JP2020180593A - On-vehicle engine control device - Google Patents

Abstract

To provide an on-vehicle engine control device which is small in a size, and can inexpensively cope with the abnormal lowering of a voltage of an on-vehicle battery by avoiding the double installation of a boosting power supply circuit.SOLUTION: An on-vehicle engine control device comprises a CPU 20 which is supplied with power from an on-vehicle battery 10 via a power supply relay 11, a power supply diode 21 and a constant voltage power supply 23, and performs at least the fuel injection control of an on-vehicle engine, and a boosting power supply circuit 30 for boosting a power supply voltage Vbb which is supplied from the power relay 11, and performing quick drive by applying a high voltage to a fuel injection electromagnetic coil 14a by using a boosting voltage Vh in a short time. The boosting voltage Vh is applied to an input of the constant voltage power supply 23 via an auxiliary power supply connecting element 25Ad, and the auxiliary power supply connecting element 25Ad is circuit-closed in an inoperable state of the CPU 20, and disconnected by a command of the CPU 20 which is operated accompanied by a rise of the power supply voltage.SELECTED DRAWING: Figure 1

Description

The present application relates to an in-vehicle engine control device.

There are known in-vehicle electronic devices that have improved the limit performance of the operation of the on-board microprocessor against an abnormal drop in battery voltage that occurs when the engine is cold-started due to a deteriorated in-vehicle battery. For example, according to the power supply device for in-vehicle electronic devices disclosed in Patent Document 1, when the ignition switch is closed, power is supplied to the boost control power supply unit and 5V is supplied to the boost control unit, while the starter switch is opened. At that time, the transistor is opened by the AND gate, and the power supply voltage of the battery is applied to the power supply device via the ignition switch, the coil, and the diode.
Then, when the starter switch is closed, the transistor is intermittently controlled, and the capacitor is charged by the electromagnetic energy of the coil to be charged to, for example, DC12V regulated by the voltage monitoring unit, and the boost control unit is charged. , DC5V from the boost control unit power supply and DC5V from the power supply device are combined and fed via a diode.

Therefore, even if the power supply voltage of the battery drops due to the power supply to the starter, the power supply voltage to the boost control unit is maintained at DC5V for a while due to the residual voltage of the capacitor, and eventually the charging voltage of the capacitor is initially increased by the boost operation of the boost control unit. It recovers to 12V, and even if the recovery of the power supply voltage of the battery is delayed, the power supply device can supply a stable 5V voltage.
The power supply device includes first and second constant voltage power supplies (not shown), and the first constant voltage power supply is supplied from the battery via the ignition switch to the CPU and the control circuit unit. It is presumed that the second constant voltage power supply is directly supplied from the battery and operates, and is used as a backup power supply for the RAM memory in the CPU.

Japanese Unexamined Patent Publication No. 08-149704 (Fig. 1, summary)

The boost control device in the power supply device for in-vehicle electronic devices according to Patent Document 1 is a low boost power supply circuit that generates a boost voltage equivalent to the power supply voltage of the battery. Therefore, this is a high boost power supply circuit for fuel injection control. It is uneconomical because it cannot be used as a booster circuit and it is necessary to install a double booster circuit.
However, when such a low boost power supply circuit is abolished and only a high boost power supply circuit of DC70V, which is indispensable for fuel injection control, is used, a microprocessor for fuel injection control is used from this high boost power supply circuit. In addition to adding a voltage auxiliary circuit to the constant voltage power supply that supplies power to the power supply, protective measures to prevent excessive voltage from being applied, preventing a decrease in fuel injection control capability during high-speed engine rotation, and appropriately timing the voltage auxiliary There is a need.

The present application discloses a technique for solving the above-mentioned problems, and is a small-sized and inexpensive in-vehicle engine control device capable of dealing with an abnormal voltage drop of an in-vehicle battery by avoiding double installation of a boost power supply circuit. The purpose is to provide.

The in-vehicle engine control device disclosed in the present application includes a microprocessor in which a power supply voltage is applied from an in-vehicle battery, a stabilized voltage is supplied via a constant voltage power supply, and at least fuel injection control for the in-vehicle engine is performed, and the power supply voltage. It is an in-vehicle engine control device equipped with a step-up power supply circuit that generates a step-up voltage that boosts the voltage and rapidly drives an electromagnetic coil for fuel injection.
An input voltage whose backflow is prevented by a feeding diode is applied to the constant voltage power supply from the power supply voltage, or is applied via a step-down power supply circuit, and the boosted voltage is applied to the constant voltage power supply or the constant voltage power supply. An auxiliary power supply connection element to be applied to the input portion of the step-down power supply circuit is provided.
The auxiliary power supply connection element is closed-circuit driven when the value of the power supply monitoring voltage, which is the divided voltage of the power supply voltage, is equal to or less than the first lower limit voltage.
The first lower limit voltage corresponds to the lower limit value of the power supply monitoring voltage corresponding to the minimum input voltage of the constant voltage power supply from which the regulated voltage is obtained or the step-down power supply circuit.
The microprocessor is characterized in that when the value of the power supply monitoring voltage exceeds the first lower limit voltage, the power supply auxiliary command is stopped and the auxiliary power supply connection element is opened.

According to the in-vehicle engine control device disclosed in the present application, it is possible to avoid the double installation of the boost power supply circuit and to obtain an in-vehicle engine control device that is compact and inexpensive to cope with an abnormal voltage drop of the in-vehicle battery.

It is the whole circuit block diagram of the vehicle-mounted engine control device which concerns on Embodiment 1. FIG. FIG. 5 is an overall circuit block diagram of an in-vehicle engine control device according to a modified form of the in-vehicle engine control device according to the first embodiment. It is a flowchart explaining the operation of the vehicle-mounted engine control device shown in FIGS. 1 and 2. It is the whole circuit block diagram of the vehicle-mounted engine control device which concerns on Embodiment 2. FIG. It is the whole circuit block diagram of the vehicle-mounted engine control device by the modified form of the vehicle-mounted engine control device according to the second embodiment. It is a flowchart explaining the operation of the vehicle-mounted engine control device shown in FIGS. 4 and 5.

Hereinafter, preferred embodiments of the vehicle-mounted engine control device according to the present application will be described with reference to the drawings. In each figure, the same reference numerals indicate the same youthful and corresponding parts.

Embodiment 1.
FIG. 1 is an overall circuit block diagram of the vehicle-mounted engine control device according to the first embodiment.
In FIG. 1, the vehicle-mounted engine control device 100A is mainly composed of a microprocessor 20, a boost power supply circuit 30, and a solenoid valve drive circuit 40. A power supply voltage Vbb is applied to the outside of the vehicle-mounted engine control device 100A from, for example, a DC12V-based vehicle-mounted battery 10 via an output contact of a power supply relay 11 that responds to a power supply switch (not shown). Further, the battery voltage Vb of the vehicle-mounted battery 10 is applied to the starting electric motor 12 of the engine via the starting relay 13 that responds to the starting switch 17.

The battery voltage Vb is normally charged to DC12 to 14V by a charging generator (not shown), but when the engine is started, the battery voltage Vb drops due to the large current flowing through the starting motor 12, and the in-vehicle battery deteriorates. At the time of cold start by 10, and at the time of low-speed rotation operation at the initial stage of engine rotation, the voltage may drop to around DC3.0V.
On the other hand, the electric load group 14 driven and controlled by the microprocessor 20 includes a plurality of fuel injection electromagnetic coils 14a individually arranged in each cylinder of the engine of a plurality of cylinders, and a motor for controlling the throttle valve opening degree. Alternatively, in the case of a gasoline engine, a gasoline ignition device is included. The sensor group 16 input to the microprocessor 20 includes an engine rotation sensor 16a, and also includes an engine rotation angle sensor, a throttle valve opening degree sensor, an intake amount sensor, an exhaust gas sensor, and the like.

Inside the in-vehicle engine control device 100A, a constant voltage power supply 23 that supplies a stabilized voltage Vcc of, for example, DC 5V and a feeding diode 21 that supplies a power supply voltage Vbb to the constant voltage power supply 23 are connected in series to the microprocessor 20. However, when the current consumption of the microprocessor 20 is large, the step-down power supply circuit 22A is inserted between the constant-voltage power supply 23 and the power supply diode 21, and the constant-voltage power supply 23 and the step-down power supply circuit 22A are inserted. The loss is shared by. For example, the value of the input voltage Vba obtained by subtracting the voltage drop due to the power supply diode 21 from the power supply voltage Vbb is DC14V, the value of the stabilizing voltage Vcc is DC5V, and the current consumption by the microprocessor 20 is 0.2A. If a linear control type that can obtain a highly accurate output voltage of about ± 1% is used as the constant voltage power supply 23 and the step-down power supply circuit 22A is not used, the power loss of the constant voltage power supply 23 Is (14-5) × 0.2 = 14W, and with this power consumption, it is difficult to miniaturize the constant voltage power supply 23 in order to suppress heat generation.

However, if the step-down power supply circuit 22A of the energization duty control method that controls the intermittent closing time / intermittent cycle is used together and the output voltage is controlled to DC7V, the power loss in the constant voltage power supply 23 is (7-5) × 0. .2 = 0.4W, which can be significantly reduced. Further, in the step-down power supply circuit 22A, the voltage drop at the time of closing the circuit is set to 1V and the energization duty is set to 7/14, so that a closing loss of 1 × 0.2 × 7/14 = 0.1W occurs, which is caused by intermittent operation. Assuming that the transient loss is 0.1 W, the total power loss is 0.4 + 0.1 + 0.1 = 0.6 W, which can also be significantly reduced.

As described above, connecting the duty-controlled step-down power supply circuit 22A and the linearly controlled constant-voltage power supply 23 in series to reduce power loss and disperse heat generation is widely used as a conventional means, and the microprocessor 20 It is selected and used as appropriate according to the scale of the load to be controlled.

