Method and system for monitoring water content in engine fuel

Abstract

The present invention discloses a method for monitoring the water content in engine fuel, which relates to diesel engine electronic technology and solves the technical problem that the current ECU cannot detect the misjudgment of the water content in fuel caused by a wiring harness disconnection fault. A first terminal voltage, a second terminal voltage, and a third terminal voltage are preset; a voltage divider device connected in parallel with the sensor is provided so that when the fuel is free of water, the sensor voltage signal collected by the ECU is the first terminal voltage; when the fuel contains water, the sensor voltage signal collected by the ECU is the second terminal voltage; when the wiring harness is disconnected, the sensor voltage signal collected by the ECU is the third terminal voltage. The present invention also discloses an engine fuel water content monitoring system. The present invention has a simple, practical, intelligent structure, flexible application, and a wide range of uses. It supplements and improves the defects of traditional monitoring systems and improves the intelligence level of the engine.

Description

Technical Field

[0001] The present invention relates to diesel engine electronic technology, and more particularly to a method and system for monitoring water content in engine fuel. Background Art

[0002] The operation of internal combustion engines places high demands on fuel quality. With the continuous advancement of common rail systems and emissions, fuel quality is becoming increasingly important. If a large amount of water in the fuel is not promptly addressed, it can seriously impact the reliability of the internal combustion engine. Therefore, a high-quality water-in-fuel alarm system is a crucial component of internal combustion engines. Accurately determining water in fuel is one way to improve the overall performance of internal combustion engines, and the internal combustion engine's fault control logic module is closely related to the water-in-fuel sensor hardware.

[0003] Currently, there are two commonly used fuel water sensors for internal combustion engines, one is float type and the other is electronic type.

[0004] The float sensor's float density lies somewhere between that of diesel and water. As the water level rises, the float rises with it. A reed tube embedded in the float triggers the sensor inside the column when the reed reaches the top, energizing the alarm circuit and activating the water level indicator. Simply put, the float sensor functions like an electrical switch.

[0005] Regardless of the type of water-in-fuel sensor (hereinafter referred to as the sensor), when it detects fuel, the sensor's resistance is very high (e.g., megohms). Since the ECU pull-up resistor is 120 kilo-ohms, the water-level sensor's voltage contribution is high, indicating that the sensor is open-circuited. The ECU pin then detects a high-level signal. When the sensor detects water, its detection terminal shorts, causing the sensor's voltage contribution to decrease and the level detected by the ECU pin to decrease. The ECU then activates the alarm system. However, current ECUs cannot determine the continuity of the sensor wiring harness. If the sensor wiring harness is open-circuited, the ECU pin will continuously output a high level. This means that regardless of the water content in the fuel, the ECU will always assume the fuel water content is within the normal range. This completely fails to reflect the true water content in the fuel, posing a significant safety risk. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to address the deficiencies of the existing technology and provide a method and system for monitoring the water content in engine fuel, which solves the problem that the current ECU cannot detect the misjudgment of the water content in fuel caused by a wiring harness break fault.

[0007] The present invention provides a method for monitoring the water content in engine fuel, wherein a first terminal voltage, a second terminal voltage, and a third terminal voltage are preset; a voltage dividing device is provided in parallel with the sensor, so that when there is no water in the fuel, the sensor voltage signal collected by the ECU is the first terminal voltage; when there is water in the fuel, the sensor voltage signal collected by the ECU is the second terminal voltage; and when the wiring harness is broken, the sensor voltage signal collected by the ECU is the third terminal voltage.

[0008] By setting different alarm voltage intervals and distinguishing the type of fault according to the voltage, the reliability and intelligence of the internal combustion engine are increased.

[0009] As a further improvement, an error range is set for the first terminal voltage, the second terminal voltage and the third terminal voltage; if the difference between the sensor voltage signal collected by the ECU and its corresponding terminal voltage is within the error range, the ECU issues a set control signal according to the sensor voltage signal; otherwise, the ECU issues a fault alarm signal.

