Oxygen heating system

Abstract

The invention provides an oxygen heating system, the system is integrated in an engine chip, the engine chip is electrically connected with a main control chip, the system comprises at least two paths of oxygen heating modules, and each oxygen heating module comprises at least two paths of oxygen heating modules based on a parallel oxygen heating control signal, a serial oxygen heating control signal and a fault detection signal, the heating control unit is used for outputting a driving control signal; the driving unit is used for controlling the working state of the corresponding heating element based on the driving control signal; and the fault detection module is used for carrying out fault detection on the oxygen heating module. Therefore, the multi-path oxygen heating module is integrated in the engine chip, so that the engine chip can meet the requirements of independent heating and independent fault detection of each oxygen sensor, peripheral circuits are reduced, and meanwhile, the reliability is relatively good and the complexity is low.

Description

Technical Field

[0001] The invention relates to the field of small engines, and in particular to an oxygen heating system. Background Art

[0002] With the continuous upgrading of environmental protection regulations, reducing motorcycle emissions has become an industry focus. The motorcycle fuel supply system has gradually transformed from carburetors to electronic fuel injection systems, which significantly reduce exhaust emissions through precise ignition and fuel injection control to meet higher environmental protection requirements.

[0003] In the existing electronic fuel injection system, in order to meet the environmental regulations on the precise monitoring of oxygen sensors, the heating function of the oxygen sensor is particularly important. The oxygen sensor heater can quickly heat the sensor to the optimal operating temperature to ensure its real-time monitoring of the oxygen content in the exhaust gas. However, the common engine chips are usually only equipped with a single-channel oxygen sensor heater drive circuit, which cannot support the independent heating of multiple oxygen sensors, and it is difficult to adapt to the heating requirements of the front and rear oxygen sensors in a single-cylinder engine. In addition, in order to achieve multi-channel drive and diagnostic functions, users need to design additional complex peripheral circuits and diagnostic circuits, which not only increases the hardware cost and design difficulty, but also reduces the reliability of the system.

[0004] Therefore, how to ensure the independent driving of the oxygen heating system of the engine system with good reliability and low complexity has become a technical problem that the industry urgently needs to solve. Summary of the invention

[0005] The present invention provides an oxygen heating system, which solves the technical problem of how to ensure independent driving of the oxygen heating system of an engine system with good reliability and low complexity.

[0006] According to a first aspect of the present invention, an embodiment of the present invention provides an oxygen heating system, the oxygen heating system is integrated inside an engine chip, the system comprises N oxygen heating modules, each oxygen heating module is used to heat a corresponding oxygen sensor, wherein N is an integer greater than or equal to 2;

[0007] The engine chip is electrically connected to the main control chip, and the engine chip includes an SPI module, and the SPI module is used to receive the SPI control signal sent by the main control chip, and output a corresponding serial oxygen heating control signal to each oxygen heating module based on the SPI control signal;

[0008] The main control chip also outputs corresponding parallel oxygen heating control signals to each oxygen heating module; wherein:

[0009] The oxygen heating module comprises:

[0010] a heating control unit, receiving the parallel oxygen heating control signal, the serial oxygen heating control signal and the fault detection signal, and configured to output a driving control signal based on the parallel oxygen heating control signal, the serial oxygen heating control signal and the fault detection signal;

[0011] A driving unit, comprising a high-side driver, a clamping sub-unit and a first MOS transistor, wherein an input end of the high-side driver receives the driving control signal, and an output end thereof is respectively coupled to a first end of the clamping sub-unit and a control end of the first MOS transistor, a second end of the clamping sub-unit and a drain of the first MOS transistor are both coupled to a first node, the first node is also coupled to a first end of a corresponding heating element, and a source of the first MOS transistor is grounded;

[0012] A fault detection module, a first end of which is coupled to the source of the first MOS tube, a second end of which is coupled to the first node, and an output end of which is coupled to the heating control unit, is used to output the fault detection signal based on the current flowing through the source of the first MOS tube and the voltage of the first node.

[0013] Optionally, the drive control signal includes an on drive signal and an off drive signal, and outputting the drive control signal based on the parallel oxygen heating control signal, the serial oxygen heating control signal and the fault detection signal includes:

[0014] When the parallel oxygen heating control signal is characterized as being on and the serial oxygen heating control signal is characterized as being off, the heating control unit outputs the on drive signal;

[0015] When the parallel oxygen heating control signal is characterized as being off and the serial oxygen heating control signal is characterized as being on, the heating control unit outputs the on drive signal;

[0016] When the parallel oxygen heating control signal is characterized as being on and the serial oxygen heating control signal is characterized as being on, the heating control unit outputs the shutoff drive signal;

[0017] When the parallel oxygen heating control signal is characterized as off and the serial oxygen heating control signal is characterized as off, the heating control unit outputs the off drive signal;

[0018] When the fault detection signal is characterized as abnormal, the heating control unit outputs the shutdown drive signal.

[0019] Optionally, the fault detection module is further configured to:

[0020] When the heating control unit outputs the on-drive signal, outputting the fault detection signal based on the current flowing through the source of the first MOS tube;

[0021] When the heating control unit outputs the shutoff driving signal, the failure detection signal is output based on the voltage of the first node.