Further, as a constant voltage power supply circuit (not shown) in the in-vehicle engine control device 100A, power is directly supplied from the battery voltage Vb, for example, a stabilized voltage of DC5V is generated to supply power to the volatile RAM memory provided in the microprocessor 20. There is a power supply for memory backup, but RAM memory has the ability to hold stored information at a voltage of DC2.5V, for example, and the load current is also small, so it is a capacitor against a battery voltage drop when starting the engine. It is possible to fully deal with it by using the charge charged in. However, assuming an abnormal situation such as disconnection of the battery terminal, the microprocessor 20 is provided with a non-volatile data memory, and immediately after the power switch is shut off, important data stored in the RAM memory is converted into non-volatile data. It can be transferred and saved to the memory so that it can be read out when the RAM memory is abnormal. Therefore, the problem of voltage drop in RAM memory will not be dealt with here.

Next, the boost power supply circuit 30 is a series circuit of the induction element 31, the switching element 32, and the current detection resistor 33 from the power supply voltage Vbb, and the induction element 31 generated when the switching element 32 is intermittently driven by the boost control circuit 37. It is configured to include a boosting capacitor 35 that is charged via the backflow prevention diode 34 by the induced energy of the above. Then, in the boost control circuit 37, after the switching element 32 is closed and power is supplied to the induction element 31, the element current If detected by the current detection resistor 33 reaches the set upper limit current If2, which is, for example, 10A. The switching element 32 is opened, and the switching element 32 is reclosed when the set cutoff time Tf, which is, for example, 10 μsec, elapses, or when the element current If is reduced to, for example, 3A, which is equal to or less than the set lower limit current If1. Intermittent control is performed.

Therefore, the boost control circuit 37 sets the current comparison circuit that opens the switching element 32 when the upper limit current If2 is reached by comparing the set reference voltage with the voltage across the current detection resistor 33, and the cutoff time Tf. A timer circuit is used, or the negative terminal of the boosting capacitor 35 is connected to the upstream terminal of the current detection resistor 33, and a positive feedback resistor is connected to the current comparison circuit to give hysteresis characteristics. When the current If decreases below the lower limit current If 1, the output of the current comparison circuit is inverted and the switching element 32 is reclosed.

Further, the boost control circuit 37 monitors the boost voltage Vh, which is the charging voltage of the boost capacitor 35, by the boost voltage divider Vf divided by the boost voltage divider resistors 36a and 36b, and corresponds to the target voltage of the boost voltage Vh. The switching element 32 is configured to maintain the open circuit state during the period from when the second voltage dividing voltage Vf2 is reached until when the voltage is lowered to the first voltage dividing voltage Vf1 or less, which is lower than the second voltage dividing voltage Vf2. ing.

Specifically, a voltage comparison circuit that compares the set reference voltage with the boosted voltage dividing voltage Vf, detects that it has reached the second voltage dividing voltage Vf2, and prohibits the intermittent operation of the switching element 32. , A positive feedback resistor is connected to this voltage comparison circuit to give hysteresis characteristics, and when the boosted voltage dividing voltage Vf decreases to the lower limit voltage Vf1 or less, the output of the voltage comparison circuit is inverted to perform intermittent operation of the switching element 32. This allows, for example, a boosted voltage Vh of DC70 to 63V.

The boost power supply circuit 30 includes a decompression delay capacitor 38c that is charged from the power supply voltage Vbb via the power supply diode 21 and the first backflow prevention element 38a, and the boost control circuit 37 uses the charging voltage of the decompression delay capacitor 38c. A certain control voltage Vc is operated as a power supply voltage to perform intermittent control of the switching element 32.
The decompression delay capacitor 38c is charged from the vehicle-mounted battery 10 in the no-load state by closing the power relay 11, and then the control voltage Vc is reduced even if the power supply voltage Vbb is attenuated by driving the starting electric motor 12. This is to slow down the attenuation so that the boost control circuit 37 can operate for a while. Therefore, even if the power relay 11 is closed and the starting electric motor 12 is driven, the boost power supply circuit 30 executes boost control by intermittent operation of the opening / closing element 32, and is equal to or higher than the boost voltage Vh corresponding to the first voltage dividing voltage Vf1. It is possible to boost the voltage to. The boost control circuit 37 operated by the control voltage Vc includes the above-mentioned reference voltage for current control and a reference voltage generation circuit for generating a reference voltage for voltage control, and the control voltage Vc is, for example, DC14V to DC4.5V. Intermittent control of the opening / closing element 32 can be performed even if the degree of fluctuation varies.

On the other hand, when the power supply voltage of the microprocessor 20 becomes, for example, DC4.5V or less, the microprocessor 20 is initialized and is in an inactive state, and when an abnormal drop in the power supply voltage Vbb occurs during the operation of the starting motor 12, fuel injection control is performed. Since all the control operations including the above are stopped, the engine cannot be started even if the starting motor 12 is rotationally driven.
However, the boost voltage Vh by the boost power supply circuit 30 is a constant voltage power supply via the connection switching element 25a which is the main element of the auxiliary power supply connection element 25Ad and the auxiliary power supply diode 26, or the constant voltage power supply 23 via the step-down power supply circuit 22A. It is applied to 23.

The auxiliary power supply connection element 25Ad is a series circuit of a connection switching element 25a which is a field effect transistor, gate resistors 25b and 25c connected to the gate circuit, and an opening / closing control element 29 which is an NPN junction transistor, and opening / closing control. A logic element 29a, which is a logic product element connected to the base terminal of the element 29, is provided, and the gate voltage of the switching control element 29 is set between the connection points of the gate resistors 25b and 25c and the source terminal of the connection switching element 25a. A protection diode 25d, which is a constant voltage diode for regulation, is connected.

The first input terminal of the logic element 29a is pulled up to the regulated voltage Vcc by the pull-up resistor 29b, and is connected to the output terminal of the microprocessor 20 to give a power supply assist command AST.
When the microprocessor 20 is inactive, the power supply assist command AST is in a floating state, and the logic level "H" is obtained by the pull-up resistor 29b. However, the same operation can be performed even if a logic negative element is provided at the first input terminal of the logic element 29a and a pull-down resistor is provided instead of the pull-up resistor 29b.
Further, a start signal STS whose logic level becomes “H” is input to the second input terminal of the logic element 29a in response to the pressing closing path of the start switch 17. Therefore, when the start switch 17 is closed, the open / close control element 29 is closed and driven by the output signal of the logic element 29a even if the microprocessor 20 is inactive, whereby the connection open / close element 25a is closed and the boost voltage Vh. Is input to the constant voltage power supply 23 via the auxiliary power supply diode 26, and the microprocessor 20 is started to start the control operation.

On the other hand, in this embodiment, the boosted voltage dividing voltage Vf is input to the microprocessor 20, and the reduced voltage Va, which is the average output voltage of the auxiliary power supply connecting element 25Ad, is controlled to be, for example, the target voltage DC14V. Has been done.
For this reason, the power supply auxiliary command AST is adapted to generate an intermittent command signal of the energization duty corresponding to the ratio of the target decompression voltage Va and the boost voltage Vh.
However, since the boosted voltage Vh rises rapidly and is finally stable at DC63 to 70V, for example, when the boosted voltage Vh is DC70V (corresponding to the second voltage dividing voltage Vf2), It may be a fixed energization duty such that the depressurized voltage Va becomes DC14V. In this case, when the boost voltage Vh reaches DC35V, which is increasing, the decompression voltage Va reaches DC7V, and the microprocessor 20 can be reliably operated.

However, since the in-vehicle engine control device 100A can withstand the jump start (two in-vehicle batteries are connected in series to supply power to the starting electric motor) when the abnormal voltage of the in-vehicle battery 10 drops, the boosted voltage is increased. If the energization duty is set to 28/70 = 0.4 so that the depressurized voltage Va becomes DC28V when Vh is DC70V, the boost voltage Vh reaches DC17.5V, which is increasing. At this point, the reduced voltage Va becomes DC7V, and the microprocessor 20 can be operated more quickly.

On the other hand, the power supply voltage monitoring circuit 50 generates a power supply monitoring voltage Vm via a smoothing circuit 50c composed of a resistor and a capacitor by dividing the power supply voltage Vbb by the battery voltage dividing resistors 50a and 50b. The monitoring voltage Vm is connected to the input terminal of the microprocessor 20. Then, the microprocessor 20 stops the power supply assist command AST when the value of the input power supply monitoring voltage Vm exceeds the set first lower limit voltage Vm1. In this embodiment, the microprocessor 20 is configured to stop. A stop command is generated by setting the logic level of the power supply auxiliary command AST to "L". Here, the first lower limit voltage Vm1 is, for example, the input voltage of the constant voltage power supply 23 (for example, DC7V) required to obtain the regulated voltage Vcc of DC5V, or when the step-down power supply circuit 22A is provided. As a further margin voltage, for example, it is a value of the power supply monitoring voltage Vm corresponding to the power supply voltage Vbb of the total voltage 9V to which DC2V is added. Therefore, if the power supply monitoring voltage Vm exceeds the first lower limit voltage Vm1, the microprocessor 20 can be reliably operated.

When the boost power supply circuit 30 starts boosting operation, the boost voltage Vh becomes a high voltage due to a time delay of several tens of msec, and a sufficient power supply voltage is quickly applied to the microprocessor 20, but power supply monitoring Since the voltage Vm is the monitoring voltage of the power supply voltage Vbb on the vehicle-mounted battery 10 side that is cut off by the power feeding diode 21, the engine rotation speed is increased by the starting electric motor 12, and the load current by the starting electric motor 12 is reduced. It is possible to exceed 1 lower limit voltage Vm1.
On the other hand, when the control operation of the microprocessor 20 starts, a fuel injection command INJ is generated when the engine rotation speed by the starting motor 12 exceeds, for example, 200 RPM, and a plurality of solenoid valves for fuel injection are generated via the solenoid valve drive circuit 40. The drive current for 14a is sequentially distributed and fed.

