Engine starting control method and device, engine and motor vehicle

Abstract

The invention relates to an engine starting control method and device, an engine and a motor vehicle. A rotating speed signal and fault information in the engine starting period are obtained; when the crankshaft and camshaft phase fault exists, a degradation starting mode is entered, and the degradation starting mode is a trial injection mode or a trial ignition mode; when the CAN communication fault information exists, the rotating speed rising trend is calculated according to the obtained engine rotating speed signal, and when the rotating speed rising trend is larger than a preset threshold value, injection or ignition is stopped, and the degradation starting mode is quitted; if the rotating speed rising trend is not larger than the preset threshold value, trial injection or trial ignition continues to be executed; when the CAN communication fault information does not exist, the motor is controlled to drag the engine to the set safe rotating speed according to the preset starting rotating speed, the set time is maintained, and engine starting is completed through the degradation starting mode.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle control, and in particular to an engine starting control method, device, engine and motor vehicle. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] New energy hybrid vehicles will use the motor to reverse the engine to start and run at low speed, which is different from the traditional vehicle method of dragging the engine to a certain speed through the starter, and then burning and working to increase the speed to a certain value before disengaging the starter. When the engine crankshaft and camshaft phase of the hybrid vehicle fail to synchronize, it will enter the test injection mode. In this mode, the accuracy of the test injection phase is generally determined by judging the rising trend of the engine speed. However, since the hybrid vehicle engine is directly dragged by the motor according to the set speed, it is impossible to determine whether the speed increase is caused by the motor dragging the engine or by the fuel combustion work in the engine. The speed increase trend cannot truly reflect the accuracy of the test injection. If the injection work continues in this mode, it will cause engine abnormalities, and in severe cases, the cylinder will melt. Summary of the invention

[0004] In order to solve the technical problems existing in the above-mentioned background technology, the present invention provides an engine starting control method, device, engine and motor vehicle, which cooperate with the engine ECU and hybrid HCU to achieve safe starting in the crankshaft camshaft phase fault mode.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A first aspect of the present invention provides an engine start control method, comprising the following steps:

[0007] Obtaining speed signal and fault information during engine starting;

[0008] When there is a crankshaft camshaft phase fault, the system enters a degraded start mode, which is a test injection mode or a test ignition mode;

[0009] When there is CAN communication fault information, the speed rising trend is calculated according to the acquired engine speed signal. When the speed rising trend is greater than the preset threshold, the injection or ignition is stopped and the degraded start mode is exited; if the speed rising trend is not greater than the preset threshold, the test injection or test ignition is continued;

[0010] When there is no CAN communication fault information, the motor is controlled to drag the engine to the set safety speed and maintain it for the set time according to the preset starting speed, and then the engine starting is completed through the degraded starting mode.

[0011] Furthermore, when there is CAN communication fault information, it is determined whether the motor is dragging the engine based on the speed increase trend. If so, injection or ignition is stopped and the degraded start mode is exited.

[0012] Furthermore, the speed acceleration calculated using the speed signal is used to reflect the speed increase trend.

[0013] Furthermore, when there is CAN communication fault information, the ECU is triggered to start the protection mode.

[0014] Furthermore, in the ECU start protection mode, the speed rising trend is calculated based on the acquired engine speed signal; when the speed rising trend is greater than the preset threshold, the ECU reports a "drag start not allowed" fault, stops injection or stops ignition, and exits the degraded start mode.

[0015] Furthermore, when there is no CAN communication fault information, the ECU sends an instruction of "allowing motor downgrade drag" to the HCU.

[0016] Furthermore, the HCU sends an "engine drag start" instruction to the motor based on the received "allow motor downgrade drag" instruction and uses the preset drag speed and drag maintenance time, and the engine is started based on the test injection mode or the test ignition mode.

[0017] A second aspect of the present invention provides an engine starting control device, comprising an ECU (electronic control unit) and an HCU (hybrid vehicle controller);

[0018] The ECU is used to obtain the speed signal and fault information during engine starting; when there is a crankshaft or camshaft phase fault, the engine enters a degraded start mode, which is a test injection mode or a test ignition mode;

[0019] When there is CAN communication fault information, the ECU startup protection mode is triggered. In the ECU startup protection mode, the ECU calculates the speed increase trend based on the acquired engine speed signal. When the speed increase trend is greater than the preset threshold, the ECU reports a "drag start not allowed" fault, the engine stops injection or stops ignition, and exits the degraded start mode; if the speed increase trend is not greater than the preset threshold, the engine continues to perform test injection or test ignition;

[0020] When there is no CAN communication fault information, the ECU sends an instruction to "allow motor downgrade drag" to the HCU. The HCU uses the preset drag speed and drag maintenance time to send an instruction to the motor to "start engine drag". The engine is started based on the test injection mode or the test ignition mode.