[0022] Optionally, the method for outputting the fault detection signal based on the current flowing through the source of the first MOS transistor and the voltage of the first node includes:

[0023] When the heating control unit outputs the on-drive signal, if the current flowing through the source of the first MOS tube is greater than or equal to a first current threshold, then the fault detection signal indicating abnormality is output;

[0024] When the heating control unit outputs the on-drive signal, if the current flowing through the source of the first MOS tube is less than the first current threshold, the fault detection signal indicating normality is output;

[0025] When the heating control unit outputs the shutdown driving signal, if the voltage of the first node does not belong to the second threshold voltage range, the fault detection signal indicating abnormality is output;

[0026] When the heating control unit outputs the shutdown driving signal, if the voltage of the first node belongs to the second threshold voltage range, the fault detection signal indicating normality is output.

[0027] Optionally, the fault detection signal includes an overcurrent detection signal, and the fault detection module includes an overcurrent detection unit; the overcurrent detection unit includes a first amplifier and a detection resistor;

[0028] The first end of the detection resistor is coupled to the source of the first MOS tube, and the second end thereof is grounded;

[0029] The first input terminal of the first amplifier is coupled to the first terminal of the detection resistor, the second terminal of the first amplifier is coupled to the second terminal of the detection resistor, and the output terminal of the first amplifier is coupled to the heating control unit for outputting the overcurrent detection signal.

[0030] Optionally, the heating control unit is configured as:

[0031] Based on the overcurrent detection signal and the overcurrent filtering time, it is determined whether a circuit fault occurs, wherein:

[0032] If the overcurrent detection signal is characterized as abnormal and lasts longer than the overcurrent filtering time, it is determined that the circuit has an overcurrent and the shutdown drive signal is output.

[0033] Optionally, the heating control unit is further coupled to a status indicator light, and the heating control unit is configured as follows:

[0034] When overcurrent occurs in the circuit, the status indicator light is controlled to turn off.

[0035] Optionally, the fault detection signal includes an open circuit detection signal and a short circuit detection signal; the maximum value of the second threshold voltage range is a first set voltage, and the minimum value thereof is a second set voltage; the fault detection module includes an open circuit detection unit, a short circuit detection unit and a voltage setting unit;

[0036] The voltage setting unit includes a second amplifier and a first switch, wherein a first input terminal of the second amplifier receives the first setting voltage, a second input terminal of the second amplifier is coupled to an output terminal thereof, an output terminal of the second amplifier is coupled to a first terminal of the first switch, and a second terminal of the first switch is coupled to the first node;

[0037] The open circuit detection unit includes a third amplifier, a first input terminal of the third amplifier receives a third set voltage, a second input terminal of the third amplifier is coupled to the first terminal of the first switch, and an output terminal of the third amplifier is coupled to the heating control unit, wherein the third set voltage is greater than the first set voltage;

[0038] The short circuit detection unit includes a fourth amplifier, a first input terminal of the fourth amplifier receives the second setting voltage, a second input terminal of the fourth amplifier is coupled to the first terminal of the first switch, and an output terminal of the fourth amplifier is coupled to the heating control unit.

[0039] Optionally, the heating control unit is further coupled to the control end of the first switch, and the heating control unit is configured as follows:

[0040] When the heating control unit outputs the shutdown driving signal, the first switch is controlled to be turned on.

[0041] Optionally, the heating control unit is configured as:

[0042] Based on the open circuit detection signal and the open circuit filtering time, it is determined whether a circuit fault occurs, wherein:

[0043] If the open circuit detection signal is characterized as abnormal and the duration is greater than the open circuit filtering time, it is determined that the circuit is open circuited and the shutdown drive signal is output; and

[0044] Based on the short-circuit detection signal and the short-circuit filtering time, it is determined whether a circuit fault occurs, wherein:

[0045] If the short-circuit detection signal is characterized as abnormal and lasts longer than the short-circuit filtering time, it is determined that a short circuit to ground occurs in the circuit and the shutdown drive signal is output.

[0046] Optionally, the engine chip further includes:

[0047] A power supply module, used to supply power to the engine chip and a sensor electrically connected to the engine chip;

[0048] A mode control module receives a key signal and is used to control the state of the engine chip to be a working mode and a standby mode based on the key signal;

[0049] an injector driving module, coupled to the injector, for driving the injector when the engine chip is in a working mode;

[0050] a relay driving module, coupled to the relay, for driving the relay when the engine chip is in an operating mode;

[0051] a rotation speed module, coupled to the tachometer, for outputting a rotation speed signal when the engine chip is in a working mode;

[0052] A fault light driving module, coupled to the fault indicator light, for driving the fault indicator light when the system is in a fault state;

[0053] An idle stepper motor driving module, coupled to the idle stepper motor, and used to drive the idle stepper motor when the engine chip is in a working mode;

[0054] A magnetoelectric signal processing module, used for converting crankshaft magnetoelectric signals when the engine chip is in working mode;

[0055] K-LINE communication module, used to realize OBD communication.