This fuel injection command INJ closes the cylinder selection element 45 with respect to the fuel injection electromagnetic coil 14a in the fuel injection electromagnetic valve of the cylinder that has reached the set crank angle position with a time width corresponding to the fuel injection amount. At the same time, the rapid feeding element 43 is closed for a moment to perform rapid feeding, and then the power supply voltage Vbb is intermittently applied via the valve opening holding element 41 and the valve opening holding diode 42, in cooperation with the commutation diode 44. The valve opening holding current is energized, and the cylinder selection element 45 and the valve opening holding element 41 are opened with the lapse of a set time width to rapidly shut off the fuel injection electromagnetic coil 14a. The plurality of cylinders are divided into a plurality of cylinder groups, and the valve opening holding element 41, the valve opening holding diode 42, the rapid feeding element 43, and the commutation diode 44 are provided for each cylinder group with respect to the cylinders of the same group. The cylinder selection element 45 is individually provided for all cylinders.

Next, a modified form of the in-vehicle engine control device described with reference to FIG. 1 will be described.
FIG. 2 is an overall circuit block diagram showing a modified form of the vehicle-mounted engine control device 100A described with reference to FIG. 1, and its configuration will be described in detail with a focus on differences from the vehicle-mounted engine control device 100A of FIG. The main difference between the vehicle-mounted engine control device 100A of FIG. 1 and the vehicle-mounted engine control device 100B of FIG. 2 is that the auxiliary power supply connecting element 25A is applied instead of the auxiliary power supply connecting element 25Ad, and the auxiliary power supply connecting element 25A is used as a power source. The correction control of the energization duty that responds to the monitoring voltage Vm is not performed. Instead, an auxiliary power supply circuit 24A is added, and a bias current energizing element 24a and a bias current energizing command BST for improving the constant voltage control characteristic of the auxiliary power supply circuit 24A are added.

In FIG. 2, the auxiliary power supply connecting element 25A has the same configuration as the auxiliary power supply connecting element 25Ad in FIG. 1, and all of them are logically coupled to the power supply auxiliary command AST that responds to the power supply monitoring voltage Vm and the start signal STS. By opening and closing the connection switching element 25a (see FIG. 1), it is determined whether or not auxiliary power supply is performed by the boosted voltage Vh. However, in the case of the auxiliary power supply connecting element 25A, the connection opening / closing element 25a is closed or opened depending on whether or not the power supply assist is performed, but the energization duty thereof is not controlled.

The auxiliary power supply circuit 24A added instead reduces the boost voltage Vh by negative feedback duty control or negative feedback linear control, and supplies a constant voltage of, for example, DC14V to the auxiliary power supply connection element 25A or the step-down power supply circuit 22A. It has become like.
Then, a bias current energization resistor 24c is connected to the output terminal of the auxiliary power supply circuit 24A via the bias current energization element 24a, and the bias current energization element 24a generates the microprocessor 20 via the bias current energization command resistor 24b. The opening and closing is controlled by the bias current energization command BST. This bias current energization command BST close-drives the bias current energization element 24a when the value of the power supply monitoring voltage Vm described above is equal to or less than the second lower limit voltage Vm2, which is a value larger than the first lower limit voltage Vm1. The value of the second lower limit voltage Vm2 is a value equal to or less than the power supply monitoring voltage Vm corresponding to, for example, DC10V corresponding to the normal lower limit value of the power supply voltage Vbb.

The constant voltage power supply 23 has a negative feedback linear control of the conduction state so that the output voltage becomes the stabilized voltage Vcc in response to the input voltage, whereas the step-down power supply circuit 22A has the same. Negative feedback duty control is performed in the conduction state so that the output voltage becomes the stable operation input voltage of the constant voltage power supply 23 in response to the input voltage, and the step-down power supply circuit 22A is provided with respect to the constant voltage power supply 23. The output voltage of the auxiliary power supply circuit 24A when used in combination may be stabilized so as to be in the range of, for example, DC9 to 14V. The output voltage of the auxiliary power supply circuit 24A when the step-down power supply circuit 22A is not used in combination with the constant voltage power supply 23 may be stabilized so as to be in the range of, for example, DC7 to 14V.

Next, the operation and operation of the vehicle-mounted engine control device 100A shown in FIG. 1 or the vehicle-mounted engine control device 100B shown in FIG. 2 will be described in detail.
First, in FIGS. 1 and 2 showing the entire circuit block diagram, when the power switch (not shown) is closed and the power relay 11 is urged and closed, the vehicle-mounted engine control devices 100A and 100B are charged with the power supply voltage Vbb by the vehicle-mounted battery 10. Is applied, a stabilized voltage Vcc is applied to the microprocessor 20 via the power supply diode 21, the step-down power supply circuit 22A, and the constant voltage power supply 23, and the microprocessor 20 at least performs fuel injection control for the engine. There is. However, when the current consumption of the microprocessor 20 is small, the step-down power supply circuit 22A may be omitted.

On the other hand, the boost power supply circuit 30 is a series circuit of the induction element 31, the switching element 32, and the current detection resistor 33 from the power supply voltage Vbb, and the induction element 31 generated when the switching element 32 is intermittently driven by the boost control circuit 37. It is composed of a boosting capacitor 35 that is charged via the backflow prevention diode 34 by the induced energy.
The boost power supply circuit 30 is rapidly driven by applying a short-time high-voltage voltage to a plurality of fuel injection electromagnetic coils 14a via the solenoid valve drive circuit 40, and is driven according to the required fuel injection amount. It is designed to be rapidly shut off after the valve opening assist control is performed. However, the above operation is for the case where the power supply voltage Vbb is normal and the microprocessor 20 and the boost power supply circuit 30 are operating normally, and after the power switch is closed, power is supplied to the starting motor 12. When a low voltage abnormality occurs at the time when the engine starts to rotate, the auxiliary power supply connecting element 25Ad or 25A is used to deal with this problem.

Next, the control operation of the in-vehicle engine control devices 100A and 100B shown in FIGS. 1 and 2 when a low voltage abnormality occurs will be described in detail with reference to the flowchart of FIG.
In FIG. 3, step S310 is a step in which the power supply relay 11 operates due to the closing of the power supply switch (not shown), and the boosted voltage Vh is generated by the boosted power supply circuit 30.
Subsequent step S311 is a step in which the microprocessor 20 is inactive and the power supply auxiliary command AST is not generated, but the start signal STS is generated and the auxiliary power supply is performed by the auxiliary power supply connection element 25Ad or 25A.
Subsequent step S300 is an operation start step of the voltage control program which is one of the control programs of the microprocessor 20.
In the following step S301a, it is confirmed whether or not the start switch 17 is closed, and if it is not closed, NO is determined and the process proceeds to step S309 of the operation end process, and if it is closed, YES is determined. This is a determination step for shifting to step S301b.

In the following step S301b, the power supply monitoring voltage Vm obtained by the power supply voltage monitoring circuit 50 and the value of the boosted voltage dividing voltage Vf which is the voltage dividing voltage of the boosting capacitor 35 are read through a multi-channel AD converter (not shown). Is.
In the following step S302, it is determined whether or not the value of the power supply monitoring voltage Vm read in step S301b is equal to or less than the second lower limit voltage Vm2, and if it is equal to or less than the second lower limit voltage Vm2, YES is determined and step S303 is performed. If it exceeds the limit, NO is determined, and the determination step proceeds to step S309 of the operation end process. The value of the second lower limit voltage Vm2 is a value equal to or less than the power supply monitoring voltage Vm corresponding to the normal lower limit value of the power supply voltage Vbb, and if it is a 12V in-vehicle battery, for example, the power supply monitoring voltage corresponding to DC10V. It is a value of Vm.
In step S303, the bias current energization command BST shown in FIG. 2 is generated, and a minute load current is energized to the auxiliary power supply circuit 24A by the bias current energization element 24a to improve the accuracy of constant voltage control. It is a step of.

In the following step S304a, it is determined whether or not the value of the power supply monitoring voltage Vm read in step S301b is equal to or less than the first lower limit voltage Vm1, and if it is equal to or less than the first lower limit voltage Vm1, a YES determination is made to perform the step. It is a determination step of shifting to S305a, determining NO if it exceeds the limit, and shifting to step S304b. The first lower limit voltage Vm1 corresponds to the lower limit value of the power supply monitoring voltage Vm corresponding to the minimum input voltage of the constant voltage power supply 23 or the step-down power supply circuit 22A for obtaining the regulated voltage Vcc. The first lower limit voltage Vm1 is, for example, DC7V if it is the input voltage of the constant voltage power supply 23 required to obtain the regulated voltage Vcc of DC5V, and if it has the step-down power supply circuit 22A, there is a further margin. As the voltage, for example, it is the value of the power supply monitoring voltage Vm corresponding to the power supply voltage Vbb of the total voltage 9V to which DC2V is added.

In step S304b, the output of the logic element 29a in the auxiliary power supply connection element 25Ad or 25A is stopped by setting the logic level of the power supply assistance command AST to “L”, and the power supply assistance by the auxiliary power supply connection element 25Ad or 25A is stopped. This is a step of shifting to step S309 of the operation end step.

Step S305a determines whether or not the value of the boosted voltage dividing voltage Vf is equal to or less than the intermediate voltage Vf0, determines YES if the intermediate voltage is Vf0 or less, and proceeds to step S306. This is a determination step in which the determination is performed and the process proceeds to step S305b. If the maximum value of the step-up voltage Vh of the intermediate voltage Vf0 is, for example, DC70V and the maximum voltage applied to the step-down power supply circuit 22A or the constant voltage power supply 23 is limited to, for example, DC28V, the step-up voltage Vh is DC28V. It is set to the value of the boosted voltage dividing voltage Vf at a certain time.
In step S305b, the energization duty of the connection switching element 25a in the auxiliary power supply connection element 25Ad is restricted to 40% by alternately reversing the logic level of the power supply auxiliary command AST, and the boost voltage Vh is DC70V. The value of the decompression voltage Va, which is the average output voltage of the auxiliary power supply connection element 25Ad, is set to DC28V, and the step is a step of shifting to step S309 of the operation end step. Steps S305a and S305b are steps executed by the in-vehicle engine control device 100A of FIG.

Next, step S306 is a step in which the duty control of the power supply assist command AST is not performed, and when the determination in step S304a is YES, the logic level is always set to “H” and the process proceeds to step S309 of the operation end step.

