Dynamic working condition self-adaptive control method and fuel injection method of small-displacement diesel engine

Abstract

The invention discloses a self-adaptive control method for dynamic working conditions of a small-displacement diesel engine. The self-adaptive control method comprises the following steps: S1, predicting an operation mode through multi-source signal fusion; and S2, based on the prediction result, executing a pre-pressurization mode or a pressure relief buffer mode. Aiming at the special working condition requirement that a small-displacement diesel engine (4.0 L-5. 0L) is matched with a 30-type (3-ton) lightweight loader, the invention particularly focuses on solving the problems of transient response delay and fuel economy deterioration caused by frequent start and stop and sudden load change of a traditional diesel engine in a V-shaped operation cycle.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering machinery power systems, and in particular to the special working conditions of a small-displacement diesel engine (4.0L-5.0L) supporting a Type 30 (3-ton) lightweight loader. The present invention specifically focuses on solving the problems of transient response hysteresis and fuel economy degradation caused by frequent start-stop and load mutations in a traditional diesel engine in a "V-type operating cycle". Background Art

[0002] Traditional turbochargers rely on the engine's power to drive the turbine to rotate, and the worm gear is coaxially connected to the compressor, so the rotation of the turbine will drive the compressor to rotate, thereby increasing the density of the intake gas and achieving the effect of supercharging. However, the above structure has a "turbo lag" phenomenon, that is, the increase in supercharging pressure will lag behind the moment when the engine's operating conditions change.

[0003] Existing patent document CN116480458A discloses a hybrid power system, control method and vehicle, which uses an improved supercharger to divide the traditional coaxially connected turbocharger into two subsystems, a turbine and a compressor, and controls them separately. The turbine end is connected to the generator, and the exhaust gas generated by the engine combustion drives the turbine to rotate to generate electricity, and the generated electricity is stored in the battery. The compressor end is connected to the motor, which draws power from the battery and controls the speed regulating motor through the inverter.

[0004] Existing patent document CN115711173A discloses a vehicle boost control method, electronic device and readable storage medium, which sets the first valve opening value corresponding to multiple vehicle driving conditions on the first preset valve opening table to a smaller value and / or fully closed, so that when the exhaust gas bypass valve is in a first pressure area and in a first acceleration state, the exhaust gas bypass valve adjusts the valve opening according to the first preset valve opening table and in combination with the vehicle driving conditions, so that the exhaust gas bypass valve can have a smaller opening or remain in a fully closed state in the first pressure area (for example, a non-boost area), thereby reserving a certain amount of exhaust gas energy for the boost equipment in advance, so that the turbine speed is maintained at a relatively high level, thereby further accelerating the dynamic response speed of the boost.

[0005] At present, the problems of small-displacement diesel engine loaders include:

[0006] 1. When a small-displacement diesel engine is matched with a lightweight loader, the turbocharger has significant inertia hysteresis (0-100% boost pressure response time > 2.5 seconds), resulting in insufficient torque when the bucket cuts into the material;

[0007] 2. Traditional mechanical boost control cannot adapt to the dynamic requirements of short-cycle (10-15 seconds) operation cycles;

[0008] 3. Small-displacement diesel engines are prone to the contradiction of "excessive fuel injection and incomplete combustion" under sudden load, resulting in a surge in black smoke emissions and fuel consumption;

[0009] 4. The traditional injection MAP diagram cannot adapt to the drastic fluctuations of load during the loader operation cycle (such as the sudden change time from no load to full load is less than 0.3 seconds);

[0010] 5. The lightweight design leads to an imbalance in the inertia ratio of the diesel engine-transmission system, causing resonance (amplitude > 0.15mm) in the low speed range (800-1200rpm);

[0011] 6. The traditional suspension system cannot take into account both vibration reduction and power transmission efficiency.

[0012] The disclosure of the above background technology content is only used to assist in understanding the concept and technical solution of the present invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of the present application. Summary of the invention

[0013] The (main) purpose of the present invention is to propose a dynamic condition adaptive control method for a small-displacement diesel loader that reduces the influence of turbo hysteresis and improves power responsiveness, as well as a fuel injection method that avoids black smoke emissions and a surge in fuel consumption under sudden load.

[0014] To this end, the present invention proposes a dynamic operating condition adaptive control method and a fuel injection method for a small-displacement diesel engine loader.

[0015] Preferably, the present invention may also have the following technical features:

[0016] The dynamic operating condition adaptive control method of a small-displacement diesel engine comprises the following steps:

[0017] S1, predicting the operation mode through multi-source signal fusion;

[0018] S2. Based on the prediction result, execution includes performing a pre-boost mode or a pressure relief buffer mode.

