Idling traveling auxiliary fault judgment method and system for electronic control engine

Abstract

The invention discloses a method and a system for judging an idling traveling block auxiliary fault of an electronic control engine, which mainly comprises the following steps of: when an idling traveling block fault occurs, judging whether an idling traveling block auxiliary diagnosis starting condition is met or not; if the starting idling traveling block auxiliary diagnosis condition is met, auxiliary diagnosis is started, the current target rotating speed of an engine is locked, the automatic exhaust temperature correction function of each cylinder is closed, and then whether the starting idling traveling block auxiliary diagnosis condition is met or not is judged; if the starting condition is met, whether the ith cylinder has a fault or not is judged, and if the ith cylinder has the fault, a corresponding diagnosis signal is generated; if no fault exists, fault diagnosis is carried out on the (i + 1) th cylinder; and finally, a fault prompt is output, current target rotating speed locking is relieved, and the automatic exhaust temperature correction function of each cylinder is started. Therefore, on the premise that reliable operation of the engine is guaranteed, when the idling traveling block fault occurs, the idling traveling block auxiliary diagnosis function is utilized, the fault cylinder is automatically recognized, and the method has the advantages of being easy to operate and low in cost.

Description

Technical Field

[0001] The present invention relates to the technical field of electronically controlled engines, and in particular to an electronically controlled engine idle wandering auxiliary fault determination method and system. Background Art

[0002] Limited by the consistency of the mechanical structure of the fuel injection pump, the consistency of the fuel supply of each fuel injection pump deteriorates as the fuel supply decreases under the same power-on time. Under idling conditions, the engine has no additional load demand, the engine speed is the lowest and there is no additional load demand. At this time, the required fuel volume is the smallest. It is possible that the fuel injection pumps of some cylinders cannot supply fuel normally due to the current short power-on time.

[0003] The speed control program of the electronically controlled engine has been set in the ECU in advance. By judging the difference between the current speed and the target speed, the PID control is used to adjust the increase or decrease of the circulating fuel supply of the engine, so as to maintain the stability of the engine speed. In the idling condition, if some cylinders are controlled according to the current smaller power-on time, no fuel injection occurs, resulting in misfire of the cylinder in a certain working cycle of the engine, reduced work of the single cylinder, and reduced engine speed. When the actual engine speed is lower than the target speed, the PID control intervenes and actively increases the circulating fuel supply of the engine (i.e., increases the power-on time of each cylinder). The cylinder fires and works, and the overall work of the diesel engine exceeds the required work. The actual engine speed exceeds the target speed, and the PID control intervenes and actively reduces the circulating fuel supply of the engine (i.e., reduces the power-on time of each cylinder). Repeatedly, the cylinder has intermittent work, the diesel engine speed is unstable, and the problem of wandering occurs. Summary of the invention

[0004] In view of the above-mentioned deficiencies, the technical problem to be solved by the present invention is: to provide an electronically controlled engine idle wandering auxiliary fault determination method and system, which, under the premise of ensuring reliable operation of the engine, utilizes the idle wandering auxiliary diagnosis function to automatically and quickly identify the faulty cylinder when an idle wandering fault occurs, so as to eliminate the idle wandering fault, and the present invention has the advantages of simple operation and low cost.

[0005] In order to solve the above technical problems, the technical solution of the present invention is:

[0006] A method for determining an electronically controlled engine idle wandering auxiliary fault comprises the following steps:

[0007] S10, determining whether the engine has an idle wandering fault;

[0008] S20: If an idle wandering fault occurs, determine whether the idle wandering auxiliary diagnosis conditions are met;

[0009] S30, if the idle cruise auxiliary diagnosis start-up condition is met, generating a corresponding start-up diagnosis signal;

[0010] S40, according to the start-up diagnosis signal, lock the current engine target speed and turn off the automatic exhaust temperature correction function of each cylinder, and then determine whether the idle cruise auxiliary diagnosis conditions are met;

[0011] If the idle cruise auxiliary diagnosis start-up condition is met, execute S50;

[0012] S50, judging whether i is greater than n, where n is the total number of cylinders and i is a variable with an initial value of 1;

[0013] If i is not greater than n, diagnose whether the i-th cylinder has a fault;

[0014] If there is a fault in the i-th cylinder, a diagnostic signal corresponding to the i-th cylinder fault is generated;

[0015] If there is no fault in the i-th cylinder, let i=i+1 and execute S50;

[0016] S60: Output the i-th cylinder fault prompt according to the diagnosis signal, turn off the idle cruise auxiliary diagnosis, release the current target speed lock, and turn on the automatic exhaust temperature correction function of each cylinder.