In step S309 of the operation end process, the program shifts to another control program, for example, shifts to step S300 of the operation start step again within a calculation cycle of 5 msec, and the subsequent control flow is cyclically executed.

In the above description, the energization duty to the connection switching element 25a is 40% or 100%, but if a plurality of steps of control are further performed, the voltage applied to the step-down power supply circuit 22A or the constant-voltage power supply 23 is suppressed, and the step-up voltage Vh The depressurized voltage Va can be rapidly increased as the voltage increases.

Further, the output voltage of the auxiliary power supply connecting element 25Ad or 25A supplies an auxiliary voltage to the boost control circuit 37 via the first backflow prevention element 38a, thereby discharging the charge initially charged to the decompression delay capacitor 38c. While suppressing it, the control operation of the boost control circuit 37 at the time of abnormally low voltage is stabilized.

As described in detail above, in the vehicle-mounted engine control devices 100A and 100B shown in FIGS. 1 and 2, a power supply voltage Vbb is applied from the vehicle-mounted battery 10 via the power supply relay 11, and a stabilized voltage is applied via the constant voltage power supply 23. A microprocessor 20 to which Vcc is supplied to control fuel injection to at least an in-vehicle engine, and a boost power supply circuit 30 to generate a boost voltage Vh for boosting the power supply voltage Vbb and rapidly driving the fuel injection electromagnetic coil 14a. It is an in-vehicle engine control device equipped with
An input voltage Vba whose backflow is prevented by the power feeding diode 21 is directly applied to the constant voltage power supply 23 from the power supply voltage Vbb, or is indirectly applied via the step-down power supply circuit 22A, and the boosted voltage Vh is fixed. Auxiliary power supply connecting element 25Ad or 25A to be applied to the input portion of the voltage power supply 23 or the step-down power supply circuit 22A is provided.
The auxiliary power supply connection element 25Ad or 25A is closed-driven when the value of the power supply monitoring voltage Vm, which is the voltage dividing voltage of the power supply voltage Vbb, is equal to or less than the first lower limit voltage Vm1.
The first lower limit voltage Vm1 corresponds to the lower limit value of the power supply monitoring voltage Vm corresponding to the minimum input voltage of the constant voltage power supply 23 or the step-down power supply circuit 22A for obtaining the regulated voltage Vcc, and the microprocessor 20 uses the power supply. When the value of the monitoring voltage Vm exceeds the first lower limit voltage Vm1, the power supply auxiliary command AST is stopped and the auxiliary power supply connecting element 25Ad or 25A is opened.

The boost power supply circuit 30 is a series circuit of the induction element 31, the switching element 32, and the current detection resistor 33 from the power supply voltage Vbb, and the induction energy of the induction element 31 generated when the switching element 32 is intermittently driven by the boost control circuit 37. It is composed of a step-up capacitor 35 that is charged via the backflow prevention diode 34.
The boost control circuit 37 opens the switching element 32 when the element current If detected by the current detection resistor 33 reaches the set upper limit current If2 after the switching element 32 is closed and the power is supplied to the induction element 31. When the set cutoff time Tf elapses or the element current If decreases below the set lower limit current If1, the switching element 32 is reclosed and the circuit is reclosed.
After monitoring the boosted voltage dividing voltage Vf of the boosting voltage Vh, which is the charging voltage of the boosting capacitor 35, and reaching the second voltage dividing voltage Vf2 corresponding to the target voltage of the boosting voltage Vh, from the second voltage dividing voltage Vf2. The switching element 32 is configured to maintain the open circuit state during the period until the first voltage dividing voltage Vf1 or less is low.
The boost power supply circuit 30 further includes a decompression delay capacitor 38c charged from the feeding diode 21 via the first backflow prevention element 38a, and the boost control circuit 37 powers the control voltage Vc which is the charging voltage of the decompression delay capacitor 38c. It operates as a voltage to perform intermittent control of the opening / closing element 32.

As described above, the boost control circuit 37 provided in the boost power supply circuit 30 for generating the boost voltage Vh for fuel injection control is charged from the power supply voltage Vbb via the power supply diode 21 and the first backflow prevention element 38a. It is operated by the control voltage Vc which is the charging voltage of the decompression delay capacitor 38c.
Therefore, the decompression delay capacitor 38c is charged by the in-vehicle battery in the no-load state before the start operation of the engine, and even if the power supply voltage Vbb of the in-vehicle battery 10 is attenuated and lowered by the drive current of the starting electric motor 12, the boost control circuit 37 The control voltage Vc for operating the power supply voltage Vc does not decrease rapidly, and by increasing the capacitance of the decompression delay capacitor 38c, boost control is maintained during an abnormally low voltage period until the power supply voltage Vbb recovers. There are features that can be done. It should be noted that this feature is the same for the second embodiment described later and the modified form thereof.

Further, the power supply monitoring voltage Vm is connected as an input signal to the microprocessor 20, and it is determined by the microprocessor 20 whether or not the power supply monitoring voltage Vm exceeds the value of the first lower limit voltage Vm1.
When the value of the power supply monitoring voltage Vm of the auxiliary power supply connection element 25Ad or 25A is equal to or less than the first lower limit voltage Vm1 and the engine start switch 17 is pressed and closed, the operating state of the microprocessor 20 is Closed drive regardless
When the power supply monitoring voltage Vm exceeds the value of the first lower limit voltage Vm1, the microprocessor 20 stops the power supply auxiliary command AST and the auxiliary power supply connection element 25Ad or 25A is opened even if the start switch 17 is pressed and closed. It has become so.

As described above, the auxiliary power connection element 25Ad or 25A that applies the boost voltage Vh for fuel injection control to the constant voltage power supply 23 or the step-down power supply circuit 22A, which is the power supply circuit for the microprocessor 20 for fuel injection control, is an in-vehicle battery. When the power supply voltage Vbb of No. 10 is abnormally lowered, the engine start switch 17 is closed so that the circuit is closed.
Therefore, when the start switch 17 is not closed, the auxiliary power connection element 25Ad or 25A is opened to prevent the boosting power from flowing out to the microprocessor 20 side, and the boosting operation is performed promptly. There is a feature that the boosted voltage Vh can be obtained.

Further, the microprocessor 20 sets the intermittent duty γ = Va / Vh of the power supply auxiliary command AST so that the average output voltage of the auxiliary power supply connection element 25Ad becomes the set reduced voltage Va while monitoring the boosted voltage dividing voltage Vf. Decide and
The reduced voltage Va is set to a voltage in an intermediate region between the maximum value of the power supply voltage Vbb and the maximum value of the boosted voltage Vh, or is selectively set to a target value of at least a plurality of steps before and after the voltage in the intermediate region. There is.

As described above, the power supply auxiliary command AST for the auxiliary power supply connecting element 25Ad generated by the microprocessor 20 performs duty control of intermittent operation so that the average output voltage of the auxiliary power supply connecting element 25Ad becomes the set reduced voltage Va. It has become like.
Therefore, it is possible to suppress the application of an excessively high voltage to the constant voltage power supply 23 or the step-down power supply circuit 22A connected in series with the constant voltage power supply 23, and to suppress the application of an excessively high voltage to a small and inexpensive constant voltage power supply having low withstand voltage performance. There is a feature that 23 or the step-down power supply circuit 22A can be used. It should be noted that this feature is the same for the second embodiment described later.

Further, an auxiliary power supply circuit 24A is connected in series between the auxiliary power supply connection element 25A and the boost voltage Vh.
The output voltage of the auxiliary power supply circuit 24A is applied as an input voltage of the constant voltage power supply 23 or the step-down power supply circuit 22A via the auxiliary power supply connection element 25A and the auxiliary power supply diode 26.
The constant voltage power supply 23 is linearly controlled in a conduction state so that the output voltage becomes a regulated voltage Vcc in response to the input voltage.
The step-down power supply circuit 22A has a negative feedback duty control of the conduction state so that the output voltage becomes the stable operation input voltage of the constant voltage power supply 23 in response to the input voltage.
The auxiliary power supply circuit 24A is negatively feedback controlled so that the output voltage becomes equal to or less than the maximum value of the power supply voltage Vbb of the vehicle-mounted battery 10 in response to the boost voltage Vh which is the input voltage thereof.

As described above, the auxiliary power supply circuit 24A is connected between the auxiliary power supply connection element 25A and the boost voltage Vh, and the negative feedback control is performed so that the output voltage is equal to or less than the maximum value of the power supply voltage Vbb of the vehicle-mounted battery 10. Has been done.
Therefore, it is not necessary to improve the withstand voltage performance of the constant voltage power supply 23 and the step-down power supply circuit 22A, the auxiliary voltage can be applied by a compact and inexpensive configuration, and the auxiliary power supply circuit 24A itself performs the rated operation for a short time. Therefore, there is a feature that a linear control method in which power loss increases with high accuracy or a duty control method with low loss even if output voltage fluctuation occurs can be used.

Further, a bias current energizing resistor 24c is connected to the output terminal of the auxiliary power supply circuit 24A via a bias current energizing element 24a.
The bias current energization element 24a is open / closed controlled by the bias current energization command BST generated by the microprocessor 20 via the bias current energization command resistor 24b.
The bias current energization command BST close-drives the bias current energization element 24a when the value of the power supply monitoring voltage Vm is equal to or less than the second lower limit voltage Vm2, which is a value larger than the first lower limit voltage Vm1.
The value of the second lower limit voltage Vm2 is a value equal to or less than the monitoring voltage Vm corresponding to the normal lower limit value of the power supply voltage Vbb.

As described above, when the power supply monitoring voltage Vm is equal to or less than the second lower limit voltage Vm2 and the power supply auxiliary command AST for the auxiliary power supply connection element 25A is generated, the bias current is transmitted to the auxiliary power supply circuit 24A via the bias current current-carrying element 24a. It is being supplied.
Therefore, since the auxiliary power supply circuit 24A is not in the no-load state, the constant voltage control accuracy is improved, and the circuit is opened in the normal state where the power supply assistance is not required, so that the useless bias current is cut off. It should be noted that this feature is the same for the modified form of the second embodiment described later.

