High-pressure fuel pump driving device and control method thereof

Abstract

The invention discloses a high-pressure fuel pump driving device and a control method thereof, and relates to the technical field of engines, the device comprises a cam shaft and a cam shaft mounting cover; the cam shaft penetrates into the shaft hole of the mounting cover cap, and each shaft neck of the cam shaft is matched with the corresponding shaft neck on the mounting cover cap; a high-pressure oil pump driving cam on the camshaft is arranged close to a tail journal of the camshaft; the tail shaft neck of the cam shaft selects different widths according to strength requirements, and the shaft tube diameter of the cam shaft also selects different inner diameters and outer diameters according to the strength requirements. According to the high-pressure fuel pump driving device and the control method thereof, the problem that due to the fact that the driving force of a 500 bar high-pressure oil pump is increased, the cam shaft is abraded or fractured due to fatigue can be solved.

Description

Technical Field

[0001] This application relates to the field of engine technology, and in particular to a high-pressure fuel pump drive device and its control method. Background Technology

[0002] With increasing demands for fuel efficiency and emissions reduction in engines, direct injection combustion technology has been adopted. This technology uses a high-pressure fuel pump to pressurize and deliver fuel to the engine cylinders, improving fuel atomization and combustion efficiency. Current engines commonly use 350 bar fuel injection technology to improve power output and fuel economy. With even higher requirements for fuel efficiency and emissions, engines are increasingly adopting 500 bar fuel injection technology.

[0003] Compared to 350 bar fuel injection technology, 500 bar fuel injection technology significantly improves fuel atomization. The higher pressure atomizes the fuel into finer particles, resulting in more uniform mixing with air and more complete combustion. This helps to further improve combustion efficiency, reduce fuel consumption, reduce pollutant emissions, and increase power output.

[0004] The fifth-generation Volkswagen EA888 engine has already increased the fuel system operating pressure to 500 bar. 500-bar high-pressure injection technology will play an even greater role in the future of engines.

[0005] The adoption of a 500-bar ultra-high-pressure fuel injection pump significantly increases the force required to drive the fuel pump. Therefore, how to drive the 500-bar high-pressure fuel pump needs to be considered. Summary of the Invention

[0006] The purpose of this invention is to provide a high-pressure fuel pump drive device and its control method, which can solve the problem of camshaft wear or fatigue fracture caused by the increased driving force of the 500bar high-pressure fuel pump.

[0007] This invention provides the following solution:

[0008] According to one aspect of the present invention, a high-pressure fuel pump drive device is provided, the high-pressure fuel pump drive device comprising:

[0009] Camshaft, and camshaft mounting cover;

[0010] The camshaft passes through the shaft hole of the mounting cover, and each journal of the camshaft mates with the corresponding journal on the mounting cover;

[0011] The high-pressure oil pump on the camshaft drives the cam to be positioned close to the camshaft tail journal;

[0012] The tail journal of the camshaft is selected with different widths according to the strength requirements, and the diameter of the camshaft tube is also selected with different inner and outer diameters according to the strength requirements.

[0013] Optionally, the high-pressure oil pump drive cam has a camshaft journal only on its front side, and no camshaft support journal is provided on its rear side.

[0014] Optionally, a camshaft can be used to drive a high-pressure oil pump.

[0015] Optionally, an electronic oil pump can be used for high-pressure oil pumps.

[0016] Optionally, the angles of the high-pressure oil pump drive cam and the valve drive cam can be optimized so that the combined dynamic torque of the two is less than the dynamic torque of each of them individually.

[0017] According to two aspects of the present invention, a control method for a high-pressure fuel pump drive device is provided, applied to the high-pressure fuel pump drive device described above, the control method for the high-pressure fuel pump drive device comprising:

[0018] Obtain the predetermined oil pressure under engine operating conditions;

[0019] Determine if the oil pressure has reached the predetermined pressure;

[0020] If the oil pressure reaches the predetermined pressure, adjust the high-pressure oil pump injection pressure.

