Hybrid control method for natural gas engine

Abstract

The invention provides a natural gas engine hybrid control method, which relates to the technical field of natural gas engines, and comprises the following steps: when a vehicle is in a strong transient working condition, distributing a required torque to a motor and a natural gas engine according to a preset logic; and when the vehicle is in a heavy-load working condition and the natural gas engine is knocked, controlling the natural gas engine to reduce the preset torque, and controlling the motor to increase the preset torque. And the knocking conditions of large loads and strong transient working conditions are reduced, and the reliability of the engine is improved. The motor participates in torque distribution, so that the engine can be prevented from running in an area where knocking easily occurs. Knocking can be prevented, and then gas consumption can be reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas engines, and in particular to a hybrid control method for a natural gas engine. Background Art

[0002] Since the gas engine uses a throttle to control the amount of gas, the throttle opening is small under low load conditions, and there is negative pressure in the manifold, which will increase the oil consumption. Under high load or strong transient conditions, knock is prone to occur. The current method of suppressing knock in gas engines is to reduce the advance angle, which will increase gas consumption. In addition, when the gas quality changes, it will also affect the knock situation of the engine operation. Summary of the invention

[0003] The present application provides a natural gas engine hybrid control method to at least solve the problems existing in the related art.

[0004] According to one aspect of an embodiment of the present application, a natural gas engine hybrid control method is provided, including: when the vehicle is in a strong transient condition, the required torque is distributed to the motor and the natural gas engine according to a preset logic; when the vehicle is in a high load condition and the natural gas engine detonates, the natural gas engine is controlled to reduce the preset torque, and the motor is controlled to increase the preset torque.

[0005] As an optional implementation, it also includes: obtaining the vehicle's real-time throttle opening, real-time throttle change rate, real-time vehicle speed, manifold pressure demand value and actual manifold pressure; if the vehicle's real-time throttle opening is greater than a preset throttle opening value, the real-time throttle change rate is greater than a preset throttle change rate value, the real-time vehicle speed is less than a preset hysteresis speed value, and the difference between the manifold pressure demand value and the actual manifold pressure is greater than a preset pressure difference, then the vehicle is in a strong transient operating condition.

[0006] As an optional implementation, when the vehicle is in a strong transient operating condition, allocating the required torque to the motor and the natural gas engine according to a preset logic includes: determining a transient torque distribution coefficient based on a transient characterization coefficient; and allocating the required torque to the motor and the natural gas engine according to a preset logic based on the transient torque distribution coefficient.

[0007] As an optional implementation, determining the transient torque distribution coefficient according to the transient characterization coefficient includes: determining the transient characterization coefficient according to the required torque, the current torque value and the maximum torque at the current speed.

[0008] As an optional implementation, when the vehicle is in a high-load condition and the natural gas engine has detonation, controlling the natural gas engine to reduce a preset torque and controlling the motor to increase the preset torque includes: obtaining the detonation intensity; determining a high-load torque distribution coefficient based on the detonation intensity, the high-load torque distribution coefficient being positively correlated with the detonation intensity; and determining the preset torque based on the high-load torque distribution coefficient.

[0009] As an optional implementation, determining the preset torque according to the heavy load torque distribution coefficient includes: determining the motor required torque and the engine required torque according to the heavy load torque distribution coefficient; and determining the preset torque according to the motor required torque and the engine required torque.

[0010] As an optional implementation, when the vehicle is in a strong transient operating condition, after the required torque is distributed to the motor and the natural gas engine according to a preset logic, if the natural gas engine detonates, the transient characterization coefficient is increased by a first preset step size.

[0011] As an optional implementation, when the vehicle is in a high-load condition and the natural gas engine has knock, the natural gas engine is controlled to reduce a preset torque, and the motor is controlled to increase the preset torque. If the natural gas engine still has knock, the high-load torque distribution coefficient is increased by a second preset step.

[0012] As an optional implementation, it also includes: when the vehicle is in a low-speed and low-load condition and the power has not reached the upper limit, if the engine has no large load demand, the engine is controlled to increase the load and operate at low speed and medium load, and the engine is controlled to provide power outside the load for power generation.

[0013] As an optional implementation, when the power level is lower than a preset power value, the engine is controlled to operate at medium to high loads, avoiding operating areas with smaller throttle valves and operating areas where knock is likely to occur.

[0014] In an embodiment of the present application, a natural gas engine hybrid control method is provided, including: when the vehicle is in a strong transient condition, the required torque is distributed to the motor and the natural gas engine according to a preset logic; when the vehicle is in a heavy load condition and the natural gas engine has a knock, the natural gas engine is controlled to reduce the preset torque, and the motor is controlled to increase the preset torque. The knock situation under heavy load and strong transient conditions is reduced, and the engine reliability is improved. Using the motor to participate in torque distribution can avoid the engine from running in an area prone to knock. It can prevent knocking, thereby reducing gas consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0017] Figure 1 It is a flow chart of an optional natural gas engine hybrid control method provided according to an embodiment of the present application. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0019] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0020] Since the gas engine uses a throttle to control the amount of gas, the throttle opening is small under low load conditions, and there is negative pressure in the manifold, which will increase the oil consumption. Under high load or strong transient conditions, knock is prone to occur. The current method of suppressing knock in gas engines is to reduce the advance angle, which will increase gas consumption. In addition, when the gas quality changes, it will also affect the knock situation of the engine operation.