[0017] Preferably, the S20 includes:

[0018] If an idle wandering fault occurs, a corresponding first prompt signal is generated;

[0019] According to the first prompt signal, prompting the user to confirm whether to start the idle cruise auxiliary diagnosis;

[0020] Determining whether a first confirmation signal corresponding to the user's permission to start the idle cruise auxiliary diagnosis is received;

[0021] If the first confirmation signal is received, the condition for starting idle cruise auxiliary diagnosis is met.

[0022] Preferably, the S20 further includes:

[0023] If the first confirmation signal is received, it is then determined whether an end signal corresponding to the end of the idle cruise auxiliary diagnosis is received;

[0024] If the end signal is not received, the conditions for starting idle cruise auxiliary diagnosis are met.

[0025] In a preferred embodiment, the step of determining whether the idle cruise auxiliary diagnosis condition is met according to the start-up diagnosis signal in S40 includes:

[0026] generating a corresponding second prompt signal according to the startup diagnostic signal;

[0027] According to the second prompt signal, the user is prompted to confirm again whether to start the idle cruise auxiliary diagnosis;

[0028] Determining whether a second confirmation signal corresponding to the user's permission to start the idle cruise auxiliary diagnosis is received;

[0029] If the second confirmation signal is received, the idle cruise auxiliary diagnosis starting condition is met, and S50 is executed.

[0030] Preferably, the S50 includes:

[0031] S500, determining whether i is greater than n, where n is the total number of cylinders and i is a variable with an initial value of 1;

[0032] If i is not greater than n, execute S501;

[0033] S501, increasing the power-on time of the i-th cylinder according to the preset power-on time step a;

[0034] S502, determining whether the engine has an idle wandering fault;

[0035] S503, if there is an idle wandering fault, determine whether the cumulative increase in the power-on time of the i-th cylinder is greater than a preset maximum correction value;

[0036] If there is no idle wandering fault, a diagnostic signal corresponding to the i-th cylinder fault is generated;

[0037] S504: If the cumulative increase in the power-on time of the i-th cylinder is not greater than the preset maximum correction value, execute S501;

[0038] If the cumulative increase in the power-on time of the i-th cylinder is greater than the preset maximum correction value, i=i+1, and S500 is executed;

[0039] The step S60 includes: outputting the i-th cylinder fault prompt according to the diagnosis signal, turning off the idle cruise auxiliary diagnosis, clearing the power-on time value increased by the current cylinder, releasing the current target speed lock and turning on the automatic exhaust temperature correction function of each cylinder.

[0040] Preferably, the S10 includes:

[0041] Determine whether the current operating condition of the engine is an idle condition;

[0042] If the engine is currently operating at idle speed

[0043] Determining whether the engine speed fluctuation rate is less than a preset fluctuation threshold;

[0044] If the speed fluctuation rate is not less than the fluctuation threshold, the engine will have an idle wandering fault.

[0045] Preferably, the S502 is specifically:

[0046] Determining whether the engine speed fluctuation rate is less than a preset fluctuation threshold;

[0047] If the speed fluctuation rate is less than the fluctuation threshold, the engine does not have an idle wandering fault;

[0048] If the speed fluctuation rate is not less than the fluctuation threshold, the engine has an idle wandering fault.

[0049] An electronically controlled engine idle wandering auxiliary fault determination system comprises an electronic control unit and a working condition detection unit, an auxiliary diagnosis confirmation unit and an idle wandering auxiliary diagnosis unit which are electrically connected to the electronic control unit respectively;

[0050] The operating condition detection unit is used to determine whether the engine has an idle wandering fault. If the engine has an idle wandering fault, the corresponding diagnostic signal is transmitted to the electronic control unit, and the electronic control unit starts the auxiliary diagnosis confirmation unit according to the received diagnostic signal;