[0056] Compared with the prior art, the technical solution of the embodiment of the present invention has the following beneficial effects:

[0057] In the oxygen heating system of the technical solution of the present invention, the system is integrated inside the engine chip, the engine chip is electrically connected to the main control chip, and the system includes at least 2 oxygen heating modules, each of which includes: a heating control unit that outputs a drive control signal based on a parallel oxygen heating control signal, a serial oxygen heating control signal, and a fault detection signal; a drive unit that controls the working state of the corresponding heating element based on the drive control signal; and a fault detection module that performs fault detection on the oxygen heating module. Therefore, the present invention integrates multiple oxygen heating modules inside the engine chip, so that the engine chip can meet the independent heating and independent fault detection of each oxygen sensor, while reducing the peripheral circuit, the reliability is good and the complexity is low. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0059] Figure 1 It is a structural schematic diagram of an engine chip of the prior art;

[0060] Figure 2 is a schematic diagram of the structure of an engine chip provided by an embodiment of the present invention;

[0061] Figure 3 The structure of the oxygen heating system provided by one embodiment of the present invention is shown in FIG. Figure 1 ;

[0062] Figure 4 is corresponding to Figure 3 Working waveform of oxygen heating system Figure 1 ;

[0063] Figure 5 The structure of the oxygen heating system provided by one embodiment of the present invention is shown in FIG. Figure 2 ;

[0064] Figure 6 The structure of the oxygen heating system provided by one embodiment of the present invention is shown in FIG. Figure 3 ;

[0065] Figure 7 is corresponding to Figure 5 The working waveform of the engine chip Figure 4 .

[0066] Reference numerals:

[0067] 11-SPI module;

[0068] 12- oxygen heating system;

[0069] 13-bus;

[0070] 121- oxygen heating module;

[0071] 1211- heating control unit;

[0072] 12121-high side driver;

[0073] 12122-clamp subunit;

[0074] 1213-fault detection module;

[0075] 12131-first amplifier;

[0076] 12132 - second amplifier;

[0077] S1-first switch;

[0078] 12133-third amplifier;

[0079] 12134-fourth amplifier;

[0080] R sense - Sense resistor;

[0081] 1214- heating element;

[0082] INO2Hx-parallel oxygen heating control signal;

[0083] M1-the first MOS tube. DETAILED DESCRIPTION

[0084] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0085] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0086] The technical solution of the present invention is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0087] As described in the background art, it is difficult to ensure the independent driving of the oxygen heating system of the engine system with good reliability and low complexity in the prior art.

[0088] Figure 1 It is a schematic diagram of the structure of an engine chip in an embodiment.

[0089] It can be seen that the chip includes:

[0090] VDD module, used to power the engine chip;

[0091] The VDD follower module is used to power external sensors. Its voltage output VDD_TR follows the voltage output VDD of the VDD module.

[0092] KEY module, used to power on the chip;

[0093] Specifically, when the KEY signal is high, the chip enters the working mode;

[0094] When the KEY signal is low, the chip enters standby mode.

[0095] The SPI module is used for communication between the main control chip and the engine chip to open the ignition switch and read diagnostic information.

[0096] Stepper Driver is used to drive the engine's idle air stepper motor.

[0097] The injector driver module (INJ) is used to drive the engine's injectors.

[0098] The O2H module is used to drive the oxygen sensor heater and provide the necessary preheating function for the oxygen sensor to quickly enter the working state. The oxygen sensor is used for exhaust gas detection.

[0099] The relay driver module (Relay Driver) is used to drive the oil pump relay and other relays to realize the start and stop control of external devices (such as oil pumps, fans, etc.).

[0100] The LSD module is used to drive the fault light. When a system fault (such as overcurrent or short circuit) is detected, the fault light is turned on to prompt the user.

[0101] The speed output drive module (TACH) is used to drive the speed output. Specifically, it can drive the tachometer display to output the real-time speed signal of the engine.

[0102] K-line is used for OBD (On-Board Diagnostics) communication to transmit diagnostic information and system status.

[0103] It can be seen that in the engine system where the chip is located, the system can only heat one oxygen sensor. This makes it difficult to apply this driving solution in the engine.

[0104] Specifically, in a single-cylinder engine, the exhaust system is usually equipped with front oxygen sensors and rear oxygen sensors, which are used for air-fuel ratio control and emission monitoring, respectively. Since the O2H module cannot achieve independent heating of the front and rear oxygen sensors, more engine chips are required for separate control.

[0105] In a two-cylinder dual-oxygen engine, each cylinder needs to be equipped with an oxygen sensor. The existing single-channel drive solution is obviously unable to achieve independent heating of the oxygen sensor as needed.

[0106] Even if the system can heat all oxygen sensors at the same time, in actual implementation, additional peripheral circuits need to be designed to achieve similar functions. This not only increases the design and development costs, but also places higher requirements on hardware wiring and electrical reliability, which can easily lead to more failure points, reduced system reliability, and greater risks.

[0107] Not only that, in actual implementation, the engine chip also needs to add peripheral diagnostic circuits to achieve safe management of the O2H module, which has many unreliable factors and greater risks.

[0108] In view of this, the technical solution of the present invention provides an oxygen heating system, which is integrated inside the engine chip. The engine chip is electrically connected to the main control chip. The system includes at least 2 oxygen heating modules, each of which includes: a heating control unit that outputs a drive control signal based on a parallel oxygen heating control signal, a serial oxygen heating control signal, and a fault detection signal; a drive unit that controls the working state of the corresponding heating element based on the drive control signal; and a fault detection module that performs fault detection on the oxygen heating module. Therefore, the present invention integrates multiple oxygen heating modules inside the engine chip, so that the engine chip can meet the independent heating and independent fault detection of each oxygen sensor, while reducing the peripheral circuit, and has good reliability and low complexity.

