A mechanical pump engine in-cylinder brake control system and method

Abstract

The application discloses a mechanical pump engine in-cylinder brake control system and method, and belongs to the technical field of engines.The system comprises a driver's cab brake switch, a clutch switch, a fuel pump switch, a brake controller, an engine speed sensor and an in-cylinder brake.The driver's cab brake switch, the clutch switch and the fuel pump switch are connected in series, and are used for acquiring the driver's braking intention, the clutch pedal state and the throttle pedal state respectively; the engine speed sensor is used for collecting the engine speed.The brake controller controls the in-cylinder brake to be opened when all the three switches are closed and the engine speed is greater than a preset threshold, and controls the in-cylinder brake to be closed when any condition is not met.The application can release the high pressure of the engine compression stroke under the safe working condition, consume the downhill kinetic energy of the vehicle, improve the auxiliary braking efficiency and reduce the overheat failure risk of the service brake.

Description

Technical Field

[0001] This invention belongs to the field of engine technology, and in particular relates to a control system and method for an in-cylinder brake in a mechanical pump engine. Background Technology

[0002] Heavy vehicles typically require continuous braking to control speed when driving on long downhill slopes in mines, mountainous areas, and other heavy-load conditions. Prolonged reliance on wheel brakes can lead to decreased braking efficiency or even thermal failure due to continuous overheating. In-cylinder brakes can convert the engine into an air compressor, releasing high-pressure gas during the compression stroke to dissipate vehicle kinetic energy, thereby sharing the load on the service brakes and improving downhill safety. Compared to exhaust butterfly valve brakes, in-cylinder brakes act directly on the engine valve mechanism, offering advantages such as high braking power, low exhaust back pressure, and less impact on engine components. Furthermore, mechanical pump diesel engines offer high reliability, making them suitable for complex heavy-load conditions in mines and mountainous areas. However, in-cylinder brakes can only provide auxiliary deceleration and cannot replace the service brake to bring the vehicle to a complete stop. Their activation requires coordination with driver intent, clutch status, throttle position, and engine speed. Therefore, it is necessary to provide an in-cylinder brake control scheme suitable for mechanical pump diesel engines. Summary of the Invention

[0003] To address the problem of difficulty in coordinating brake control based on driver intent, clutch status, throttle position, and engine speed when using in-cylinder brakes in existing mechanical pump diesel engines, this invention provides a control system and method for in-cylinder brakes in mechanical pump engines. This invention aims to ensure that the in-cylinder brakes only engage when the vehicle's transmission is engaged, the engine has stopped supplying fuel, and the engine speed meets braking requirements. This improves the reliability of in-cylinder brake control and reduces the risk of service brake overheating and failure under heavy-load, long downhill conditions.

[0004] To achieve the above objectives, the present invention provides a mechanical pump engine cylinder brake control system, including a cab brake switch, a clutch switch, a fuel pump switch, a brake controller, an engine speed sensor, and a cylinder brake. The cab brake switch outputs a cylinder brake activation signal based on the driver's operation. The clutch switch cooperates with the clutch pedal rocker arm to close when the clutch pedal is in its initial position and disengage when the clutch pedal is depressed. The fuel pump switch cooperates with the mechanical fuel pump's switch lever to close when the accelerator pedal is in its initial position and disengage when the accelerator pedal is depressed. The cab brake switch, clutch switch, and fuel pump switch are connected in series. The engine speed sensor collects engine speed signals. The brake controller is electrically connected to the cab brake switch, clutch switch, fuel pump switch, and engine speed sensor, respectively, and controls the cylinder brake to open when all three switches are closed and the engine speed is greater than a preset speed threshold, and controls the cylinder brake to close when any condition is not met.

[0005] Preferably, the preset speed threshold is 1000 rpm; when the engine speed is greater than 1000 rpm, the brake controller allows the in-cylinder brake to open; when the engine speed is less than or equal to 1000 rpm, the brake controller controls the in-cylinder brake to close.