[0021] A third aspect of the present invention provides an engine, which is a hybrid engine and is equipped with the above-mentioned engine starting control device.

[0022] A fourth aspect of the present invention is a motor vehicle equipped with the above-mentioned engine.

[0023] Compared with the prior art, one or more of the above technical solutions have the following beneficial effects:

[0024] When a hybrid engine has a crankshaft-camshaft phase fault, and the fault information of the crankshaft-camshaft cannot be transmitted to the HCU, since it is impossible to determine whether the rising trend of the speed is caused by the motor dragging the engine or by the fuel combustion work in the engine, the start protection mode is triggered, and the engine is started by the coordinated control of the HCU and ECU; in the test injection or test ignition mode, the rising trend of the speed is quite different from the rising trend of the speed in the motor drag mode. Therefore, after the start protection mode is triggered, according to the speed rising trend, it is judged whether there is a situation of motor dragging the engine at this time. If so, the test injection or test ignition is stopped, and the fault information of not allowing drag start is reported, so as to avoid the safety hazards caused by the failure to use the speed rising trend to reflect the accuracy of the test injection or test ignition, and reduce or even avoid the risk of cylinder top melting. When the fault information of the crankshaft-camshaft can be transmitted to the HCU, the motor drags the engine according to the preset starting speed to complete the start. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0026] Figure 1 It is a schematic diagram of hybrid vehicle engine starting control provided by one or more embodiments of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0028] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0029] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0030] Terminology explanation:

[0031] ECU, Electronic Control Unit, is the comprehensive control device of the engine. It is responsible for receiving and analyzing information from various engine sensors. After precise calculations through built-in programs, it issues instructions to regulate related actuators, thereby ensuring that the engine can maintain the best operating state under various operating conditions.

[0032] HCU, Hybrid Control Unit, is responsible for managing the entire powertrain. HCU will sense the driver's operating intention, the vehicle's driving status, and the working status of key components such as the engine, gearbox, motor, and battery in real time, and accurately adjust the torque distribution between the engine and motor, control the on and off of the high-voltage circuit, and decide on the start and stop of the engine, the activation of various accessories, and other operations.

[0033] Test injection mode: This mode means that when the engine crankshaft and camshaft phase failure cannot be synchronized, a certain cylinder is injected through test injection, and the engine speed change trend of the corresponding cylinder after injection is detected to see if it meets the preset conditions to determine whether the cylinder is injected correctly. If the conditions are not met, the engine is turned 360 degrees and a test injection is performed on the symmetrical cylinder to determine the phase.

[0034] If the hybrid vehicle is equipped with a spark-ignition engine rather than a compression-ignition engine, it is tested through a test ignition. The test ignition is the same as the test injection in principle, except that the spark plug ignition process is added.

[0035] Crankshaft-camshaft phase fault refers to the phase relationship between the crankshaft and the camshaft, and there is an error in signal synchronization or physical position, such as a deviation in the relative position between the crankshaft and the camshaft, which may be caused by looseness, wear or improper installation of the timing belt or chain. When this deviation exceeds a certain range, the engine fault code will be triggered.

[0036] CAN communication failure refers to a problem in data communication between the engine control unit (ECU) and other related controllers or sensors through the CAN bus, which causes the ECU to be unable to send information to other related controllers or sensors, or the ECU to be unable to receive information from other related controllers or sensors, resulting in the ECU possibly being unable to identify certain potential problems.

[0037] As introduced in the background technology, when a traditional vehicle is started, the starter is used to drag the engine to a certain speed, and the engine phase is synchronized to perform combustion and work. After the speed rises to a certain value, the engine is disengaged from the starter and the engine completes the starting process.

[0038] Hybrid vehicles do not have a dedicated starter. Instead, the motor that originally provides power output is used to drive the engine to start and run at low speed.

[0039] When the hybrid vehicle's engine crankshaft and camshaft phases fail to synchronize, the vehicle will enter the test injection mode, which determines whether the test injection phase is accurate by judging the rising trend of the engine speed. However, since the hybrid vehicle's engine is directly driven by the motor according to the set speed, it is impossible to determine whether the rising trend of the speed is caused by the motor driving the engine or by the fuel combustion work in the engine. As a result, the rising trend of the speed cannot truly reflect the accuracy of the test injection. If the injection work continues in this mode, the engine will be abnormal, and in severe cases, the cylinder will melt.