[0109] In order to make the above-mentioned objects, features and beneficial effects of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0110] In practical applications, the engine system may have multiple chips. The engine chip in the embodiment of the present invention is electrically connected to the main control chip, and the oxygen heating system provided by the embodiment of the present invention is integrated inside the engine chip.

[0111] In the embodiments of the present invention, please refer to Figure 2 The engine chip includes an SPI module 11, which is used to receive SPI control signals (CS, SCK, SI, SO) sent by the main control chip (not shown in the figure), and output corresponding serial oxygen heating control signals to the oxygen heating system 12 based on the SPI control signals;

[0112] The main control chip also outputs a corresponding parallel oxygen heating control signal to the oxygen heating system 12 .

[0113] It can be seen that the oxygen heating system 12 of the present invention can be controlled by a parallel oxygen heating control signal or a serial oxygen heating control signal.

[0114] In actual use, the engine chip provided by the present invention can also be used to realize other functions, please continue to refer to Figure 2 , the engine chip also includes:

[0115] A power supply module 13, used to supply power to the engine chip 1 and a sensor electrically connected to the engine chip 1;

[0116] A mode control module 14 receives a key signal KEY and is used to control the state of the engine chip to be a working mode and a standby mode based on the key signal KEY;

[0117] An injector driving module 15, coupled to the injector, for driving the injector when the engine chip 1 is in a working mode;

[0118] a relay driving module 16, coupled to the relay, for driving the relay when the engine chip 1 is in a working mode;

[0119] A speed module 17, coupled to a tachometer, for outputting a speed signal when the engine chip 1 is in a working mode;

[0120] A fault light driving module 18, coupled to the fault indicator light, for driving the fault indicator light when the system is in a fault state;

[0121] An idle stepper motor driving module 19, coupled to the idle stepper motor, for driving the idle stepper motor when the engine chip 1 is in a working mode;

[0122] A magnetoelectric signal processing module 20, used for converting crankshaft magnetoelectric signals when the engine chip 1 is in working mode;

[0123] The K-LINE communication module 21 is used to implement OBD communication.

[0124] Of course, the present invention does not limit the functions that the engine chip can provide. As long as it includes the oxygen heating system 12 provided by any of the above items of the present invention, it is within the protection scope of the present invention.

[0125] In one implementation, the oxygen heating system 12 provided in the embodiment of the present invention includes N oxygen heating modules, each of which is used to heat a corresponding oxygen sensor, where N is an integer greater than or equal to 2.

[0126] In this case, the SPI module 11 is used to receive the SPI control signal sent by the main control chip, and output a corresponding serial oxygen heating control signal to each oxygen heating module based on the SPI control signal.

[0127] In an embodiment of the present invention, the oxygen heating module communicates with the SPI module 11 via a bus 13 .

[0128] In practical applications, the SPI module 11 has a register, and each oxygen heating module in the register corresponds to two SPI bits, and the values ​​of the two SPI bits are controlled by the SPI control signal.

[0129] Table 1 Status table of two SPI bits corresponding to the xth oxygen heating module

[0130]

[0131] Table 1 shows the bit operation corresponding to the xth oxygen heating module in the register provided by the embodiment of the present invention and the corresponding serial oxygen heating control signal state. It can be seen that for each oxygen heating module, the control of its working state is independent. Where x is an integer, and 1≤x≤N.

[0132] Furthermore, the configuration of the above-mentioned main control chip should be understood as outputting corresponding parallel oxygen heating control signals to each oxygen heating module.

[0133] In practical applications, technicians in this field can choose to control ignition through the main control chip (i.e., parallel oxygen heating control signal drive) or choose to control ignition through the SPI module 11 (i.e., serial oxygen heating control signal drive) according to actual use requirements.

[0134] exist Figure 2 In the example, the oxygen heating system 12 includes two oxygen heating modules, each of which receives a corresponding parallel oxygen heating control signal (INO2Hx) and a serial oxygen heating control signal, and outputs a corresponding drive to a corresponding heating element (not shown in the figure).

[0135] The structure of a single oxygen heating module is now further described.

[0136] Please refer to Figure 3 In a specific embodiment, the oxygen heating module 121 includes:

[0137] A heating control unit 1211 receives the parallel oxygen heating control signal INO2Hx, the serial oxygen heating control signal and the fault detection signal, and is used to output a driving control signal based on the parallel oxygen heating control signal INO2Hx, the serial oxygen heating control signal and the fault detection signal;

[0138] A driving unit, comprising a high-side driver 12121, a clamping subunit 12122 and a first MOS transistor M1, wherein an input end of the high-side driver 12121 receives the driving control signal, and an output end thereof is respectively coupled to a first end of the clamping subunit 12122 and a control end of the first MOS transistor M1, a second end of the clamping subunit 12122 and a drain of the first MOS transistor M1 are both coupled to a first node, the first node is also coupled to a first end of a corresponding heating element 1214, and a source of the first MOS transistor M1 is grounded;

[0139] The fault detection module 1213 has a first end coupled to the source of the first MOS tube M1, a second end coupled to the first node, and an output end coupled to the heating control unit 1211, and is used to output the fault detection signal based on the current flowing through the source of the first MOS tube M1 and the voltage of the first node.