[0021] Determine whether the fuel injection pressure has reached the target pressure;

[0022] If the injection pressure reaches the target pressure, adjust the phaser to the predetermined angle;

[0023] Determine whether the phaser has reached the predetermined target angle.

[0024] Optional, also includes:

[0025] If the oil pressure cannot be fed back normally or is abnormal, adjust the phaser to the initial position.

[0026] Optional, also includes:

[0027] If the injection pressure cannot be fed back normally or is abnormal, adjust the phaser to the initial position.

[0028] Optional, also includes:

[0029] Obtain engine operating conditions.

[0030] Optional, also includes:

[0031] Obtain the engine oil pressure sensor signal.

[0032] The above solution achieves the following beneficial technical effects:

[0033] 1) The camshaft can still be used to drive the 500bar high-pressure oil pump. It can withstand the force of driving the 500bar high-pressure oil pump, but there will be no wear or damage to the camshaft or the high-pressure oil pump.

[0034] 2) Ordinary hydraulic phase adjusters can still be used for adjustment. There is no need to worry that insufficient adjustment force of the hydraulic phase adjuster will lead to poor phase adjustment stability and subsequent jamming and damage. There is no need to use electric phase adjusters, which are more expensive but have stronger driving force.

[0035] 3) Existing chain systems and engine layouts can be used to maintain a compact layout and simple component structure.

[0036] In summary, a 500-bar high-pressure oil pump can be used with the current engine structure and configuration, which is low-cost and meets reliability requirements. Attached Figure Description

[0037] Figure 1 This is a structural diagram of a high-pressure fuel pump drive device provided in one or more embodiments of the present invention;

[0038] Figure 2 This is a schematic diagram of the electronic control subsystem in a high-pressure fuel pump drive device provided in one or more embodiments of the present invention;

[0039] Figure 3 This is a schematic diagram of the camshaft diameter position provided in one or more embodiments of the present invention;

[0040] Figure 4 This is a flowchart of a control method for a high-pressure fuel pump drive device provided in one or more embodiments of the present invention;

[0041] Figure 5 This is a flowchart of a control method for a high-pressure fuel pump drive device provided in one or more embodiments of the present invention;

[0042] Figure 6 This is a flowchart of a control method for a high-pressure fuel pump drive device provided in one or more embodiments of the present invention;

[0043] Figure 7 This is a flowchart of a control method for a high-pressure fuel pump drive device provided in one or more embodiments of the present invention. Detailed Implementation

[0044] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Figure 1 This is a structural diagram of a high-pressure fuel pump drive device provided in one or more embodiments of the present invention. See also... Figure 1 The high-pressure fuel pump drive unit includes: a high-pressure fuel pump 1, a camshaft position sensor 2, a camshaft mounting cover 3, a camshaft support journal 31, a high-pressure fuel pump mounting hole 32, a camshaft 4, a high-pressure fuel pump drive cam 41, a camshaft tail journal 42, a camshaft tube 43, a valve drive cam 44, and a VCT assembly 5.

[0046] After adopting 500bar fuel injection technology, the driving force of the 500bar high-pressure fuel pump increases by approximately 20% compared to the traditional 350bar high-pressure fuel pump. If the camshaft is still used for driving, it will place a significant load on the camshaft, potentially leading to wear or fatigue fracture if poorly designed. Traditional 350bar high-pressure fuel pumps are driven by the camshaft; if the 500bar high-pressure fuel pump can also be driven by the camshaft, it would be advantageous in terms of engine compactness and system simplification. If the camshaft cannot be used to drive the 500bar high-pressure fuel pump, a crankshaft or other additional shafts would be needed, increasing the complexity of the engine system, raising engine costs, and hindering engine simplification and compactness.

[0047] To address the aforementioned problems in the prior art, this embodiment still uses a camshaft for driving, and the fit between the camshaft and the camshaft mounting cover is a through-shaft type.

[0048] Each journal of the camshaft mates with a corresponding journal on the mounting cover.