[0019] Furthermore, the multi-source signals include the boom hydraulic pressure gradient, the pilot valve opening change rate and the GNSS positioning trajectory. An operation mode classification model is constructed based on the boom hydraulic pressure gradient, the pilot valve opening change rate and the GNSS positioning trajectory, and the switching of the "loading-operating-unloading" operation mode is predicted through the operation mode classification model.

[0020] Furthermore, based on the boom hydraulic pressure gradient and pilot valve opening change rate data, LSTM is used for learning and analysis to identify the correlation between the boom hydraulic pressure gradient, the pilot valve opening change rate and each operating mode; the spatial position of the loader is determined by the random forest algorithm to enhance the credibility of the predicted operating mode.

[0021] Furthermore, the pre-boost mode includes: before the shovel loading stage is triggered, the boost pressure is increased to a first preset pressure through an electronically controlled wastegate valve, and the first preset pressure is 50-80% of the target value.

[0022] Furthermore, the pre-boost mode is started 0.1-0.6s before the shovel loading phase is triggered.

[0023] Furthermore, before the shovel loading phase is triggered, the boost pressure is increased to 60-70% of the target value through the electronically controlled wastegate valve.

[0024] Furthermore, the pressure relief buffer mode includes: opening a pulse pressure relief valve during the unloading stage to slowly reduce the boost pressure.

[0025] Furthermore, a load-sensitive segmented fuel injection method applied to a sudden load includes the following steps:

[0026] S101, dynamically classifying the load level according to the crankshaft speed fluctuation rate (Δn / Δt) and the cylinder pressure rising slope (dP / dθ);

[0027] S102, based on the real-time mapping between the load level and the injection parameters, correct the injection oil quantity in real time.

[0028] Furthermore, the load level includes 3 levels:

[0029] Level 1, at this time, the crankshaft speed fluctuation rate Δn / Δt is less than 50rpm / ms, and steady-state economic injection is performed;

[0030] Level, crankshaft speed fluctuation rate: 50≤Δn / Δt<120, perform transition compensation injection, including main injection advance angle +1.5°CA, post-injection amount 3mg / cyc;

[0031] Level 3, crankshaft speed fluctuation rate Δn / Δt ≥ 120, transient enhanced injection is performed, including main injection + pre-injection double pulse, and the injection pressure is increased to 220MPa.

[0032] Furthermore, based on the Kalman filter, the load level of the next cycle is predicted, and the rail pressure and injection pulse width are adjusted in advance to achieve the goal of regulating the injection oil amount.

[0033] Compared with the prior art, the beneficial effects of the present invention include: determining the range of the first preset pressure through bench testing, so that the pre-boost can be in a reasonable range between the turbine inertia hysteresis and the pressure reserve, which can reduce hysteresis and avoid the risk of increased energy consumption or surge caused by premature boost. Through dynamic load classification and real-time mapping of injection parameters, millisecond-level fuel strategy switching is achieved, solving the problem of transient combustion stability of small-displacement diesel engines, and avoiding problems such as black smoke emissions and fuel consumption surges under sudden load. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a flow chart of the present invention.

[0035] Figure 2 It is a flow chart of the segmented fuel injection method of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail below in conjunction with specific implementations and with reference to the accompanying drawings. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope of the present invention and its application.

[0037] Non-limiting and non-exclusive embodiments will be described with reference to the following figures, wherein like reference numerals refer to like parts unless otherwise specifically stated.

[0038] like Figure 1 The small displacement diesel engine dynamic condition adaptive control method shown includes the following steps:

[0039] S1, predicting the operation mode through multi-source signal fusion;

[0040] The multi-source signals include the boom hydraulic pressure gradient, the pilot valve opening change rate and the GNSS positioning trajectory. An operation mode classification model is constructed based on the boom hydraulic pressure gradient, the pilot valve opening change rate and the GNSS positioning trajectory. The switching of the "loading-operating-unloading" operation mode is predicted through the operation mode classification model.

[0041] The operation mode includes the shoveling stage, the operation stage and the unloading stage. The operation mode classification model is constructed by the long short-term memory network (LSTM) and the random forest algorithm to achieve the complementarity of time-space features. Based on the boom hydraulic pressure gradient and the pilot valve opening rate change data, LSTM is used for learning and analysis to identify the correlation between the boom hydraulic pressure gradient, the pilot valve opening rate change and each operation mode. The spatial position of the loader is determined by the random forest algorithm to further enhance the credibility of the predicted operation mode.

[0042] The boom hydraulic pressure gradient range is 0-45MPa / ms, preferably 0-35MPa / ms.

[0043] S2. Based on the prediction results, the turbocharger dynamic coupling control strategy is executed to perform a pre-boost mode or a pressure relief buffer mode.