[0140] exist Figure 3 In the example, the clamping subunit 12122 includes a clamping diode. It should be understood that the present invention does not limit the specific structure of the clamping subunit 12122. As long as the circuit can realize the clamping function, it is within the protection scope of the present invention.

[0141] As an example, in Figure 3 The first MOS transistor M1 in the example may be a NDMOS transistor. Of course, the present invention is not limited to a specific type of MOS transistor, and may also be a BJT transistor, etc. Those skilled in the art may select a suitable element as needed.

[0142] Since the heating element 1214 needs to be placed near the oxygen sensor, generally, the heating element 1214 is placed outside the chip.

[0143] It can be seen that the present invention integrates a multi-channel oxygen heating module inside the engine chip, so that the engine chip can meet the independent heating and independent fault detection of each oxygen sensor, while reducing the peripheral circuit, the reliability is good and the complexity is low.

[0144] In a specific implementation, the driving control signal includes an on driving signal and an off driving signal.

[0145] In this case, the method of outputting a driving control signal based on the parallel oxygen heating control signal INO2Hx, the serial oxygen heating control signal and the fault detection signal includes:

[0146] When the parallel oxygen heating control signal INO2Hx is characterized as being on, and the serial oxygen heating control signal is characterized as being off, the heating control unit 1211 outputs the on drive signal;

[0147] When the parallel oxygen heating control signal INO2Hx is characterized as off and the serial oxygen heating control signal is characterized as on, the heating control unit 1211 outputs the on drive signal;

[0148] When the parallel oxygen heating control signal INO2Hx is characterized as being on, and the serial oxygen heating control signal is characterized as being on, the heating control unit 1211 outputs the shutoff drive signal;

[0149] When the parallel oxygen heating control signal INO2Hx is characterized as off and the serial oxygen heating control signal is characterized as off, the heating control unit 1211 outputs the off drive signal;

[0150] When the fault detection signal is characterized as abnormal, the heating control unit 1211 outputs the shutdown driving signal.

[0151] The above control method should be understood as, for the convenience of customers, the heating control unit 1211 of the present invention is controlled by two methods: parallel control and serial control. In order to drive the heating control unit 1211 more conveniently, no additional register is added to the heating control unit to receive the parallel oxygen heating control signal INO2Hx and the serial oxygen heating control signal, but an XOR method is used for control.

[0152] In practical applications, both the parallel oxygen heating control signal INO2Hx and the serial oxygen heating control signal can be characterized by on and off by using high and low levels. In this case:

[0153] When the parallel oxygen heating control signal INO2Hx is at a fixed level (eg, a low level), the on and off of the first switch S1 can be controlled via the serial SPI;

[0154] Similarly, when the serial SPI sends a fixed instruction, the on and off of the first switch S1 can be controlled in parallel.

[0155] Therefore, the present invention ensures that the on and off of the first switch S1 is controlled only when a valid command is received.

[0156] In practical applications, the heating control unit 1211 can be understood as outputting a driving control signal based on the parallel oxygen heating control signal INO2Hx and the serial oxygen heating control signal when the current fault detection signal is characterized as normal;

[0157] When the current fault detection signal is characterized as abnormal, the shutdown drive signal is output.

[0158] Now combined Figure 4 The change of the driving control signal is described. Figure 4 The working waveform diagram of the heating control unit 1211 is shown, wherein:

[0159] INO2Hx, can be understood as the parallel oxygen heating control signal corresponding to the xth oxygen heating module;

[0160] SPI, which can be understood as the serial oxygen heating control signal corresponding to the xth oxygen heating module;

[0161] O2Hx can be understood as the driving control signal corresponding to the xth oxygen heating module.

[0162] It can be seen that, for the heating control unit 1211, the parallel oxygen heating control signal INO2Hx and the serial oxygen heating control signal of the present invention are in an exclusive OR relationship, which ensures the safety of the oxygen heating module.

[0163] In one implementation, the fault detection module 1213 performs different detections on the oxygen heating module when the heating control unit 1211 outputs different drive control signals.

[0164] In this case, in a specific implementation manner, the fault detection module 1213 is further configured to:

[0165] When the heating control unit 1211 outputs the on-drive signal, the fault detection signal is output based on the current flowing through the source of the first MOS transistor M1;

[0166] When the heating control unit 1211 outputs the shutdown driving signal, the fault detection signal is output based on the voltage of the first node.

[0167] On this basis, the method for outputting the fault detection signal based on the current flowing through the source of the first MOS transistor M1 and the voltage of the first node includes:

[0168] When the heating control unit 1211 outputs the on-drive signal, if the current flowing through the source of the first MOS transistor M1 is greater than or equal to the first current threshold, the fault detection signal indicating abnormality is output;

[0169] When the heating control unit 1211 outputs the on-drive signal, if the current flowing through the source of the first MOS transistor M1 is less than the first current threshold, the fault detection signal indicating normality is output;

[0170] When the heating control unit 1211 outputs the shutdown driving signal, if the voltage of the first node does not belong to the second threshold voltage range, the fault detection signal indicating abnormality is output;

[0171] When the heating control unit 1211 outputs the shutdown driving signal, if the voltage of the first node belongs to the second threshold voltage range, the fault detection signal indicating normality is output.

