JPH0248732B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a failure diagnosis device for a pressure switch for increasing fuel in an electronically controlled fuel injection internal combustion engine with a turbocharger, and in particular, an intake air pressure switch suitable for use in an electronically controlled fuel injection internal combustion engine with a turbocharger installed in a vehicle such as an automobile. The present invention relates to a failure diagnosis device for a fuel increase pressure switch for an electronically controlled fuel injection internal combustion engine equipped with a turbocharger, which detects the supercharging state by a turbocharger from the system pressure and has a fuel increase pressure switch for increasing the amount of fuel during supercharging.

[Conventional technology]

A turbocharger uses exhaust gas from the engine to rotate a turbine, and a compressor connected to the turbine pressurizes and supercharges the intake air, promoting the engine's intake action and effectively utilizing energy. amount, engine speed,
2. Description of the Related Art Electronically controlled fuel injection internal combustion engines are known in which an electronic control device calculates an optimal fuel amount according to cooling water temperature, etc., and injects fuel from a fuel injection nozzle. In an internal combustion engine equipped with this electronically controlled fuel injection, when the turbocharger is also used, the state in which the intake air is supercharged by the turbocharger is detected from the intake air pressure in the intake system, for example, a surge tank, and the supercharging state is detected. Generally, a fuel increase pressure switch is provided to increase the amount of fuel, and when a supercharging state is detected by this fuel increase pressure switch, the amount of fuel injected from the fuel injection nozzle is increased. It is true.

[Problem to be achieved by the invention]

However, if this fuel increase pressure switch fails, the following problems may occur depending on the manner of the failure. That is, for example, when the fuel increase pressure switch is a normally closed type, the hose connecting the intake system surge tank and the fuel increase pressure switch may come off, or the diaphragm inside the fuel increase pressure switch may be torn. If high pressure is no longer generated in the fuel increase pressure switch, the fuel increase pressure switch will no longer be able to detect the supercharging state, and the fuel will not be increased during supercharging, resulting in a decrease in engine output. The catalyst temperature may become overheated due to insufficient intake air or a very large amount of intake air. On the other hand, if the non-supercharging state cannot be detected due to poor contact of the fuel increase pressure switch or connector falling off, the fuel will continue to be increased even though it is in the non-supercharging state.
This causes deterioration of fuel efficiency. If the fuel increase pressure switch malfunctions as described above, if a supercharging indicator lamp that is directly driven by the output of the fuel increase pressure switch is installed in the driver's seat of the vehicle, the problem will occur during supercharging. It is also possible for the driver to determine whether the fuel increase pressure switch has continuously failed by not lighting the lamp or by constantly lighting the lamp. However, if a vehicle is not equipped with a supercharging indicator lamp because it is equipped with an intake pressure gauge, or if an abnormality only occurs occasionally even if a supercharging indicator lamp is installed, However, it was difficult to diagnose a malfunction in the fuel increase pressure switch using this supercharging indicator lamp. The present invention has been made in order to eliminate the above-mentioned drawbacks of the conventional technology, and even in vehicles where a supercharging indicator lamp is not installed or in cases where an abnormality occurs only occasionally, the fuel increase pressure switch can be prevented from malfunctioning. The purpose of the present invention is to provide a failure diagnosis device for a pressure switch for fuel increase in an electronically controlled fuel injection internal combustion engine equipped with a turbocharger, which can reliably diagnose engine output and prevent deterioration of fuel efficiency. do.

[Means to achieve the task]

The present invention detects the supercharging state due to the turbocharger from the pressure of the intake system and detects the supercharging state by the turbocharger, and detects the fuel increase pressure switch for increasing the amount of fuel at the time of supercharging. In the diagnostic device, means for detecting or calculating at least one of the throttle valve opening, the intake air amount, and the basic injection amount of the internal combustion engine, including the throttle valve opening, and the detected throttle valve opening and the intake air amount. When at least one of the air amount and the calculated basic injection amount is equal to or greater than a predetermined value, and the fuel increase pressure switch detects a non-supercharging state, the fuel increase pressure switch detects supercharging. means for determining a failure on the detection side; and when the detected throttle valve opening is below a predetermined value and the fuel increase pressure switch detects a supercharging state, the fuel increase pressure switch The above object is achieved by having means for determining a failure on the supply detection side.