[0006] Preferably, the clutch switch is located on the movement path of the clutch pedal rocker arm; when the clutch pedal is in the initial position, the clutch pedal rocker arm touches the clutch switch and closes it; when the clutch pedal is depressed, the clutch pedal rocker arm moves away from the clutch switch and disengages it.

[0007] Preferably, the fuel pump switch is located at the mechanical fuel pump; when the accelerator pedal is in the initial position, the fuel pump switch contacts and closes with the switch lever; when the accelerator pedal is depressed, the switch lever disengages from the fuel pump switch and disconnects it.

[0008] Preferably, the in-cylinder brake includes a solenoid valve and a brake plunger. The brake controller is electrically connected to the solenoid valve. After the solenoid valve is opened, high-pressure oil enters the oil circuit of the in-cylinder brake through the solenoid valve and drives the brake plunger to extend.

[0009] Preferably, the brake plunger cooperates with the exhaust valve brake rocker arm mechanism to drive the exhaust valve brake rocker arm mechanism to perform in-cylinder braking action when the brake plunger extends.

[0010] Preferably, when any one of the switches in the cab brake switch, the clutch switch, and the fuel pump switch is turned off, the brake controller cuts off the power supply to the in-cylinder brake.

[0011] The present invention provides a method for controlling an in-cylinder brake in a mechanical pump engine, comprising the following steps: The driver's in-cylinder brake activation command is obtained through the cab brake switch. The clutch pedal is detected to be in its initial position via a switch at the clutch. The accelerator pedal is detected to be in its initial position via a switch at the fuel pump. Engine speed is obtained through an engine speed sensor; When the cab brake switch is closed, the clutch switch is closed, the fuel pump switch is closed, and the engine speed is greater than the preset speed threshold, the cylinder brake is opened. When any of the switches is open or the engine speed is less than or equal to a preset speed threshold, the in-cylinder brake is closed.

[0012] Preferably, controlling the opening of the in-cylinder brake includes: the brake controller supplies power to the solenoid valve of the in-cylinder brake, causing the solenoid valve to open, and high-pressure oil enters the oil circuit of the in-cylinder brake through the solenoid valve and drives the brake plunger to extend, so that the exhaust valve brake rocker arm mechanism performs the in-cylinder braking action.

[0013] Preferably, the brake controller cuts off the power supply to the solenoid valve, causing the high-pressure oil to stop driving the brake plunger, the brake plunger to retract from the braking position, and the exhaust valve brake rocker arm mechanism to return to the non-braking state.

[0014] Compared with the prior art, the present invention has the following beneficial technical effects: This invention enables mechanical pump engines to reliably utilize in-cylinder brakes without relying on exhaust butterfly valve-type exhaust brakes. By acting on the engine valve mechanism and releasing high-pressure gas during the compression stroke, the engine can consume the vehicle's kinetic energy when descending a slope, achieving braking power higher than exhaust braking that simply blocks the exhaust pipe, thereby improving engine braking efficiency. Simultaneously, the lower exhaust pipe back pressure generated by in-cylinder braking helps reduce the adverse effects of braking on engine components and can share the service brake load under heavy-load, long downhill conditions, reducing the risk of service brake performance degradation or failure due to continuous heating. Attached Figure Description

[0015] Figure 1 This is a block diagram of the control system in the mechanical pump engine in-cylinder brake control system and method of the present invention; Figure 2 This is a schematic diagram of the switch installation position at the clutch in a mechanical pump engine in-cylinder brake control system and method of the present invention; Figure 3 This is a schematic diagram of the switch installation position at the fuel pump in a mechanical pump engine in-cylinder brake control system and method of the present invention; Figure 4 This is a schematic diagram of the structure of the solenoid valve for the cylinder brake in a mechanical pump engine cylinder brake control system and method of the present invention. Figure 5 This is a schematic diagram of the working state of the brake plunger in the cylinder brake system and method of a mechanical pump engine according to the present invention.

[0016] Attached reference numerals: 1. Clutch switch; 2. Clutch pedal rocker arm; 3. Fuel pump switch; 4. Switch lever; 5. Solenoid valve; 6. Brake plunger. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. 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.