[0049] The high-pressure oil pump on the camshaft drives the cam as close as possible to the camshaft tail journal. The camshaft tail journal can be selected with different widths to enhance strength. The camshaft tube diameter can also be selected with different inner and outer diameters to meet strength requirements.

[0050] The above structural design can prevent wear on the high-pressure oil pump drive cam and tail shaft journal caused by increased force on the high-pressure oil pump drive cam on the camshaft, resulting in large deformation at the high-pressure oil pump drive cam.

[0051] Meanwhile, because the high-pressure oil pump drive cam on the camshaft is located close to the camshaft tail journal, the tail journal's width and outer diameter can be adjusted according to strength requirements. The camshaft tube can also be strengthened by increasing its inner and outer diameters. Therefore, the high-pressure oil pump drive cam only needs a camshaft journal on its front side, eliminating the need for a separate camshaft support journal on its rear side, resulting in a compact engine layout in axial space. Furthermore, using a camshaft to drive the high-pressure oil pump allows it to be located closest to the fuel injector, further enhancing the compact layout of the fuel injection system.

[0052] Additionally, it should be noted that after the camshaft drives the 500bar high-pressure oil pump cam, the camshaft torque is the sum of the torques from the valve-driven cam and the high-pressure oil pump-driven cam. If the dynamic torque fluctuation of the camshaft increases, the corresponding load on the chain will be greater, resulting in higher chain stress and requiring additional investment to improve the chain's fatigue strength.

[0053] In other words, using a 500-bar technical solution may cause excessive fatigue in the chain, thereby affecting the overall operation of the device.

[0054] To address the aforementioned problems in the prior art, this embodiment optimizes the angles of the high-pressure oil pump drive cam and the valve drive cam, making the combined dynamic torque of the two less than their individual dynamic torques, thereby reducing the load on the chain and allowing the use of a low-cost narrow chain.

[0055] Specifically, see Figure 1 The most critical components of the high-pressure fuel pump drive unit are: 1. High-pressure fuel pump, 2. Camshaft position sensor, 3. Camshaft mounting cover, 4. Camshaft, and 5. VCT assembly.

[0056] The high-pressure oil pump 1 is installed at the end of the camshaft 4. It is connected to the camshaft 4 through the camshaft mounting cover 3, thereby enabling the camshaft 4 to drive the high-pressure oil pump 1.

[0057] A camshaft position sensor 2 is also installed on the camshaft 4. The function of the camshaft position sensor 2 is to sense the current rotational position of the camshaft.

[0058] At the very front of the camshaft 4, there is a VCT assembly 5. The main purpose of the VCT assembly 5 is to facilitate the engine's drive of the camshaft 4.

[0059] Figure 2 This is a structural diagram of the electronic control subsystem in a high-pressure fuel pump drive device provided in one or more embodiments of the present invention. See also... Figure 2 The electronic control subsystem of the high-pressure fuel pump drive unit includes: ECU, camshaft position sensor, oil pressure sensor, and MP pressure sensor. These sensors transmit the sensed parameters to the ECU, enabling the ECU to perform corresponding control operations.

[0060] The ECU controls the VCT component and the electronic oil pump.

[0061] Figure 3 This is a schematic diagram showing the position of the camshaft diameter according to one or more embodiments of the present invention. See also Figure 3Along the extension direction of the camshaft, from the end of the camshaft forward, a high-pressure oil pump 1, a camshaft position sensor 2, a camshaft mounting cover 3, a camshaft 4, and a VCT assembly 5 are arranged in sequence.

[0062] More specifically, the camshaft 4 includes: a high-pressure oil pump driven cam 41, a camshaft tail journal 42, a camshaft tube 43, and a valve driven cam 44.

[0063] To meet the strength requirements of the new application scenario, the high-pressure oil pump driving cam 41 on camshaft 4 is positioned as close as possible to the camshaft tail journal 42. The camshaft tail journal 42 can be selected with different widths to enhance strength, depending on the strength requirements. The diameter of the camshaft tube 43 can also be selected with different inner and outer diameters according to the strength requirements.