[0040] Therefore, the following embodiments provide an engine starting control method, device, engine and motor vehicle, which cooperate with the engine ECU and hybrid HCU to achieve safe starting in the crankshaft camshaft phase fault mode.

[0041] Embodiment 1:

[0042] An engine starting control method comprises the following steps:

[0043] Obtaining speed signal and fault information during engine starting;

[0044] When there is a crankshaft camshaft phase fault, the system enters a degraded start mode, which is a test injection mode or a test ignition mode;

[0045] When there is CAN communication fault information, the startup protection mode is triggered. In the startup protection mode, the speed increase trend is calculated according to the acquired engine speed signal. When the speed increase trend is greater than the preset threshold, the injection or ignition is stopped and the degraded startup mode is exited; if it is not greater than the preset threshold, the test injection or test ignition is continued;

[0046] When there is no CAN communication fault information, the motor is controlled to drag the engine to the set safe speed according to the preset starting speed, and then the starting is completed through the degraded starting mode.

[0047] In this embodiment, Figure 1 As shown, during the T15 power-on and dragging process, the ECU obtains the real-time engine speed signal, crankshaft and camshaft phase-related fault information, and CAN communication-related fault information;

[0048] When there is a crankshaft and camshaft phase fault, the engine enters a degraded start mode, and the degraded start mode in this embodiment is a test injection mode;

[0049] Determine whether the ECU has a fault that affects CAN communication at this time;

[0050] If there is a fault in CAN communication, the ECU cannot send the fault information of the crankshaft and camshaft to the HCU. In order to prevent the motor from continuing to drag the engine, causing the engine to pull the cylinder or melt the top, it is necessary to determine whether there is motor drag at this time based on the speed acceleration. If there is, stop the injection and report the fault that does not allow drag start; specifically:

[0051] If there is a fault in CAN communication, the ECU startup protection mode is triggered. In the ECU startup protection mode, the speed rising trend is calculated based on the acquired engine speed signal. In this embodiment, the speed acceleration is selected to reflect the speed rising trend; when the speed rising trend is greater than the preset threshold, the ECU reports a "drag start not allowed" fault, stops injection and exits the test injection mode; if it is not greater than the preset threshold, the test injection mode continues.

[0052] If there is no CAN communication related fault, the ECU sends a command to allow the HCU to downgrade and start. At this time, the motor acts as a starter. The HCU drags the engine to a certain safe speed based on the preset starting speed, and the engine enters the test injection mode to automatically start the downgrade. Specifically:

[0053] If there is no CAN communication-related fault, the ECU sends an instruction to "allow motor downgrade towing" to the HCU. Based on the downgraded towing state, the preset towing speed and towing maintenance time, the HCU sends an instruction to "engine reverse towing start" to the motor, and the engine is started based on the test injection mode.

[0054] In the above process, by coordinating the engine's ECU and HCU, when a crankshaft-camshaft phase fault occurs in the hybrid engine and the HCU can reliably receive the crankshaft-camshaft fault information, the motor is controlled to drag the engine to complete the start according to the preset starting speed.

[0055] Since there is a big difference between the rising trend of speed in normal test injection mode and the rising trend of speed in motor reverse drag mode, when HCU cannot receive the fault information of crankshaft and camshaft, the ECU will be triggered to start the protection mode. According to the rising trend of speed, it is judged whether there is a situation of motor dragging the engine at this time. If so, it will stop and exit the test injection mode, and report the fault information that drag start is not allowed, so as to avoid the safety hazard caused by the rising trend of speed failing to truly reflect the accuracy of test injection, and reduce or even avoid the risk of cylinder pulling and top melting.

[0056] Embodiment 2:

[0057] This embodiment provides an engine starting control device, including an ECU (electronic control unit) and an HCU (hybrid vehicle controller);

[0058] The ECU is used to obtain the speed signal and fault information during engine starting; when there is a crankshaft or camshaft phase fault, the engine enters a degraded start mode, which is a test injection mode or a test ignition mode;

[0059] When there is CAN communication fault information, the ECU startup protection mode is triggered. In the ECU startup protection mode, the ECU calculates the speed increase trend based on the acquired engine speed signal. When the speed increase trend is greater than the preset threshold, the ECU reports a "drag start not allowed" fault, the engine stops injection or stops ignition, and exits the degraded start mode; if the speed increase trend is not greater than the preset threshold, the engine continues to perform test injection or test ignition;

[0060] When there is no CAN communication fault information, the ECU sends an instruction to "allow motor downgrade drag" to the HCU. The HCU uses the preset drag speed and drag maintenance time to send an instruction to the motor to "start engine drag". The engine is started based on the test injection mode or the test ignition mode.