[0018] like Figure 1 As shown in the figure, an embodiment of the present invention discloses a mechanical pump engine cylinder brake control system, including a 24V power supply, a cab brake switch, a clutch switch 1, a fuel pump switch 3, a brake controller, an engine speed sensor, and a cylinder brake. The cab brake switch is located in the cab and is used to receive the driver's cylinder brake activation command; the clutch switch 1 is located near the clutch pedal rocker arm 2 and is used to detect whether the clutch pedal is in its initial position; the fuel pump switch 3 is located near the mechanical fuel pump and cooperates with the switch lever 4 to detect whether the accelerator pedal is in its initial position; the engine speed sensor is used to acquire the engine speed signal in real time; the brake controller receives signals from the cab brake switch, clutch switch 1, fuel pump switch 3, and engine speed sensor, and controls the solenoid valve 5 of the cylinder brake to be energized or de-energized according to each signal.

[0019] In this embodiment, the brake controller is a small ECU used to control the in-cylinder brake. A 24V power supply provides operating power to the cab brake switch, clutch switch 1, fuel pump switch 3, and the brake controller. The in-cylinder brake is connected to the vehicle body grounding terminal. The cab brake switch, clutch switch 1, and fuel pump switch 3 form a series connection. Only when all three switches are closed does the brake controller receive the power supply conditions corresponding to the in-cylinder braking request. That is, the brake controller will only supply power to the solenoid valve 5 to open the in-cylinder brake if the driver actively activates the in-cylinder braking function, the clutch is engaged, the accelerator pedal is not depressed, and the engine speed is higher than a preset speed threshold. If any of the above conditions are not met, the brake controller will not supply power to the solenoid valve 5, and the in-cylinder brake will remain closed.

[0020] Specifically, when the driver determines that the vehicle is entering a long downhill section and needs to reduce the service brake load, they can activate the brake switch in the cab. Once the cab brake switch is closed, it indicates that the driver has the subjective intention to activate the cylinder brake, and this activation command is transmitted to the subsequent control circuit. If the driver does not activate the cab brake switch, even if switch 1 at the clutch and switch 3 at the fuel pump are closed and the engine speed meets the threshold, the cylinder brake will not activate, thus preventing the cylinder brake from engaging when the driver has no braking need.

[0021] like Figure 2 As shown, the clutch switch 1 and the clutch pedal rocker arm 2 are correspondingly arranged. When the driver does not depress the clutch pedal, the clutch pedal remains in its initial position, the clutch remains connected to the transmission, and the clutch pedal rocker arm 2 touches the clutch switch 1, causing the clutch switch 1 to close and conduct. At this time, the engine output is not disconnected from the vehicle's transmission system, and the braking force generated by the engine's reverse drag can be transmitted to the wheels through the transmission. When the driver depresses the clutch pedal, the clutch pedal rocker arm 2 disengages from the clutch switch 1, the clutch switch 1 disengages, and the cylinder brake closes, thereby preventing the cylinder brake from engaging when the vehicle is in neutral or when power transmission is interrupted.

[0022] like Figure 3 As shown, the fuel pump switch 3 is located at the mechanical fuel pump and corresponds to the switch lever 4. When the driver does not depress the accelerator pedal, the accelerator pedal is in its initial position, the fuel pump throttle is closed, and the fuel pump switch 3 contacts the switch lever 4, closing the switch 3 and indicating that the mechanical fuel pump is not currently supplying fuel to the engine for power. When the driver depresses the accelerator pedal, the switch lever 4 moves with the throttle control mechanism and disengages from the fuel pump switch 3, causing the fuel pump switch 3 to open and the cylinder brake to close. Therefore, the cylinder brake is only allowed to be activated when the engine is no longer outputting positive power, preventing the simultaneous occurrence of engine-driven and cylinder-braking conditions.