[0064] Figure 4 This is a flowchart illustrating a control method for a high-pressure fuel pump drive device provided in one or more embodiments of the present invention. See also... Figure 4 The control method for the high-pressure fuel pump drive device includes the following operating steps:

[0065] S41, obtain the predetermined oil pressure under engine operating conditions.

[0066] S42 determines whether the oil pressure has reached the predetermined pressure.

[0067] S43, if the oil pressure reaches the predetermined pressure, adjust the high-pressure oil pump injection pressure.

[0068] S44 determines whether the fuel injection pressure has reached the target pressure.

[0069] S45, if the injection pressure reaches the target pressure, adjust the phaser to the predetermined angle.

[0070] S46, determine whether the phaser has reached the predetermined target angle.

[0071] The problem this embodiment needs to solve is to facilitate the stable use of the phaser.

[0072] Specifically, after the camshaft drives the 500bar high-pressure oil pump, the average torque of the camshaft increases. The phaser needs sufficient driving force to adjust the camshaft phase. If the phaser's driving force is insufficient, it manifests as poor control stability when driving the camshaft, the camshaft failing to stably adjust to the target phase, and even phaser failure, potentially leading to engine failure. Since ordinary hydraulic phasers are driven by oil pressure, whether the phaser has sufficient driving force depends on two factors: whether the oil pressure is high enough and the camshaft driving torque. Under a certain camshaft driving torque, using an ordinary hydraulic phaser, when the oil pressure is high enough, the phaser has sufficient driving force and can function normally. However, when the oil pressure is below a certain value, the phaser lacks sufficient driving force, raising concerns about the phaser's control stability and reliability. The drive system proposed in this invention still aims to use ordinary hydraulic phasers because of their low cost, which benefits engine costs. Especially at low engine speeds, if the oil pressure is low, phaser adjustment will be problematic. Therefore, to achieve this goal, appropriate usage methods or control strategies are needed. Firstly, using an electronic oil pump allows for electronic regulation of oil supply pressure, unaffected by engine speed. However, higher oil pressure isn't always better. Therefore, by considering the oil pressure required for various operating conditions and combining it with control strategies, a conventional phaser can be used safely and stably.

[0073] In the control process provided in this embodiment, the most important control core is that the phaser must be adjusted only after the oil pressure and the high-pressure oil pump injection pressure are confirmed to meet the predetermined values.

[0074] Specifically, the first step is to obtain the predetermined oil pressure under engine operating conditions. After obtaining the oil pressure under engine operating conditions, it is determined whether the obtained oil pressure has reached the predetermined pressure.

[0075] Only after confirming that the oil pressure has reached the predetermined pressure should the injection pressure of the high-pressure oil pump be adjusted.

[0076] After confirming that the oil pressure has reached the predetermined pressure, it is then determined whether the injection pressure of the high-pressure oil pump has reached the target pressure. Only if the injection pressure has reached the target pressure will the phaser angle adjustment operation be executed.

[0077] Once the phase sensor is adjusted to the target angle, the control objective of the entire control process has been achieved, and the control process ends.

[0078] Figure 5 This is a flowchart illustrating a control method for a high-pressure fuel pump drive device provided in one or more embodiments of the present invention. See also... Figure 5The control method for the high-pressure fuel pump drive device includes the following operating steps:

[0079] S51, obtain engine operating conditions.

[0080] S52, acquire the engine oil pressure sensor signal.

[0081] S53 obtains the predetermined oil pressure under engine operating conditions.

[0082] S54 determines whether the oil pressure has reached the predetermined pressure.

[0083] S55, if the oil pressure reaches the predetermined pressure, adjust the high-pressure oil pump injection pressure.

[0084] S56 determines whether the fuel injection pressure has reached the target pressure.

[0085] S57, if the injection pressure reaches the target pressure, adjust the phaser to the predetermined angle.