[0051] The auxiliary diagnosis confirmation unit is used to determine whether the idle cruising auxiliary diagnosis start condition is met, and if the condition is met, transmit a start signal to the electronic control unit; if the condition is not met, transmit an end signal to the electronic control unit; the electronic control unit controls the idle cruising auxiliary diagnosis unit to start according to the received start signal, and controls the idle cruising auxiliary diagnosis unit to end according to the received end signal;

[0052] After the idle cruise auxiliary diagnosis unit is started, the current engine target speed is locked and the automatic exhaust temperature correction function of each cylinder is turned off, and fault diagnosis is performed on each cylinder, and the corresponding diagnosis result is transmitted to the electronic control unit;

[0053] The electronic control unit outputs the i-th cylinder fault prompt according to the received diagnosis result, turns off the idle cruise auxiliary diagnosis, releases the current target speed lock and turns on the automatic exhaust temperature correction function of each cylinder.

[0054] A preferred method is that the idle wandering auxiliary diagnosis unit is used to increase the power-on time of the i-th cylinder according to a preset power-on time step, and then determine whether the engine has an idle wandering fault. If the idle wandering fault does not exist, a diagnostic signal corresponding to the i-th cylinder fault is generated. If the idle wandering fault still exists, it is determined whether the cumulatively increased power-on time of the i-th cylinder is greater than a preset maximum correction value. If the cumulatively increased power-on time of the i-th cylinder is not greater than the preset maximum correction value, the i-th cylinder is diagnosed repeatedly. If the cumulatively increased power-on time of the i-th cylinder is greater than the preset maximum correction value, the i+1 cylinder is diagnosed again.

[0055] Preferably, the system further comprises a preset unit electrically connected to the electronic control unit, wherein the preset unit is used to preset a maximum correction threshold.

[0056] After adopting the above technical solution, the beneficial effects of the present invention are:

[0057] The electronically controlled engine idle wandering auxiliary fault determination method and system of the present invention mainly first determines whether the engine has an idle wandering fault; if an idle wandering fault occurs, then determines whether the idle wandering auxiliary diagnosis condition is met; if the idle wandering auxiliary diagnosis condition is met, the current engine target speed is locked and the automatic exhaust temperature correction function of each cylinder is turned off, and then determines whether the idle wandering auxiliary diagnosis condition is met; if the idle wandering auxiliary diagnosis condition is met, then diagnose whether the i-th cylinder has a fault; if the i-th cylinder has a fault, a diagnostic signal corresponding to the i-th cylinder fault is generated; if the i-th cylinder does not have a fault, repeat the above steps to diagnose the next cylinder; according to the diagnostic signal, the i-th cylinder fault prompt is output, the current target speed lock is released, and the automatic exhaust temperature correction function of each cylinder is turned on. It can be seen that the present invention can automatically identify the faulty cylinder and eliminate the idle wandering fault by using the idle wandering auxiliary diagnosis function when an idle wandering fault occurs, under the premise of ensuring reliable operation of the engine, and the present invention has the advantages of simple operation and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is a flow chart of the auxiliary fault determination method of the electronically controlled engine idle wandering in the present invention;

[0059] Figure 2 It is a principle block diagram of the electronically controlled engine idle wandering auxiliary fault determination system of the present invention. DETAILED DESCRIPTION

[0060] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0061] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0062] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0063] The automatic exhaust temperature correction involved in the present invention specifically refers to: the ECU increases or decreases the fuel supply per cycle of a single cylinder within a certain temperature difference range based on the difference in exhaust temperature of each cylinder measured by analysis; the wandering fault specifically refers to: the actual speed fluctuates greatly periodically and the engine runs unstably; the idle condition refers to the engine being in a no-load operating state.

[0064] like Figure 1 As shown, a method for determining an electronically controlled engine idle wandering auxiliary fault comprises the following steps:

[0065] Step S10, determining whether the engine has an idle wandering fault;

[0066] Step S20: If an idle wandering fault occurs, determine whether the idle wandering auxiliary diagnosis condition is met;

[0067] Step S30: if the idle cruise auxiliary diagnosis start-up condition is met, a corresponding start-up diagnosis signal is generated;

[0068] If the idle cruise auxiliary diagnosis start condition is not met, a corresponding end signal is generated, and then the idle cruise auxiliary diagnosis (mode or function) is ended or exited according to the end signal. The present invention ensures that the automatic exhaust temperature correction function is turned off and the normal operation of the engine is not affected when diagnosing a cylinder by setting the start condition.