As described above, the in-vehicle engine control devices 100A and 100B according to the first embodiment are a constant voltage power supply 23 that supplies power to the microprocessor 20 for fuel injection control, or a step-down power supply circuit that is connected in series to the constant voltage power supply 23. A boost voltage Vh for fuel injection is applied to 22A via the auxiliary power connection elements 25Ad and 25A, and the auxiliary power connection elements 25Ad and 25A are monitoring voltages of the power supply voltage Vbb of the vehicle-mounted battery 10. Even when the microprocessor 20 is inactive and the power supply assist command AST is not generated when Vm is abnormally lowered, the circuit is closed-driven. The monitoring voltage Vm drops abnormally when the start switch 17 of the start motor 12 is closed, and the rotation speed is usually equal to or lower than the idle rotation speed of the engine. Therefore, the frequency of fuel injection is high. Is, for example, about 1/10 of the maximum engine speed of 6000 RPM, and does not affect the fuel injection performance.

Therefore, in an abnormal environment due to deterioration of the vehicle-mounted battery 10 or cold weather, when the battery voltage drops abnormally due to the drive current of the starting motor 12 by the engine starting operation, the control operation of the microprocessor 20 is maintained to start the engine. It is possible to improve the limit state that can be carried out, and there is an effect that low voltage countermeasures having a small and inexpensive configuration can be taken without affecting the fuel injection performance.

Further, when the step-down power supply circuit 22A is connected in series between the power supply voltage Vbb and the constant voltage power supply 23, when the power supply voltage Vbb of the vehicle-mounted battery 10 is sufficiently raised in the normal operation state after the engine is started. In addition, the power supply loss can be shared by the step-down power supply circuit 22A and the constant voltage power supply circuit 23 to disperse the heat generation, and the power supply voltage Vbb of the vehicle-mounted battery 10 drops abnormally to cause the auxiliary power supply connection elements 25Ad and 25A. When the circuit is closed, the boosted high voltage Vh is depressurized and applied to the constant voltage power supply 23 to prevent deterioration of the output voltage accuracy of the constant voltage power supply 23, and a small and inexpensive low withstand voltage product should be used. Can be done.

Embodiment 2.
Next, the in-vehicle engine control device according to the second embodiment will be described.
FIG. 4 is an overall circuit block diagram of the vehicle-mounted engine control device according to the second embodiment.
The configuration of the second embodiment will be described in detail with a focus on the differences from the in-vehicle engine control device 100A of FIG.
In FIG. 4, the differences between the vehicle-mounted engine control device 100C according to the second embodiment and the vehicle-mounted engine control device 100A according to the first embodiment of FIG. 1 are as follows.
The first difference is that the input terminal of the power supply voltage Vbb is divided into two, one of which is provided with the power supply voltage monitoring circuit 50 to generate the power supply monitoring voltage Vm, while the other is boosted power supply monitoring. A circuit 51 is provided to generate a boosted power supply monitoring voltage Vn, and a parallel power feeding diode 27 extending from the other power supply terminal to one power supply terminal is added accordingly.

As a result, power is supplied to the microprocessor 20 regardless of which of the power supply terminals has a poor contact, but when the other power supply terminal has a poor contact, power is not supplied to the boost power supply circuit 30 and the electromagnetic valve drive circuit 40. The state is determined by the microprocessor 20 by relatively comparing the presence / absence of the power supply monitoring voltage Vm and the presence / absence of the boosted power supply monitoring voltage Vn. The current flowing through the power supply terminal on the microprocessor 20 side is, for example, about 2A including the current flowing through the input / output interface circuit of the DC12V system, whereas the current flowing through the power supply terminal on the booster circuit side is, for example, 10A or more. Since the current flows, it is not possible for the power supply terminal on the microprocessor 20 side to assist the poor contact of the power supply terminal on the booster circuit side.

The second difference is that the power supply auxiliary command AST and the start signal STS are input to the logic element 29a in the auxiliary power connection element 25Ad in FIG. 1, whereas the logic element 29a in the auxiliary power connection element 25Bd in FIG. 4 is input. Only the power supply assist command AST is input in parallel to the microprocessor 20, and the engine rotation detection pulse Ne is input to the microprocessor 20 as an alternative to the start signal STS.
As a result, the auxiliary power supply connection element 25Bd has the above-mentioned power supply monitoring voltage Vm of the first lower limit voltage Vm1 or less and the engine rotation speed of, for example, an idle rotation speed of 600 RPM or less, regardless of whether or not the start switch 17 is operated. Occasionally, the connection opening / closing element 25a (see FIG. 1) is closed.

The third difference is that the auxiliary power supply diode 26 in FIG. 1 is connected to the downstream position of the power supply diode 21 regardless of the presence or absence of the step-down power supply circuit 22A, whereas the auxiliary power supply diode 26 in FIG. 4 is step-down. It is connected to the connection point between the power supply circuit 22B and the constant voltage power supply 23. Along with this, the reduced pressure voltage Va by the auxiliary power supply connecting element 25Bd is applied to the boost control circuit 37 as the control voltage Vc via the added second backflow prevention element 38b, but in the case of FIG. 1, the second backflow The prevention element 38b is unnecessary and joins the first backflow prevention element 38a via the auxiliary power feeding diode 26.

Next, a modified form of the vehicle-mounted engine control device 100C described with reference to FIG. 4 will be described.
FIG. 5 is an overall circuit block diagram showing a modified form of the vehicle-mounted engine control device 100C described with reference to FIG. 4, and the configuration thereof will be described in detail with a focus on differences from the vehicle-mounted engine control device 100C of FIG.
The main difference between the vehicle-mounted engine control device 100C of FIG. 4 and the vehicle-mounted engine control device 100D of FIG. 5 is that the auxiliary power supply connecting element 25B is applied instead of the auxiliary power supply connecting element 25Bd of FIG. 4, and the auxiliary power supply connecting element 25B is applied. In 25B, the correction control of the energization duty corresponding to the power supply monitoring voltage Vm is not performed. Instead, an auxiliary power supply circuit 24B is added, and in order to improve the constant voltage control characteristics of the auxiliary power supply circuit 24B, the bias current energization element 24a and the bias current energization command BST described in FIG. 2 are added. Has been done.

In FIG. 5, the auxiliary power supply connecting element 25B has the same configuration as the auxiliary power supply connecting element 25Bd in FIG. 4 (which is the same as the auxiliary power supply connecting element 25Ad in FIG. 1), and both have a power supply monitoring voltage Vm and rotation. The connection switching element 25a (see FIG. 1) is opened and closed by the power supply auxiliary command AST that responds to the sensor 16a, and it is determined whether or not auxiliary power supply is performed by the boosted voltage Vh. However, in the case of the auxiliary power supply connecting element 25B, the connection opening / closing element 25a is closed or opened depending on whether or not the power supply assist is performed, but the energization duty thereof is not controlled.

The auxiliary power supply circuit 24B added instead reduces the boost voltage Vh by negative feedback duty control or negative feedback linear control, and supplies, for example, a constant voltage of DC14V to the auxiliary power supply connection element 25B. Then, a bias current energization resistor 24c is connected to the output terminal of the auxiliary power supply circuit 24B via the bias current energization element 24a, and the bias current energization element 24a generates the microprocessor 20 via the bias current energization command resistor 24b. The opening and closing is controlled by the bias current energization command BST.
This bias current energization command BST close-drives the bias current energization element 24a when the value of the power supply monitoring voltage Vm described above is equal to or less than the second lower limit voltage Vm2, which is a value larger than the first lower limit voltage Vm1. The value of the second lower limit voltage Vm2 is a value equal to or less than the power supply monitoring voltage Vm corresponding to, for example, DC10V corresponding to the normal lower limit value of the power supply voltage Vbb.

The constant voltage power supply 23 has a negative feedback linear control of the conduction state so that the output voltage becomes the stabilized voltage Vcc in response to the input voltage, whereas the step-down power supply circuit 22B has the same. The conduction state is negatively feedback duty controlled so that the output voltage becomes the stable operation input voltage of the constant voltage power supply 23 in response to the input voltage, and the output voltage of the auxiliary power supply circuit 24B is, for example, DC7 to 14V. It suffices if it is stabilized so as to be within the range of.
Therefore, according to the power supply circuit configuration according to the embodiment of FIG. 5, the power supply voltage Vbb of the vehicle-mounted battery 10 is abnormally lowered in the low rotation speed state during the engine start, and the boost power supply circuit 30 starts the boosting operation. Even in the process of increasing the boosted voltage Vh immediately after that, the power supply can be assisted to the constant voltage power supply 23 without being affected by the voltage drop by the step-down power supply circuit 22B.

Next, the operation and operation of the vehicle-mounted engine control device 100C shown in FIG. 4 or the vehicle-mounted engine control device 100D shown in FIG. 5 will be described in detail.
First, in FIGS. 4 and 5 showing the entire circuit block diagram, when the power switch (not shown) is closed and the power relay 11 is urged and closed, the vehicle-mounted engine control devices 100C and 100D are subjected to the power supply voltage Vbb by the vehicle-mounted battery 10. Is applied, a stabilized voltage Vcc is applied to the microprocessor 20 via the feeding diode 21, the step-down power supply circuit 22B, and the constant voltage power supply 23, and the microprocessor 20 at least performs fuel injection control for the engine. There is.

On the other hand, the boost power supply circuit 30 is a series circuit of the induction element 31, the switching element 32, and the current detection resistor 33 from the power supply voltage Vbb, and the induction element 31 generated when the switching element 32 is intermittently driven by the boost control circuit 37. It is configured to include a step-up capacitor 35 that is charged via a backflow prevention diode 34 by inductive energy.
The boost power supply circuit 30 is rapidly driven by applying a short-time high-voltage voltage to a plurality of fuel injection electromagnetic coils 14a via the solenoid valve drive circuit 40, and is driven according to the required fuel injection amount. It is designed to be rapidly shut off after the valve opening assist control is performed. However, the above operation is when the power supply voltage Vbb is normal and the microprocessor 20 and the boost power supply circuit 30 are operating normally. After the power switch is closed, power is supplied to the starting motor 12. When a low voltage abnormality occurs at the time when the engine starts to rotate, the auxiliary power supply connecting element 25Bd or 25B is used to deal with this problem.

