Four-cylinder engine crankshaft torsional vibration control method, computer storage medium and program

Abstract

The invention discloses a four-cylinder engine crankshaft torsional vibration control method, which comprises the following steps: acquiring rotation angle and angular velocity signals of four mass blocks of a four-cylinder engine crankshaft, and calculating control force to control crankshaft torsional vibration through a controller which comprises an upper-layer controller and a lower-layer controller, according to the control method, sliding mode surfaces and control rates of an upper controller and a lower controller are respectively designed, and a total control law of the controllers is obtained through weighted summation of control laws of the upper controller and the lower controller. The invention further discloses a computer storage medium and a program for realizing the control method. The torsional vibration of the crankshaft can be improved, the operation stability of an engine is improved, and buffeting and control instability are avoided.

Description

Technical Field

[0001] This invention relates to a method for controlling engine crankshaft vibration, a computer storage medium and a program, belonging to the field of engine system vibration suppression technology. Background Technology

[0002] As a major moving component of the engine, the crankshaft system experiences tangential and normal forces that vary periodically in magnitude and direction, causing it torsion vibration. Due to its relatively long length, low torsional stiffness, and large moment of inertia, the crankshaft's torsional vibration frequency is low, making it prone to resonance within the engine's operating speed range. This can lead to significant noise, accelerated wear of other components, and even crankshaft breakage.

[0003] As the core moving component of a four-cylinder engine, the crankshaft system exhibits the following characteristics in its torsional vibration:

[0004] 1) Second-order primary and secondary excitation: The cylinder burst pressure generates excitation torque with a frequency of twice the crankshaft speed (energy ratio of about 50%-70%), which is prone to resonance;

[0005] 2) Multi-mass coupling characteristics: The moment of inertia at the flywheel end accounts for more than 80%, and the stiffness of the free end is much lower than that at the flywheel end, resulting in vibration energy being concentrated at the free end;

[0006] 3) Ignition phase difference: The firing order of the four-cylinder engine results in a π / 2 phase difference in the excitation of each cylinder, which aggravates the timing interference of vibration.

[0007] Current methods for controlling crankshaft torsional vibration have the following shortcomings:

[0008] 1) Models that often rely on fixed parameters are difficult to dynamically track the time-varying characteristics of the excitation frequency.

[0009] The four-cylinder engine is dominated by the second-order principal harmonic excitation, and its frequency changes in real time with the crankshaft speed. Therefore, existing crankshaft torsional vibration control methods are difficult to achieve precise control.

[0010] 2) Neglecting timing phase differences

[0011] The firing order of a four-cylinder engine results in a timing phase difference of π(i-1) / 2 (i=1,2,3,4) between the excitations of each cylinder. Since the phase difference is not incorporated into the control logic, the timing interference of the multi-cylinder excitation cannot be canceled, leading to the superposition of torque pulsations. Modeling with "average excitation" will ignore the instantaneous torque impact caused by the phase difference, further amplifying the vibration at the free end.

[0012] 3) Lack of coordination with crankshaft structural characteristics: The inertia and stiffness of the flywheel end and the free end of a four-cylinder engine are significantly different, but the traditional method uses "unified control logic": it does not distinguish between the characteristics of "stable dominant speed" of the flywheel end and "vibration sensitivity" of the free end, and the control energy distribution is unreasonable (such as excessive suppression of the flywheel end speed, resulting in uncontrolled vibration of the free end); it relies on empirical weight allocation and is not physically related to the crankshaft inertia ratio and stiffness ratio, resulting in poor universality on different four-cylinder engine models.

[0013] Therefore, existing crankshaft torsional vibration control methods are not well adapted to the time-varying excitation, nonlinear disturbances, timing phase differences, and structural characteristics of four-cylinder engines. In engineering applications, their vibration suppression efficiency is insufficient, and the free end jitter amplitude is high, which often makes it difficult to meet the requirements of precise and robust torsional vibration control for four-cylinder engines. Summary of the Invention

[0014] To address the aforementioned deficiencies in the prior art, the present invention aims to provide a method for controlling the torsional vibration of a four-cylinder engine crankshaft. This method solves the vibration control challenges unique to four-cylinder engines, such as second-order primary harmonic excitation, large inertia at the flywheel end coupled with low stiffness at the free end, and a 90° ignition phase difference. It improves the torsional vibration of the crankshaft and enhances the smoothness of engine operation. The present invention also provides a computer storage medium and program for implementing this control method.

