Engine electric-free hand-pull starting system and control method thereof

Abstract

A manual start system for an engine without electricity and its control method relate to the field of switching power supply technology. Through improvements to the internal circuitry and power supply logic, it enables a manual engine start system that can successfully start an emergency engine with a minimum input of 17VAC_RMS. The system includes a manual generator for generating fluctuating AC voltage through manual operation; a flyback switching power supply module whose input is connected to the manual generator to convert the fluctuating AC voltage into a stable DC voltage; an electronic fuel injection system connected to the main output of the flyback switching power supply module, powered by the main output; and a battery connected to the charging output of the flyback switching power supply module via a charging management unit. The flyback switching power supply module includes a rectifier and filter unit, a flyback converter main circuit containing a control chip and a transformer, a low-voltage start unit, an output feedback unit, and an auxiliary power supply unit for powering the control chip.

Description

Technical Field

[0001] This invention relates to the field of switching power supply equipment technology, specifically to a manual start system for an engine without power and its control method. Background Technology

[0002] In emergency starting scenarios for general-purpose engines (especially electronic fuel injection engines), when the battery is severely depleted or has failed, the engine is often started by manually pulling the starter pull tab. However, modern electronic fuel injection systems require a stable low-voltage DC power supply (typically 12V or 24V) to operate properly and drive the fuel pump, ECU (electronic control unit), and ignition system. Therefore, a separate power module is needed to convert the meager mechanical energy (or residual battery energy) generated during the manual starting process into a stable voltage for the electronic fuel injection system, thus assisting in a successful engine start.

[0003] Existing related technologies typically use flyback switching power supplies as the core conversion circuit. Flyback converters are widely used in small to medium power AC-DC conversion applications due to their simple structure, low cost, and good electrical isolation. Their basic working principle is as follows: the input AC power is rectified and filtered to obtain high-voltage DC power. Through the periodic switching of the main switching transistor (such as a MOSFET), energy is stored in a high-frequency transformer, and when the transistor is turned off, the energy is released to the secondary side, and after rectification and filtering, a stable DC voltage is output.

[0004] However, traditional flyback switching power supplies have the following significant drawbacks and shortcomings when applied to the above-mentioned emergency start-up scenarios: 1. Narrow input voltage range and poor low-voltage start-up capability: The start-up circuit of traditional flyback power supplies is usually designed to operate at the rated input voltage. When the input voltage is low (for example, in the initial stage of manual start-up, the input voltage obtained from the remaining battery or limited inductive energy may be lower than the conventional threshold), the start-up circuit cannot provide sufficient start-up current and voltage to the control chip (such as PWM controller), causing the power module to fail to start normally. This means that when the battery power is extremely low, the electronic fuel injection system cannot obtain the required power, the engine cannot start, and its practicality in emergency scenarios is severely limited.

[0005] 2. Limited adaptability to high voltage input, and significant challenges in device selection and reliability; To cover a wider input range, traditional solutions may require complex circuit designs or the use of high-voltage devices, which not only increases design difficulty and cost, but also the startup circuit itself may generate severe heat due to continuous operation at high voltage input, affecting long-term reliability.

[0006] 3. In specific application scenarios, the overall system design is insufficient; traditional solutions usually only focus on the power conversion function itself and lack system-level optimization for the special working condition of "pulling start"; for example, they do not fully consider how to prioritize the power supply of the electronic fuel injection system under extremely low input conditions, and how to intelligently manage the relationship between battery charging and system power supply, which leads to the limited energy being consumed by the battery in reverse when the battery is severely depleted, thus reducing the start success rate.

[0007] 4. Low compatibility between protection mechanisms and scenarios; protection circuits of general power supplies (such as overcurrent and overvoltage protection) may not be fully adapted to the inrush current and complex operating conditions during engine startup, which may lead to unnecessary false protection or insufficient protection.

[0008] In summary, existing technologies, when applied to emergency manual start-up scenarios for general-purpose engines without power, generally suffer from technical bottlenecks such as narrow input voltage range, inability to start under low voltage, poor high voltage adaptability, and deficiencies in system-level design. These bottlenecks result in low start-up success rates, poor user experience, and may delay response time and cause property damage in emergency situations. Therefore, there is an urgent need for a switching power supply module that can effectively overcome the above-mentioned defects to meet the requirements of stable operation under an extremely wide input voltage range (especially low input voltage) and reliable support for emergency engine starting. Summary of the Invention

[0009] I. Technical problems to be solved This invention addresses the shortcomings of existing technologies by proposing a manual engine start system and its control method without electricity. Through improvements to the internal circuitry and power supply logic, the system enables the emergency engine to be started successfully with a minimum input of 17VAC_RMS by manually pulling the engine starter pull, and the maximum input operating voltage can reach 350VAC_RMS. This allows the module to achieve engine start in general-purpose (electronic fuel injection) emergency starting applications with only 3-4 manual pulls and less physical effort.