Next, the control operations of the vehicle-mounted engine control device 100C shown in FIG. 4 and the vehicle-mounted engine control device 100D shown in FIG. 5 when a low voltage abnormality occurs will be described in detail with reference to the flowchart of FIG.
In FIG. 6, step S610 is a step in which the power relay 11 is operated by closing the power switch (not shown) and the boost voltage Vh is generated by the boost power circuit 30.
Subsequent step S611 is a step in which the auxiliary power supply connecting element 25Bd or 25B performs auxiliary power supply because the microprocessor 20 is inactive and the power supply auxiliary command AST is not generated, but the engine is not rotating.
Subsequent step S600 is an operation start step of the voltage control program which is one of the control programs of the microprocessor 20.

In the following step S601, the value of the power supply monitoring voltage Vm obtained by the power supply voltage monitoring circuit 50, the value of the boosted power supply monitoring voltage Vn obtained by the boosted power supply monitoring circuit 51, and the value of the boosted voltage divided voltage Vf in the case of FIG. 4 Is a step of reading through a multi-channel AD converter (not shown) and reading the rotation detection pulse Ne to calculate the rotation speed N of the engine.
In the following step S607a, it is determined that the relationship between the power supply monitoring voltage Vm and the boosted power supply monitoring voltage Vn is Vm << Vn, and the boosted power supply monitoring voltage Vn is generated but the power supply monitoring voltage Vm is not generated. When this is done, YES is determined and the process proceeds to step S607b. When the relationship between the power supply monitoring voltage Vm and the boosted power supply monitoring voltage Vn is Vm≈Vn, NO is determined and the process proceeds to step S608a. This is a judgment step.
Step S607b is a step in which it is determined that the power supply terminal on the microprocessor 20 side has a poor contact, the first abnormality notification is performed, and the process proceeds to step S608a.

In step S608a, it is determined that the relationship between the power supply monitoring voltage Vm and the boosted power supply monitoring voltage Vn is Vm >> Vn, and the power supply monitoring voltage Vm is generated but the boosted power supply monitoring voltage Vn is not generated. When, YES is determined and the process proceeds to step S608b, and when the relationship between the power supply monitoring voltage Vm and the boosted power supply monitoring voltage Vn is Vm≈Vn, NO is determined and the process proceeds to step S602. It is a step.
Step S608b is a step in which it is determined that the power supply terminal on the boost power supply 30 side has a poor contact, a second abnormality notification for prohibiting the engine start operation is performed, and the process proceeds to step S609 of the operation end step.

In the following step S602, it is determined whether or not the value of the power supply monitoring voltage Vm read in step S601 is equal to or less than the second lower limit voltage Vm2, and if it is equal to or less than the second lower limit voltage Vm2, YES is determined and step S603 is performed. If it exceeds the limit, NO is determined, and step S609 of the operation end step is a determination step.
The value of the second lower limit voltage Vm2 is a value equal to or less than the power supply monitoring voltage Vm corresponding to the normal lower limit value of the power supply voltage Vbb, and if it is a 12V in-vehicle battery, for example, the power supply monitoring voltage Vm corresponding to DC10V. It is the value of.

In step S603, the bias current energization command BST described with reference to FIG. 5 is generated, and a minute load current is energized to the auxiliary power supply circuit 24B by the bias current energization element 24a to improve the accuracy of constant voltage control. It is a step.
In the following step S604a, it is determined whether or not the value of the power supply monitoring voltage Vm read in step S601 is equal to or less than the first lower limit voltage Vm1, and if it is equal to or less than the first lower limit voltage Vm1, a YES determination is made and step S605a If it exceeds the limit, NO is determined, and the process proceeds to step S604b.
The first lower limit voltage Vm1 corresponds to the lower limit value of the power supply monitoring voltage Vm corresponding to the minimum input voltage of the step-down power supply circuit 22B for obtaining the stabilized voltage Vcc, and the stabilized voltage Vcc of DC5V. A power supply corresponding to a power supply voltage Vbb having a total voltage of 9 V, which is the sum of, for example, DC7V as the input voltage of the constant voltage power supply 23 required for obtaining the above voltage and DC2V as a further margin voltage due to having the step-down power supply circuit 22B. It is the value of the monitoring voltage Vm.

In step S604b, the output of the logic element 29a in the auxiliary power supply connection element 25Bd or 25B is stopped by setting the logic level of the power supply assistance command AST to “L”, and the power supply assistance by the auxiliary power supply connection element 25Bd or 25B is stopped. This is a step of shifting to step S609 of the operation end step.
In step S605a, it is determined whether or not the engine rotation speed N calculated in step S601 is less than the idle rotation speed N0, and if it is less than the idle rotation speed N0, YES is determined to proceed to step S606 and idle. If the rotation speed is N0 or more, NO is determined and the process proceeds to step 605b.
In step S605b, although the determination in step S605a is equal to or higher than the idle rotation speed N0, the determination in step S604a gives an abnormality notification that the power supply voltage Vbb is too small, and the voltage shifts to step S609 in the operation end step. It is an abnormality notification step.
In step S606, in the case of FIG. 4, duty control is performed based on the boosted voltage dividing voltage Vf to generate the power supply assist command AST, and in the case of FIG. 5, the logic level of the power supply auxiliary command AST is always set to “H”. This is a step of shifting to step S609 of the operation end step.

In step S609 of the operation end step, the process shifts to another control program, for example, shifts to step S600 of the operation start step again within a calculation cycle of 5 msec, and the subsequent control flow is cyclically executed.
The energization duty of the connection switching element 25a in the case of FIG. 4 is set to 50% or 100% depending on the value of the step-up voltage dividing voltage Vf as in the case of FIG. 3, but it can be fixed by further controlling in a plurality of steps. The voltage applied to the voltage power supply 23 can be suppressed, and the reduced voltage Va can be rapidly increased as the boosted voltage Vh increases.
Further, the output voltage of the auxiliary power supply connecting element 25Bd or 25B is supplied as an auxiliary voltage to the boost control circuit 37 via the second backflow prevention element 38b, thereby discharging the charge initially charged to the decompression delay capacitor 38c. The control operation of the boost control circuit 37 at the time of abnormally low voltage is stabilized while suppressing the above.

As described in detail above, in the vehicle-mounted engine control devices 100C and 100D shown in FIGS. 4 and 5, a power supply voltage Vbb is applied from the vehicle-mounted battery 10 via the power supply relay 11, and a stabilized voltage is applied via the constant voltage power supply 23. A microprocessor 20 to which Vcc is supplied to control fuel injection to at least an in-vehicle engine, and a boost power supply circuit 30 to generate a boost voltage Vh for boosting the power supply voltage Vbb and rapidly driving the fuel injection electromagnetic coil 14a. In-vehicle engine control devices 100C and 100D equipped with and
An input voltage Vba whose backflow is prevented by a power feeding diode 21 is indirectly applied to the constant voltage power supply 23 via the step-down power supply circuit 22B, and a boost voltage Vh is applied to the input portion of the constant voltage power supply 23. Auxiliary power connection element 25Bd or 25B to apply
The auxiliary power supply connection element 25Bd or 25B is closed-driven when the value of the power supply monitoring voltage Vm, which is the divided voltage of the power supply voltage Vbb, is equal to or less than the first lower limit voltage Vm1, and the first lower limit voltage Vm1 is The value of the power supply monitoring voltage Vm corresponds to the lower limit value of the power supply monitoring voltage Vm corresponding to the minimum input voltage of the step-down power supply circuit 22B for obtaining the stabilized voltage Vcc, and the value of the power supply monitoring voltage Vm is the first lower limit voltage of the microprocessor 20. When Vm1 is exceeded, the power supply auxiliary command AST is stopped and the auxiliary power supply connection element 25Bd or 25B is opened.

The power supply monitoring voltage Vm is connected as an input signal to the microprocessor 20, and it is determined by the microprocessor 20 whether or not the power supply monitoring voltage Vm exceeds the value of the first lower limit voltage Vm1.
A rotation detection pulse Ne generated by a rotation sensor 16a that responds to engine rotation is input to the microprocessor 20, and the microprocessor 20 generates a rotation speed detection signal N proportional to the engine rotation speed.
When the value of the power supply monitoring voltage Vm is equal to or less than the first lower limit voltage Vm1 and the rotation speed detection signal N is less than the set idle rotation speed N0, the auxiliary power supply connection element 25Bd or 25B of the microprocessor 20 Closed drive regardless of operating conditions,
When it is detected that the rotation speed detection signal N is equal to or higher than the idle rotation speed N0, the microprocessor 20 stops the power supply auxiliary command AST, and the auxiliary power supply connection element 25Bd or 25B is deactivated and opened. There is.

As described above, the auxiliary power supply connecting element 25Bd or 25B that applies the boost voltage Vh for fuel injection control to the constant voltage power supply 23 that is the power supply circuit for the microprocessor 20 for fuel injection control is the power supply voltage Vbb of the vehicle-mounted battery 10. When the engine speed is abnormally low, the engine speed is less than the idle speed N0, so that the circuit is closed.
Therefore, before the engine speed increases and the required boost power of the boost power supply circuit 30 for high-frequency fuel injection increases, the auxiliary power supply to the constant voltage power supply 23 for the microprocessor 20 is stopped. It has a feature that can prevent deterioration of boosting performance.

The decompression voltage Va, which is the output voltage of the auxiliary power supply connection element 25Bd, is applied to the decompression delay capacitor 38c via the second backflow prevention element 38b to become the control voltage Vc for the boost control circuit 37.