[Effect]

The present invention focuses on the fact that the supercharging effect of the turbocharger increases as the engine load increases,
By determining the opening degree of the throttle valve, the intake air amount, or the basic injection amount, the boost pressure is predicted and a malfunction of the fuel increase pressure switch is determined. In other words, there is a region in which a turbocharger whose throttle valve opening, intake air amount, or basic injection amount is equal to or greater than a predetermined value is always in a supercharged state, and a region where a turbocharger whose throttle valve opening is less than a predetermined value is always in a non-supercharged state. Judging the area. As a result, the state of the fuel increase pressure switch may detect a non-supercharged state even though the fuel increase pressure switch is in a supercharged state, or the fuel increase pressure switch may detect a non-supercharged state even though it is in a non-supercharged state. If the supercharging state is detected, an abnormality in the fuel increase pressure switch can be detected. It should be noted that, as a matter of course, the abnormality of the fuel increase pressure switch includes mechanical failure and electrical failure. In other words, mechanical failure of the actuator inside this switch, mechanical failure of the external structure up to this actuator, failure due to short circuit or disconnection of the electric circuit from inside this switch to input to the failure judgment device, etc. It is.

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. The first embodiment of the present invention is as shown in FIG.
A turbocharger 12 consisting of a compressor 14 disposed in the intake passage 10 and a turbine 18 disposed in the exhaust passage 16, an intake air amount signal a output from an air flow meter 20 disposed in the intake passage 10, and engine rotation. The basic injection amount is calculated according to the intake air amount and the engine speed from the ignition primary signal b outputted from the ignition device (not shown) in synchronization with Oxygen concentration signal c in the exhaust gas of
Throttle valve fully open signal d and throttle valve fully closed signal e output from a throttle valve opening detection switch 26 that generates an output according to the fully open state and fully closed state of the throttle valve 24 disposed in the intake passage 10, engine water A cooling water temperature signal f output from a cooling water temperature sensor 30 disposed in the jacket 28, and a fuel increase signal output from a fuel increase pressure switch 36 connected to a surge tank 32 disposed in the middle of the intake passage 10 by a conduit 34. g,
and compressor 14 of turbocharger 12
An intake passage 10 and a conduit 3 for detecting abnormally high intake pressure between the downstream side and the upstream side of the throttle valve 24
The basic injection amount is increased or decreased in accordance with the abnormal high pressure signal h output from the abnormal high pressure detection pressure switch 40 connected by 8, and a fuel injection signal i is output to the fuel injection valve 44 disposed in the intake manifold 42. In an electronically controlled fuel injection internal combustion engine with turbocharging having an electronic control device 46, a fault diagnosis circuit 50 as shown in detail in FIG. 2 is provided in the electronic control device 46, and the fault diagnosis circuit 50
If a failure of the fuel increase pressure switch 36 or the like is detected in accordance with the output of the fuel increase pressure switch 36, this is displayed or stored by the failure display device 52. In FIG. 1, 100 denotes a bypass passage 102 that bypasses the turbine 18 of the exhaust passage 16;
is a safety valve disposed in the bypass passage 100,
104 connects the safety valve 10 via a link 106
diaphragm valve for actuating 2, 108
110 is a conduit that communicates the diaphragm chamber of the diaphragm valve 104 with the downstream side of the compressor 14 and the upstream side of the throttle valve 24 in the intake passage 10;
is a catalytic converter disposed downstream of the exhaust passage 16. As shown in detail in FIG. 2, the fault diagnosis circuit 50 detects the fully closed state of the throttle valve 24 by the throttle valve opening detection switch 26, and also detects the overflow state by the normally closed fuel increase pressure switch 36. When the fuel supply state is detected, that is, when the output of the fuel increase pressure switch 36 is an open signal, the throttle valve is fully closed for diagnosing a failure on the non-supercharging detection side of the fuel increase pressure switch 36. The non-supercharging side failure detection circuit 54 has an AND circuit 56 that outputs the logical product of the close signal e and the fuel increase signal g, and the throttle valve opening detection switch 26 causes the throttle valve 24 to open to a predetermined opening or more. The air flow meter 20 detects that the intake air amount is equal to or higher than a predetermined flow rate, and the fuel increase pressure switch 36 detects a non-supercharging state. In order to diagnose a failure on the supercharging detection side of the fuel increase pressure switch 36, the intake air amount signal a output from the air flow meter 20 is set to a predetermined value, e.g.
A comparison circuit 60 that generates an output when the intake air amount is greater than 130 to 150m ² /h, the output of the comparison circuit 60 and the throttle valve opening detection switch 26
The first AND circuit 62 outputs the logical product of the output and the throttle valve fully open signal d. By delaying the output of the first AND circuit 62 for a predetermined period of time, for example, the response of the fuel increase pressure switch during sudden acceleration can be improved. Delay circuit 6 to prevent transient abnormality determination due to delay