[0023] The engine speed sensor is electrically connected to the brake controller and continuously sends engine speed signals to the brake controller. The brake controller determines whether the engine is in a suitable speed range for engaging the in-cylinder brake based on the engine speed signal. In this embodiment, the preset speed threshold is 1000 rpm. When the engine speed is greater than 1000 rpm, if the cab brake switch, clutch switch 1, and fuel pump switch 3 are all closed, the brake controller supplies power to the solenoid valve 5 of the in-cylinder brake, and the in-cylinder brake engages. When the engine speed is less than or equal to 1000 rpm, the brake controller either does not supply power to the solenoid valve 5 or cuts off the power supply to the solenoid valve 5, and the in-cylinder brake closes. Therefore, the closing conditions of the three mechanical switches and the condition that the engine speed is greater than 1000 rpm constitute a series AND logic; the in-cylinder brake will only engage after all three conditions are met.

[0024] like Figure 4 and Figure 5 As shown, the in-cylinder brake includes a solenoid valve 5 and a brake plunger 6. After the brake controller supplies power to the solenoid valve 5, the solenoid valve 5 opens, and high-pressure oil enters the corresponding oil circuit of the in-cylinder brake through the solenoid valve 5, driving the brake plunger 6 to extend. The brake plunger 6 cooperates with the exhaust valve brake rocker arm mechanism, causing the exhaust valve brake rocker arm mechanism to operate according to the in-cylinder braking requirements. At the set moment of the engine compression stroke, it releases the high-pressure gas in the cylinder, causing the engine to switch from output power state to air compression state that consumes the vehicle's kinetic energy. During the dragging process, the engine consumes the vehicle's kinetic energy, thus forming an auxiliary braking force acting on the entire vehicle.

[0025] When solenoid valve 5 is de-energized, high-pressure oil can no longer drive brake plunger 6 to extend, brake plunger 6 retracts from the braking position, exhaust valve brake rocker arm mechanism returns to non-braking state, and cylinder brake closes. Since the cab brake switch, clutch switch 1, and fuel pump switch 3 all use a series control method, if any switch is disconnected, the brake controller will not meet the external conditions for supplying power to solenoid valve 5, thus disengaging the cylinder brake. This reduces the possibility of accidental brake activation due to driver error or unsuitable vehicle conditions.

[0026] The complete working process of this embodiment is as follows: After the vehicle travels to a long downhill section, the driver activates the cab brake switch; if the driver does not depress the clutch pedal, the clutch pedal rocker arm 2 contacts the clutch switch 1 and closes it; if the driver does not depress the accelerator pedal, the fuel pump throttle is in the closed state, and the fuel pump switch 3 contacts the switch control lever 4 and closes it; with all three switches closed, the brake controller reads the engine speed signal through the engine speed sensor; when the engine speed is greater than 1000 rpm, the brake controller supplies power to the solenoid valve 5, the solenoid valve 5 opens, and the high-pressure oil drives the brake plunger 6 to extend and drive the exhaust valve brake rocker arm mechanism to move, thus opening the cylinder brake. If the driver closes the cab brake switch, depresses the clutch pedal, depresses the accelerator pedal, or the engine speed is less than or equal to 1000 rpm, the brake controller cuts off the power supply to the solenoid valve 5, and the cylinder brake closes.

[0027] Through the above control method, mechanical pump engines can utilize in-cylinder brakes without relying on exhaust butterfly valve-type exhaust braking. In-cylinder brakes act directly on the engine valve mechanism, increasing engine braking power by releasing high-pressure gas during the compression stroke. Their braking efficiency is superior to exhaust braking formed by simply blocking the exhaust pipe. Simultaneously, the lower exhaust pipe back pressure helps reduce the adverse effects of exhaust braking on engine components and is suitable for heavy-load, long downhill driving conditions such as in mines and mountainous areas. It should be noted that in-cylinder brakes are auxiliary braking devices; their main function is to share the braking load during long downhill driving and reduce the risk of overheating and failure of the service brakes. The final stopping of the vehicle is still achieved by the service braking system on the wheels.