[0010] II. Specific Technical Solutions A control method for a manual start system for an engine without electricity, applied in a system including a manual generator, a flyback switching power supply module, an electronic fuel injection module, and a battery module, the method comprising: Start-up phase: In response to the manual operation, the first AC voltage generated by the manual generator is rectified and filtered to obtain the DC bus voltage; energy is extracted from the DC bus voltage through the low-voltage start-up circuit to provide the start-up voltage for the control chip of the flyback switching power supply module, enabling it to start working; Power supply and feedback stage: Under the control of the control chip, the flyback switching power supply module generates the main output through its transformer to power the electronic fuel injection system; at the same time, the main output is regulated and regulated through a sampling feedback circuit. Self-sustaining and charging phase: After the flyback switching power supply module is started, the auxiliary winding of its transformer provides continuous auxiliary power to the control chip; when the DC bus voltage is detected to reach the charging enable threshold, the battery charging circuit is started to charge the battery, and a unidirectional isolation element is used to prevent the battery from discharging to the electronic fuel injection system.

[0011] Implementation principle and working principle: Compared with existing manual starter power supplies, this solution defines the overall timing and energy management framework for system operation: consisting of four stages: startup, power supply, self-sustaining, and charging. This forms a core logic of phased, intelligent allocation of limited energy. Under the limited and fluctuating energy generated by manual operation, the solution ensures successful execution of the entire startup process by clearly defining stages and prioritizing startup before charging. This resolves the fundamental concern of "whether the energy is sufficient." Even under extreme constraints, the solution achieves optimal dynamic resource scheduling under conditions of weak human power and drastic fluctuations.

[0012] Preferably, the step of extracting energy from the DC bus voltage through the low-voltage startup circuit is specifically a dynamic balance startup process, which includes: when the DC bus voltage rises to the turn-on threshold of the startup NMOS transistor Q1, the startup NMOS transistor Q1 is turned on and outputs; the output voltage of the low-voltage startup circuit is sampled by voltage division; when the sampled value exceeds the first threshold, the shutdown transistor Q2 is controlled to turn on, so as to pull down the gate voltage of the startup NMOS transistor Q1 and turn it off; after the startup NMOS transistor Q1 is turned off, the DC bus voltage recharges its gate capacitance through the startup resistor RM1, repeating the above turn-on and turn-off process to form a dynamic balance, thereby providing stable startup energy for the control chip; The beneficial effect of this preferred method is that it utilizes NMOS threshold and feedback control to form a self-oscillating charge pump. It is not a linear regulator, but dynamically switches between the on and off states of Q1, efficiently "pumping" energy when the input voltage is extremely low. This is the key to achieving the core indicator of 17VAC startup, and it can extract energy from weak power sources with extremely high efficiency, reducing the startup voltage threshold to an unprecedentedly low level, directly solving the problem of the narrow input voltage range in the background technology.

[0013] Preferably, the method further includes a wide-range input power supply step, in which power is drawn from the DC bus through an independent wide-input step-down converter to provide the control chip with a stable operating voltage covering the DC input range of 30V to 500V, serving as a backup or supplement to the auxiliary power supply. The advantage of this preferred method is that when the auxiliary power supply is started, after the engine speed has stabilized, i.e. after startup is complete, the generator itself can generate a large voltage. At this time, the high voltage generated is reduced by the step-down converter to stably supply power to the electronic fuel injection module.

[0014] Preferably, the system also includes an output fault protection step, which detects the current output from the main circuit. When an overcurrent or short-circuit signal is detected, a latching protection circuit is triggered to lock the compensation terminal voltage of the control chip at the off level, thereby stopping the operation of the flyback switching power supply module. The latching protection state will be maintained until the DC bus voltage drops below the reset threshold. The advantage of this preferred method is that by using a latching circuit instead of conventional self-resetting protection, once triggered, the state remains unchanged unless the power is completely cut off or the voltage drops below the trigger holding current. In emergency scenarios, this forces users to manually restart the device after troubleshooting, avoiding the secondary damage or danger that may be caused by repeatedly attempting to start the device under unknown fault conditions, which conforms to the safety-first emergency product design principle.

[0015] Preferably, the step of detecting the main output current is performed after the power supply and feedback phase, and is only enabled after confirming that the DC bus voltage exceeds the second threshold. The beneficial effect of this preferred option is that the enabling of the charging circuit is linked to the input voltage threshold, and charging is only started when it is detected that the engine has been successfully started and has entered a higher speed for power generation. This ensures that in the most difficult initial stage of manual start, all energy is used to protect the electronic fuel injection system, completely eliminating the possibility of battery charging and engine starting "competing for energy".