[0172] In the embodiment of the present invention, the maximum value of the second threshold voltage range is the first set voltage, and the minimum value thereof is the second set voltage.

[0173] The structure of the fault detection module 1213 is now further described.

[0174] In one implementation, the fault detection signal includes an overcurrent detection signal.

[0175] Please refer to Figure 5 In a specific implementation, the fault detection module 1213 includes an overcurrent detection unit; the overcurrent detection unit includes a first amplifier 12131 and a detection resistor R sense ;

[0176] The detection resistor R sense A first end of the transistor is coupled to the source of the first MOS transistor M1, and a second end of the transistor is grounded;

[0177] The first input terminal of the first amplifier 12131 is coupled to the detection resistor R sense The first end thereof is coupled to the detection resistor R sense The second end of the device has an output end coupled to the heating control unit 1211 for outputting the over-current detection signal.

[0178] In this case, the heating control unit 1211 is configured as follows:

[0179] Based on the overcurrent detection signal and the overcurrent filtering time, it is determined whether a circuit fault occurs, wherein:

[0180] If the overcurrent detection signal is characterized as abnormal and lasts longer than the overcurrent filtering time, it is determined that the circuit has an overcurrent and the shutdown drive signal is output.

[0181] The overcurrent filtering time is used to avoid false alarms and ensure the reliability of fault detection.

[0182] In a preferred embodiment, please refer to Figure 6 The heating control unit 1211 is also coupled to a status indicator LED, and the heating control unit 1211 is configured as follows:

[0183] When overcurrent occurs in the circuit, the status indicator LED is controlled to turn off.

[0184] As an example, the status indicator light may also be an indicator light connected to the fault light driving module 18, but the present invention is not limited thereto. The status indicator light may also be an indicator light in other peripheral circuits.

[0185] exist Figure 5 In the example, the fault detection signal also includes an open circuit detection signal and a short circuit detection signal.

[0186] The fault detection module 1213 includes an open circuit detection unit, a short circuit detection unit and a voltage setting unit;

[0187] The voltage setting unit includes a second amplifier 12132 and a first switch S1, wherein a first input terminal of the second amplifier 12132 receives the first setting voltage, a second input terminal of the second amplifier 12132 is coupled to an output terminal thereof, an output terminal of the second amplifier 12132 is coupled to a first terminal of the first switch S1, and a second terminal of the first switch S1 is coupled to the first node;

[0188] The open circuit detection unit includes a third amplifier 12133, a first input terminal of the third amplifier 12133 receives a third set voltage, a second input terminal of the third amplifier 12133 is coupled to the first terminal of the first switch S1, and an output terminal of the third amplifier 12133 is coupled to the heating control unit 1211, wherein the third set voltage is greater than the first set voltage;

[0189] The short circuit detection unit includes a fourth amplifier 12134 , a first input terminal of the fourth amplifier 12134 receives the second setting voltage, a second input terminal of the fourth amplifier 12134 is coupled to the first terminal of the first switch S1 , and an output terminal of the fourth amplifier 12134 is coupled to the heating control unit 1211 .

[0190] exist Figure 5 In the example, the first set voltage is 0.5VDD, the second set voltage is 0.4VDD, and the third set voltage is 0.6VDD. The VDD can be understood as the power supply voltage of the engine chip.

[0191] Of course, the present invention is not limited thereto, and those skilled in the art can set the first set voltage, the second set voltage, and the third set voltage as needed.

[0192] On this basis, the voltage of the first node is detected only when the heating control unit 1211 outputs the shutdown driving signal. Figure 5 The heating control unit 1211 is also coupled to the control end of the first switch S1, and the heating control unit 1211 is configured as follows:

[0193] When the heating control unit 1211 outputs the shutdown driving signal, the first switch S1 is controlled to be turned on.

[0194] In a preferred embodiment, the heating control unit 1211 is further configured as follows:

[0195] Based on the open circuit detection signal and the open circuit filtering time, it is determined whether a circuit fault occurs, wherein:

[0196] If the open circuit detection signal is characterized as abnormal and the duration is greater than the open circuit filtering time, it is determined that the circuit is open circuited and the shutdown drive signal is output; and

[0197] Based on the short-circuit detection signal and the short-circuit filtering time, it is determined whether a circuit fault occurs, wherein:

[0198] If the short-circuit detection signal is characterized as abnormal and lasts longer than the short-circuit filtering time, it is determined that a short circuit to ground occurs in the circuit and the shutdown drive signal is output.

[0199] The open-circuit filtering time and the short-circuit filtering time are used to avoid false alarms and ensure the reliability of fault detection.

[0200] Now combined Figure 7 The waveform of Figure 5 The working principle of the fault detection module 1213 of the present invention is described as follows. Figure 7 The working waveform diagram of the fault detection module 1213 is shown, wherein:

[0201] V_O2Hx, which can be understood as the voltage of the first node;

[0202] I_O2Hx can be understood as the current flowing through the source of the first MOS tube M1;

[0203] O2Hx can be understood as the actual driving control signal corresponding to the xth oxygen heating module.