[0015] The technical solution of this invention is as follows: A method for controlling torsional vibration of a four-cylinder engine crankshaft, comprising:

[0016] The rotation angle and angular velocity signals of the four mass blocks of the crankshaft of a four-cylinder engine are collected. The controller calculates the control force and outputs it to the active torsional damper to control the torsional vibration of the crankshaft. The controller includes an upper controller and a lower controller.

[0017] The upper-level controller is an adaptive sliding mode controller, and the sliding surface of the upper-level controller is:

[0018]

[0019] e1=θ1(t)-θ ref (t), ω n It is the second-order fundamental frequency of the excitation torque of the four-cylinder engine, θ1(t) is the torsional angular displacement of the first mass block of the crankshaft, which is the flywheel, θ ref (t) represents the set reference angular displacement;

[0020] The sliding mode control law of the upper-level controller is:

[0021]

[0022] T1(t) is the periodic excitation torque of the first cylinder, C1 is the damping coefficient of the first crankshaft mass block, K1 is the torsional stiffness of the first crankshaft mass block, θ2(t) is the torsional angular displacement of the second crankshaft mass block, the second crankshaft mass block being the mass block immediately adjacent to the first crankshaft mass block, and J1 is the moment of inertia of the first crankshaft mass block. For online gain estimation, sat() is the saturation function;

[0023] The lower-level controller is an adaptive sliding mode controller, and the sliding surface of the lower-level controller is:

[0024]

[0025] e2(t) = θ1(t) - θ4(t), where θ4(t) is the torsional angular displacement of the fourth mass of the crankshaft, which is the mass farthest from the flywheel. λ2 is an empirically set positive real number, whose value can be adjusted through simulation to balance the system's response speed and stability; here, λ2 = 5. δ is the phase compensation coefficient (dimensionless), whose value is determined based on the ignition phase difference (π / 2) and excitation frequency of the four-cylinder engine, and is calibrated experimentally to achieve optimal interference cancellation; here, δ = 0.1.

[0026] It is the instantaneous phase of the excitation of each cylinder. As a reference phase, This represents the phase difference between each cylinder.

[0027] The sliding mode control law of the lower-level controller is:

[0028]

[0029] J4 is the moment of inertia of the fourth mass block of the crankshaft, and T4(t) is the periodic excitation torque of the fourth cylinder. For online gain estimation;

[0030] The overall control rate of the controller is:

[0031] u(t)=αu1(t)+βu2(t), where α and β are weighting coefficients.

[0032] Furthermore, θ ref (t) = ωt, where ω is the nominal angular velocity of the engine.

[0033] Furthermore, the aforementioned The adaptive rate is The The adaptive rate is ρ1>0, ρ2>0.

[0034] Furthermore, the saturation function sat() is:

[0035]

[0036] Furthermore, R1(r) and R4(r) are determined by the engine-excited torsional vibration model.

[0037] R1(r)=R0sin(4πnr / 60), T4(t)=T0sin(4πnt / 60+3π / 2),

[0038] T0 is the harmonic amplitude, and n is the crankshaft speed.

[0039] Further, K4 is the torsional stiffness of the fourth mass block of the crankshaft.

[0040] Another technical solution of the present invention is: a computer storage medium storing a computer program thereon, wherein when the computer program is executed by a processor, the aforementioned four-cylinder engine crankshaft torsional vibration control method is implemented.

[0041] Another technical solution of the present invention is: a computer program, which, when executed by a processor, implements the aforementioned four-cylinder engine crankshaft torsional vibration control method.

[0042] The advantages of this invention compared to the prior art are:

[0043] This patent addresses the shortcomings of existing four-cylinder engine crankshaft torsional vibration control, such as the inability of fixed parameter models to track time-varying excitation frequencies, neglect of ignition phase differences, failure to distinguish between the structural characteristics of the flywheel end and the free end, severe chattering in traditional sliding mode, and lack of physical correlation in weight allocation. It adopts a hierarchical adaptive sliding mode control method, in which the upper-level controller tracks the flywheel end speed, the lower-level controller suppresses relative vibration of the free end (by designing a phase compensation term to offset π / 2 phase difference interference), and the weighting coefficients are designed based on the inertia ratio and stiffness ratio to achieve reasonable energy allocation. A saturation function is used to replace the sign function to weaken chattering.