As described above, the second backflow prevention element 38b is connected between the auxiliary power supply connection element 25Bd and the boost control circuit 37.
Therefore, in cooperation with the decompression delay capacitor 38c charged from the power supply voltage Vbb via the first backflow prevention element 38a, the charging voltage of the decompression delay capacitor 38c is discharged while charging from the second backflow prevention element 38b. There is a feature that the boost power supply circuit 30 can be operated stably. This also applies to the case of claim 8 in the modified form 2.
In the case of the first embodiment and its modified form, the auxiliary feeding diode 26 also functions as the second backflow prevention element 38b, and only the first backflow prevention element 38a needs to be provided. ..

An auxiliary power supply circuit 24B is connected in series between the auxiliary power supply connection element 25B and the boost voltage Vh, and the output voltage of the auxiliary power supply circuit 24B is determined via the auxiliary power supply connection element 25B and the auxiliary power supply diode 26. It is applied as the input voltage of the constant voltage power supply 23 to the connection position of the voltage power supply 23 and the step-down power supply circuit 22B.
The constant voltage power supply 23 is negatively feedback linearly controlled in the conduction state so that the output voltage becomes the stabilized voltage Vcc in response to the input voltage, whereas the step-down power supply circuit 22B has the input voltage. The conduction state is negatively feedback duty controlled so that the output voltage becomes the stable operation input voltage of the constant voltage power supply 23 in response to the above.
The auxiliary power supply circuit 24B is negatively feedback controlled so that the output voltage becomes equal to or less than the maximum value of the power supply voltage Vbb of the vehicle-mounted battery 10 in response to the boost voltage Vh which is the input voltage thereof.

As described above, the auxiliary power supply circuit 24B is connected between the auxiliary power supply connection element 25B and the boost voltage Vh, and the negative feedback control is performed so that the output voltage is equal to or less than the maximum value of the power supply voltage Vbb of the vehicle-mounted battery 10. Has been done.
Therefore, it is not necessary to improve the withstand voltage performance of the constant voltage power supply 23 and the step-down power supply circuit 22B, the auxiliary voltage can be applied by a compact and inexpensive configuration, and the auxiliary power supply circuit 24B itself performs the rated operation for a short time. Therefore, there is a feature that a linear control method in which power loss increases with high accuracy or a duty control method with low loss even if output voltage fluctuation occurs can be used.
The same applies to the first embodiment and the second embodiment for the constant voltage power supply 23 and the step-down power supply circuit 22B.

The power supply terminal for connecting the power supply voltage Vbb is divided into a first terminal for supplying power to the microprocessor 20 and a second terminal for supplying power to the boost power supply circuit 30, and the second terminal is further divided into a second terminal. The power supply voltage monitoring circuit 50 for forming a power supply circuit to the microprocessor 20 via the parallel power supply diode 27 and obtaining the power supply monitoring voltage Vm is connected to the first terminal, whereas it is connected to the second terminal. Is provided with a boost power supply monitoring circuit 51 that generates a boost power supply monitoring voltage Vn.
The microprocessor 20 relatively compares the values of the power supply monitoring voltage Vm and the boosted power supply monitoring voltage Vn, and in the first state where the boosted power supply monitoring voltage Vn is generated but the power supply monitoring voltage Vm is not generated, the above-mentioned In the second state in which it is determined that the contact of the first terminal is poor, the first abnormality notification output is generated, and the boost power supply monitoring voltage Vn is not generated even though the power supply monitoring voltage Vm is generated, the second state is described. It is determined that the contact of the terminals is poor, and a second abnormality notification output is generated.

As described above, the power supply terminal for connecting the power supply voltage Vbb is divided into a power supply terminal for the microprocessor 20 side and a power supply terminal for the boost power supply circuit 30 side, and a power supply voltage monitoring circuit 50 is provided for each. The power supply to the microprocessor 20 side is supplied from both power supply terminals via the parallel power supply diode 27, and the microprocessor 20 relatively compares both monitoring voltages and one power supply terminal. It is designed to detect poor contact and notify the abnormality.
Therefore, when the power supply terminal to the microprocessor 20 side has a poor contact, the abnormality notification of the first state prompting maintenance and inspection is performed, and when the power supply terminal to the boost power supply circuit 30 side has a poor contact, the engine start is prohibited. There is a feature that the abnormality notification of the second state can be performed to prevent the in-vehicle battery 10 from being discharged.
The feeding current to the boost power supply circuit 30 side is overwhelmingly larger than the feeding current to the microprocessor 20 side, and the normal operation of the microprocessor 20 is maintained by parallel feeding to the microprocessor 20. It is something that can be done. Further, even in the case of the above-described first embodiment and its modified form, the same abnormality determination function can be added by dividing the power supply terminal into two parts.

Although the present application describes various exemplary embodiments and examples, the various features, embodiments, and functions described in one or more embodiments are applications of a particular embodiment. It is not limited to, but can be applied to embodiments alone or in various combinations.
Therefore, innumerable variations not illustrated are envisioned within the scope of the techniques disclosed in the present application. For example, it is assumed that at least one component is modified, added or omitted, and further, at least one component is extracted and combined with the components of other embodiments.

10 In-vehicle battery, 11 Power relay, 12 Start motor, 13 Start relay, 14 Electric load group, 14a Electromagnetic coil for fuel injection, 16 Sensor group, 16a Rotation sensor, 17 Start switch, 20 Microprocessor, 21 Power supply diode, 22A, 22B step-down power supply circuit, 23 constant voltage power supply, 24A, 24B auxiliary power supply circuit, 24a bias current energization element, 24b bias current energization command resistance, 24c bias current energization resistance, 25A, 25Ad, 25B, 25Bd auxiliary power supply connection element, 25a connection Switching element, 25b, 25c gate resistance, 25d protection diode, 26 auxiliary feeding diode, 27 parallel feeding diode, 29 switching control element, 29a logic element, 29b pull-up resistance, 30 boost power supply circuit, 31 induction element, 32 switching element, 33 Current detection resistance, 34 Backflow prevention diode, 35 Boost capacitor, 36a, 36b Boost voltage division resistance, 37 Boost control circuit, 38a First backflow prevention element, 38b Second backflow prevention element, 38c Decompression delay capacitor, 40 Electromagnetic valve drive Circuit, 41 valve opening holding element, 42 valve opening holding diode, 43 rapid feeding element, 44 commutation diode, 45 cylinder selection element, 50 power supply voltage monitoring circuit, 50a, 50b battery voltage dividing resistance, 50c smoothing circuit, 51 boost power supply Monitoring circuit, 100A, 100B, 100C, 100D In-vehicle engine controller, AST power supply auxiliary command, BST bias current energization command, If element current, If1 lower limit current, If2 upper limit current, INJ fuel injection command, N rotation speed detection signal, N0 Idle rotation speed, Ne rotation detection pulse, STS start signal, Tf cutoff time, Va decompression voltage, Vb battery voltage, Vba input voltage, Vbb power supply voltage, Vc control voltage, Vcc stabilization voltage, Vf boost voltage division voltage, Vf1 1 voltage division voltage, Vf2 2nd voltage division voltage, Vh boost voltage, Vm power supply monitoring voltage, Vm1 1st lower limit voltage, Vm2 2nd lower limit voltage, Vn boost power supply monitoring voltage, γ intermittent duty.

The in-vehicle engine control device disclosed in the present application includes a microprocessor in which a power supply voltage is applied from an in-vehicle battery, a stabilized voltage is supplied via a constant voltage power supply, and at least fuel injection control for the in-vehicle engine is performed, and the power supply voltage. a vehicle engine control apparatus and a booster power supply circuit for generating a boosted voltage to drive the electromagnetic coil for a fuel injection boosts the,
An input voltage that is prevented from flowing back by a power supply diode is applied to the constant voltage power supply, or an input voltage that is stepped down via a step- down power supply circuit is applied, and the step-up voltage is applied. Auxiliary power supply connecting element applied to the input portion of the constant voltage power supply or the step-down power supply circuit is provided.
The auxiliary power supply connection element is closed-circuit driven when the value of the power supply monitoring voltage, which is the divided voltage of the power supply voltage, is equal to or less than the first lower limit voltage.
The first lower limit voltage corresponds to the lower limit value of the power supply monitoring voltage corresponding to the minimum input voltage of the constant voltage power supply from which the regulated voltage is obtained or the step-down power supply circuit.
The microprocessor is characterized in that when the value of the power supply monitoring voltage exceeds the first lower limit voltage, the power supply auxiliary command is stopped and the auxiliary power supply connection element is opened.

Next, the boost power supply circuit 30 is generated when the induction element 31 connected to the power supply voltage Vbb , the switching element 32, the current detection resistor 33 are connected in series, and the switching element 32 is intermittently driven by the boost control circuit 37. It is configured to include a step-up capacitor 35 that is charged via the backflow prevention diode 34 by the induction energy of the induction element 31. Then, in the boost control circuit 37, after the switching element 32 is closed and power is supplied to the induction element 31, the element current If detected by the current detection resistor 33 reaches the set upper limit current If2, which is, for example, 10A. The opening / closing element 32 is opened, and the opening / closing element 32 is reclosed when the set cutoff time Tf, which is, for example, 10 μsec, elapses, or when the element current If is reduced to, for example, 3A, which is equal to or less than the set lower limit current If1. Intermittent control is performed.

On the other hand, the boost power supply circuit 30 is a series circuit of the induction element 31 connected to the power supply voltage Vbb , the switching element 32, and the current detection resistor 33, and the induction generated when the switching element 32 is intermittently driven by the boost control circuit 37. It is composed of a step-up capacitor 35 that is charged via a backflow prevention diode 34 by the induced energy of the element 31.
The boost power supply circuit 30 is rapidly driven by applying a short-time high-voltage voltage to a plurality of fuel injection electromagnetic coils 14a via the solenoid valve drive circuit 40, and is driven according to the required fuel injection amount. It is designed to be rapidly shut off after the valve opening assist control is performed. However, the above operation is for the case where the power supply voltage Vbb is normal and the microprocessor 20 and the boost power supply circuit 30 are operating normally, and after the power switch is closed, power is supplied to the starting motor 12. When a low voltage abnormality occurs at the time when the engine starts to rotate, the auxiliary power supply connecting element 25Ad or 25A is used to deal with this problem.