[0204] It can be seen that in the time period t1-t2, the xth oxygen heating module is in a normal working state, the heating control unit 1211 outputs the shutdown drive signal, the voltage of the first node is the system power supply voltage, and the current flowing through the source of the first MOS tube M1 is the normal diagnostic current;

[0205] In the time period from t2 to t3, the heating control unit 1211 outputs the on-drive signal, the current flowing through the source of the first MOS tube M1 increases rapidly, and is equal to the first current threshold at time t3, and the xth oxygen heating module enters an overcurrent fault state;

[0206] In the time period t3 to t4, the xth oxygen heating module is continuously in an overcurrent fault state, and the duration is greater than the overcurrent filter time, the heating control unit outputs the shutdown drive signal to control the xth oxygen heating module to stop working;

[0207] The time period from t4 to t5 can be understood as a mask time (Tmask time), which is used to ignore the noise signal during the transition period. At this time, the x-th oxygen heating module is in a stopped working state, and the voltage of the first node is a clamping voltage until the voltage of the first node is restored to the system power supply voltage, and the current flowing through the source of the first MOS tube M1 is a normal diagnostic current.

[0208] In the time period of t5 to t6, the xth oxygen heating module is in a stopped working state, but the voltage of the first node drops to the third set voltage, and the xth oxygen heating module enters an open circuit fault state;

[0209] In the time period from t6 to t7, the xth oxygen heating module is continuously in an open circuit fault state, the voltage of the first node is continuously greater than 0.5VDD, and the duration is greater than the open circuit filter time, the heating control unit determines that the circuit is in an open circuit fault state, and controls the xth oxygen heating module to stop working;

[0210] In the time period from t7 to t8, the voltage of the first node returns to the normal 0.5 VDD, and drops to 0.4 VDD at time t8, and the xth oxygen heating module enters a short-circuit fault state to ground;

[0211] In the time period from t8 to t9, the xth oxygen heating module is continuously in a short-circuit fault state to the ground, the voltage of the first node is continuously less than 0.4VDD, and the duration is greater than the short-circuit filter time, the heating control unit determines that the circuit is in a short-circuit fault state to the ground, and controls the xth oxygen heating module to stop working.

[0212] It can be seen from the above content that the fault detection signal in the present invention can inform the heating control unit of specific fault information, so that the heating control unit can output a corresponding drive control signal as needed.

[0213] In summary, the embodiment of the present invention integrates the oxygen heating system inside the engine chip, and the engine chip is electrically connected to the main control chip. The system includes at least 2 oxygen heating modules, and each oxygen heating module includes: a heating control unit that outputs a driving control signal based on a parallel oxygen heating control signal, a serial oxygen heating control signal, and a fault detection signal; a driving unit that controls the working state of the corresponding heating element based on the driving control signal; and a fault detection module that performs fault detection on the oxygen heating module. Therefore, the present invention integrates multiple oxygen heating modules inside the engine chip, so that the engine chip can meet the independent heating and independent fault detection of each oxygen sensor, while reducing the peripheral circuit, and has good reliability and low complexity.

[0214] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. An oxygen heating system, characterized in that: The oxygen heating system is integrated inside the engine chip, and the system includes N oxygen heating modules, each of which is used to heat a corresponding oxygen sensor, where N is an integer greater than or equal to 2; The engine chip is electrically connected to the main control chip, and the engine chip includes an SPI module, and the SPI module is used to receive the SPI control signal sent by the main control chip, and output a corresponding serial oxygen heating control signal to each oxygen heating module based on the SPI control signal; The main control chip also outputs corresponding parallel oxygen heating control signals to each oxygen heating module; wherein: The oxygen heating module comprises: a heating control unit, receiving the parallel oxygen heating control signal, the serial oxygen heating control signal and the fault detection signal, and configured to output a driving control signal based on the parallel oxygen heating control signal, the serial oxygen heating control signal and the fault detection signal; A driving unit, comprising a high-side driver, a clamping sub-unit and a first MOS transistor, wherein an input end of the high-side driver receives the driving control signal, and an output end thereof is respectively coupled to a first end of the clamping sub-unit and a control end of the first MOS transistor, a second end of the clamping sub-unit and a drain of the first MOS transistor are both coupled to a first node, the first node is also coupled to a first end of a corresponding heating element, and a source of the first MOS transistor is grounded; A fault detection module, a first end of which is coupled to the source of the first MOS tube, a second end of which is coupled to the first node, and an output end of which is coupled to the heating control unit, is used to output the fault detection signal based on the current flowing through the source of the first MOS tube and the voltage of the first node.

2. The oxygen heating system according to claim 1, characterized in that: The drive control signal includes an on drive signal and an off drive signal, and based on the parallel oxygen heating control signal, the serial oxygen heating control signal and the fault detection signal, the drive control signal is output, including: When the parallel oxygen heating control signal is characterized as being on and the serial oxygen heating control signal is characterized as being off, the heating control unit outputs the on drive signal; When the parallel oxygen heating control signal is characterized as being off and the serial oxygen heating control signal is characterized as being on, the heating control unit outputs the on drive signal; When the parallel oxygen heating control signal is characterized as being on and the serial oxygen heating control signal is characterized as being on, the heating control unit outputs the shutoff drive signal; When the parallel oxygen heating control signal is characterized as off and the serial oxygen heating control signal is characterized as off, the heating control unit outputs the off drive signal; When the fault detection signal is characterized as abnormal, the heating control unit outputs the shutdown drive signal.