[0044] Compared with traditional methods, this invention brings the flywheel end speed control error close to zero, reduces free end vibration energy by more than 60%, and reduces chatter amplitude by 50%, significantly improving crankshaft operation stability and anti-interference ability. Moreover, the parameter design is deeply coordinated with the physical characteristics of the crankshaft, and the convergence of the control system has been confirmed by Lyapunov stability proof, demonstrating engineering adaptability and versatility. Attached Figure Description

[0045] Figure 1 This is a simplified schematic diagram of a four-degree-of-freedom crankshaft torsional vibration system.

[0046] Figure 2 For reference, see the angular displacement diagram.

[0047] Figure 3 This represents the angular displacement of the flywheel end mass block.

[0048] Figure 4 This is a diagram showing the angular velocity of the mass block at the flywheel end.

[0049] Figure 5 This is the angular velocity diagram for the second mass block.

[0050] Figure 6 This is the angular velocity diagram for the third mass block.

[0051] Figure 7 This is a diagram showing the angular velocity of the mass block at the free end of the crankshaft.

[0052] Figure 8 This is the control force diagram for an adaptive sliding mode controller.

[0053] Figure 9 This is the control force diagram for a traditional sliding mode controller. Detailed Implementation

[0054] The present invention will be further described below with reference to embodiments, but these are not intended to limit the scope of the invention.

[0055] This embodiment describes a method for controlling the torsional vibration of a four-cylinder engine crankshaft. It employs a hierarchical control strategy to design a controller with an upper-level controller and a lower-level controller. The controller collects the rotation angle and angular velocity signals of the four mass blocks of the crankshaft in real time, and calculates the control force based on this, which is then output through an active torsional damper to control the torsional vibration of the crankshaft.

[0056] The upper-level controller and the lower-level controller are established using the following methods.

[0057] 1. Establish a mathematical model for engine-excited torsional vibration:

[0058] The excitation torque of an engine cylinder originates from the periodic force exerted by the combustion pressure within the cylinder on the crankshaft and connecting rod mechanism, which can be simplified using engineering methods. Based on the engine's basic parameters, the amplitude of the primary harmonic order of this four-cylinder engine is determined using a lookup table method. Assuming its power stroke order is 1-3-4-2, the phase difference of the excitation torque between each cylinder is π / 2, and the primary harmonic order is 2nd (frequency...). The excitation torque can be approximated as:

[0059]

[0060] Where T0 is the harmonic amplitude, obtained from the engine characteristic curve. R i (t) represents the excitation torsional vibration force generated by the i-th (i = 1, 2, 3, 4) cylinder. Let n be the phase of the i-th mass block, and n be the crankshaft speed (r / min).

[0061] Phase is defined as:

[0062] Cylinder 1 (i=1): (Initial phase);

[0063] 3 cylinders (i=2): (Phase delay of 90°);

[0064] 4 cylinders (i=3): (Phase delay 180°);

[0065] 2 cylinders (i=4): (Phase delay 270°).

[0066] This model directly reflects the timing excitation disturbance of the four-cylinder engine, providing input for the phase compensation term in the control law of the subsequent lower-level controller, so that the control force and the disturbance are superimposed in opposite phase to cancel the timing disturbance.

[0067] 2. Establish a torsional vibration model of a four-cylinder engine crankshaft.

[0068] Figure 1 This is a simplified system for four-degree-of-freedom crankshaft torsional vibration. The crankshaft system of a four-cylinder engine can be simplified as a chain system consisting of four mass blocks connected by elastic shaft sections and dampers. The torsional vibration of the crankshaft is caused by the periodic burst pressure excitation of the cylinders, which may lead to resonance and needs to be suppressed through control methods. Therefore, the following set of dynamic equations can be established:

[0069]

[0070] The four equations above represent the torsional vibration dynamics equations for each mass block. Where θ i Let θ1 represent the torsional angular displacement of the i-th (i = 1, 2, 3, 4) mass block, and θ4 represent the crankshaft front end (free end). u(t) is the control input (actuator power). J i C i K i Let T represent the moment of inertia, damping coefficient, and torsional stiffness of the i-th mass block, respectively. These parameters can be obtained from actual engine measurements. Clearly, the flywheel end has the largest moment of inertia, damping coefficient, and stiffness. i (t) represents the periodic excitation torque of the i-th cylinder, the magnitude of which is determined by the mathematical model of engine excitation torsional vibration. d1(t) and d4(t) represent the nonlinear disturbances (such as nonlinear friction of the shaft system, torque fluctuations, etc.) experienced by the flywheel end mass block and the free end mass block, respectively. The upper limit of the amplitude can be calibrated through bench testing, and its upper limit value can be determined, i.e.: It can be calibrated by bench testing.

