Engine control method for hybrid vehicle

Abstract

An embodiment of the present application provides an engine control method for a hybrid vehicle. The control method includes: controlling the engine power to switch between at least a first power point and a second power point according to a preset condition, wherein the first power point and the second power point are located between an ignition point and a maximum power point, and the second power point is higher than the first power point. The engine control method of the embodiment of the present application achieves good fuel economy.

Description

Technical Field

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

[0002] In series hybrid mode, the engine drives the generator to generate electricity, while the battery provides some energy to drive the electric motor. A single-speed hybrid transmission allows the engine to use excess power to charge the battery when it exceeds the vehicle's required power. When the engine's output falls short, the battery provides the remaining power. Alternatively, a two- or three-speed hybrid transmission can be used to meet daily driving needs by shifting gears under varying operating conditions.

[0003] However, in the related art, the engine is at one power point for a long time, and it can only achieve low fuel consumption within a narrow range of operating conditions, but cannot achieve low fuel consumption within a wider range of operating conditions, resulting in poor fuel economy. Summary of the Invention

[0004] In view of this, the main purpose of the embodiments of the present application is to provide an engine control method for a hybrid vehicle with better fuel economy.

[0005] To achieve the above objectives, the technical solution of the embodiment of the present application is implemented as follows:

[0006] An embodiment of the present application provides an engine control method for a hybrid vehicle, the control method comprising:

[0007] The power of the engine is controlled to switch between at least a first power point and a second power point according to preset conditions, wherein the first power point and the second power point are located between the ignition point and the maximum power point, and the second power point is higher than the first power point.

[0008] In one embodiment, controlling the power of the engine to switch between at least a first power point and a second power point according to a preset condition includes:

[0009] The power of the engine is controlled to switch between at least the first power point and the second power point according to the vehicle demand power corresponding to the current operating condition of the hybrid vehicle.

[0010] In one embodiment, when the vehicle demand power is within a set power range, the engine power is controlled to be at the first power point; when the vehicle demand power is greater than the upper limit value of the set power range, the engine power is controlled to be at the second power point, wherein the first power point is within the set power range and the second power point is greater than the upper limit value of the set power range.

[0011] In one embodiment, the range of the set power interval under the vehicle acceleration condition is greater than the range of the set power interval under the vehicle deceleration condition.

[0012] In one implementation, the first power point is an average power point; and / or the second power point is a high power point.

[0013] In one embodiment, the method further includes: when the power of the engine is switched to the first power point, controlling the engine to operate at a first set speed, where the first set speed is a speed corresponding to a minimum fuel consumption value matching the first power point.

[0014] In one embodiment, the first set rotation speed is not less than 2200 rpm and not more than 2700 rpm.

[0015] In one embodiment, the method further includes: when the power of the engine is switched to the second power point, controlling the engine to operate at a second set speed, where the second set speed is a speed corresponding to a minimum fuel consumption value matching the second power point.

[0016] In one embodiment, the second set rotation speed is not less than 3500 rpm and not more than 4000 rpm.

[0017] In one embodiment, the method further includes: when the power of the engine is at the ignition point, controlling the engine speed to be at a third set speed, the third set speed being the speed corresponding to the minimum emission matching the ignition point; and / or, the third set speed being the speed corresponding to both the minimum emission and the minimum fuel consumption value matching the ignition point.

[0018] In one embodiment, the third set rotational speed is not less than 1400 rpm and not more than 1600 rpm.

[0019] In one embodiment, the method further includes: when the vehicle power requirement reaches a limit power requirement, controlling the engine power to switch to a maximum power point.

[0020] In one embodiment, the method further includes: when the power of the engine is switched to the maximum power point, controlling the speed of the engine to be at a minimum speed that matches the maximum power point.

