pressure change rate is greater than the pressure change rate threshold, the current operating condition is a transient condition. If the intake manifold pressure change rate is not greater than the pressure change rate threshold, then the current operating condition is a steady-state condition.

4. The method for controlling the performance of a methanol engine according to claim 1, characterized in that, The set air-fuel ratio is obtained from the preset set air-fuel ratio MAP, which is calibrated using engine speed and load.

5. The method for controlling the performance of a methanol engine according to claim 1, characterized in that, The steady-state correction factor is obtained from the preset steady-state correction factor MAP, which is calibrated using the set air-fuel ratio and load.

6. The method for controlling the performance of a methanol engine according to claim 2, characterized in that, The transient correction factor is obtained from the preset transient correction factor MAP, which is calibrated using the air-fuel ratio deviation.

7. The method for controlling the performance of a methanol engine according to claim 2, characterized in that, The real-time air-fuel ratio is calculated by measuring the oxygen concentration in the exhaust gas using an oxygen sensor and a preset air-fuel ratio model.

8. The method for controlling the performance of a methanol engine according to claim 1, characterized in that, It also includes the following steps: When starting the engine, determine whether the engine is a cold start; If the engine is cold-started, find the preset cold-start correction factor; The energizing time of the ignition coil is corrected using a cold start correction factor. If the engine is not cold-started, then discontinue the ignition coil energizing time correction.

9. The method for controlling the performance of a methanol engine according to claim 8, characterized in that, The step of determining whether the engine is a cold start includes: When the engine starts, the real-time coolant temperature of the engine is obtained; Determine if the real-time water temperature is lower than the preset water temperature threshold; If the real-time water temperature is lower than the water temperature threshold, the engine is cold-started; If the real-time water temperature is not lower than the water temperature threshold, then the engine is not cold-started.

10. A control system for the performance of a methanol engine, characterized in that, It includes an electronic control unit and a parameter detection unit, a working condition detection unit, a correction factor acquisition unit, a power-on time correction unit, and an ignition module, all of which are electrically connected to the electronic control unit. The parameter detection unit is used to detect the engine's current coolant temperature, current speed, and intake manifold pressure, and transmit the corresponding parameter signals to the electronic control unit. The electronic control unit then transmits the parameter signals to the operating condition detection unit and the correction factor acquisition unit. The operating condition detection unit is used to determine whether the engine is cold-started based on the received current water temperature, and transmits the corresponding cold-start determination signal to the electronic control unit. The operating condition detection unit is used to determine the current operating condition of the engine based on the received intake manifold pressure, and transmits the corresponding current operating condition determination signal to the electronic control unit. The electronic control unit then transmits the cold-start determination signal and the current operating condition determination signal to the correction factor acquisition unit. The correction factor acquisition unit is used to find the corresponding cold start correction factor when the engine is cold-started and transmit it to the power-on time correction unit. The correction factor acquisition unit is used to obtain the corresponding steady-state correction factor according to the current speed and current load when the engine is in steady-state operating condition and transmit the steady-state correction factor to the power-on time correction unit. The correction factor acquisition unit is used to obtain the corresponding transient correction factor according to the air-fuel ratio deviation between the real-time air-fuel ratio and the set air-fuel ratio when the engine is in transient operating condition and transmit the transient correction factor to the power-on time correction unit. The power-on time correction unit uses a cold start correction factor, a steady-state correction factor, or a transient correction factor to correct the current power-on time of the ignition coil, and transmits the corrected power-on time to the electronic control unit. The electronic control unit then transmits the power-on time to the ignition module, and the ignition module controls the ignition coil.

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