[0071] 3. Establish the state-space expression for crankshaft torsional vibration.

[0072] Based on the above set of dynamic equations, a state-space expression for the crankshaft's torsional vibration can be established. The state variables are then considered. We can obtain:

[0073]

[0074] Where A is the system matrix, B is the input matrix, and C is the external disturbance matrix.

[0075]

[0076] 4. Design of upper-level and lower-level controllers

[0077] The control objective for crankshaft torsional vibration can be decomposed into upper-level control and lower-level control. The upper-level control tracks the target crankshaft speed, while the lower-level control suppresses the relative vibration between the mass blocks.

[0078] 1) Upper-level controller design

[0079] The ideal rotational state of a crankshaft is uniform rotation, with angular displacement increasing linearly. Therefore, a reference angular displacement θ is set. ref (t) = ωt, where ω is the engine's nominal angular velocity, one of the engine's fundamental parameters, and the tracking error is defined as follows:

[0080] e1(t)=θ1(t)-θ ref (t)=θ1(t)-ωt,

[0081] The controller's control objective is e1(t)→0. Here, only the angular displacement error of the first mass is selected because it is the flywheel end, and its rotational inertia, torsional stiffness, and damping are much greater than the other three mass blocks. This achieves good control results while simplifying the control system and reducing costs.

[0082] Crankshaft torsional vibration has several typical characteristics: firstly, strong nonlinearity, with the cylinder detonation excitation torque changing abruptly with rotational speed; secondly, strong coupling, with the phase difference among the four cylinders leading to complex transmission of vibration energy; and thirdly, time-varying parameters, with rotational speed changes causing excitation frequency drift. These are precisely the scenarios that sliding mode control excels at solving. Therefore, both the upper and lower level controllers of this invention are adaptive sliding mode controllers.

[0083] Considering that torsional vibration in a four-cylinder engine is essentially a second-order dynamics problem, the crankshaft system can be modeled as a mass-spring-damped system. For example... As shown in the formula, The directly related inertial torque is the core characteristic of vibration energy. C1 is the damping coefficient of the first crankshaft mass, K1 is the torsional stiffness of the first crankshaft mass, θ2(t) is the torsional angular displacement of the second crankshaft mass, which is the mass immediately adjacent to the first crankshaft mass, and J1 is the moment of inertia of the first crankshaft mass. Simultaneously, the excitation torque T of the four-cylinder engine... i The second-order dominant frequency ω of (t) n These items need to be specifically offset.

[0084] Therefore, the sliding surface of the upper controller is designed as follows:

[0085]

[0086] As can be seen from the sliding surface, including Item, at the same time ω n By directly using it as a parameter and embedding it into the sliding surface, the excitation frequency is combined with the sliding control to achieve active cancellation of the resonant frequency.

[0087] The sliding mode control law of the upper-level controller is composed of the equivalent control u eq and switching robust control u sw constitute.

[0088] (1) Calculate the equivalent control u eq

[0089] make Find the equivalent term of the sliding mode control law. At this point, the disturbance term d1 (controlled by the switching term) is not considered:

[0090]

[0091] From the dynamic equation of the first mass block, we can obtain:

[0092]

[0093] Substitution We can obtain:

[0094]

[0095] Due to θ ref (t) = ωt, therefore

[0096] We can obtain:

[0097]

[0098] (2) Calculate the switching control u sw

[0099] The approach rate of conventional sliding mode control requires a preset approach rate coefficient. This leads to severe chattering, so adaptive switching control is chosen. At the same time, a saturation function is selected instead of a sign function.

[0100]

[0101] in, For online gain estimation, and with an adaptive rate of ρ1>0 represents the adaptive gain rate.

[0102] Let the estimation error of γ1 be... γ1 is the upper bound of the ideal gain, and it is assumed that γ1 changes slowly, then Constructing Lyapunov functions:

[0103]

[0104] In the formula, ρ1>0 is the adaptive gain coefficient.

[0105] Differentiating with respect to V1, we get:

[0106]

[0107] From the above formula, we can obtain:

[0108] when hour, The system gradually stabilizes.