4. A second circuit for outputting the AND of the output of the delay circuit 64 and the fuel increase signal g of the output of the fuel increase pressure switch 36 inverted by the inversion circuit 66;
Supercharging side failure detection circuit 58 consisting of AND circuit 68
and an OR outputting the logical sum of the supercharging side failure detection circuit 58 output and the non-supercharging side failure detection circuit 54 output.
It consists of a circuit 70 and a timer 72 that holds the output of the OR circuit 70 for a predetermined period of time suitable for display, for example 5 seconds. The action will be explained below. Engine exhaust passage 16
The turbine 18 provided in the engine rotates depending on the exhaust pressure, that is, the engine load condition. Then, the compressor 14 connected to the turbine 18 rotates in the intake passage 10, thereby pressurizing the intake air.
Supercharged intake air is supplied to the engine combustion chamber 8. In this way, the turbine 18 and the compressor 14 cooperate to constitute a known turbocharger 12. On the other hand, the intake air amount is converted into an intake air amount signal a by the air flow meter 20, the required fuel amount is calculated according to the intake air amount by the electronic control device 46, and the engine speed is also calculated from the ignition primary signal b. Referring to this, fuel is injected from the fuel injection valve 44. In order to prevent the intake air from being overcharged due to the rotation of the compressor 14, the compressor 1
Intake pressure is introduced into the diaphragm valve 104 from the intake passage 10 upstream of the throttle valve 24 downstream of the throttle valve 24 through the conduit 108, and when the intake pressure reaches a predetermined value, for example, 350 mmHg or more, the intake pressure is introduced into the turbine 18 through the link 106.
A safety valve 102 provided on the upstream side of the exhaust gas is opened to allow a portion of the exhaust gas to be exhausted from the bypass passage 100. As a result, the exhaust pressure that rotates the turbine 18 decreases, and the exhaust pressure that rotates the turbine 18 and compressor 14 decreases.
Since the rotational force of the engine decreases, the intake pressure also decreases, and excessive supercharging of intake air is prevented. However, if a malfunction occurs in the diaphragm valve 104, the link 106, the safety valve 102, etc., such a safety mechanism will not operate properly, so as a safety measure in that case, abnormally high pressure is A detection pressure switch 40 is connected, and this abnormal high pressure detection pressure switch 40
As a result, the intake pressure is equal to the safety valve activation set pressure (350
mmHg), for example, 620 mmHg, an abnormally high pressure signal h is sent to the electronic control unit 46. In this case, the electronic control device 46 ensures safety by stopping fuel injection by the fuel injection valve 44, regardless of engine operating conditions, for example. Further, a fuel increase pressure switch 36 connected to the surge tank 32 via a conduit 34 outputs a fuel increase signal g to the electronic control unit 46 when the intake pressure reaches a predetermined pressure, for example, 100 mmHg or more. do. At this time, the electronic control device 46 outputs the fuel injection signal i that has been corrected to increase the amount to the fuel injection valve 44. In the supercharging side failure detection circuit 58 of the failure diagnosis circuit 50, the comparison circuit 60 output and the throttle valve fully open signal d
When the logical product is established between the two, the first AND circuit 6
2 becomes "1", which is input to the second AND circuit 68 via the delay circuit 64. second
Since the other input terminal of the AND circuit 68 receives a signal obtained by inverting the output signal of the fuel increase pressure switch 36 by the inverting circuit 66, the logical product between the inverted signal and the output of the delay circuit 64 is input. If this holds true, the output of the second AND circuit 68 is “1”
becomes. Then, the output of the OR circuit 70 also becomes "1", and the output is inputted to the fault display device 52 via the timer 72, and the fault display device 52 is driven to display a fault. Here, even if the failure is instantaneous and the output of the OR circuit 70 momentarily returns from ``1'' to ``0'', the failure indicator will remain active for only the time set by the timer 72, for example 5 seconds. 5
2 continues to be driven. Therefore, it is easy for the driver to confirm the failure. On the other hand, also in the non-supercharging side failure detection circuit 54,
Similarly, when a logical product is established between the throttle valve fully closed signal e and the fuel increase signal g output from the fuel increase pressure switch 36, the output of the AND circuit 56 becomes "1", and the OR circuit 70 and timer 72 are activated. After that, the failure display device 52 is driven for a predetermined period of time. FIG. 3 shows an example of an electric circuit embodying the failure diagnosis circuit 50 used in the first embodiment. This electric circuit not only detects an abnormality in the fuel increase pressure switch 36 but also detects abnormal high pressure in the pressure switch 40.
Also includes a circuit that displays an abnormality in the supercharging system when abnormally high pressure is detected by the comparison circuit 60.
, a transistor 120 that is turned on and off by the output of the comparison circuit 60, and a resistor 1 for inputting the output of the transistor 120 to the operational amplifier 122, which will be described later.