[0061] When a hybrid engine has a crankshaft-camshaft phase fault, and the crankshaft-camshaft fault information cannot be transmitted to the HCU, it is impossible to determine whether the rising trend of the speed is caused by the motor dragging the engine or by the fuel combustion work in the engine, so the start protection mode is triggered. In this mode, according to the speed increase trend, it is judged whether there is a situation of motor dragging the engine at this time. If so, the test injection or test ignition is stopped, and the fault information of not allowing the drag start is reported, avoiding the safety hazards caused by the failure to use the speed increase trend to reflect the accuracy of the test injection or test ignition, and reducing or even avoiding the risk of cylinder top melting. When the crankshaft-camshaft fault information can be transmitted to the HCU, the motor drags the engine according to the preset starting speed to complete the start.

[0062] Embodiment three:

[0063] This embodiment provides a hybrid engine equipped with the above-mentioned starting control device.

[0064] Embodiment 4:

[0065] This embodiment provides a motor vehicle having a hybrid engine, and the hybrid engine is equipped with the above-mentioned starting control device.

[0066] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An engine starting control method, characterized in that: The following steps are involved: Obtaining speed signal and fault information during engine starting; When there is a crankshaft camshaft phase fault, the system enters a degraded start mode, which is a test injection mode or a test ignition mode; When there is CAN communication fault information, the speed increase trend is calculated according to the acquired engine speed signal. When the speed increase trend is greater than the preset threshold, the injection or ignition is stopped, and the degraded start mode is exited; If the speed increase trend is not greater than the preset threshold, the test injection or test ignition is continued; When there is no CAN communication fault information, the motor is controlled to drag the engine to the set safety speed and maintain it for the set time according to the preset starting speed, and then the engine starting is completed through the degraded starting mode.

2. The engine starting control method according to claim 1, characterized in that: When there is CAN communication fault information, determine whether the motor is dragging the engine based on the speed increase trend. If so, stop injection or ignition and exit the degraded start mode.

3. The engine starting control method according to claim 1, characterized in that: The speed acceleration calculated using the speed signal is used to reflect the speed increase trend.

4. The engine starting control method according to claim 1, characterized in that: When there is CAN communication fault information, the ECU is triggered to start the protection mode.

5. The engine starting control method according to claim 1, characterized in that: In the ECU start protection mode, the speed rising trend is calculated based on the acquired engine speed signal; when the speed rising trend is greater than the preset threshold, the ECU reports a "drag start not allowed" fault, stops injection or stops ignition, and exits the degraded start mode.

6. The engine starting control method according to claim 1, characterized in that: When there is no CAN communication fault information, the ECU sends an instruction to the HCU to "allow motor downgrade drag".

7. The engine starting control method according to claim 6, characterized in that: Based on the received "allow motor downgrade drag" instruction, the HCU uses the preset drag speed and drag maintenance time to send an "engine drag start" instruction to the motor, and the engine is started based on the test injection mode or the test ignition mode.

8. A device for implementing the hybrid engine starting control method according to any one of claims 1 to 7, characterized in that: Including ECU and HCU; The ECU is used to obtain the speed signal and fault information during engine starting; when there is a crankshaft or camshaft phase fault, the engine enters a degraded start mode, which is a test injection mode or a test ignition mode; When there is CAN communication fault information, the ECU startup protection mode is triggered. In the ECU startup protection mode, the ECU calculates the speed increase trend based on the acquired engine speed signal. When the speed increase trend is greater than the preset threshold, the ECU reports the "drag start not allowed" fault, the engine stops injection or stops ignition, and exits the degraded start mode; if the speed increase trend is not greater than the preset threshold, the engine continues to perform test injection or test ignition; When there is no CAN communication fault information, the ECU sends an "allow motor downgrade drag" instruction to the HCU. The HCU uses the preset drag speed and drag maintenance time to send an "engine drag start" instruction to the motor, and the engine completes the start based on the test injection mode or the test ignition mode.

9. An engine, characterized in that: The engine is a hybrid engine and has the hybrid engine starting control device according to claim 8 .

10. A motor vehicle, characterized in that: A motor as claimed in claim 9 is provided.

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