[0109] Therefore, the overall sliding mode control law of the upper-level controller is:

[0110]

[0111] 2) Lower-level controller design

[0112] The lower-level control suppresses the relative vibration between the mass blocks. Similar to the upper-level controller, it only selects the angular displacement (maximum relative angular displacement) of the first mass block relative to the fourth mass block (free end). By using the phase difference (270°) between T1(t) and T4(t), it actively cancels the vibration energy transfer between the flywheel end and the free end, solving the vibration sensitivity problem caused by the low stiffness of the free end.

[0113] Therefore, the tracking error is defined as: e2(t) = θ1(t) - θ4(t), and the control objective of the controller is e2(t) → 0.

[0114] Design the sliding surface of the lower-level controller:

[0115]

[0116] Where θ4(t) is the torsional angular displacement of the fourth mass block of the crankshaft, which is the mass block farthest from the flywheel; λ2 is an empirically set positive real number, whose value can be adjusted through simulation to balance the system response speed and stability, here λ2=5; δ is the phase compensation coefficient, whose value is determined based on the ignition phase difference (π / 2) and excitation frequency of the four-cylinder engine, and is calibrated experimentally to achieve optimal interference cancellation, here δ=0.1. In the function, As a reference phase, The meaning is the same as before; it represents the phase difference between each cylinder. It is the instantaneous phase of the excitation of each cylinder.

[0117] The sliding mode control law of the lower-level controller is composed of the equivalent control u eq2 and switching robust control u sw2 constitute.

[0118] (1) Calculate the equivalent control u eq2

[0119] make Find the equivalent term of the sliding mode control law. Then:

[0120]

[0121] Ignoring the interference terms (handled by the switching terms), we can obtain the following from the aforementioned crankshaft dynamics equation (2):

[0122]

[0123] exist The expression contains a coupling term between the third mass block and the free end. In the crankshaft torsional vibration model of a four-cylinder engine, the free end (the fourth mass block) has the lowest stiffness, and its vibration response is typically significantly greater than that of the other mass blocks. This leads to the vibration of the adjacent mass block (the third mass block) being dominated by the free end, with the coupling term having a very small influence. Finite element simulations verify that the coupling energy of the middle block accounts for 3.2% to 4.8% of the total vibration energy. At this point, the coupling effect between the third mass block and the free end can be approximately ignored relative to the inertial force and excitation force of the free end itself. Therefore, It can be approximated as

[0124] Substitution We can obtain:

[0125]

[0126] but:

[0127]

[0128] (2) Calculate the switching control u sw2

[0129] Similarly, to prevent severe chattering, an adaptive switching control method with a combined saturation function is chosen.

[0130]

[0131] in, Similarly, it involves online gain estimation, and the adaptive rate is... ρ2>0 represents the adaptive gain rate.

[0132] Let the estimation error of γ2 be... γ2 is the upper bound of the ideal gain, and it is assumed that γ2 changes slowly, i.e. Reconstruct the Lyapunov function:

[0133]

[0134] In the formula, ρ1>0 is the adaptive gain coefficient.

[0135] Taking the derivative with respect to V2, we get:

[0136]

[0137] Substitution as well as Substituting this into the dynamic equation, we get:

[0138]

[0139] From the above formula, we can see that:

[0140] when hour, The system gradually stabilizes.

[0141] in,

[0142] Therefore, the overall sliding mode control law of the lower-level controller is:

[0143] J4 is the moment of inertia of the fourth mass block of the crankshaft, and T4(t) is the periodic excitation torque of the fourth cylinder.

[0144] 3) Design of the overall control law

[0145] In a hierarchical control strategy, the total control law of the controller is the weighted sum of the upper-level control law u1(t) and the lower-level control law u2(t). That is:

[0146] u(t)=αu1(t)+βu2(t),

[0147] In the formula, α and β are weighting coefficients.

[0148] α represents the upper-level control weight, corresponding to the flywheel end; β represents the lower-level control weight, corresponding to the free end. Since the rotational inertia (J1) of the flywheel end (mass block 1) is dominant, it needs to be assigned a higher weight to stabilize the global rotational speed. The free end (mass block 4) has the least stiffness and requires a higher weight to suppress its large-amplitude vibration.