[0069] Step S40, according to the start-up diagnostic signal, lock the current engine target speed and turn off the automatic exhaust temperature correction function of each cylinder, and then determine whether the conditions for starting the idle cruise auxiliary diagnosis are met; wherein the automatic exhaust temperature correction function of each cylinder is turned off to prevent the automatic exhaust temperature correction function from being turned on to correct the oil amount of the faulty cylinder, thereby affecting the faulty cylinder identification.

[0070] If the idle cruise auxiliary diagnosis start-up condition is met, step S50 is executed;

[0071] If the conditions for starting the idle cruise auxiliary diagnosis are not met, a corresponding end signal is generated, and then the idle cruise auxiliary diagnosis (mode or function) is ended or exited according to the end signal.

[0072] Step S50, determine whether i is greater than n, where n is the total number of cylinders, i is a variable with an initial value of 1, and i is a positive integer; through this determination, the reliability of idle cruise auxiliary diagnosis is guaranteed.

[0073] If i is not greater than n, diagnose whether the i-th cylinder has a fault;

[0074] If there is a fault in the i-th cylinder, a diagnostic signal corresponding to the i-th cylinder fault is generated;

[0075] If there is no fault in the i-th cylinder, i=i+1, execute step S50;

[0076] It should be noted that the i value can be set in real time through the human-computer interaction unit, or a preset initial value can be used, that is, the diagnosis and judgment can be started from the first cylinder. The i value can be used to assist in identifying the injection pump with a large consistency deviation by observing the operating status of the diesel engine, so as to quickly lock the faulty cylinder, thereby improving the efficiency of fault diagnosis and elimination of idle hunting faults.

[0077] In addition, this step may also include: if i is greater than n, generating a prompt signal and an end signal, issuing a prompt to notify the user according to the prompt signal, and ending the idle cruise auxiliary diagnosis according to the end signal, further ensuring the reliability of the operation of the present invention.

[0078] Step S60: outputting the i-th cylinder fault prompt according to the diagnosis signal, releasing the current target speed lock and starting the automatic exhaust temperature correction function of each cylinder.

[0079] The electronically controlled engine idle wandering auxiliary fault determination method of the present invention mainly first determines whether the engine has an idle wandering fault; if an idle wandering fault occurs, then determines whether the idle wandering auxiliary diagnosis conditions are met, so as to ensure that the premise of using the idle wandering auxiliary diagnosis is that it does not affect the normal operation of the engine; if the idle wandering auxiliary diagnosis conditions are met, the current engine target speed is locked and the automatic exhaust temperature correction function of each cylinder is turned off to avoid the automatic exhaust temperature correction function from affecting the idle wandering auxiliary diagnosis, thereby ensuring the reliable implementation of the idle wandering auxiliary diagnosis. It can be seen that the present invention, under the premise of ensuring the reliable operation of the engine, uses the idle wandering auxiliary diagnosis function to automatically identify the faulty cylinder and eliminate the idle wandering fault when an idle wandering fault occurs, and the present invention has the advantages of simple operation and low cost.

[0080] In this embodiment, step S20 specifically includes:

[0081] If an idle wandering fault occurs, a corresponding first prompt signal is generated;

[0082] According to the first prompt signal, prompting the user to confirm whether to start the idle cruise auxiliary diagnosis;

[0083] It should be noted that the present invention can prompt the user to confirm by displaying through a visual interface. Of course, the user can also be prompted to confirm by a prompt sound.

[0084] Determining whether a first confirmation signal corresponding to the user's permission to start the idle cruise auxiliary diagnosis is received;

[0085] It should be noted that: the user can input the first confirmation signal through the human-computer interaction interface, buttons, etc.

[0086] If the first confirmation signal is received, the condition for starting idle cruise auxiliary diagnosis is met.

[0087] A preferred solution is that if the first confirmation signal is received, it is determined whether an end signal corresponding to the end of the idle cruise auxiliary diagnosis is received; similarly, the user can input the end signal through the human-computer interaction interface, buttons, etc., and this step allows the user to end the idle cruise auxiliary diagnosis at any time, thereby meeting usage requirements.

[0088] If the end signal is not received, the conditions for starting idle cruise auxiliary diagnosis are met.