[0044] The pre-boost mode includes: before the shoveling stage is triggered, the boost pressure is increased to a first preset pressure through an electronically controlled exhaust bypass valve (EWG), thereby reducing the torque response delay. The first preset pressure is 50-80% of the target value, preferably 60-70%. The pressure value of the first preset pressure is variable and can be set according to the torque response requirement. The target value is the target pressure required for the shoveling stage. Preferably, the pre-boost mode is started 0.1-0.6s before the shoveling stage is triggered, for example, the pre-boost mode is started 0.2s before the shoveling stage is triggered, or the pre-boost mode is started 0.3s before the shoveling stage is triggered, or the pre-boost mode is started 0.5s before the shoveling stage is triggered. The range of the first preset pressure is determined by bench testing, so that the pre-boost can be in a reasonable range between the turbine inertia hysteresis and the pressure reserve, which can not only reduce hysteresis, but also avoid the risk of increased energy consumption or surge caused by premature boost.

[0045] In one example, when using the above-mentioned prediction operation scheme for a 30-type loader, the pre-boost mode is started 0.3s before the shoveling stage is triggered, and the boost pressure is increased to 70% of the target value through the electronically controlled exhaust gas bypass valve (EWG). When the shoveling condition is executed, the torque response time from 0-90% of the shoveling condition is shortened from 1.8s to 0.9s. The torque response efficiency is significantly improved, and the peak value of the turbine blade temperature fluctuation can be greatly reduced by pre-boosting. The peak value of the turbine blade temperature fluctuation from 0-90% (for example, since the pressure has been increased to 70% before the shoveling condition, when entering the shoveling condition, it is actually only increased from 70 to 90%) of the pre-boost scheme is 40% lower than the peak value of the turbine blade temperature fluctuation of the original scheme (no boost, the supercharger is from 0-90% torque in the shoveling condition), thereby reducing the working intensity of the supercharger turbine blade, reducing the maintenance cost of the turbine blade, and increasing the service life.

[0046] The pressure relief buffer mode includes: opening a pulse pressure relief valve during the unloading stage to slowly reduce the boost pressure and avoid turbine surge. Preferably, the boost pressure is slowly reduced at a slope of ≤0.05 MPa / ms.

[0047] LSTM is used to analyze the real-time dynamic working conditions of the loader, and then the random forest algorithm is used to process the GNSS positioning trajectory signal to predict the loader's operating intention when switching to the "loading-transferring-unloading" stage working condition. Then, the turbocharger dynamic coupling control strategy is executed according to the predicted operating intention.

[0048] Combination Figure 2 , a load-sensitive segmented fuel injection method applied to a sudden load, comprising the following steps:

[0049] S101, dynamically classify the load level by the crankshaft speed fluctuation rate (Δn / Δt) and the cylinder pressure rising slope (dP / dθ): Preferably, the load level includes 3 levels,

[0050] Level 1 (Δn / Δt<50rpm / ms): Steady-state economic injection (λ=1.8-2.0);

[0051] Level 2 (50≤Δn / Δt<120): Transition compensation injection (main injection advance angle +1.5°CA, post-injection fuel amount 3mg / cyc);

[0052] Level 3 (Δn / Δt≥120): Transient enhanced injection (main injection + pre-injection double pulse, injection pressure increased to 220MPa).

[0053] S102, real-time correction of injection fuel quantity based on load level. Through dynamic load classification and real-time mapping of injection parameters, millisecond-level fuel strategy switching is achieved to solve the problem of transient combustion stability of small-displacement diesel engines and avoid problems such as black smoke emissions and fuel consumption surges under sudden load.

[0054] For example, based on the Kalman filter, the load level of the next cycle is predicted, and the rail pressure and injection pulse width are adjusted in advance to achieve the goal of regulating the injection oil amount.

[0055]

[0056] Among them, Kp=0.12, Kd=0.08, based on bench calibration data.

[0057] In some example applications, the fuel consumption of a typical working cycle (loading-transferring-unloading) of a 30-type loader is reduced by 9.2%, black smoke emissions are reduced by 65%, and the life of key fuel system components such as injectors and high-pressure pumps is extended by 30%. The use of a dynamic oil quantity correction strategy not only saves energy and reduces emissions, but also reduces costs.

[0058] In a more preferred embodiment, the resonance is balanced by connecting a variable inertia flywheel, including integrating a variable inertia flywheel (mass 3.5-5kg) at the output end of the diesel engine, and dynamically adjusting the effective inertia through an electromagnetic clutch:

[0059] At low speed (800-1200rpm) and heavy load, the flywheel (+15% inertia) is connected to suppress torque fluctuations;

[0060] Disengage the flywheel at high speed (>1200rpm) and light load to reduce rotation resistance.