24, a diode 126, a resistor 128, a diode 130, a resistor 131, and the AND
An operational amplifier 122 that functions as circuits 56, 62 and 68, a resistor 132 and a diode 134 that function as the delay circuit 64, and a capacitor 138 to delay the output of the operational amplifier 122 for a predetermined time. A resistor 136 and a capacitor 138 that serve as the timer 72 to hold the time, for example, 5 seconds, bias resistors 140 and 142, and a feedback resistor 1 for comparing the output of the capacitor 138 with a reference value.
44, an output resistor 146 and an operational amplifier 148;
A transistor 152 that is turned on and off in response to a signal input from the operational amplifier 148 via a diode 150, an output resistor 154, and a fuel increase signal g output from the fuel increase pressure switch 36 is connected to the above calculation via the diode 156. Input resistors 158 and 160 for inputting to the inverting side terminal of the amplifier 122 and whether or not the throttle valve fully closed signal e output from the throttle valve opening detection switch 26 is input to the inverting input terminal of the operational amplifier 148. It is composed of a resistor 162 and a diode 164 for switching, and a diode 166 and a resistor 162 for inputting to the inverting input terminal of the operational amplifier 148. Also, as shown in detail in FIG. 3, the failure display device 52 includes a diode 170 to which the output of the failure diagnosis circuit 50 is input,
It is composed of a transistor 174 to which the output of 70 is inputted via a Zener diode 172, a light emitting diode 176, and resistors 178 and 180. In the first embodiment described above, only the failure of the fuel increase pressure switch 36 can be detected with high accuracy. A second embodiment of the invention is shown in FIG. In this embodiment, the comparison circuit and the first AND circuit are omitted in the supercharging side failure detection circuit 74 similar to the first embodiment, and the throttle valve is in the fully open state by the throttle valve opening degree detection switch 26. is detected, and
When the non-supercharging state is detected by the fuel increasing pressure switch 36, it is diagnosed as a failure on the supercharging detection side of the fuel increasing pressure switch 36. The other points are the same as those of the first embodiment, so the explanation will be omitted. In this embodiment, the circuit is simplified. A third embodiment of the invention is shown in FIG. In this embodiment, the first AND circuit is omitted in the supercharging side failure detection circuit 76 similar to the first embodiment, and the air flow meter 20 detects that the intake air amount is equal to or higher than a predetermined flow rate. Moreover, when the non-supercharging state is detected by the fuel increase pressure switch 36, the fuel increase pressure switch 3
6 is diagnosed as a failure on the supercharging detection side. The other points are the same as those of the first embodiment, so the explanation will be omitted. In this embodiment as well, the circuit is simple. A fourth embodiment of the invention is shown in FIG. In this embodiment, the supercharging side failure detection circuit 78 is connected to the ignition primary signal b.
a shaping/frequency dividing circuit 80 that shapes and divides the frequency, converts it into a reciprocal of the engine rotational speed, and outputs it; and a division circuit that divides the intake air amount signal a output from the air flow meter 20 by the output of the shaping/frequency dividing circuit 80. circuit 8
2, a determination circuit 84 that generates an output "1" when the pulse width in the basic injection amount signal output from the division circuit 82 is equal to or greater than a set value, and a delay circuit 86.
and an inversion circuit 66 similar to that of the first embodiment.
AND circuit 68, and the pulse width of the basic fuel injection amount signal calculated according to the output signal of the air flow meter 20 is greater than or equal to the set value, and the fuel increase pressure switch 36 When a supercharging state is detected, it is diagnosed as a failure on the supercharging detection side of the fuel increase pressure switch 36. The other points are the same as those of the first embodiment, so the explanation will be omitted. In this embodiment, the ignition primary signal b is shaped and
The signal is inputted to a frequency dividing circuit 80, converted into a reciprocal of the rotational speed, and inputted to a dividing circuit 82. In the divider circuit 82, on the one hand, the air flow meter 20
The output intake air amount signal a is input, the two are divided, and the basic injection amount signal is sent to the discrimination circuit 8.
4 is input. In this discrimination circuit 84,
The pulse width of the basic injection amount signal is compared with the set value,
If the basic injection pulse width is greater than or equal to the set value,
Generates output “1”. The output of this discrimination circuit 84 is input to the AND circuit 68 via the delay circuit 86, and when a logical product is established between it and the inverted signal of the fuel increase signal g output from the fuel increase pressure switch 36,
The output of the AND circuit 68 becomes "1", and the output passes through the OR circuit 70 and the timer 72 and drives the failure display device 52. In this embodiment, failure diagnosis of the fuel increase pressure switch 36 can be performed with extremely high accuracy. In each of the above embodiments, a device that stores and retains the failure status for a predetermined period of time is used as the failure display device, but the configuration of the failure display device is not limited to this, and can be used in factories, etc. It is also possible to use a storage device that stores the failure status until the vehicle is parked.