[0149] (1) Design of α: Based on inertia energy distribution

[0150] Rotational kinetic energy at the flywheel end: E1=J1ω 2 / 2,

[0151] Rotational kinetic energy of the free end: E4 = J4ω 2 / 2,

[0152] Therefore, design

[0153] (2) β design: based on flexibility (inverse of stiffness) allocation

[0154] Flywheel end flexibility:

[0155] Free end flexibility:

[0156] Therefore, design

[0157] That is, the overall control law K4 is the torsional stiffness of the fourth mass block of the crankshaft.

[0158] This embodiment establishes a system state-space expression based on the engine excitation torsional vibration model and the four-cylinder engine crankshaft torsional vibration model, and uses a hierarchical control strategy to establish separate controllers for control. The simulation results of the controllers are as follows: Figure 2-9 As shown. From Figure 2 , Figure 3 It can be seen that the angular displacement of the flywheel end mass block is consistent with the reference angular displacement. Figures 4 to 7 It can be seen that the angular velocity of the four masses remains stable at 200 rad / s. Figure 8 , Figure 9 As can be seen, the chattering phenomenon is significantly improved when using an adaptive sliding mode controller compared to a traditional sliding mode controller. Therefore, this controller achieves the desired control effect.

[0159] Finally, it should be noted that the specific methods of the above embodiments can form a computer program product. Therefore, the computer program product implemented in this application can be stored on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.).

Claims

1. A method for controlling torsional vibration of a four-cylinder engine crankshaft, characterized in that, include: The rotation angle and angular velocity signals of the four mass blocks of the crankshaft of a four-cylinder engine are collected. The controller calculates the control force and outputs it to the active torsional damper to control the torsional vibration of the crankshaft. The controller includes an upper controller and a lower controller. The upper-level controller is an adaptive sliding mode controller, and the sliding surface of the upper-level controller is: e1=θ1(t)-θ ref (t), ω n It is the second-order fundamental frequency of the excitation torque of the four-cylinder engine, θ1(t) is the torsional angular displacement of the first mass block of the crankshaft, which is the flywheel, θ ref (t) represents the set reference angular displacement; The sliding mode control law of the upper-level controller is: T1(r) is the periodic excitation torque of the first cylinder, C1 is the damping coefficient of the first crankshaft mass block, K1 is the torsional stiffness of the first crankshaft mass block, θ2(t) is the torsional angular displacement of the second crankshaft mass block, the second crankshaft mass block being the mass block immediately adjacent to the first crankshaft mass block, and J1 is the moment of inertia of the first crankshaft mass block. For online gain estimation, sat() is the saturation function; The lower-level controller is an adaptive sliding mode controller, and the sliding surface of the lower-level controller is: e2 = θ1(t) - θ4(t), where θ4(t) is the torsional angular displacement of the fourth mass of the crankshaft, which is the mass farthest from the flywheel, λ2 is an empirically set positive real number, and δ is the phase compensation coefficient. It is the instantaneous phase of the excitation of each cylinder. The sliding mode control law of the lower-level controller is: J4 is the moment of inertia of the fourth mass block of the crankshaft, and T4(t) is the periodic excitation torque of the fourth cylinder. For online gain estimation; The overall control rate of the controller is: u(t)=αu1(t)+βu2(t), α and β are weighting coefficients.

2. The method for controlling crankshaft torsional vibration of a four-cylinder engine according to claim 1, characterized in that, θ ref (t) = ωt, where ω is the nominal angular velocity of the engine.

3. The method for controlling crankshaft torsional vibration of a four-cylinder engine according to claim 1, characterized in that, The The adaptive rate is The The adaptive rate is ρ1>0, ρ2>0.

4. The method for controlling crankshaft torsional vibration of a four-cylinder engine according to claim 1, characterized in that, The saturation function sat() is:

5. The method for controlling crankshaft torsional vibration of a four-cylinder engine according to claim 1, characterized in that, T1(t) and T4(t) are determined by the engine-excited torsional vibration model. T1(t)=T0sin(4πnt / 60), T4(t)=T0sin(4πnt / 60+3π / 2), T0 is the harmonic amplitude, and n is the crankshaft speed.

6. The method for controlling crankshaft torsional vibration of a four-cylinder engine according to claim 1, characterized in that, K4 is the torsional stiffness of the fourth mass block of the crankshaft.

7. A computer storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the four-cylinder engine crankshaft torsional vibration control method according to any one of claims 1 to 6.

8. A computer program, characterized in that, When the computer program is executed by the processor, it implements the four-cylinder engine crankshaft torsional vibration control method according to any one of claims 1 to 6.

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