[0016] Preferably, the battery charging circuit is a Buck-type constant current and constant voltage charging circuit, and the charging enable threshold is set according to the generator voltage corresponding to the expected speed after the engine starts, so as to ensure that energy is preferentially supplied to the electronic fuel injection system in the initial stage of manual start; the beneficial effect of this preferred option is that...

[0017] A manual start system for an engine without electricity includes a manual generator for generating fluctuating AC voltage through manual operation; a flyback switching power supply module, the input of which is connected to the manual generator for converting the fluctuating AC voltage into a stable DC voltage; an electronic fuel injection system connected to the main output of the flyback switching power supply module and powered by the main output; and a battery connected to the charging output of the flyback switching power supply module via a charging management unit. The flyback switching power supply module includes a rectifier and filter unit, a flyback converter main circuit comprising a control chip and a transformer, a low-voltage start unit, an output feedback unit, and an auxiliary power supply unit for powering the control chip.

[0018] Preferably, the low-voltage startup unit includes a startup resistor RM1, a startup NMOS transistor Q1, voltage divider sampling resistors R10 and R13, and a shutdown transistor Q2, to form the dynamic balance startup circuit.

[0019] Preferably, the system further includes: a wide-input buck power supply unit, the input of which is connected to the output of the rectifier and filter unit, and the output of which is connected to the power supply of the control chip; and an output overcurrent self-locking protection unit, which includes a current-sensing operational amplifier (U5A) and a latching element (SCR1). Preferably, the charging management unit includes an enable control circuit, which is used to shut down the battery charging circuit when the DC bus voltage is lower than the charging enable threshold.

[0020] The beneficial effects of this invention are as follows: 1. This invention, through a dynamic balance starting method and a corresponding low-voltage starting unit, adopts the intermittent oscillating charge pump principle based on NMOS transistors, which can efficiently extract energy from weak AC inputs as low as 17VAC_RMS. It successfully solves the core problem that traditional flyback switching power supplies cannot start under low-voltage conditions generated by manual pulling, and significantly reduces the manpower required for emergency engine starting.

[0021] 2. Provides an extremely wide input voltage range and ultra-high operational reliability: The wide input step-down power supply method and corresponding units add an independent high-voltage backup power supply path for the control chip; this enables the power module to not only adapt to an extremely wide input range of 17VAC to 350VAC, but also ensures that the power supply to the control chip remains stable when the input voltage fluctuates drastically or the load changes suddenly, effectively preventing unexpected system restarts and significantly improving robustness under complex and harsh operating conditions.

[0022] 3. This invention implements fault protection through an output fault self-locking protection method and corresponding units, using latching circuits such as SCR1 to achieve fault protection; once an overcurrent or short circuit is detected, the module will be locked in the off state until the power is completely cut off; this forces the user to manually restart after troubleshooting, avoiding secondary damage that may be caused by repeated attempts under unknown faults, which is in line with the design principle of prioritizing safety in emergency equipment.

[0023] 4. Intelligent allocation and management of system energy: Energy is scheduled on demand and in a time-sharing manner; during the initial startup phase, non-core functions are temporarily disabled by enabling control to save energy; once the engine starts successfully and the input voltage increases, the battery charging function is automatically activated; at the same time, the possibility of the battery consuming startup energy in reverse is completely eliminated through the isolation diode D13; this whole strategy ensures that the limited initial energy is concentrated on the most critical engine ignition task, fundamentally guaranteeing the success rate of emergency startup.

[0024] 5. The present invention has optimized the design of the specific circuit implementation; for example, the low-voltage start-up unit uses discrete components to form a dynamic balance circuit, which is simple, reliable and low cost; the wide input buck unit adopts the mature and efficient Buck topology, which has good stability; the charging management unit integrates charging, isolation and reverse connection protection, which improves safety and simplifies user operation; these designs together ensure that the whole system achieves excellent performance goals while having good manufacturability and market competitiveness. Attached Figure Description

[0025] Figure 1 This embodiment presents a circuit diagram of the hand-pull generator end of a hand-pull starter system for an engine without electricity.

[0026] Figure 2 This embodiment presents a low-voltage starting unit circuit diagram of an engine power-off manual pull-start system.

[0027] Figure 3 This embodiment presents a flyback converter main circuit diagram for a manual start system for an engine without electricity.

[0028] Figure 4 This embodiment presents a feedback unit circuit diagram for an engine start-up system without electric power.

[0029] Figure 5 This embodiment presents a circuit diagram of a wide-input step-down power supply unit for an engine starter system without electric power.

[0030] Figure 6 This embodiment presents a circuit diagram of an overcurrent protection unit for a manual start system for an engine without power.

[0031] Figure 7 This embodiment presents a circuit diagram of the electronic fuel injection system for a manual start system for an engine without electricity.

[0032] Figure 8 This embodiment presents a circuit diagram of the charging management unit of an engine starter system without electric power. Detailed Implementation

[0033] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0034] like Figure 1-8 As shown:

[0035] Please see Figure 1-8The present invention provides an engine start system without electricity, which mainly includes: a hand-operated generator 100, a flyback switching power supply module, an electronic fuel injection system 300, and a battery.