[0086] S58 determines whether the phaser has reached the predetermined target angle.

[0087] It should be understood that adjusting the phaser angle is a prerequisite for specific engine operating conditions. Adjustment of the engine phaser angle is only necessary when the engine is under certain specific operating conditions.

[0088] Therefore, in the solution provided in this embodiment, it is first necessary to obtain the engine's operating conditions.

[0089] After obtaining the engine's operating conditions, the next step is to acquire the engine's oil pressure sensor signal. Acquiring the oil pressure sensor signal prepares for the next step of obtaining the engine's oil pressure under operating conditions. Only with a stable oil pressure sensor signal can the oil pressure under operating conditions be further obtained, allowing for a determination of whether it is appropriate to adjust the phaser angle.

[0090] Similar to the previous embodiments of the present invention, the execution process in this embodiment ends when the phaser is adjusted to the target angle. The phaser being adjusted to the target angle means that the ordinary phaser can be used stably, and the control objective of the control process has been achieved. Therefore, the control process can end.

[0091] Figure 6 This is a flowchart illustrating a control method for a high-pressure fuel pump drive device provided in one or more embodiments of the present invention. See also... Figure 6 The control method for the high-pressure fuel pump drive device includes the following operating steps:

[0092] S61 obtains the predetermined oil pressure under engine operating conditions.

[0093] S62 determines whether the oil pressure has reached the predetermined pressure.

[0094] S63, if the oil pressure reaches the predetermined pressure, adjust the high-pressure oil pump injection pressure.

[0095] S64. If the oil pressure cannot be fed back normally or is abnormal, adjust the phaser to the initial position.

[0096] S65 determines whether the fuel injection pressure has reached the target pressure.

[0097] S66, if the injection pressure reaches the target pressure, adjust the phaser to the predetermined angle.

[0098] S67. If the injection pressure cannot be fed back normally or is abnormal, adjust the phaser to the initial position.

[0099] S68 determines whether the phaser has reached the predetermined target angle.

[0100] The biggest difference between this embodiment and the previous embodiments of the present invention is that it adds operating steps for abnormal oil pressure, and further adds operating steps for abnormal injection pressure.

[0101] It should be understood that the obtained oil pressure may reach the predetermined pressure, or the oil pressure may not be able to be fed back normally in this application, or the fed back oil pressure may be outside the normal range and be an abnormal value.

[0102] Unlike the normal oil pressure acquisition procedure, if the oil pressure parameter itself is not normally acquired, or if the acquired oil pressure is an abnormal value, such as a value less than zero, then subsequent steps in the control process should not be executed. Simultaneously, the phaser needs to be adjusted to its initial position.

[0103] The same situation occurs during the acquisition of fuel injection pressure parameters. If the fuel injection pressure parameters cannot be acquired normally, or if the acquired fuel injection pressure parameters are themselves abnormal values, then no further control operations are required. Simultaneously, the phaser needs to be adjusted to its initial position, and no further phaser angle adjustment operations should be performed.

[0104] In other words, in the technical solution given in this embodiment, the adjustment operation of the phase angle will only be performed if both the oil pressure and the injection pressure parameters can be obtained normally and the obtained oil pressure and injection pressure parameters are normal.

[0105] Figure 7 This is a flowchart illustrating a control method for a high-pressure fuel pump drive device provided in one or more embodiments of the present invention. See also... Figure 7 The control method for the high-pressure fuel pump drive device includes the following operating steps:

[0106] S701, obtain engine operating conditions.

[0107] S702, acquires the engine oil pressure sensor signal.

[0108] S703 obtains the predetermined oil pressure of the engine under operating conditions.

[0109] S704 determines whether the oil pressure has reached the predetermined pressure.

[0110] S705, if the oil pressure cannot be fed back normally or is abnormal.

[0111] S706, adjust the phaser to the initial position.

[0112] S707, if the oil pressure reaches the predetermined pressure.

[0113] S708, adjusts the injection pressure of the high-pressure oil pump.

