JP2000337192A - Engine control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently use the excessive fuel left in a fuel tank to prevent a vehicle from being inoperable by a lack of fuel by limiting the fuel supply to each cylinder according to the fuel residual quantity and the engine operating state in an engine control device having a fuel consumption reducing means. SOLUTION: A fuel residual quantity sensor 23 is mounted within a fuel tank 11, and its detection signal is inputted to an engine control device 17. The engine control device 17 inputs the detection signals of engine operating state detected by an air flowmeter 7, a crank angle sensor 18 and the like. On the basis of the detection signals of fuel residual quantity and engine operating state, an injector 13 is controlled so as to effectively use the remaining fuel. For example, the fuel supply from the injection to each cylinder 1a is stopped or limited, or the intake air quantity to each cylinder 1a is limited, so that a vehicle can travel to the closest fuel supplying facility. Further, a fuel reside alarm lamp is lighted to alarm the residue of fuel is small.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine control device, and more particularly, to an engine control device that ensures an operation function as much as possible while preventing operation failure due to running out of fuel in a fuel tank or the like.

[0002]

2. Description of the Related Art In general, a fuel device comprises a fuel injection device (injector), a fuel pump, a fuel tank, and the like. The remaining amount of fuel in the fuel tank is determined by detecting a float in the fuel tank and its state. This is detected by the output signal of the level sensor that performs the detection. Conventional engine control devices for running out of fuel in a fuel tank or the like control the operating state of an engine to control at least the vehicle speed to be lower than a predetermined vehicle speed when the remaining amount of fuel in the fuel tank of the vehicle reaches a predetermined value. In order to lower the catalyst temperature, specifically, there is a technique for performing thinning of fuel injection, thinning of ignition, retard control of ignition, control of closing an intake throttle valve, and the like (Japanese Patent Laid-Open No. No. 2-149750).

[0003] Another conventional engine control device is designed so that when the remaining amount of fuel in the fuel tank is small, the fuel consumption is smaller than when the remaining amount is large. A technique for performing a reduction operation or the like in an operating state region (see Japanese Patent Application Laid-Open No. 3-267538), a means for detecting the remaining fuel amount of a fuel tank is provided, and it is detected that the remaining fuel amount has fallen below a predetermined level. At this time, a technique for controlling the fuel injection device to perform thinning injection (Japanese Patent Laid-Open No. 6-330787).
Japanese Patent Application Laid-Open No. H10-61514 discloses a technique in which when the remaining amount of fuel becomes equal to or less than a specified value, an engine operating time from that time to the time when the fuel runs out is calculated and a warning is issued (see Japanese Patent Application Laid-Open No. 10-61514).

[0004]

The technique disclosed in Japanese Patent Application Laid-Open No. 2-149750 uses the vehicle speed as an information source. However, in order to reduce the fuel consumption in various engine operating states. It is necessary to reduce the fuel consumption more finely and accurately by using not only the vehicle speed but also various driving states as information sources.

The technique disclosed in Japanese Patent Application Laid-Open No. 3-267538 changes the air-fuel ratio of the engine according to the remaining amount of fuel. The air-fuel ratio not only limits the improvement of the engine output, but also limits the engine output. Providing a lean air-fuel ratio causes heat damage to exhaust system components, and thus has the disadvantage of limiting the degree of freedom in setting the components.

Further, the technique disclosed in Japanese Patent Application Laid-Open No. Hei 6-330787 is to thin out fuel injection without considering various engine operating conditions. And the like. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an engine control apparatus having a fuel consumption reducing unit for reducing the fuel consumption of an engine, wherein the surplus remaining in a fuel tank is provided. An object of the present invention is to provide an engine control device that uses a fuel efficiently to prevent inoperability due to running out of fuel in a fuel tank or the like and secure an operation function.