[0036] The specific connection circuit of the hand-operated generator is as follows: Figure 1 The generator produces AC power by hand-cranking and then connects the output of the hand-operated generator 100 to the input of the flyback switching power supply module to integrate the generated AC power into stable DC power. The fluctuating AC voltage (typically ranging from 17VAC RMS to 350VAC RMS) generated by the manual operation is then input to the power supply module.

[0037] The flyback switching power supply module includes at least two output terminals: a main output terminal Vout_main and a charging output terminal Vout_chg. The main output terminal Vout_main is connected to the electronic fuel injection system 300 to provide it with a stable operating voltage, which is 14.2V DC in this solution. The charging output terminal Vout_chg is connected to the battery through a charging management unit 500 for charging the battery.

[0038] The flyback switching power supply module contains multiple functional units, and their core connection relationship is as follows: The input terminal of the rectifier and filter unit 210 serves as the total input terminal of the module, receiving AC power from the hand-operated generator 100. The rectifier and filter unit 210 includes a bridge rectifier circuit composed of diodes D1, D3, D4, D8, D10, and D24. An electrolytic capacitor C27 and a general-purpose capacitor CF2 are connected in parallel at the output terminal of the bridge rectifier circuit for voltage regulation and filtering. The output terminal of the rectifier and filter unit 210 generates a fluctuating DC bus voltage VIN_H, which is simultaneously fed to the low-voltage start-up unit 220, the flyback converter main circuit 230, and the wide-input step-down power supply unit 240.

[0039] The output of the low-voltage startup unit 220 is connected to the power supply pin VCC of the control chip IC1 to provide startup energy. The low-voltage startup unit 220 includes resistors RM1, RM4, and R6 connected in parallel to the DC bus to obtain the bus voltage VIN_H. The other end of resistor RM1 is connected to the drain (D) of NMOS transistor Q1, and the gate (G) of the NMOS transistor is connected to the other end of resistor R6 via resistor R7. The source (S) of NMOS transistor Q1 is reduced to the startup voltage VF by diode D5 and then connected to the power supply pin VCC of IC1. When the bus voltage VIN_H reaches the threshold value for turning on NMOS transistor Q1, NMOS transistor Q1 is turned on, allowing the bus voltage VIN_H to smoothly enter the control chip IC1, thus driving the control chip IC1 with very little energy. However, if the output voltage of the bus voltage VIN_H is too high, it will affect the normal operation of the control chip IC1. In this circuit, there is a second branch on the side where resistor R7 is connected to NMOS transistor Q1. This second branch is connected to switch transistor Q2, which can be either a MOSFET or a transistor. The input terminal of switch transistor Q2 is connected to resistor R7, and the output terminal of switch transistor Q2 is grounded. The control terminal of switch transistor Q2 is connected to the source (S) terminal of NMOS transistor Q1 through diode DM1, where the anode of diode DM1 is connected to the source (S) terminal of NMOS transistor Q1. The advantage of this circuit is that when the output voltage of NMOS transistor Q1 exceeds a set value, this voltage will drive the control terminal of switch transistor Q2 to turn off, causing the gate (G) terminal of NMOS transistor Q1 to ground, thus disconnecting NMOS transistor Q1 and preventing excessively high voltage output from the control chip IC1. In practice, after normal startup, there is no need to use a hand crank. At this time, the bus voltage VIN_H is relatively high, so it can no longer be powered by the low-voltage startup unit 220. To achieve this, the other end of resistor RM4 is grounded through resistors RM7 and RM8 connected in series. A bypass is set between resistors RM7 and RM8, and a diode DM2 is set in the bypass. The negative terminal of diode DM2 is connected to the control terminal of switch Q2. When the voltage is too high, the voltage will directly close switch Q2, so that the gate of NMOS transistor Q1 is always grounded, keeping it in the open state, avoiding power consumption after startup or damage caused by excessive voltage fluctuations.

[0040] After normal startup, the voltage generated at the output terminal of the hand-operated generator 100 is between 30V and 500V. Since the low-voltage startup unit 220 is locked under the action of MOSFET Q2, the bus voltage VIN_H is directly output to the wide-input step-down power supply unit 240. The output of the wide-input step-down power supply unit 240 is connected to the power supply pin VCC of the control chip IC1. The DC step-down unit includes a BUCK step-down circuit composed of a DC step-down chip U7, an inductor L1, and a diode D27, and specifically step-downs the voltage to 13V to provide stable power to the control chip IC1.

[0041] The transformer T1 in the flyback converter main circuit 230 has at least three windings: a primary winding, a secondary winding that supplies power to the main output, and an auxiliary winding that provides continuous operating power to the control chip IC1. The output of the auxiliary winding is rectified and filtered to form an auxiliary power supply VCC_aux, which is also connected to the VCC pin of the control chip IC1 through diode D16.