[0114] S709 determines whether the fuel injection pressure has reached the target pressure.

[0115] S710, if the fuel injection pressure cannot be fed back normally or is abnormal.

[0116] S711, adjust the phaser to the initial position.

[0117] S712, adjust the phaser to the predetermined angle.

[0118] S713 determines whether the phaser has reached the predetermined target angle.

[0119] In the technical solution provided in this embodiment, the operating conditions of the engine are first obtained.

[0120] After completing the acquisition of operating conditions, the oil pressure sensor signal is acquired.

[0121] Next, obtain the predetermined oil pressure under engine operating conditions.

[0122] After obtaining the predetermined oil pressure under certain operating conditions, the obtained oil pressure sensor signal is compared with the predetermined oil pressure to see if the current oil pressure has reached the predetermined pressure.

[0123] If the comparison result shows that the oil pressure has reached the predetermined pressure, then proceed with the subsequent steps as normal.

[0124] If the oil pressure cannot be obtained normally, or if an abnormality occurs, the phaser will be adjusted to the initial position, and no further steps will be performed.

[0125] Once the oil pressure reaches the predetermined pressure, the injection pressure of the high-pressure oil pump is adjusted.

[0126] The process of adjusting the fuel injection pressure is as follows:

[0127] First, determine whether the fuel injection pressure can reach the target pressure.

[0128] If the injection pressure becomes abnormal or cannot be obtained normally during this process, the phaser will be adjusted to the initial position and no further steps will be performed.

[0129] If the injection pressure reaches the target pressure, the phaser is adjusted to the target angle.

[0130] Finally, determine whether the phaser has reached the target angle.

[0131] Through the above adjustment and control process, the safe and stable use of ordinary phasers is ensured.

[0132] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-pressure fuel pump drive device, characterized in that, The high-pressure fuel pump drive device includes: Camshaft, and camshaft mounting cover; The camshaft passes through the shaft hole of the mounting cover, and each journal of the camshaft mates with the corresponding journal on the mounting cover; The high-pressure oil pump on the camshaft drives the cam to be positioned close to the camshaft tail journal; The tail journal of the camshaft is selected with different widths according to the strength requirements, and the diameter of the camshaft tube is also selected with different inner and outer diameters according to the strength requirements.

2. The apparatus according to claim 1, characterized in that, The high-pressure oil pump drive cam only has a camshaft journal on its front side, and no camshaft support journal is provided on its rear side.

3. The apparatus according to claim 1, characterized in that, A camshaft is used to drive a high-pressure oil pump.

4. The apparatus according to claim 1, characterized in that, The high-pressure oil pump uses an electronic oil pump.

5. The apparatus according to claim 1, characterized in that, Optimize the angles of the high-pressure oil pump drive cam and the valve drive cam so that the combined dynamic torque of the two is less than the dynamic torque of each of them individually.

6. A control method for a high-pressure fuel pump drive device, applied to the high-pressure fuel pump drive device according to any one of claims 1 to 5, characterized in that, The control method for the high-pressure fuel pump drive device includes: Obtain the predetermined oil pressure under engine operating conditions; Determine if the oil pressure has reached the predetermined pressure; If the oil pressure reaches the predetermined pressure, adjust the high-pressure oil pump injection pressure. Determine whether the fuel injection pressure has reached the target pressure; If the injection pressure reaches the target pressure, adjust the phaser to the predetermined angle; Determine whether the phaser has reached the predetermined target angle.

7. The control method according to claim 6, characterized in that, Also includes: If the oil pressure cannot be fed back normally or is abnormal, adjust the phaser to the initial position.

8. The control method according to claim 6, characterized in that, Also includes: If the injection pressure cannot be fed back normally or is abnormal, adjust the phaser to the initial position.

9. The control method according to claim 6, characterized in that, Also includes: Obtain engine operating conditions.

10. The control method according to claim 6, characterized in that, Also includes: Obtain the engine oil pressure sensor signal.

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