[0021] An embodiment of the present application provides an engine control method for a hybrid vehicle, which sets two power points between the ignition point and the maximum power point. By controlling the power of the engine to switch between multiple points according to preset conditions, the engine can be prevented from operating at only one power point for a long time. Thus, under different operating conditions, the engine can be controlled to operate at a power that is more matched with the operating conditions, thereby meeting the requirements for efficient operation of the engine within a wider range of operating conditions, and realizing low fuel consumption driving of the hybrid vehicle, thereby having better fuel economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a flow chart of an engine control method for a hybrid vehicle according to an embodiment of the present application;

[0023] Figure 2 Schematic diagram of the relationship between engine power point and speed according to an embodiment of the present application.

[0024] Description of Reference Numerals

[0025] Set the power range to 10; the ignition point is X1; the first power point is X2; the second power point is X3; and the maximum power point is X4. DETAILED DESCRIPTION

[0026] An embodiment of the present application provides an engine control method for a hybrid vehicle. Figure 1 , control methods include:

[0027] Step S1: Controlling the power of the engine to switch between at least a first power point X2 and a second power point X3 according to preset conditions.

[0028] The first power point X2 and the second power point X3 are located between the ignition point X1 and the maximum power point X4, and the second power point X3 is higher than the first power point X2.

[0029] The engine control method of the embodiment of the present application can be applied to a series hybrid vehicle and a parallel-parallel hybrid vehicle having a series structure.

[0030] Ignition point X1 refers to the power used when the engine starts.

[0031] The maximum power point X4 is the maximum power that the engine can reach, which is the power that can meet full-load conditions.

[0032] The first power point X2 and the second power point X3 are both calculated through simulation based on the hybrid vehicle in which the engine is installed and its operating conditions. For example, the first power point is the average power point, which refers to the average power calculated when the engine is installed in the hybrid vehicle. This ensures that the engine's power is controlled to operate at the most efficient point when the hybrid vehicle is operating at low load.

[0033] For example, the second power point X3 is the high power point. The high power point is the power level at which the hybrid vehicle's engine can operate efficiently under high-load operating conditions (such as acceleration and hill climbing). By using the high power point, when the driver's vehicle is operating under relatively high loads, the problem of excessive battery charging and discharging caused by insufficient energy provided by the first power point X2 can be avoided, thereby extending the battery's service life.

[0034] Specifically, the power of the engine is controlled to switch between at least a first power point X2 and a second power point X3 according to preset conditions. For example, other power points are provided between the ignition point X1 and the maximum power point X4. The power of the engine can be controlled to switch between the power points according to preset conditions.

[0035] For example, the power of the engine may be controlled to be at the ignition point X1 or the maximum power point X4 according to preset conditions.

[0036] The engine control method of the embodiment of the present application is to set at least two power points between the ignition point X1 and the maximum power point X4, and to control the power of the engine to switch between multiple points according to preset conditions to avoid the engine running at only one power point for a long time. Thus, under different operating conditions, the engine can be controlled to operate at a power that is more matched with the operating conditions, thereby meeting the requirements for efficient operation of the engine within a wider range of operating conditions, and realizing low fuel consumption driving of hybrid vehicles, thereby having better fuel economy.

[0037] The selection of preset conditions can be set according to the structure and actual needs of the hybrid vehicle. For example, the engine power is controlled to switch between at least a first power point X2 and a second power point X3 according to the vehicle demand power corresponding to the current operating condition of the hybrid vehicle.

[0038] Specifically, hybrid vehicles operate in a range of conditions during transportation. For example, based on the vehicle's movement mode, these operating conditions include starting, acceleration, constant speed, deceleration, turning, uphill and downhill driving, and parking. Based on the driver's control method, these operating conditions include gear shifting, coasting (coasting with the vehicle disengaged, coasting in neutral, accelerating, and coasting), braking (emergency braking, speed-controlled braking, and braking with the vehicle braked), throttle control, steering, and reversing. Based on the load condition, these operating conditions include unloaded, fully loaded (equal to the rated load), and overloaded (exceeding the rated load).

[0039] Different vehicle power requirements exist under different operating conditions and operating loads. According to the different vehicle power requirements, the engine power can be switched to a more efficient power point between the first power point X2 and the second power point X3, thereby achieving efficient operation of the engine.