The boost power supply circuit 30 is a series circuit of the induction element 31 connected to the power supply voltage Vbb , the switching element 32, and the current detection resistor 33, and the induction element 31 generated when the switching element 32 is intermittently driven by the boost control circuit 37. It is composed of a step-up capacitor 35 which is charged via the backflow prevention diode 34 by the induced energy of the above.
The boost control circuit 37 opens the switching element 32 when the element current If detected by the current detection resistor 33 reaches the set upper limit current If2 after the switching element 32 is closed and the power is supplied to the induction element 31. When the set cutoff time Tf elapses or the element current If decreases below the set lower limit current If1, the switching element 32 is reclosed and the circuit is reclosed.
After monitoring the boosted voltage dividing voltage Vf of the boosting voltage Vh, which is the charging voltage of the boosting capacitor 35, and reaching the second voltage dividing voltage Vf2 corresponding to the target voltage of the boosting voltage Vh, from the second voltage dividing voltage Vf2. The switching element 32 is configured to maintain the open circuit state during the period until the first voltage dividing voltage Vf1 or less is low.
The boost power supply circuit 30 further includes a decompression delay capacitor 38c charged from the feeding diode 21 via the first backflow prevention element 38a, and the boost control circuit 37 powers the control voltage Vc which is the charging voltage of the decompression delay capacitor 38c. It operates as a voltage to perform intermittent control of the opening / closing element 32.

On the other hand, the boost power supply circuit 30 is a series circuit of the induction element 31 connected to the power supply voltage Vbb , the switching element 32, and the current detection resistor 33, and the induction generated when the switching element 32 is intermittently driven by the boost control circuit 37. It is configured to include a step-up capacitor 35 that is charged via the backflow prevention diode 34 by the induced energy of the element 31.
The boost power supply circuit 30 is rapidly driven by applying a short-time high-voltage voltage to a plurality of fuel injection electromagnetic coils 14a via the solenoid valve drive circuit 40, and is driven according to the required fuel injection amount. It is designed to be rapidly shut off after the valve opening assist control is performed. However, the above operation is when the power supply voltage Vbb is normal and the microprocessor 20 and the boost power supply circuit 30 are operating normally. After the power switch is closed, power is supplied to the starting motor 12. When a low voltage abnormality occurs at the time when the engine starts to rotate, the auxiliary power supply connecting element 25Bd or 25B is used to deal with this problem.

Claims (10)

A power supply voltage is applied from the vehicle-mounted battery, a stabilized voltage is supplied via a constant-voltage power supply, and at least a microprocessor that controls fuel injection for the vehicle-mounted engine and an electromagnetic coil for fuel injection that boosts the power supply voltage are rapidly driven. An in-vehicle engine control device equipped with a boost power supply circuit that generates a boost voltage to drive.
An input voltage that is prevented from flowing back by a feeding diode is applied to the constant voltage power supply from the power supply voltage, or is applied via a step-down power supply circuit.
An auxiliary power supply connection element for applying the step-up voltage to the input portion of the constant-voltage power supply or the step-down power supply circuit is provided.
The auxiliary power supply connection element is closed-circuit driven when the value of the power supply monitoring voltage, which is the divided voltage of the power supply voltage, is equal to or less than the first lower limit voltage.
The first lower limit voltage corresponds to the lower limit value of the power supply monitoring voltage corresponding to the minimum input voltage of the constant voltage power supply from which the regulated voltage is obtained or the step-down power supply circuit.
The microprocessor is an in-vehicle engine control device, characterized in that the power supply auxiliary command is stopped and the auxiliary power supply connecting element is opened when the value of the power supply monitoring voltage exceeds the first lower limit voltage. The boost power supply circuit is a backflow prevention diode due to a series circuit of an induction element, an switching element, and a current detection resistor from the power supply voltage, and an induced energy of the induction element generated when the switching element is intermittently driven by the boost control circuit. Consists of a booster capacitor, which is charged via
The boost control circuit opens and sets the switching element when the element current detected by the current detection resistor reaches a set upper limit current after the switching element is closed and power is supplied to the induction element. When the cutoff time elapses or the element current decreases below the set lower limit current, the switching element is reclosed and the circuit is reclosed.
The boosted voltage dividing voltage of the boosted voltage is monitored, and after reaching the second voltage dividing voltage corresponding to the target voltage of the boosted voltage, the voltage drops below the first voltage dividing voltage lower than the second voltage dividing voltage. The opening / closing element is configured to maintain the open circuit state until the voltage is changed.
The boost power supply circuit further includes a decompression delay capacitor that is charged from the feed diode via a first backflow prevention element.
The vehicle-mounted engine control device according to claim 1, wherein the boost control circuit operates using a control voltage which is a charging voltage of the decompression delay capacitor as a power supply voltage to perform intermittent control of the switching element. The power supply monitoring voltage is connected as an input signal to the microprocessor, and whether or not the power supply monitoring voltage exceeds the value of the first lower limit voltage is determined by the microprocessor.
The auxiliary power supply connection element is driven to close the circuit regardless of the operating state of the microprocessor when the value of the power supply monitoring voltage is equal to or lower than the first lower limit voltage and the engine start switch is pressed and closed. When the power supply monitoring voltage exceeds the value of the first lower limit voltage, the microprocessor stops the power supply auxiliary command and opens the auxiliary power supply connection element even if the start switch is pressed and closed. The vehicle-mounted engine control device according to claim 1 or 2. The power supply monitoring voltage is connected as an input signal to the microprocessor, and whether or not the power supply monitoring voltage exceeds the value of the first lower limit voltage is determined by the microprocessor.
A rotation detection pulse generated by a rotation sensor that responds to engine rotation is input to the microprocessor, and the microprocessor generates a rotation speed detection signal proportional to the engine rotation speed.
When the value of the power supply monitoring voltage is equal to or lower than the first lower limit voltage and the rotation speed detection signal is less than the set idle rotation speed, the auxiliary power supply connection element has nothing to do with the operating state of the microprocessor. Closed drive to
When it is detected that the rotation speed detection signal is equal to or higher than the idle rotation speed, the microprocessor stops the power supply auxiliary command and the auxiliary power supply connection element is deactivated and opened. Item 4. The in-vehicle engine control device according to item 1 or 2. The microprocessor determines the intermittent duty of the power supply auxiliary command so that the average output voltage of the auxiliary power supply connection element becomes a set reduced voltage while monitoring the step-up voltage dividing voltage of the boosted voltage.
The depressurized voltage is set to a voltage in an intermediate region between the maximum value of the power supply voltage and the maximum value of the boosted voltage, or is selectively set to a target value of at least a plurality of steps before and after the voltage in the intermediate region. The vehicle-mounted engine control device according to any one of claims 2 to 4, wherein the vehicle-mounted engine control device is provided. The microprocessor determines the intermittent duty of the power supply auxiliary command so that the average output voltage of the auxiliary power supply connection element becomes a set reduced voltage while monitoring the step-up voltage dividing voltage of the boosted voltage.
The decompression voltage is set to a voltage in an intermediate region between the maximum value of the power supply voltage and the maximum value of the boost voltage, or is selectively set to a target value of at least a plurality of steps before and after the voltage in the intermediate region. The vehicle-mounted engine control device according to claim 2, wherein the voltage is applied to the decompression delay capacitor via a second backflow prevention element to obtain the control voltage for the boost control circuit. An auxiliary power supply circuit is connected in series between the auxiliary power supply connection element and the boosted voltage.
The output voltage of the auxiliary power supply circuit is applied as an input voltage of the constant voltage power supply or the step-down power supply circuit via the auxiliary power supply connection element and the auxiliary power supply diode.
The constant voltage power supply is linearly controlled in a negative feedback state so that the output voltage is the stabilized voltage in response to the input voltage of the step-down power supply circuit, whereas the step-down power supply circuit is the step-down power supply. Negative feedback duty control is performed so that the output voltage is the stable operation input voltage of the constant voltage power supply in response to the input voltage of the circuit.
2. The auxiliary power supply circuit is characterized in that it is negatively feedback controlled so that the output voltage is equal to or less than the maximum value of the power supply voltage of the vehicle-mounted battery in response to the boosted voltage which is the input voltage. 4. The in-vehicle engine control device according to any one of 4. The vehicle-mounted engine control device according to claim 2, wherein the output voltage of the auxiliary power supply connecting element is applied as the control voltage to the boost control circuit via the second backflow prevention element. A bias current current-carrying resistor is connected to the output terminal of the auxiliary power supply circuit via a bias current-carrying element.
The bias current energization element is controlled to open and close by the bias current energization command generated by the microprocessor via the bias current energization command resistor.
The bias current energization command close-drives the bias current energization element when the value of the power supply monitoring voltage is equal to or less than the second lower limit voltage, which is a value larger than the first lower limit voltage.
The vehicle-mounted engine control device according to claim 7, wherein the value of the second lower limit voltage is a value equal to or lower than the power supply monitoring voltage corresponding to the normal lower limit value of the power supply voltage. The power supply terminal to which the power supply voltage is connected is divided into a first terminal for supplying power to the microprocessor and a second terminal for supplying power to the boost power supply circuit, and the second terminal is the micro via a parallel feeding diode. Configure a power supply circuit to the processor
The power supply voltage monitoring circuit for obtaining the power supply monitoring voltage is connected to the first terminal, whereas the second terminal is provided with a boosted power supply monitoring circuit for generating a boosted power supply monitoring voltage.
The microprocessor relatively compares the values of the power supply monitoring voltage and the boosted power supply monitoring voltage, and in the first state in which the boosted power supply monitoring voltage is generated but the power supply monitoring voltage is not generated, the microprocessor In the second state in which it is determined that the contact of the first terminal is poor and the first abnormality notification output is generated, and the power supply monitoring voltage is generated but the boosted power supply monitoring voltage is not generated, the second state is described. The vehicle-mounted engine control device according to any one of claims 2 to 9, wherein a second abnormality notification output is generated by determining that the terminal contact is poor.

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