[0007]

In order to achieve the above object,
The engine control device according to the present invention basically includes an operation state detection unit that detects an operation state of the engine, a remaining fuel amount detection unit that detects a remaining amount of fuel in a fuel tank, and the operation state detection unit. Fuel consumption reducing means for reducing the fuel consumption of the engine based on the output signal from the fuel remaining amount detecting means, wherein the fuel consumption reducing means changes the remaining amount of fuel and the operating state of the engine. Accordingly, the fuel consumption of the engine is reduced by restricting the fuel supply to each cylinder of the engine, or the intake air amount of the engine is reduced according to the remaining amount of fuel and the operating state of the engine. The restriction reduces the fuel consumption of the engine.

[0008] The engine control device of the present invention having the above-described structure improves the fuel use efficiency by using the relationship between the remaining fuel amount and the operating state based on the fuel cut speed or the throttle opening limit value. Even if the remaining fuel amount becomes small, the fuel cut can be performed under as wide an operating condition as possible without limiting the degree of freedom of setting. Further, in a specific aspect of the engine control device of the present invention, the fuel consumption reducing means operates when the engine speed is equal to or higher than a predetermined value, and the predetermined value is determined based on a remaining amount of fuel in the fuel tank. Alternatively, it is calculated from the remaining amount of fuel in the fuel tank and the output torque of the engine.

Further, the fuel consumption reducing means operates when the idle state of the engine continues for a predetermined time,
The predetermined time is calculated from the remaining amount of fuel in the fuel tank or from the remaining amount of fuel in the fuel tank and the outside air temperature. Furthermore, the fuel consumption reducing means is activated when the acceleration state of the vehicle is equal to or higher than a predetermined value, and the predetermined value is determined from the remaining fuel amount in the fuel tank or the remaining fuel amount in the fuel tank. It is calculated from the amount, the acceleration state of the vehicle, and the speed of the vehicle, or operates when the power transmission means of the vehicle does not connect the engine and the drive wheels.

The engine control apparatus of the present invention configured as described above can reduce the fuel consumption not only when the vehicle does not contribute to the movement of the vehicle due to an overdraft, but also when the vehicle speed is high and the acceleration is high. In addition, since the fuel can be cut in accordance with various operating environments, a comfortable operating state can be maintained.

Further, the engine control device includes warning display means for issuing a warning to a driver based on an output signal from the fuel remaining amount detecting means when the remaining amount of fuel in the fuel tank is low. The fuel for the engine is a liquid fuel or a gaseous fuel. With the engine control device of the present invention configured as described above, the driver can be warned in advance of a fuel cut when the remaining fuel amount is low, and it is possible to avoid erroneous recognition as an engine failure.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an engine control device according to the present invention will be described below in detail with reference to the drawings. FIG. 1 shows an overall configuration of an engine system including an engine control device 17 according to each embodiment of the present invention.

The engine 1 is a direct injection engine. An intake valve 2 is provided at the head of each cylinder 1a of the engine 1.
And an exhaust valve 3, and an intake pipe 10
, An exhaust pipe 20 and a spark plug 16 are arranged.
The air taken into each cylinder 1a is taken in from an inlet 6 of an air cleaner 5, passes through an air flow meter 7 which is a means for measuring the amount of intake air, and enters a collector 8 via a throttle valve 4. The air sucked into the collector 8 is
Each cylinder 1a is distributed to each intake pipe 10,
To the combustion chamber in each cylinder 9.

The combustion exhaust gas from the combustion chamber in the cylinder 9 is discharged out of the engine 1 through an exhaust pipe 20 and a catalyst 21. On the other hand, fuel such as gasoline
1 is sucked and pressurized by a fuel pump 12, and the pressurized fuel is regulated to a constant pressure (for example, 3 kg / cm ² ) by a fuel pressure regulator 14, and then is injected into an injector 13.
Is supplied to a fuel system having Then, the fuel is injected into the intake pipe 10 from the injector 13 provided in each cylinder 9, and the injected fuel is ignited by the ignition plug 16 in response to an ignition signal whose voltage is increased by the ignition coil 15.