[0040] In one embodiment, please refer to Figure 2 When the vehicle demand power is within the set power range 10, the engine power is controlled to be at a first power point X2. When the vehicle demand power is greater than the upper limit of the set power range 10, the engine power is controlled to be at a second power point X3, wherein the first power point X2 is within the set power range 10 and the second power point X3 is greater than the upper limit of the set power range 10.

[0041] Specifically, when the vehicle's required power is within the set power range 10, the engine operates at the power of the first power point X2. The difference between the vehicle's required power and the first power point X2 is supplemented by the battery or converted into electrical energy and absorbed by the battery. When the vehicle's required power is greater than the upper limit of the set power range 10, the engine operates at the power of the second power point X3 and cooperates with the battery at the same time.

[0042] It should be noted that the first power point X2 can be set at the median position of the set power interval 10. Under the condition that the first power point X2 is within the set power interval 10, the upper limit or lower limit of the set power interval 10 can also be set to a multiple of the first power point X2.

[0043] In addition, under different operating conditions, the range of the power interval 10 may also be set differently.

[0044] For example, the range of the power interval under the vehicle acceleration condition is set to be greater than the range of the power interval 10 under the vehicle deceleration condition.

[0045] That is to say, compared with the vehicle acceleration condition, the engine power at the second power point X3 is applicable to a wider range of operating conditions under the vehicle deceleration condition, that is, the range of required power values ​​is wider. This is to enable the engine to operate at a higher power under the vehicle deceleration condition, so as to facilitate matching with the gearbox.

[0046] In a specific embodiment, the first power point X2 is the average power point, the second power point X3 is the high power point, and under vehicle acceleration conditions, the lower limit of the power interval 10 is set to 2 / 3 times the average power point, and the upper limit of the power interval 10 is set to 1.5 times the average power point.

[0047] Under the vehicle deceleration condition, the lower limit of the power interval 10 is set to 5 / 6 times the average power point, and the upper limit of the power interval 10 is set to 1.2 times the average power point.

[0048] In a specific embodiment, the lower limit of the power range 10 is set to the ignition point X1.

[0049] In one embodiment, please refer to Figure 2 The control method further includes: when the power of the engine is switched to the first power point X2, controlling the engine to run at a first set speed, where the first set speed is a speed corresponding to a minimum fuel consumption value that matches the first power point X2.

[0050] That is to say, when the engine power is switched to the first power point X2, the speed corresponding to the lowest point of engine fuel consumption that meets the power requirement is selected, that is, the first set speed, and the engine is controlled to run at the first set speed, thereby further improving the fuel economy of the engine.

[0051] In some embodiments, the first set rotational speed is not less than 2200 rpm and not more than 2700 rpm. For example, the first set rotational speed is 2500 rpm.

[0052] In one embodiment, please refer to Figure 2 The control method further includes: when the power of the engine is switched to the second power point X3, controlling the engine to operate at a second set speed, where the second set speed is a speed corresponding to a minimum fuel consumption value that matches the second power point X3, thereby improving the fuel economy when the engine operates at the second power point X3.

[0053] In some embodiments, the first set rotation speed is not less than 3500 rpm and not more than 4000 rpm.

[0054] It should be noted that when determining the first set speed or the second set speed through the minimum fuel consumption value, the vehicle's NVH (noise, vibration and harshness) performance can also be combined. Generally speaking, the lower the engine speed, the better the vehicle's NVH performance.

[0055] In one embodiment, please refer to Figure 2 The control method further includes: when the engine power is at the ignition point X1, controlling the engine speed to be at a third set speed, the third set speed being a speed corresponding to the minimum emission amount matching the ignition point X1.

[0056] Specifically, by selecting the lowest emission amount to determine the engine speed at the ignition point X1, carbon emissions can be reduced and emission performance can be guaranteed.

[0057] Of course, when there are multiple speed points that meet the minimum emission value, the speed that also meets the minimum fuel consumption value can be selected.

[0058] In some embodiments, the third set speed is not less than 1400 rpm and not more than 1600 rpm. For example, the first set speed is 1500 rpm.