[0061] The use of an inertia-compensated flywheel can effectively reduce resonance when a sudden load is applied.

[0062] Examples and comparative data:

[0063] In the verification of the 5L diesel engine matching the 30-type loader:

[0064] index Traditional Solution The present invention Optimization range Shovel loading cycle time (s) 9.8 8.3 ↓15.3％ Comprehensive fuel consumption (L / h) 14.6 13.2 ↓9.6％ Turbo response delay(s) 1.2 0.55 ↓54.2％ Cab noise (db(A)) 82 76 ↓7.3％

[0065] It can be seen that the application of the method of the present invention has a significant improvement over the traditional solution, and has significant effects on reducing costs and protecting the environment.

[0066] Those skilled in the art will appreciate that numerous variations to the above description are possible, and that the examples and figures are intended only to describe one or more specific implementations.

[0067] Although what is considered as exemplary embodiments of the present invention has been described and described, it will be understood by those skilled in the art that various changes and substitutions may be made thereto without departing from the spirit of the present invention. In addition, many modifications may be made to adapt specific situations to the teachings of the present invention without departing from the central concept of the present invention described herein. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but the present invention may also include all embodiments and their equivalents that fall within the scope of the present invention.

Claims

1. A dynamic operating condition adaptive control method for a small-displacement diesel engine, characterized in that: The steps include: S1, predicting the operation mode through multi-source signal fusion; S2. Based on the prediction result, execution includes performing a pre-boost mode or a pressure relief buffer mode.

2. The small displacement diesel engine dynamic condition adaptive control method according to claim 1, characterized in that: The multi-source signals include the boom hydraulic pressure gradient, the pilot valve opening change rate and the GNSS positioning trajectory. An operation mode classification model is constructed based on the boom hydraulic pressure gradient, the pilot valve opening change rate and the GNSS positioning trajectory. The switching of the "loading-operating-unloading" operation mode is predicted through the operation mode classification model.

3. The small displacement diesel engine dynamic condition adaptive control method according to claim 2, characterized in that: Based on the boom hydraulic pressure gradient and pilot valve opening change rate data, LSTM is used for learning and analysis to identify the correlation between the boom hydraulic pressure gradient, the pilot valve opening change rate and each operating mode. The spatial position of the loader is determined by the random forest algorithm to enhance the credibility of the predicted operating mode.

4. The small displacement diesel engine dynamic condition adaptive control method as claimed in claim 2, characterized in that: The pre-boost mode includes: before the shovel loading stage is triggered, the boost pressure is increased to a first preset pressure through an electronically controlled wastegate valve, and the first preset pressure is 50-80% of the target value.

5. The small displacement diesel engine dynamic condition adaptive control method according to claim 4, characterized in that: The pre-boost mode is started 0.1-0.6s before the shovel loading phase is triggered.

6. The small displacement diesel engine dynamic condition adaptive control method according to claim 4, characterized in that: Before the shovel loading phase is triggered, the boost pressure is increased to 60-70% of the target value via an electronically controlled wastegate valve.

7. The small displacement diesel engine dynamic condition adaptive control method according to claim 2, characterized in that: The pressure relief buffer mode includes: opening a pulse pressure relief valve during the unloading stage to slowly reduce the boost pressure.

8. The small displacement diesel engine dynamic condition adaptive control method according to claim 2, characterized in that: A load-sensitive segmented fuel injection method applied to a sudden load includes the following steps: S101, dynamically dividing the load level according to the crankshaft speed fluctuation rate Δn / Δt and the cylinder pressure rising slope dP / dθ; S102, based on the real-time mapping between the load level and the injection parameters, correct the injection oil quantity in real time.

9. The small displacement diesel engine dynamic condition adaptive control method according to claim 8, characterized in that: The load level includes 3 levels, Level 1, at this time, the crankshaft speed fluctuation rate Δn / Δt is less than 50rpm / ms, and steady-state economic injection is performed; Level, crankshaft speed fluctuation rate: 50≤Δn / Δt<120, perform transition compensation injection, including main injection advance angle +1.5°CA, post-injection amount 3mg / cyc; Level 3, crankshaft speed fluctuation rate Δn / Δt ≥ 120, transient enhanced injection is performed, including main injection + pre-injection double pulse, and the injection pressure is increased to 220MPa.

10. The small displacement diesel engine dynamic condition adaptive control method according to claim 9, characterized in that: Based on the Kalman filter, the load level of the next cycle is predicted, and the rail pressure and injection pulse width are adjusted in advance to achieve the goal of regulating the injection oil amount.

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