A control unit (engine control device) 17 includes a signal indicating the intake air flow rate from the air flow meter 7, an angle signal of a crankshaft 19 from a crank angle sensor 18, and a catalyst 21 in an exhaust pipe 20. An exhaust gas detection signal or the like from an A / F sensor 22 provided in front is input.

The signal of the intake air flow rate detected by the air flow meter 7 is processed by a filter processing means or the like (not shown) in the engine control device 17 to be converted into an air amount, and then divided by the engine speed. The air-fuel ratio is stoichiometric (A / F
= 14.7) to calculate the basic fuel injection pulse width per cylinder, that is, the basic fuel injection amount. And the engine control device 17
After performing various fuel amount corrections according to the operating state of the engine based on the basic fuel injection amount to derive the fuel injection amount, the injector 13 is driven to supply fuel to each cylinder 1a.

A / F sensor 22 provided in exhaust pipe 20
From the output signal, it is possible to know the actual air-fuel ratio of the exhaust gas.
A desired air-fuel ratio state can be obtained by adjusting the amount of supplied fuel based on the output signal of the A / F sensor 22 and performing closed loop control.

A fuel level sensor 2 is provided in the fuel tank 11.
The fuel level sensor 23 detects the liquid level of the fuel, and outputs the detection signal to a fuel level detecting means (not shown) of the engine control device 17. The engine control device 17 stores in advance the relationship between the remaining amount of fuel and the liquid level determined in advance according to the shape of the fuel tank 11, and detects the remaining fuel amount based on the output liquid level. be able to. The engine control device 17 includes a vehicle speed sensor, an outside air temperature,
A signal from sensors indicating the acceleration or other driving state is input, and the detection signal is used as driving state detecting means (not shown).
Is calculated and output.

The detection signal of the operating state and the detection signal of the remaining amount of fuel input to the engine control device 17 are supplied to the fuel remaining amount detecting means and the operating state detecting means, and the fuel consumption reducing means (not shown). And the vehicle is moved to the fuel supply facility, so that the remaining fuel is controlled to be used effectively, and the result is used to control the injector 13 via fuel injector driving means (not shown).

The control by the fuel consumption reducing means includes:
There are those that stop and restrict the fuel supply in each cylinder 1a, and those that restrict the amount of intake air in each cylinder 1a. In addition,
Although it is conceivable to stop the ignition operation, it is not employed because unburned fuel may reach the exhaust system and cause the catalyst to generate heat.

The detection signal of the fuel remaining amount sensor 23 is
It is output to a fuel remaining amount warning lamp via the fuel remaining amount detecting means and the fuel remaining amount warning means (not shown), and is turned on when it is detected that the fuel remaining amount is small. The warning light can be turned on and off by the engine control device 17.

FIG. 2 shows the distribution of the fuel consumption rate between the engine speed and the output torque. The fuel efficiency is the amount of fuel consumed to generate a unit engine output. In general, an engine has a small pumping loss, that is, a good fuel efficiency in a high output torque state. However, at an output torque in the vicinity of the fully opened state, the fuel efficiency deteriorates in order to protect the high-temperature engine from the injected fuel by cooling. Therefore, it can be seen from the engine speed that the fuel efficiency tends to deteriorate in the low speed and high speed regions.

Here, the engine control device 1 of the present embodiment
7 enables the vehicle to move to one of the fuel supply facilities and refuel when the remaining amount of fuel in the fuel tank 11 is small, based on the fuel efficiency ratio between the engine speed and the output torque. Therefore, the remaining fuel is used effectively, that is, the fuel use efficiency is increased, and the operation is performed in a state where the fuel efficiency is good and the engine driving is not seriously hindered.