[0059] It should be noted that the first set speed, the second set speed and the third set speed are all set values. During the actual operation of the engine, the actual speed of the engine will fluctuate within a certain range around the first set speed, the second set speed and the third set speed respectively.

[0060] In one embodiment, the control method further includes: when the vehicle power requirement reaches the limit power requirement, controlling the engine power to switch to the maximum power point X4.

[0061] It should be noted that the maximum power demand refers to the maximum power demand that a hybrid vehicle can achieve, such as the power demand under heavy or full load conditions. By controlling the engine power to switch to the maximum power point X4, the hybrid vehicle can cope with various extreme usage scenarios.

[0062] In a specific embodiment, the control method further includes: when the power of the engine is switched to the maximum power point X4, controlling the speed of the engine to be at the lowest speed matching the maximum power point X4.

[0063] Specifically, the engine power is controlled at the maximum power point X4, and the speed is controlled to be the lowest speed under the power to maintain good vehicle NVH performance.

[0064] In the description of this application, the descriptions with reference to the terms "in one embodiment", "in some embodiments", "in a specific embodiment", or "exemplary" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present application. In this application, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine different embodiments or examples described in this application and features of different embodiments or examples without contradiction.

[0065] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application are intended to be within the scope of protection of the present application.

Claims

1. A method for controlling an engine of a hybrid vehicle, characterized in that: The control method includes: Controlling the power of the engine to switch between at least a first power point and a second power point according to a preset condition, wherein the first power point and the second power point are located between an ignition point and a maximum power point, and the second power point is higher than the first power point; Controlling the power of the engine to switch between at least the first power point and the second power point according to the vehicle demand power corresponding to the current operating condition of the hybrid vehicle; When the vehicle demand power is within a set power range, the engine power is controlled to be at the first power point; when the vehicle demand power is greater than an upper limit of the set power range, the engine power is controlled to be at the second power point, wherein the first power point is within the set power range and the second power point is greater than the upper limit of the set power range; An upper limit value of the set power interval is greater than the first power point, and a lower limit value of the set power interval is less than the first power point.

2. The engine control method for a hybrid vehicle according to claim 1, wherein: The range of the set power interval under the vehicle acceleration condition is greater than the range of the set power interval under the vehicle deceleration condition.

3. The engine control method of a hybrid vehicle according to claim 1, wherein: The first power point is an average power point; and / or the second power point is a high power point.

4. The engine control method for a hybrid vehicle according to any one of claims 1 to 3, characterized in that: The method further includes: when the power of the engine is switched to the first power point, controlling the engine to operate at a first set speed, where the first set speed is a speed corresponding to a minimum fuel consumption value matching the first power point.

5. The engine control method for a hybrid vehicle according to claim 4, wherein: The first set rotation speed is not less than 2200 rpm and not more than 2700 rpm.

6. The engine control method for a hybrid vehicle according to any one of claims 1 to 3, characterized in that: The method further includes: when the power of the engine is switched to the second power point, controlling the engine to operate at a second set speed, where the second set speed is a speed corresponding to a minimum fuel consumption value matching the second power point.

7. The engine control method for a hybrid vehicle according to claim 6, wherein: The second set rotation speed is not less than 3500 rpm and not more than 4000 rpm.

8. The engine control method for a hybrid vehicle according to any one of claims 1 to 3, characterized in that: The method also includes: when the power of the engine is at the ignition point, controlling the engine speed to be at a third set speed, the third set speed being the speed corresponding to the minimum emission matching the ignition point; and / or, the third set speed being the speed corresponding to both the minimum emission and the minimum fuel consumption value matching the ignition point.

9. The engine control method for a hybrid vehicle according to claim 8, wherein: The third set rotation speed is not less than 1400 rpm and not more than 1600 rpm.

10. The engine control method for a hybrid vehicle according to any one of claims 1 to 3, characterized in that: The method further includes: when the vehicle power requirement reaches a limit power requirement, controlling the power of the engine to switch to a maximum power point.

11. The engine control method for a hybrid vehicle according to claim 10, wherein: The method further includes: when the power of the engine is switched to the maximum power point, controlling the speed of the engine to be at a minimum speed matching the maximum power point.

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