[0042] In specific implementation, the positive terminal of the primary winding is connected to the DC bus, and the negative terminal of the primary winding is connected to the input terminal of the switching transistor Q7. In this embodiment, the switching transistor Q7 is specifically a MOSFET. The driving terminal of the switching transistor Q7 is connected to the pulse output terminal GD of the control chip IC1, and the output terminal of the switching transistor Q7 is grounded through resistor R27. That is, the switching transistor Q7 is turned on and off by the pulse issued by the control chip IC1, so that the DC voltage of the bus changes into an alternating voltage, thereby providing input to the transformer T1. In practice, the positive terminal of the auxiliary winding is connected to the positive terminal of diode D15 through resistor R80, and the negative terminal of diode D15 is connected to the negative terminal of the auxiliary winding and grounded through resistor R82. The negative terminal of diode D15 is also connected to the positive terminal of diode D16, and the positive terminal of diode D16 is connected to the VCC terminal of control chip IC1. When the generator starts up or the voltage generated by the generator exceeds the set value, the auxiliary winding stably supplies power to control chip IC1. The positive terminal of the secondary winding is connected to a diode group D2. The positive terminals of the two diodes in the diode group D2 are connected together and then connected to the positive terminal of the secondary winding. The negative terminals of the two diodes are connected together and then connected to the positive terminal of the electronic fuel injection system 300. The negative terminal of the electronic fuel injection system is grounded through resistor R45. In addition, in order to avoid abnormal conditions such as overcurrent in the electronic fuel injection system, it is necessary to monitor and control the electronic fuel injection system. In practical implementation, a resistor R30 is connected to the negative terminal of diode group D2. The other end of resistor R30 is connected to the positive terminal of the light-emitting end of optocoupler U1. The negative terminal of the light-emitting end of optocoupler U1 is grounded. The input terminal of the light-receiving end of optocoupler U1 is connected to one of the COMP terminals of control chip IC1. At this time, the voltage of the electronic fuel injection system is actually detected through the negative terminal of diode group D2. When this voltage fluctuates, it drives the feedback signal to be transmitted to the COMP terminal of control chip IC1 through optocoupler U1. At this time, control chip IC1 can control the duty cycle of switching transistor Q7 according to the feedback signal. This achieves closed-loop control. In this circuit, to ensure the stability of the feedback signal, the negative terminal of the light-emitting end of the optocoupler U1 is connected to a resistor R35 and a thyristor U2, respectively. Specifically, it is connected to the input terminal of the thyristor U2. The control terminal of the thyristor U2 is connected to the negative terminal of the diode group D2 through a resistor R40 and grounded through a resistor R43. The output terminal of the thyristor U2 is grounded. A capacitor C21 is also connected to the input terminal of the thyristor U2. The other end of the capacitor C21 is connected between a resistor R40 and a resistor R43. A resistor R41 and a capacitor C22 are also connected in parallel in the branch of the capacitor C21.

[0043] In implementation, to better monitor the electronic fuel injection system and prevent faults such as overcurrent, a feedback unit 250 is also included. The two ends of resistor R45 are respectively connected to the positive and negative terminals of operational amplifier U5A. The output terminal of operational amplifier U5A is connected to the base of transistor Q13 through a drive circuit. The collector of transistor Q13 is connected to the negative terminal of the light-emitting end of optocoupler U3. The positive terminal of the light-emitting end of optocoupler U3 is connected to the negative terminal of diode group D2. The input terminal of the light-receiving side of optocoupler U3 is connected to the negative terminal of diode D5 or diode D20, and this light-receiving side is also connected to the collector of transistor Q5. The output terminal is connected to the base of transistor Q5 through a current-limiting protector with SCR1, and the emitter of transistor Q5 is connected to the base of transistor Q6 through resistor R4. The collector of transistor Q6 is connected to the input terminal of the light-receiving side of optocoupler U1, and the emitter of transistor Q6 is grounded. In practice, operational amplifier U5A forms a differential amplifier to detect the voltage drop across the sampling resistor R45 connected in series in the main output circuit. This voltage drop is proportional to the output current. The amplified signal is sent to a delay circuit composed of resistors R92 and R94, capacitor C41 and transistor Q12 to ignore the legitimate inrush current at the moment of engine start-up. The delayed current detection signal is compared with a reference voltage (e.g., corresponding to 1.5 times the rated current) generated by a resistor divider. When the detection signal exceeds the reference voltage, the comparator circuit composed of operational amplifier U5A or its output high level triggers the gate of the thyristor SCR1, causing SCR1 to conduct and latch. The conducting SCR1 controls a turn-off circuit composed of transistors Q5, Q6, etc., forcibly pulling down the compensation terminal COMP voltage of the optocoupler U1, thereby turning off the PWM output and stopping the entire flyback power supply. Due to the characteristics of SCR1, this protection state will be locked until the DC bus voltage VIN_H drops completely, such as below 30VDC, causing the SCR1 anode to lose power before it can be reset. This self-locking protection mechanism requires manual restart after eliminating faults such as output short circuits, avoiding repeated attempts to restart the equipment under fault conditions and causing secondary damage.