[0028] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A mechanical pump engine in-cylinder brake control system, characterized in that, The system includes a cab brake switch, a clutch switch, a fuel pump switch, a brake controller, an engine speed sensor, and an in-cylinder brake. The cab brake switch outputs an in-cylinder brake activation signal based on the driver's operation. The clutch switch engages with the clutch pedal rocker arm to close when the clutch pedal is in its initial position and disengage when the clutch pedal is depressed. The fuel pump switch engages with the mechanical fuel pump's control lever to close when the accelerator pedal is in its initial position and disengage when the accelerator pedal is depressed. The cab brake switch, clutch switch, and fuel pump switch are connected in series. The engine speed sensor collects engine speed signals. The brake controller is electrically connected to the cab brake switch, clutch switch, fuel pump switch, and engine speed sensor, respectively, and controls the in-cylinder brake to open when all three switches are closed and the engine speed is greater than a preset speed threshold, and controls the in-cylinder brake to close when any of the conditions are not met.

2. The mechanical pump engine cylinder brake control system according to claim 1, characterized in that, The preset speed threshold is 1000 rpm; when the engine speed is greater than 1000 rpm, the brake controller allows the in-cylinder brake to open; when the engine speed is less than or equal to 1000 rpm, the brake controller controls the in-cylinder brake to close.

3. The mechanical pump engine cylinder brake control system according to claim 1, characterized in that, The clutch switch is located on the movement path of the clutch pedal rocker arm; when the clutch pedal is in the initial position, the clutch pedal rocker arm touches the clutch switch and closes it; when the clutch pedal is depressed, the clutch pedal rocker arm moves away from the clutch switch and disengages it.

4. The mechanical pump engine cylinder brake control system according to claim 1, characterized in that, The fuel pump switch is located at the mechanical fuel pump; when the accelerator pedal is in the initial position, the fuel pump switch contacts and closes with the switch lever; when the accelerator pedal is depressed, the switch lever disengages from the fuel pump switch and disconnects it.

5. A mechanical pump engine cylinder brake control system according to claim 1, characterized in that, The cylinder brake includes a solenoid valve and a brake plunger. The brake controller is electrically connected to the solenoid valve. After the solenoid valve is opened, high-pressure oil enters the oil circuit of the cylinder brake through the solenoid valve and drives the brake plunger to extend.

6. A mechanical pump engine cylinder brake control system according to claim 5, characterized in that, The brake plunger works in conjunction with the exhaust valve brake rocker arm mechanism to drive the exhaust valve brake rocker arm mechanism to perform in-cylinder braking when the brake plunger extends.

7. A mechanical pump engine cylinder brake control system according to any one of claims 1-6, characterized in that, When any one of the switches in the cab brake switch, clutch switch, or fuel pump switch is turned off, the brake controller cuts off the power supply to the in-cylinder brake.

8. A control method employing the mechanical pump engine in-cylinder brake control system according to any one of claims 1 to 7, characterized in that, Includes the following steps: The driver's in-cylinder brake activation command is obtained through the cab brake switch. The clutch pedal is detected to be in its initial position via a switch at the clutch. The accelerator pedal is detected to be in its initial position via a switch at the fuel pump. Engine speed is obtained through an engine speed sensor; When the cab brake switch is closed, the clutch switch is closed, the fuel pump switch is closed, and the engine speed is greater than the preset speed threshold, the cylinder brake is opened. When any of the switches is open or the engine speed is less than or equal to a preset speed threshold, the in-cylinder brake is closed.

9. A method for controlling an in-cylinder brake in a mechanical pump engine according to claim 8, characterized in that, Controlling the opening of the cylinder brake includes: the brake controller supplies power to the solenoid valve of the cylinder brake, causing the solenoid valve to open, and high-pressure oil enters the oil circuit of the cylinder brake through the solenoid valve and drives the brake plunger to extend, so that the exhaust valve brake rocker arm mechanism performs the cylinder braking action.

10. A method for controlling an in-cylinder brake in a mechanical pump engine according to claim 8, characterized in that, The brake controller cuts off the power supply to the solenoid valve, causing the high-pressure oil to stop driving the brake plunger. The brake plunger then exits the braking position, and the exhaust valve brake rocker arm mechanism returns to the non-braking state.

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