【Effect of the invention】

As explained above, according to the present invention, even if the supercharging indicator lamp is not set or an abnormality occurs only occasionally, it is possible to reliably detect the failure state of the fuel increase pressure switch. Therefore, it is possible to proactively warn before a serious failure occurs, to quickly perform a failure diagnosis at the factory, and it also has the excellent effect of preventing a decrease in engine output and deterioration of fuel efficiency. have

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of an electronically controlled fuel injection internal combustion engine with a turbocharger equipped with a failure diagnosis device for a fuel increase pressure switch for an electronically controlled fuel injection internal combustion engine with a turbocharger according to the present invention. 2 is a block diagram showing a first embodiment of the fault diagnosis device used in the first embodiment, and FIG. 3 is an electric circuit diagram showing a specific circuit example of the first embodiment. FIG. 4 is a block diagram showing a second embodiment of a failure diagnosis device for a fuel increase pressure switch for an electronically controlled fuel injection internal combustion engine with turbocharging according to the present invention, and FIG. 5 similarly shows a third embodiment. FIG. 6 is a block diagram also showing the fourth embodiment. 8...Engine combustion chamber, 10...Intake passage, 1
2...Turbocharger, 14...Compressor, 16...Exhaust passage, 18...Turbine, 20
... Air flow meter, 26 ... Throttle valve opening detection switch, 32 ... Surge tank, 36 ... Pressure switch for fuel increase, 40 ... Pressure switch for abnormally high pressure detection, 46 ... Electronic control device, 50 ... Failure diagnosis circuit, 52... Failure display device, 54... Non-supercharging side failure detection circuit, 58, 74, 76, 78...
...Supercharging side failure detection circuit, 56, 62, 68...
AND circuit, 60... Comparison circuit, 64, 86...
Delay circuit, 66... Inverting circuit, 70... OR circuit, 72... Timer, 80... Shaping/dividing circuit,
82...Division circuit, 84...Discrimination circuit.

Claims (1)

[Scope of Claims] 1. Fuel increasing pressure for an electronically controlled fuel injection internal combustion engine with turbocharging having a fuel increasing pressure switch for detecting the supercharging state by turbocharging from the intake system pressure and increasing the amount of fuel during supercharging. A fault diagnosis device for a switch, comprising means for detecting or calculating at least one of the throttle valve opening, intake air amount, and basic injection amount of the internal combustion engine, including the throttle valve opening; and the detected throttle valve opening. When at least one of the intake air flow rate, intake air amount, and calculated basic injection amount is equal to or greater than a predetermined value, and the fuel increase pressure switch detects a non-supercharging state, the fuel increase pressure switch means for determining a failure on the supercharging detection side of the
and means for determining a failure on the non-supercharging detection side of the fuel increasing pressure switch when the fuel increasing pressure switch detects a supercharging state. Trouble diagnosis device for engine fuel increase pressure switch.