[0089] In this embodiment, the step S40 of determining whether the idle cruise auxiliary diagnosis condition is met according to the start-up diagnosis signal includes:

[0090] generating a corresponding second prompt signal according to the startup diagnostic signal;

[0091] According to the second prompt signal, the user is prompted to confirm again whether to start the idle cruise auxiliary diagnosis;

[0092] It should be noted that: the present invention can pop up a prompt on the human-computer interaction interface according to the second prompt signal so as to quickly obtain reconfirmation, thereby ensuring the efficiency of auxiliary diagnosis.

[0093] Determining whether a second confirmation signal corresponding to the user's permission to start the idle cruise auxiliary diagnosis is received;

[0094] If the second confirmation signal is received, the idle cruise auxiliary diagnosis starting condition is met, and step S50 is executed.

[0095] The electronically controlled engine idle wandering auxiliary fault determination method of the present invention enhances user confirmation through a first prompt signal and a second prompt signal, and ensures that the idle wandering auxiliary diagnosis is performed without affecting the normal operation of the engine, thereby ensuring the reliability of the engine operation.

[0096] In this embodiment, step S50 specifically includes:

[0097] Step S500, determine whether i is greater than n, where n is the total number of cylinders and i is a variable with an initial value of 1;

[0098] If i is not greater than n, execute step S501;

[0099] Step S501, increase the power-on time of the i-th cylinder according to the preset power-on time step a; specifically, according to the power-on time step a preset by the electronic control unit, gradually increase the power-on time of the i-th cylinder on the basis of the original power-on time, that is, increase the fuel injection amount of this cylinder.

[0100] Step S502: determine whether the engine has an idle wandering fault; this step specifically includes:

[0101] Determine whether the engine speed fluctuation rate is less than a preset fluctuation threshold; the speed fluctuation rate is the absolute value of the difference between the target speed and the actual speed and the percentage of the target speed;

[0102] If the speed fluctuation rate is less than the preset fluctuation threshold, the engine does not have an idle wandering fault;

[0103] If the speed fluctuation rate is not less than the preset fluctuation threshold, the engine has an idle wandering fault.

[0104] Step S503: If there is an idle wandering fault, determine whether the accumulated power-on time of the i-th cylinder is greater than a preset maximum correction value; the maximum correction value may be the maximum correction value in the automatic exhaust temperature correction function.

[0105] If there is no idle wandering fault, a diagnostic signal corresponding to the i-th cylinder fault is generated;

[0106] Step S504: If the cumulative increase in the power-on time of the i-th cylinder is not greater than the preset maximum correction value, execute step S501;

[0107] If the cumulative increase in the power-on time of the i-th cylinder is greater than the preset maximum correction value, let i=i+1 and execute step S500;

[0108] It should be noted that: the present invention limits the total value of the increased power-on time to be less than the maximum correction value of the power-on time in the automatic exhaust temperature correction function to avoid exceeding the maximum correction oil volume of a single cylinder.

[0109] Step S60 includes: outputting the i-th cylinder fault prompt according to the diagnosis signal, clearing the increased power-on time value of the current cylinder, releasing the current target speed lock, and starting the automatic exhaust temperature correction function of each cylinder.

[0110] In summary, when the fuel supply of a single cylinder is increased, if the cylinder is a faulty cylinder, intermittent ignition will no longer occur, and the engine speed will quickly stabilize. When the speed fluctuation rate is identified to be less than the fluctuation threshold A%, the cylinder can be determined to be a faulty cylinder, and the user is reminded to replace it, the auxiliary diagnosis function is turned off, the power-on time value increased by the current cylinder is cleared, the current target speed lock is released, and the automatic exhaust temperature correction function of each cylinder is turned on. If the speed fluctuation rate does not meet the requirements after the above operations are performed on the cylinder, the above operations are performed on other cylinders in turn until the faulty cylinder is confirmed.

[0111] In this embodiment, step S10 specifically includes:

[0112] Determine whether the current operating condition of the engine is an idle condition;

[0113] If the current engine operating condition is idle condition;

[0114] Determine whether the actual engine speed fluctuation rate is less than a preset fluctuation threshold;

[0115] If the actual speed fluctuation rate is not less than the fluctuation threshold, the engine will have an idle wandering fault.

[0116] Through the above steps, whether the idle wandering fault occurs can be detected quickly and accurately.