FIG. 3 shows the relationship between the remaining fuel amount and the fuel cut-off speed in the first embodiment of the engine control device 17, and FIG. 4 is a timing chart showing the operating state of FIG. The fuel consumption reducing means of the engine control device 17 of the first embodiment is for stopping the supply of fuel in each cylinder 1a. In FIG. 3, the horizontal axis indicates the fuel remaining amount in the fuel remaining amount detecting means. The vertical axis indicates the number of revolutions to be subjected to a fuel cut, which is a criterion for stopping the fuel supply in each cylinder 1a. Then, the fuel cut speed is compared with the actual engine speed. When the actual engine speed is high, the fuel is cut off and the fuel supply is stopped.

That is, when the remaining fuel amount is large, the fuel cut rotation speed is set to a high value, and as the remaining fuel amount decreases, the fuel cut rotation speed becomes a low value. It is set to the minimum value at which operation can be maintained. By using such a relationship between the remaining fuel amount and the fuel cut rotation speed, even if the remaining fuel amount becomes small, the degree of freedom in setting is not limited, and the fuel cut can be performed under the widest possible operating conditions. Can be.

FIG. 4 is a timing chart of the accelerator opening, the engine speed and the fuel injection in the fuel cut. The behavior of the engine speed and the fuel injection permission / prohibition signal for the accelerator operation when the remaining fuel amount is small. It is shown. First, when the accelerator opening operation is performed in a state where the engine speed is low, the engine speed increases with the engine output. The engine speed is shown in FIG.
Reaches the rotation speed VV which is the target of the fuel cut determined from
The fuel consumption reducing means determines that the fuel supply is prohibited, and the fuel supply to each cylinder 1a is stopped, the engine output decreases, and the engine speed decreases. Thereafter, when the engine rotation speed falls below the fuel cut rotation speed VV, the fuel consumption reduction means determines permission of fuel supply, starts fuel supply to each cylinder 1a, and the engine rotation speed again increases. Thus, the fuel cut rotation speed VV is reached, and thereafter, the above operation is repeated until the accelerator closing operation is performed.

When the accelerator closing operation is performed while the engine speed is near the fuel cut speed VV, the engine output decreases. Then, even when the fuel consumption reduction means permits the fuel supply, the engine speed does not reach the fuel cut speed VV, and the fuel cut is not performed.

Therefore, as shown in FIG. 3, the fuel cut rotation speed with respect to the fuel remaining amount is determined, and when the engine rotation speed is equal to or higher than the fuel cut rotation speed, the fuel cut of each cylinder 1a is performed. When the number is low, the engine can be prevented from running at a high engine speed, the inoperability due to running out of fuel can be prevented, and the driving function can be ensured.

FIG. 5 shows a second embodiment of the engine control device 17. Engine control device 1 of second embodiment
The fuel consumption reduction means 7 stops the fuel supply in each cylinder 1a, and determines the fuel cut rotation speed VV as a factor for determining the fuel remaining amount in the first embodiment and the engine load. They differ in that they are determinants. Note that the engine load and the engine output torque are synonymous parameters.

Each line of WW, XX, YY, ZZ shown in FIG. 5 represents each fuel cut rotation speed with respect to the engine load determined from the remaining fuel amount. Here, the remaining fuel amounts are determined in ascending order. The line ZZ is a line when the remaining fuel amount is sufficient, and in this case, the restriction of the fuel cut does not work. Therefore, there is no inflection point for the engine load. When the amount of remaining fuel becomes small, a fuel cut rotation speed characteristic indicated by a line YY is obtained. That is, when the engine load is high, the fuel is cut even at the same engine speed as when the engine load is low. When the remaining fuel amount is further reduced, the characteristic shifts to the characteristic shown by the line XX, and the fuel is cut at a lower engine speed than the line YY over the entire load range. This is the same for the WW line. The processing after the fuel cut rotation speed is determined is the same as that in FIG.

Therefore, in the present embodiment, the engine high-speed operation of the first embodiment can be avoided, and the high-output torque operation of the engine can also be avoided. FIGS. 6 and 7 show a third embodiment of the engine control device 17. FIG. 6 illustrates the running resistance of a vehicle that consumes the engine output. The horizontal axis indicates the vehicle speed, and the vertical axis indicates the running resistance.