[0010] Furthermore, the third terminal voltage is set to the voltage source voltage output by the voltage source connected to the ECU pull-up resistor; the second terminal voltage is set to 1V; and the first terminal voltage is set to half of the sum of the second terminal voltage and the third terminal voltage.

[0011] Furthermore, the error range is ±(0.2-0.5)V.

[0012] An engine fuel water content monitoring system includes an ECU, a voltage source, a pull-up resistor RL, and a sensor; a first pin and a second pin of the ECU are electrically connected to two ends of the sensor, respectively, and the first pin of the ECU is electrically connected to the voltage source via the pull-up resistor RL; and further includes a voltage divider; the voltage divider is electrically connected to the sensor;

[0013] The ECU is used to monitor the water content in the fuel according to the monitoring method.

[0014] By adding a voltage divider, the present invention achieves a voltage output at one end of the sensor when the fuel is water-free; a voltage at the other end when the fuel contains water; and a voltage different from either end when the wiring harness is broken. By setting different alarm voltage ranges in the ECU, the fault type can be identified based on the terminal voltage. This method requires minimal modification and is very easy to implement.

[0015] Furthermore, the voltage dividing device is mainly composed of a voltage dividing resistor RZ.

[0016] Furthermore, one end of the pull-up resistor RL connected to the sensor is electrically connected to the first pin of the ECU via the first resistor R1.

[0017] Beneficial effects

[0018] The advantages of this invention lie in its ability to enhance the reliability and intelligence of internal combustion engines by using a voltage divider connected in parallel with the sensor and setting different alarm voltage ranges in the ECU to distinguish fault types based on voltage levels. This simple and easy-to-implement modification addresses the shortcomings of traditional monitoring systems and enhances the intelligence of the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the circuit structure of the monitoring system of the present invention. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the embodiments, but this does not constitute any limitation to the present invention. Any limited number of modifications made by anyone within the scope of the claims of the present invention are still within the scope of the claims of the present invention.

[0021] The present invention provides a method for monitoring the water content in engine fuel. First, second, and third terminal voltages are preset in the ECU. A voltage divider is provided in parallel with the sensor, so that when the fuel is free of water, the sensor voltage signal collected by the ECU is the first terminal voltage; when the fuel is water-containing, the sensor voltage signal collected by the ECU is the second terminal voltage; and when the wiring harness is disconnected, the sensor voltage signal collected by the ECU is the third terminal voltage. The voltage divider allows the ECU to determine the water content in the fuel and the continuity of the sensor wiring harness based on the collected sensor voltage signals, thereby improving the electronic control intelligence and operational safety of the internal combustion engine.

[0022] Taking into account the floating output voltage of the voltage source and the internal resistance of the sensor harness, in order to ensure that the ECU can more accurately judge the collected sensor signal and its corresponding terminal voltage, this embodiment sets an error range for the first terminal voltage, the second terminal voltage and the third terminal voltage.

[0023] If the difference between the sensor voltage signal collected by the ECU and its corresponding terminal voltage is within the error range, the ECU will issue a set control signal based on the sensor voltage signal. For example, when the sensor voltage signal collected by the ECU is equal to the first terminal voltage, the ECU determines that there is no water in the fuel and will operate normally. When the sensor voltage signal collected by the ECU is equal to the second terminal voltage, the ECU determines that there is water in the fuel and will issue a water-in-fuel alarm signal. When the sensor voltage signal collected by the ECU is equal to the third terminal voltage, the ECU determines that the sensor wiring harness is open and will issue a wiring harness open alarm signal.

[0024] If the difference between the sensor voltage signal collected by the ECU and its corresponding terminal voltage is outside the error range, the ECU will issue a fault alarm signal to remind the staff that the monitoring system has a fault and needs to be repaired. This setting can well ensure the reliability of the monitoring system operation.

[0025] Preferably, the error range is ±(0.2-0.5) V. More specifically, ±0.5 V. Limiting the error between the sensor voltage signal collected by the ECU and the terminal voltage to within ±0.5 V can ensure the stability and reliability of the monitoring system and avoid misjudgment.