[0117] Embodiment 2:

[0118] like Figure 2 As shown, an electronically controlled engine idle wandering auxiliary fault judgment system can apply the electronically controlled engine idle wandering auxiliary fault judgment method described in Example 1. The system includes an electronic control unit and a working condition detection unit, an auxiliary diagnosis confirmation unit, an idle wandering auxiliary diagnosis unit and a preset unit electrically connected to the electronic control unit respectively. The preset unit is used to preset a maximum correction threshold; it also includes a speed sensor and a human-computer interaction unit. The engine speed is detected by the speed sensor, and the human-computer interaction unit is used to perform human-computer interaction. The human-computer interaction unit may include a display screen and buttons, etc.

[0119] The working condition detection unit in the present invention is used to determine whether the engine has an idle wandering fault. If the engine has an idle wandering fault, the corresponding diagnostic signal is transmitted to the electronic control unit, and the electronic control unit starts the auxiliary diagnosis confirmation unit according to the received diagnostic signal. Specifically, when the engine is in a no-load operating state, that is, when the engine is operating in an idle condition, the electronic control unit calculates the speed fluctuation rate, and the speed fluctuation rate is the absolute value of the difference between the target speed and the actual speed and the percentage of the target speed. When the speed fluctuation rate is greater than or equal to the preset fluctuation threshold value A%, the engine has an idle wandering fault. When the speed fluctuation rate is less than the fluctuation threshold value A%, the engine does not have an idle wandering fault.

[0120] The auxiliary diagnosis confirmation unit in the present invention is used to determine whether the conditions for starting the idle wandering auxiliary diagnosis are met. If the conditions are met, a start signal is transmitted to the electronic control unit. If the conditions are not met, an end signal is transmitted to the electronic control unit. The electronic control unit controls the idle wandering auxiliary diagnosis unit to start according to the received start signal, and controls the idle wandering auxiliary diagnosis unit to end according to the received end signal. Specifically, when an idle wandering fault occurs, the relevant information for starting the idle wandering auxiliary diagnosis is output to the visual interface, prompting the user to confirm whether the idle wandering auxiliary diagnosis is required; when the user confirms to perform the diagnosis, it can be determined that the conditions for starting the idle wandering auxiliary diagnosis are met. A preferred solution is that when the user manually inputs the end of the idle wandering auxiliary diagnosis, it can be determined that the conditions for starting the idle wandering auxiliary diagnosis are not met. Of course, whether the conditions for starting the idle wandering auxiliary diagnosis are met is not limited to those listed above, and can be set according to actual operating needs.

[0121] After the idle wandering auxiliary diagnosis unit in the present invention is started, the current engine target speed is locked and the automatic exhaust temperature correction function of each cylinder is turned off, and fault diagnosis is performed on each cylinder, and the corresponding diagnosis result is transmitted to the electronic control unit; in this embodiment, the idle wandering auxiliary diagnosis unit is used to increase the power-on time of the i-th cylinder according to a preset power-on time step, and then determine whether the engine has an idle wandering fault. If there is no idle wandering fault, a diagnostic signal corresponding to the i-th cylinder fault is generated. If the idle wandering fault still exists, it is determined whether the cumulatively increased power-on time of the i-th cylinder is greater than the preset maximum correction value. If the cumulatively increased power-on time of the i-th cylinder is not greater than the preset maximum correction value, the diagnosis of the i-th cylinder is repeated. If the cumulatively increased power-on time of the i-th cylinder is greater than the preset maximum correction value, the i+1-th cylinder is diagnosed again.

[0122] Based on the received diagnosis results, the electronic control unit outputs the i-th cylinder fault prompt, turns off the idle cruise auxiliary diagnosis, releases the current target speed lock and turns on the automatic exhaust temperature correction function of each cylinder.

[0123] When the electronically controlled engine idle wandering auxiliary fault determination system of the present invention is in use, when the operating condition detection unit detects that an idle wandering fault occurs, it transmits a corresponding diagnostic signal to the electronic control unit, and the electronic control unit starts the auxiliary diagnosis confirmation unit according to the received diagnostic signal; when the auxiliary diagnosis confirmation unit detects that the idle wandering auxiliary diagnosis starting conditions are met, the auxiliary diagnosis confirmation unit transmits a corresponding start signal to the electronic control unit, and the electronic control unit controls the idle wandering auxiliary diagnosis unit to start and perform fault diagnosis according to the received start signal.