When the engine output and the running resistance are balanced, the vehicle can run at a steady speed under the steady running resistance. The steady running resistance is a resistance when the vehicle runs on a flat road, and includes frictional resistance, air resistance, and the like. The resistance value increases in proportion to an increase in vehicle speed mainly due to air resistance.

If there is a slope on the road while the vehicle is traveling at the steady speed, a slope resistance is added to the vehicle in addition to the steady running resistance, so that a total running resistance is generated. The value of the gradient resistance is determined by the degree of the gradient. Here, when the vehicle has a small amount of fuel as described above and avoids engine high-power operation, the vehicle cannot output an engine output commensurate with the total running resistance. Therefore, the fuel consumption reducing means of the engine control device 17 of the third embodiment shown in FIG. 7 is required.

The fuel consumption reducing means stops the fuel supply in each cylinder 1a, and outputs an engine output commensurate with the total running resistance even when the engine high output operation is avoided. Is what you can do.
FIG. 7 is a flowchart showing the operation of the fuel consumption reduction means, in which calculation processing is performed at predetermined time intervals.

Step 201 performs the fuel cut rotation speed calculation as described with reference to FIG. 3 or FIG. Step 202
Determines whether the fuel cut of each of the cylinders 1a has been performed.
Then, it is determined whether or not the actual engine speed is higher than the fuel cut speed. If the actual engine speed is higher, the process proceeds to step 206, in which the fuel of each cylinder 1a is cut. In step 205, when the actual engine speed is low, the fuel cut is not performed by bypassing step 206.

In step 202, when the fuel is being cut, the routine proceeds to step 203, where the change in vehicle speed is measured or the output of an acceleration sensor is read to detect and calculate the acceleration / deceleration state of the vehicle. In step 204, a correction value of the fuel cut rotation speed is calculated according to the acceleration / deceleration state of the vehicle, which will be described later. Note that the correction value is a correction value for increasing the fuel cut rotation speed when the vehicle is in a predetermined deceleration state, and the correction enables the vehicle to obtain an engine output corresponding to the total running resistance.

Then, in step 205, it is determined whether or not the actual engine speed is higher than the fuel cut speed based on the corrected fuel cut speed. Proceeds to step 206, and performs fuel cut of each cylinder 1a.

FIG. 8 shows an example of the calculation of the correction value of the fuel cut-off speed in the step 204, wherein the horizontal axis represents the acceleration of the vehicle, the right is the upward acceleration, which is the forward direction, and the left is the reverse direction. It represents the acceleration of the descent. The vertical axis is a correction value for the fuel cut speed. As can be seen from FIG. 8, for example, when the acceleration of the vehicle is in the reverse direction, it indicates a stall state of the vehicle due to a large gradient resistance or the like. The engine speed can be increased so that the fuel cut is not performed, the engine can output a large output, and the state of stalling can be avoided.

Further, as shown in FIG. 9, the fuel cut rotation speed correction value in FIG. 8 can be set according to the vehicle speed. This is because the transmission of the vehicle has a lower gear ratio as the vehicle speed is lower, and a higher acceleration can be obtained at a low speed with an equivalent engine output as compared with a high speed. Therefore, by calculating the correction value of the fuel cut rotation speed according to the vehicle speed, more reliable engine control can be performed.

FIG. 10 shows a fourth embodiment of the engine control device 17. The fuel consumption reduction means of the engine control device 17 of the fourth embodiment is for stopping the fuel supply in each cylinder 1a, and is capable of preventing fuel consumption according to the state of the transmission. is there.

That is, the state of the transmission includes a state where the engine and the driving wheels are not fastened, for example, a P range and an N range of an automatic transmission. In this case, the fuel consumed by the engine is not used for the movement of the vehicle. Therefore, when the remaining fuel amount is small, the fuel consumption is reduced to prevent the fuel tank or the like from becoming inoperable due to running out of fuel, and to secure the driving function. . FIG.
0 is set to the engine control device 17 of the third embodiment in FIG.
Step 221 and step 228 are added.