[0026] In this embodiment, the third terminal voltage is set to the voltage source voltage output by the voltage source connected to the ECU pull-up resistor, i.e., 5V. The second terminal voltage is set to 1V. The first terminal voltage is set to half the sum of the second terminal voltage and the third terminal voltage, i.e., 3V. This configuration maximizes the difference between the three terminal voltages, effectively reducing the problem of sensor signals collected by the ECU being mapped to other terminal voltages due to monitoring system failures, thereby ensuring the accuracy of the monitoring system.

[0027] See Figure 1 An engine fuel water content monitoring system includes an ECU, a voltage source, a pull-up resistor RL, and a sensor. A first pin and a second pin of the ECU are electrically connected to two ends of the sensor, respectively, and the first pin of the ECU is electrically connected to the voltage source via the pull-up resistor RL. The ECU is configured to monitor fuel water content according to the aforementioned monitoring method.

[0028] The monitoring system also includes a voltage divider device. The voltage divider device is electrically connected to the sensor and is connected near the sensor. The voltage divider device primarily comprises a voltage divider resistor RZ. The end of the pull-up resistor RL connected to the sensor is electrically connected to the first pin of the ECU via a first resistor R1. Both the pull-up resistor RL and the first resistor R1 are located near the ECU pin.

[0029] like Figure 1 As shown, Figure 1 The variable resistor RV in the figure represents the internal resistance of the sensor.

[0030] When water is present in the fuel, the sensor's terminals are short-circuited, resulting in a variable resistor RV = 0Ω. Due to the voltage divider effect of the pull-up resistor RL and the first resistor R1, the voltage difference between the ECU's first and second pins is U = 1V ± 0.5V. Based on this, the ECU determines that the fuel contains water and issues a water-in-fuel alarm, prompting personnel to remove the water.

[0031] When the fuel contains no water, the resistance between the sensor terminals is infinite, and the variable resistor RV is considered infinite. At this point, the voltage source output voltage passes through pull-up resistor RL and is then divided by first resistor R1 and voltage divider resistor RZ, resulting in a voltage difference between the two ECU pins of U = 3V ± 0.5V. Based on this, the ECU determines that there is no water in the fuel.

[0032] When the wiring harness between the sensor and the ECU is disconnected, the voltage source's output voltage cannot pass through the sensor and / or the voltage-dividing resistor RZ, causing a loop between the two ECU pins. Consequently, one ECU pin connected to the voltage source remains at a high level, while the other remains at a low level. The voltage difference between the two ECU pins is considered to be U = 5V ± 0.5V. Based on this, the ECU determines that the wiring harness is disconnected and issues a wiring harness disconnection alarm.

[0033] In summary, this invention improves the reliability and intelligence of internal combustion engines by adding a voltage-dividing resistor, RZ, and setting different alarm voltage ranges in the ECU to distinguish fault types based on voltage levels. This simple and easy-to-implement modification addresses the shortcomings of traditional monitoring systems and enhances the intelligence of the engine.

[0034] The above is only a preferred embodiment of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the structure of the present invention. These modifications and improvements will not affect the effect of the implementation of the present invention and the practicality of the patent.

Claims

1. An engine fuel water content monitoring system, comprising an ECU, a voltage source, a pull-up resistor RL, and a sensor; a first pin and a second pin of the ECU are electrically connected to two ends of the sensor, respectively, and the first pin of the ECU is electrically connected to the voltage source via the pull-up resistor RL; characterized in that: Also includes a pressure dividing device; the pressure dividing device is electrically connected to the sensor; A first terminal voltage, a second terminal voltage, and a third terminal voltage are preset; the voltage divider is connected in parallel with the sensor so that when there is no water in the fuel, the sensor voltage signal collected by the ECU is the first terminal voltage; when there is water in the fuel, the sensor voltage signal collected by the ECU is the second terminal voltage; and when the wiring harness is broken, the sensor voltage signal collected by the ECU is the third terminal voltage; The voltage dividing device is mainly composed of a voltage dividing resistor RZ; One end of the pull-up resistor RL connected to the sensor is electrically connected to the first pin of the ECU via the first resistor R1.

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