[0124] After the idle cruise assist diagnosis unit is started, the fault diagnosis of the i-th cylinder is performed. After the diagnosis is completed, the diagnosis result is transmitted to the electronic control unit, and the electronic control unit outputs the i-th cylinder fault prompt, turns off the idle cruise assist, releases the current target speed lock, turns on the automatic exhaust temperature correction function of each cylinder, and resets various functions.

[0125] It can be seen that the present invention starts the idle wandering auxiliary diagnosis unit under the premise of ensuring reliable operation of the engine through the auxiliary diagnosis confirmation unit, and the idle wandering auxiliary diagnosis unit can quickly and reliably diagnose the faulty cylinder and prompt the user to replace the faulty cylinder, thereby solving the idle wandering fault. The electronically controlled engine idle wandering auxiliary fault determination system of the present invention has a simple structure, low cost and good versatility.

[0126] The present invention can assist in checking the consistency of the fuel injection pump system at the end user, thereby reducing the cost of technical personnel traveling to solve problems; the present invention is mainly aimed at the intermittent ignition phenomenon of a single cylinder of the engine, and automatically identifies the faulty cylinder by actively increasing the oil volume in the single cylinder and taking the speed fluctuation rate as the judgment condition.

[0127] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications made within the spirit and principles of the present invention, the same electronically controlled engine idle cruise auxiliary fault determination method and system improvement, etc., should be included in the protection scope of the present invention.

Claims

1. A method for determining an electronically controlled engine idle wandering auxiliary fault, characterized in that: The following steps are involved: S10, determining whether the engine has an idle wandering fault; S20: If an idle wandering fault occurs, determine whether the idle wandering auxiliary diagnosis conditions are met; S30, if the idle cruise auxiliary diagnosis start-up condition is met, generating a corresponding start-up diagnosis signal; S40, according to the start-up diagnosis signal, lock the current engine target speed and turn off the automatic exhaust temperature correction function of each cylinder, and then determine whether the idle cruise auxiliary diagnosis conditions are met; If the idle cruise auxiliary diagnosis start-up condition is met, execute S50; S50, judging whether i is greater than n, where n is the total number of cylinders and i is a variable with an initial value of 1; If i is not greater than n, diagnose whether the i-th cylinder has a fault; If there is a fault in the i-th cylinder, a diagnostic signal corresponding to the i-th cylinder fault is generated; If there is no fault in the i-th cylinder, set i=i+1 and execute S50; S60: Output the i-th cylinder fault prompt according to the diagnosis signal, turn off the idle cruise auxiliary diagnosis, release the current target speed lock, and turn on the automatic exhaust temperature correction function of each cylinder.

2. The electronically controlled engine idle wandering auxiliary fault determination method according to claim 1, characterized in that: The S20 includes: If an idle wandering fault occurs, a corresponding first prompt signal is generated; According to the first prompt signal, prompting the user to confirm whether to start the idle cruise auxiliary diagnosis; Determining whether a first confirmation signal corresponding to the user's permission to start the idle cruise auxiliary diagnosis is received; If the first confirmation signal is received, the condition for starting idle cruise auxiliary diagnosis is met.

3. The electronically controlled engine idle wandering auxiliary fault determination method according to claim 2, characterized in that: The S20 further includes: If the first confirmation signal is received, it is then determined whether an end signal corresponding to the end of the idle cruise auxiliary diagnosis is received; If the end signal is not received, the conditions for starting idle cruise auxiliary diagnosis are met.

4. The electronically controlled engine idle wandering auxiliary fault determination method according to claim 1, characterized in that: The step of determining whether the idle cruise auxiliary diagnosis starting condition is met according to the start diagnosis signal in S40 includes: generating a corresponding second prompt signal according to the startup diagnostic signal; According to the second prompt signal, the user is prompted to confirm again whether to start the idle cruise auxiliary diagnosis; Determining whether a second confirmation signal corresponding to the user's permission to start the idle cruise auxiliary diagnosis is received; If the second confirmation signal is received, the idle cruise auxiliary diagnosis starting condition is met, and S50 is executed.