[0044] In implementation, the operational amplifier U5A also includes an operational amplifier power supply circuit, which includes an optocoupler U4. The light-emitting input terminal of the optocoupler U4 is connected to the VCC terminal of the control chip IC1, and the light-emitting output terminal of the optocoupler is connected to the input terminal of the MOSFET Q17. The output terminal of the MOSFET Q17 is grounded, and the control terminal of the MOSFET Q17 is connected to the DC bus in sequence through resistors R1 and R3. The light-receiving input terminal of the optocoupler U4 is connected to one end of the optocoupler U1 through resistor R2 and resistor R30, receiving the same 14.2 ohm DC input. The light-receiving output terminal of the light-receiving side of the light-point coupler U4 is grounded, and is also connected to the output terminal of the MOSFET Q10 through resistor RS1. The control terminal of the MOSFET Q10 is connected between the light-receiving input terminal of the optocoupler U4 and resistor R2.

[0045] In implementation, transformer T1 is also connected to a charging winding. The negative terminal of the charging winding D12 is grounded, and the positive terminal of the charging winding D12 is connected to the positive terminal of diode D12. The negative terminal of diode D12 is connected to the VIN pin of power management chip U8. The SW pin of power management chip U8 is connected to the positive terminal of the battery through inductor L2 and diode D18. As shown in the figure, the power management chip U8 and the connected inductor L2, diode D19 and capacitor C10 constitute a BUCK charging circuit to achieve constant current and constant voltage charging. The positive terminal of diode D18 is connected back to the feedback pin FB of power management chip U8 through resistor R21 to facilitate constant current and constant voltage charging. The transistor Q14, MOSFET Q3 and Zener diode D22 connected between the positive and negative terminals of the battery constitute a reverse connection protection circuit. A charging activation circuit is connected between the positive and negative terminals of the battery. Its purpose is to activate only when the input to the electronic fuel injection system 300 reaches a threshold, ensuring that the entire flyback power supply provides energy to the electronic fuel injection system at full load at low speeds. The charging activation circuit includes an optocoupler U6. The positive terminal of the light-receiving side of the optocoupler U6 is connected to the base of transistor Q14 through resistor R101, and the negative terminal of the light-receiving side is connected to the negative terminal of the battery through diode D23. The positive terminal of the light-emitting side of the optocoupler U6 is connected to the control circuit through resistor RS4. The VCC terminal of chip IC1, the negative terminal of the light-emitting side, is connected to the input terminal of MOSFET Q16. The control terminal of MOSFET Q16 is connected to the DC bus through series resistors R106 and R107. The output terminal of MOSFET Q16 is grounded. A resistor R108 is connected in parallel between the output terminal and the control terminal of MOSFET Q16. To prevent the electronic fuel injection system from reversing the power supply to the battery, the positive terminal of the battery is connected to diode D13. The negative terminal of diode D13 is connected to the positive terminal of the electronic fuel injection system. The batteries of the electronic fuel injection system 300 share a common low-level terminal or a common negative terminal.

[0046] During implementation, the specific implementation methods of each unit of the system are as follows: Firstly, the rectifier and filter unit 210 and the low-voltage start-up unit 220: The rectifier and filter unit 210 consists of a rectifier bridge BR1 and a filter capacitor C27, which converts the AC power generated by the hand-operated generator 100 into a DC bus voltage VIN_H. The low-voltage startup unit 220 is a key circuit for enabling startup under extremely low input voltage; it includes a startup resistor RM1, an NMOS transistor Q1 as a startup switch, a voltage divider sampling network composed of resistors R10 and R13, and an NPN transistor Q2 as a shutdown control transistor.

[0047] Secondly, the flyback converter main circuit 230 and auxiliary power supply: After the control chip U1 is started, it drives the internal MOSFET or the external main switch Q7 to work, so that the primary winding of the transformer T1 performs energy storage-energy release conversion; the voltage induced by the primary and secondary windings is rectified by the rectifier diode D2 and the filter capacitor C2 to generate a stable main output voltage Vout_main, which supplies power to the electronic fuel injection system 300. The voltage induced by the auxiliary winding of transformer T1 is rectified and filtered by diode D3 and capacitor C3 to generate auxiliary power supply VCC_aux. Once the system starts normally, VCC_aux will replace the low-voltage start-up unit 220 to provide continuous and sufficient operating current for the control chip U1. At this time, the low-voltage start-up unit 220 will naturally stop working due to the reduction of the voltage difference between the source and drain of MOSFET Q1, thus reducing losses.