[0021] like Figure 1 As shown, in order to solve the above technical problems, the embodiment of the present application provides a natural gas engine hybrid control method, comprising:

[0022] When the S1 vehicle is in a strong transient condition, the required torque is distributed to the motor and the natural gas engine according to the preset logic;

[0023] S2: When the vehicle is in a heavy load condition and the natural gas engine has knock, the natural gas engine is controlled to reduce a preset torque, and the motor is controlled to increase the preset torque.

[0024] Reduce the knocking situation under heavy load and strong transient conditions, and improve engine reliability. Using the motor to participate in torque distribution can avoid the engine running in areas prone to knocking. It can prevent knocking and thus reduce gas consumption.

[0025] As an optional implementation, it also includes: obtaining the vehicle's real-time throttle opening, real-time throttle change rate, real-time vehicle speed, manifold pressure demand value and actual manifold pressure; if the vehicle's real-time throttle opening is greater than a preset throttle opening value, the real-time throttle change rate is greater than a preset throttle change rate value, the real-time vehicle speed is less than a preset hysteresis speed value, and the difference between the manifold pressure demand value and the actual manifold pressure is greater than a preset pressure difference, then the vehicle is in a strong transient operating condition.

[0026] As an optional implementation, when the vehicle is in a strong transient operating condition, allocating the required torque to the motor and the natural gas engine according to a preset logic includes: determining a transient torque distribution coefficient based on a transient characterization coefficient; and allocating the required torque to the motor and the natural gas engine according to a preset logic based on the transient torque distribution coefficient.

[0027] Specifically, a transient characterization coefficient is set to quantify the degree of transient. The stronger the transient, the larger the transient coefficient. The calculation method of the transient characterization coefficient is: (torque demand value - current torque value) / (maximum torque at current speed - current torque)

[0028] As an optional implementation, determining the transient torque distribution coefficient according to the transient characterization coefficient includes: determining the transient characterization coefficient according to the required torque, the current torque value and the maximum torque at the current speed.

[0029] Specifically, for example, the transient characterization coefficient is used to look up the table to obtain the transient torque distribution coefficient α, and the total required torque is distributed to the engine and the motor through the transient coefficient. The motor required torque = α * total required torque, and the engine required torque = (1-α) * total required torque

[0030] As an optional implementation, when the vehicle is in a high-load condition and the natural gas engine has detonation, controlling the natural gas engine to reduce a preset torque and controlling the motor to increase the preset torque includes: obtaining the detonation intensity; determining a high-load torque distribution coefficient based on the detonation intensity, the high-load torque distribution coefficient being positively correlated with the detonation intensity; and determining the preset torque based on the high-load torque distribution coefficient.

[0031] As an optional implementation, determining the preset torque according to the heavy load torque distribution coefficient includes: determining the motor required torque and the engine required torque according to the heavy load torque distribution coefficient; and determining the preset torque according to the motor required torque and the engine required torque.

[0032] When the engine detects knocking under heavy vehicle load conditions, it reduces the engine torque and uses the electric motor to supplement the reduced engine torque.

[0033] A large load torque distribution coefficient β can be set, and the corresponding large load torque distribution coefficient can be obtained by looking up the table according to the knock degree collected from the knock sensor. The large load torque distribution coefficient is positively correlated with the knock intensity.

[0034] When knock is detected, torque is distributed according to the high-load torque distribution coefficient obtained by looking up the table: motor demand torque = β*current demand torque, engine demand torque = (1-β)*current demand torque.

[0035] As an optional implementation, when the vehicle is in a strong transient operating condition, after the required torque is distributed to the motor and the natural gas engine according to a preset logic, if the natural gas engine detonates, the transient characterization coefficient is increased by a first preset step size.

[0036] As an optional implementation, when the vehicle is in a high-load condition and the natural gas engine has knock, the natural gas engine is controlled to reduce a preset torque, and the motor is controlled to increase the preset torque. If the natural gas engine still has knock, the high-load torque distribution coefficient is increased by a second preset step.

[0037] Changes in gas quality will lead to different knock conditions when the engine is under heavy load. Gas with high octane number tends to knock less, while gas with low octane number tends to knock more. Therefore, the transient characterization coefficient table can be set to be self-learning. If the current engine still knocks after using the transient characterization coefficient to distribute torque under strong transient conditions, the current transient characterization coefficient will increase according to the set step size. On the contrary, if no knock occurs under strong transient conditions under the current transient characterization coefficient, the current transient characterization coefficient will decrease according to the set step size. The increase and decrease steps can be calibrated separately as needed.

[0038] Similarly, under heavy load steady-state conditions, after distributing the torque according to the current knock intensity, if knock still occurs, the heavy load torque distribution coefficient increases according to the second preset step size, and if knock does not occur, the heavy load torque distribution coefficient decreases according to a certain step size. The increase and decrease step sizes can be calibrated separately as needed.