5. The electronically controlled engine idle wandering auxiliary fault determination method according to claim 1, characterized in that: The S50 includes: S500, determining whether i is greater than n, where n is the total number of cylinders and i is a variable with an initial value of 1; If i is not greater than n, execute S501; S501, increasing the power-on time of the i-th cylinder according to the preset power-on time step a; S502, determining whether the engine has an idle wandering fault; S503, if there is an idle wandering fault, determine whether the cumulative increase in the power-on time of the i-th cylinder is greater than a preset maximum correction value; If there is no idle wandering fault, a diagnostic signal corresponding to the i-th cylinder fault is generated; S504: If the cumulative increase in the power-on time of the i-th cylinder is not greater than the preset maximum correction value, execute S501; If the cumulative increase in the power-on time of the i-th cylinder is greater than the preset maximum correction value, i=i+1, and S500 is executed; The step S60 includes: outputting the i-th cylinder fault prompt according to the diagnosis signal, turning off the idle cruise auxiliary diagnosis, clearing the power-on time value increased by the current cylinder, releasing the current target speed lock and turning on the automatic exhaust temperature correction function of each cylinder.

6. The electronically controlled engine idle wandering auxiliary fault determination method according to claim 1, characterized in that: The S10 includes: Determine whether the current operating condition of the engine is an idle condition; If the engine is currently operating at idle speed Determining whether the engine speed fluctuation rate is less than a preset fluctuation threshold; If the speed fluctuation rate is not less than the fluctuation threshold, the engine will have an idle wandering fault.

7. The electronically controlled engine idle wandering auxiliary fault determination method according to claim 5, characterized in that: The S502 is specifically as follows: Determining whether the engine speed fluctuation rate is less than a preset fluctuation threshold; If the speed fluctuation rate is less than the fluctuation threshold, the engine does not have an idle wandering fault; If the speed fluctuation rate is not less than the fluctuation threshold, the engine has an idle wandering fault.

8. An electronically controlled engine idle wandering auxiliary fault determination system, characterized in that: It includes an electronic control unit and a working condition detection unit, an auxiliary diagnosis confirmation unit and an idle speed cruise auxiliary diagnosis unit which are electrically connected to the electronic control unit respectively; The operating condition detection unit is used to determine whether the engine has an idle wandering fault. If the engine has an idle wandering fault, the corresponding diagnostic signal is transmitted to the electronic control unit, and the electronic control unit starts the auxiliary diagnosis confirmation unit according to the received diagnostic signal; The auxiliary diagnosis confirmation unit is used to determine whether the idle cruise auxiliary diagnosis start condition is met, and if the condition is met, transmit a start signal to the electronic control unit; if the condition is not met, transmit an end signal to the electronic control unit; The electronic control unit controls the idle cruise auxiliary diagnosis unit to start according to the received start signal, and the electronic control unit controls the idle cruise auxiliary diagnosis unit to end according to the received end signal; After the idle cruise auxiliary diagnosis unit is started, the current engine target speed is locked and the automatic exhaust temperature correction function of each cylinder is turned off, and fault diagnosis is performed on each cylinder, and the corresponding diagnosis result is transmitted to the electronic control unit; The electronic control unit outputs the i-th cylinder fault prompt according to the received diagnosis result, turns off the idle cruise auxiliary diagnosis, releases the current target speed lock and turns on the automatic exhaust temperature correction function of each cylinder.

9. The electronically controlled engine idle wandering auxiliary fault determination system according to claim 8, characterized in that: The idle wandering auxiliary diagnosis unit is used to increase the power-on time of the i-th cylinder according to a preset power-on time step, and then determine whether the engine has an idle wandering fault. If the idle wandering fault does not exist, generate a diagnostic signal corresponding to the i-th cylinder fault. If the idle wandering fault still exists, determine whether the cumulatively increased power-on time of the i-th cylinder is greater than a preset maximum correction value. If the cumulatively increased power-on time of the i-th cylinder is not greater than the preset maximum correction value, repeat the diagnosis of the i-th cylinder. If the cumulatively increased power-on time of the i-th cylinder is greater than the preset maximum correction value, diagnose the (i+1)th cylinder again.

10. The electronically controlled engine idle wandering auxiliary fault determination system according to claim 9, characterized in that: The system further comprises a preset unit electrically connected to the electronic control unit, wherein the preset unit is used to preset a maximum correction threshold.

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