[0048] Thirdly, wide input step-down power supply unit 240 To cope with input voltages up to 500VDC and ensure the reliability of power supply to the control chip, a wide-input buck power supply unit 240 is set up. Its core is a Buck converter chip U7 with a wide input voltage range. The input terminal of U7 is connected to VIN_H, and the output terminal generates a stable voltage (such as 13V) which is connected to the VCC pin of U1. This unit mainly works in two scenarios: first, when the input voltage is extremely high, it serves as a supplement to VCC_aux to share power consumption; second, when the output is overloaded or changes cause a transient drop in VCC_aux, it provides support to prevent the system from shutting down unexpectedly.

[0049] Fourth, feedback unit 250: When the voltage of the electronic fuel injection system exceeds the set threshold, the light-receiving side of the optocoupler U1 is turned on, forcibly pulling down the voltage at the COMP terminal of the control chip. Then, the control chip IC1 can control the duty cycle of the switching transistor Q7 according to the feedback signal to achieve closed-loop control. Fifth, overcurrent protection unit 260: This unit is the overcurrent and short-circuit detection circuit for the output of the electronic fuel injection system. A U5A operational amplifier is used in differential form to detect the current flowing through R45. Since the inrush current at the EFI output during startup needs to be ignored, we use resistors R92, R94, R96, and transistor Q12 to implement current detection and delayed output control. This current is then compared with the BE voltage of transistor Q13 as a reference voltage divider. When an overcurrent or short circuit occurs in the EFI output current (current greater than the reference comparison threshold), optocoupler U3 is triggered, allowing the input voltage VF of IC1 to drive transistor Q6 through transistor Q5 and resistor R4. This pulls the COMP signal of the driver chip low, and the current limiting protector stops the entire flyback power supply. Due to the presence of SCR1, this protection function must remain effective until the input AC voltage drops below 30VDC before it can operate normally. Considering the application scenario, this can be understood as requiring an engine restart after the fault is cleared for normal output.

[0050] Sixth, Charging Management Unit 500 The charging management unit 500 includes a Buck-type constant current / constant voltage (CC / CV) charging circuit consisting of a power management chip U8, an inductor L2, a diode D19, etc. Its input terminal is connected to an independent charging winding of the flyback converter (or obtained from the main line after voltage regulation), and its output terminal is unidirectionally connected to the battery through a diode D13. The diode D13 plays an isolation role to ensure that the battery will not draw back current from the main circuit of the electronic fuel injection system when it is severely depleted.

[0051] The key feature of this unit is its enable control. Its enable circuit consists of resistors R106, R107, R108, MOSFET Q16, resistor RS4, and optocoupler U6, which continuously monitor the DC bus voltage VIN_H. The Buck charging circuit is only enabled when VIN_H is higher than a preset charging enable threshold (e.g., the voltage when the engine has started and entered a stable power generation state). This design ensures that during the critical initial low-speed phase of manual start-up, all energy is prioritized for the electronic fuel injection system 300. Only after the engine has successfully started, the speed has increased, and the power generation voltage is sufficient will charging of the battery begin, thus achieving intelligent hierarchical management of system energy.

[0052] The control method for the above-mentioned engine no-electric manual start system includes the following steps: S101: During the startup phase, in response to the manual operation, the manual generator 100 generates a fluctuating first AC voltage, which is then rectified and filtered by the rectifier filter unit 210 to obtain the DC bus voltage VIN_H. The low-voltage startup unit 220 extracts energy from VIN_H in a "dynamic balance startup" mode to provide a startup voltage for the control chip IC1, enabling it to start working.

[0053] S102: During the power supply and feedback stage, the control chip IC1 drives the flyback converter main circuit 230 to work, and the primary and secondary windings of the transformer T1 generate the main output Vout_main to supply power to the electronic fuel injection system 300. At the same time, the output feedback unit 250 samples Vout_main and feeds it back to the control chip IC1 to achieve closed-loop voltage regulation.

[0054] S103: Self-sustaining phase. After the flyback converter main circuit 230 is working normally, the auxiliary winding of transformer T1 generates auxiliary power supply VCC_aux, which takes over the power supply to control chip IC1; the wide input buck power supply unit 240 is used as a backup for the auxiliary power supply based on the input voltage and load conditions.

[0055] S104: During the charging enable and protection phase, the output overcurrent self-locking protection unit 270 monitors the output current in real time during the power supply process. If it is determined to be a fault overcurrent / short circuit, the self-locking protection is triggered. At this point, the system jumps to S105: fault shutdown state; if the system is normal, the charging management unit 500 continuously monitors VIN_H; when VIN_H reaches the charging enable threshold, it indicates that the engine has been successfully started and the power generation is sufficient. Then proceed to S106: the charging stage, where the Buck charging circuit is activated to charge the battery with constant current and constant voltage, and unidirectional isolation is achieved through diode D13.