[0039] As an optional implementation, it also includes: when the vehicle is in a low-speed and low-load condition and the power has not reached the upper limit, if the engine has no large load demand, the engine is controlled to increase the load and operate at low speed and medium load, and the engine is controlled to provide power outside the load for power generation.

[0040] As an optional implementation, when the power level is lower than a preset power value, the engine is controlled to operate at medium to high loads, avoiding operating areas with smaller throttle valves and operating areas where knock is likely to occur.

[0041] Under low-speed and low-load conditions, the negative pressure of the intake air is large, which affects the oil consumption. Control the engine at a medium load, increase the throttle opening, control the opening of the supercharger bleed valve, and maintain the required manifold pressure value: When the power has not reached the upper limit and there is a certain margin, if the engine has no large load demand, control the engine to increase the load and operate at low speed and medium and low load. In addition to providing load, the engine uses power for power generation to avoid the engine running at a small load for a long time, reduce the manifold negative pressure, and reduce oil consumption; when the power is low, control the engine to operate at medium and high loads, avoid the working area with a small throttle and the working area prone to knocking, reduce the manifold pressure and avoid knocking; when there is no charging demand, if the engine has no power demand, control the engine to shut down, use the motor drive, and avoid long idle conditions causing increased oil consumption.

[0042] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0043] If the integrated units in the above embodiments are implemented in the form of software functional units and sold or used as independent products, they can be stored in the above computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for enabling one or more electronic devices (such as personal computers, servers, or network devices) to perform all or part of the steps of the methods described in the various embodiments of the present application.

[0044] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0045] In the several embodiments provided in the present application, it should be understood that the disclosed client can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0046] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution provided in this embodiment.

[0047] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0048] In the above embodiments of the present application, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0049] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. A natural gas engine hybrid control method, characterized in that: include: When the vehicle is in a strong transient condition, the required torque is distributed to the motor and the natural gas engine according to the preset logic; When the vehicle is in a heavy load condition and the natural gas engine has knock, the natural gas engine is controlled to reduce a preset torque, and the motor is controlled to increase the preset torque.

2. The natural gas engine hybrid control method according to claim 1, characterized in that: Also includes: Obtain the vehicle's real-time throttle opening, real-time throttle change rate, real-time vehicle speed, manifold pressure demand value, and actual manifold pressure; If the real-time throttle opening of the vehicle is greater than the preset throttle opening value, the real-time throttle change rate is greater than the preset throttle change rate value, the real-time vehicle speed is less than the preset hysteresis vehicle speed value, and the difference between the manifold pressure demand value and the actual manifold pressure is greater than the preset pressure difference, the vehicle is in a strong transient operating condition.

3. The natural gas engine hybrid control method according to claim 1, characterized in that: When the vehicle is in a strong transient operating condition, the required torque is distributed to the motor and the natural gas engine according to a preset logic, including: Determine a transient torque distribution coefficient according to the transient characterization coefficient; The required torque is distributed to the motor and the natural gas engine according to a preset logic based on the transient torque distribution coefficient.

4. The natural gas engine hybrid control method according to claim 3, characterized in that: Determining the transient torque distribution coefficient according to the transient characterization coefficient includes: The transient characterization coefficient is determined according to the required torque, the current torque value and the maximum torque at the current speed.

5. The natural gas engine hybrid control method according to claim 1, characterized in that: When the vehicle is in a heavy load condition and the natural gas engine has knock, controlling the natural gas engine to reduce a preset torque and controlling the motor to increase the preset torque includes: Get the knock intensity; determining a large load torque distribution coefficient according to the knock intensity, wherein the large load torque distribution coefficient is positively correlated with the knock intensity; The preset torque is determined according to the large load torque distribution coefficient.

6. The natural gas engine hybrid control method according to claim 5, characterized in that: Determining the preset torque according to the large load torque distribution coefficient includes: Determining the motor required torque and the engine required torque according to the heavy load torque distribution coefficient; The preset torque is determined according to the motor demand torque and the engine demand torque.

7. The natural gas engine hybrid control method according to claim 3, characterized in that: When the vehicle is in a strong transient operating condition, after the required torque is distributed to the motor and the natural gas engine according to a preset logic, if the natural gas engine knocks, the transient characterization coefficient is increased by a first preset step size.

8. The natural gas engine hybrid control method according to claim 5, characterized in that: When the vehicle is in a high-load condition and the natural gas engine knocks, the natural gas engine is controlled to reduce a preset torque, and the motor is controlled to increase the preset torque. If the natural gas engine still knocks, the high-load torque distribution coefficient is increased by a second preset step.

9. The natural gas engine hybrid control method according to claim 1, characterized in that: Also includes: When the vehicle is in a low-speed and low-load condition and the power has not reached the upper limit, if the engine has no large load demand, the engine is controlled to increase the load and operate at low speed and medium load. The controlled engine will provide power outside the load for power generation.

10. The natural gas engine hybrid control method according to claim 9, characterized in that: When the battery power is lower than the preset value, the engine is controlled to operate at medium to high loads, avoiding operating areas with smaller throttle valves and areas where knocking is likely to occur.

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