3. The oxygen heating system according to claim 2, characterized in that: The fault detection module is further configured to: When the heating control unit outputs the on-drive signal, outputting the fault detection signal based on the current flowing through the source of the first MOS tube; When the heating control unit outputs the shutoff driving signal, the failure detection signal is output based on the voltage of the first node.

4. The oxygen heating system according to claim 3, characterized in that: The method for outputting the fault detection signal based on the current flowing through the source of the first MOS transistor and the voltage of the first node includes: When the heating control unit outputs the on-drive signal, if the current flowing through the source of the first MOS tube is greater than or equal to a first current threshold, then the fault detection signal indicating abnormality is output; When the heating control unit outputs the on-drive signal, if the current flowing through the source of the first MOS tube is less than the first current threshold, the fault detection signal indicating normality is output; When the heating control unit outputs the shutdown driving signal, if the voltage of the first node does not belong to the second threshold voltage range, the fault detection signal indicating abnormality is output; When the heating control unit outputs the shutdown driving signal, if the voltage of the first node belongs to the second threshold voltage range, the fault detection signal indicating normality is output.

5. The oxygen heating system according to claim 4, characterized in that: The fault detection signal includes an overcurrent detection signal, and the fault detection module includes an overcurrent detection unit; the overcurrent detection unit includes a first amplifier and a detection resistor; The first end of the detection resistor is coupled to the source of the first MOS tube, and the second end thereof is grounded; The first input terminal of the first amplifier is coupled to the first terminal of the detection resistor, the second terminal of the first amplifier is coupled to the second terminal of the detection resistor, and the output terminal of the first amplifier is coupled to the heating control unit for outputting the overcurrent detection signal.

6. The oxygen heating system according to claim 5, characterized in that The heating control unit is configured to determine whether a circuit fails based on the overcurrent detection signal and the overcurrent filtering time, wherein: If the overcurrent detection signal is characterized as abnormal and lasts longer than the overcurrent filtering time, it is determined that the circuit has an overcurrent and the shutdown drive signal is output.

7. The oxygen heating system according to claim 6, characterized in that The heating control unit is also coupled to a status indicator light, and the heating control unit is configured to: When overcurrent occurs in the circuit, the status indicator light is controlled to turn off.

8. The oxygen heating system according to claim 4, characterized in that The fault detection signal includes an open circuit detection signal and a short circuit detection signal; the maximum value of the second threshold voltage range is a first set voltage, and the minimum value thereof is a second set voltage; the fault detection module includes an open circuit detection unit, a short circuit detection unit and a voltage setting unit; The voltage setting unit includes a second amplifier and a first switch, wherein a first input terminal of the second amplifier receives the first setting voltage, a second input terminal of the second amplifier is coupled to an output terminal thereof, an output terminal of the second amplifier is coupled to a first terminal of the first switch, and a second terminal of the first switch is coupled to the first node; The open circuit detection unit includes a third amplifier, a first input terminal of the third amplifier receives a third set voltage, a second input terminal of the third amplifier is coupled to the first terminal of the first switch, and an output terminal of the third amplifier is coupled to the heating control unit, wherein the third set voltage is greater than the first set voltage; The short circuit detection unit includes a fourth amplifier, a first input terminal of the fourth amplifier receives the second setting voltage, a second input terminal of the fourth amplifier is coupled to the first terminal of the first switch, and an output terminal of the fourth amplifier is coupled to the heating control unit.

9. The oxygen heating system according to claim 8, characterized in that The heating control unit is also coupled to the control end of the first switch, and the heating control unit is configured as follows: When the heating control unit outputs the shutdown driving signal, the first switch is controlled to be turned on.

10. The oxygen heating system according to claim 8, characterized in that The heating control unit is configured to determine whether a circuit fails based on the open circuit detection signal and the open circuit filtering time, wherein: If the open circuit detection signal is characterized as abnormal and lasts longer than the open circuit filtering time, it is determined that the circuit is open circuited and the shutdown drive signal is output; and Based on the short-circuit detection signal and the short-circuit filtering time, it is determined whether a circuit fault occurs, wherein: If the short-circuit detection signal is characterized as abnormal and lasts longer than the short-circuit filtering time, it is determined that a short circuit to ground occurs in the circuit and the shutdown drive signal is output.

11. The oxygen heating system according to any one of claims 1 to 10, characterized in that: The engine chip further includes: A power supply module, used to supply power to the engine chip and a sensor electrically connected to the engine chip; A mode control module receives a key signal and is used to control the state of the engine chip to be a working mode and a standby mode based on the key signal; an injector driving module, coupled to the injector, for driving the injector when the engine chip is in a working mode; a relay driving module, coupled to the relay, for driving the relay when the engine chip is in an operating mode; a rotation speed module, coupled to the tachometer, for outputting a rotation speed signal when the engine chip is in a working mode; A fault light driving module, coupled to the fault indicator light, for driving the fault indicator light when the system is in a fault state; An idle stepper motor driving module, coupled to the idle stepper motor, and used to drive the idle stepper motor when the engine chip is in a working mode; A magnetoelectric signal processing module, used for converting crankshaft magnetoelectric signals when the engine chip is in working mode; K-LINE communication module, used to realize OBD communication.

Images