[0056] During the process, if the input energy is interrupted (such as when manual operation stops), VIN_H will decrease, the system will reset, and wait for the next startup.

[0057] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims.

Claims

1. A control method for a manual start system for an engine without electricity, applied in a system including a manual generator, a flyback switching power supply module, an electronic fuel injection module, and a battery module, characterized in that, The method includes: Start-up phase: In response to the manual operation, the first AC voltage generated by the manual generator is rectified and filtered to obtain the DC bus voltage; energy is extracted from the DC bus voltage through the low-voltage start-up circuit to provide the start-up voltage for the control chip of the flyback switching power supply module, enabling it to start working; Power supply and feedback stage: Under the control of the control chip, the flyback switching power supply module generates the main output through its transformer to power the electronic fuel injection system; at the same time, the main output is regulated and regulated through a sampling feedback circuit. Self-sustaining and charging phase: After the flyback switching power supply module is started, the auxiliary winding of its transformer provides continuous auxiliary power to the control chip; when the DC bus voltage is detected to reach the charging enable threshold, the battery charging circuit is started to charge the battery, and a unidirectional isolation element is used to prevent the battery from discharging to the electronic fuel injection system.

2. The control method for the engine non-electric manual start system according to claim 1, characterized in that: The step of extracting energy from the DC bus voltage through the low-voltage startup circuit is specifically a dynamic balance startup process. When the DC bus voltage rises to the turn-on threshold of the startup NMOS transistor Q1, the startup NMOS transistor Q1 is turned on and outputs power. The output voltage of the low-voltage startup circuit is sampled by voltage division. When the sampled value exceeds the first threshold, the turn-off transistor Q2 is turned on to pull down the gate voltage of the startup NMOS transistor Q1, causing it to turn off. After the startup NMOS transistor Q1 is turned off, the DC bus voltage recharges its gate capacitance through the startup resistor RM1, repeating the above turn-on and turn-off process to form a dynamic balance, thereby providing stable startup energy for the control chip.

3. The control method for the engine no-electric manual start system according to claim 1, characterized in that: The method also includes a wide-range input power supply step, which draws power from the DC bus through an independent wide-input buck converter to provide the control chip with a stable operating voltage covering the DC input range of 30V to 500V, as a backup or supplement to the auxiliary power supply.

4. The control method for the engine non-electric manual start system according to claim 1, characterized in that: It also includes an output fault protection step, which detects the current output of the main circuit. When an overcurrent or short-circuit signal is detected, a latching protection circuit is triggered to lock the compensation terminal voltage of the control chip at the off level to stop the operation of the flyback switching power supply module. The latching protection state will be maintained until the DC bus voltage drops below the reset threshold.

5. The control method for the engine no-electric manual start system according to claim 4, characterized in that, The step of detecting the main output current is performed after the power supply and feedback phase, and is only enabled after confirming that the DC bus voltage exceeds the second threshold.

6. The control method for the engine no-electric manual start system according to claim 1, characterized in that, The battery charging circuit is a Buck-type constant current and constant voltage charging circuit. The charging enable threshold is set according to the generator voltage corresponding to the expected speed after the engine starts, so as to ensure that energy is preferentially supplied to the electronic fuel injection system in the initial stage of manual start.

7. A manual start system for an engine without electricity, employing the control method as described in any one of claims 1 to 6, characterized in that: This includes hand-operated generators, used to generate fluctuating AC voltage through manual operation; A flyback switching power supply module, whose input terminal is connected to the hand-operated generator, is used to convert the fluctuating AC voltage into a stable DC voltage; The electronic fuel injection system is connected to the main output terminal of the flyback switching power supply module and is powered by the main output. The battery is connected to the charging output terminal of the flyback switching power supply module via a charging management unit; The flyback switching power supply module includes: a rectifier and filter unit, a flyback converter main circuit containing a control chip and a transformer, a low-voltage start-up unit, an output feedback unit, and an auxiliary power supply unit for supplying power to the control chip.

8. The engine start-up system without electricity according to claim 7, characterized in that: The low-voltage startup unit includes a startup resistor RM1, a startup NMOS transistor Q1, voltage divider sampling resistors R10 and R13, and a shutdown transistor Q2, which together form the dynamic balance startup circuit.

9. The engine start-by-lever system without electric power according to claim 7, characterized in that, The system also includes: a wide-input step-down power supply unit, whose input is connected to the output of the rectifier and filter unit and whose output is connected to the power supply of the control chip; and an output overcurrent self-locking protection unit, which includes a current-sensing operational amplifier (U5A) and a latching element (SCR1).

10. The engine start-by-wire system without electricity according to claim 7, characterized in that, The charging management unit includes an enable control circuit, which is used to shut down the battery charging circuit when the DC bus voltage is lower than the charging enable threshold.

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