Step 221 determines whether or not the state of the transmission of the vehicle is currently in the N range when obtaining the fuel cut rotation speed. Note that this determination is made in addition to the N range,
The determination includes the P range. If the range is not the N range, the process proceeds to step 222 and thereafter, and the same processing as in FIG. 7 is performed. If the engine is in the N range, the process proceeds to step 228, where the engine speed is sufficient to maintain the idle state, and the fuel cut speed is set to a value slightly higher than the idle speed. Then, the process proceeds to step 226, and the same processing as in FIG. 7 is performed.

Thus, when the transmission as the power transmission means of the engine is not connected to the engine and the driving wheels, the idle state can be maintained, that is, the fuel consumption can be maintained at a minimum. For example, it is possible to prevent the consumption of fuel that does not contribute to the movement of the vehicle due to an emptying or the like.

FIGS. 11 and 12 show a fifth embodiment of the engine control device 17. The fuel consumption reduction means of the engine control device 17 of the fifth embodiment includes:
During idle operation, fuel supply in each cylinder 1a is stopped to prevent fuel consumption.

The idling state of the engine is essentially a state of waiting for the next oscillation to occur. In this case, it is necessary to restart the engine when it is stopped. When the remaining amount is small, the fuel supply in each cylinder 1a is stopped to prevent fuel consumption.

On the other hand, it is not appropriate to stop the fuel supply even when the idle operation state such as the temporary stop is short. Therefore, in this embodiment, when the idle operation has continued for a predetermined time, the fuel supply in each cylinder 1a is stopped. Is to stop.
FIG. 11 is a timing chart of the accelerator opening, the engine speed, and the fuel injection in the fuel cut similarly to FIG. 4, and shows the behavior of the engine speed and the permission of the fuel injection for the accelerator operation in a state where the remaining fuel amount is small. This shows a prohibition signal.

FIG. 11 shows a state in which the accelerator is fully closed from a state where the vehicle is operated with a certain accelerator opening and the engine is in an idle state. At a point in time when a predetermined time TT elapses from the time when the idle state is reached, the fuel consumption reducing means determines the prohibition of fuel supply, stops the fuel supply to each cylinder 1a, and stops the engine. As a condition for returning from the engine stop state, the starter of the engine is operated when the prohibition state has passed the predetermined time UU, and the fuel consumption reduction means determines permission of fuel supply, and the fuel supply to each cylinder 1a is stopped. Done.

FIG. 12 is a flowchart showing the operation of the fuel consumption reduction means. Step 211 is to determine whether the vehicle is currently in the idle state and the vehicle speed is equal to or lower than a predetermined vehicle speed.
It is determined whether the engine can be stopped, and if not, the timer is cleared in step 217. Otherwise, the process proceeds to step 212, where it is determined whether the starter for restart has been operated. When the starter is in the operating state, the above-described operation is performed in step 217. Otherwise, go to step 213,
The timer is counted up. The timer is
Indicates the elapsed time since the engine was able to stop,
When the vehicle is idle and the starter is not operated, the count is incremented. Otherwise, the count is cleared in step 217. Step 214 calculates a comparison value with the elapsed time. This calculation method will be described later. Step 215 determines whether or not the elapsed time is greater than the comparison value. If the elapsed time is long, the fuel consumption reducing means inhibits the fuel injection.
At 6 the fuel cut is performed. Otherwise, the process ends without performing the fuel cut.

Thus, the engine can be stopped by the fuel cut when the idle state continues for a predetermined time, and can be restarted when the starter is operated. FIG. 13 shows an example of the comparison value calculation with the timer elapsed time in step 214, and shows the relationship between the remaining fuel amount and the fuel cut grace time until the fuel cut, and the grace time is set based on the remaining fuel amount. Is done.

That is, when the remaining fuel amount is large, the grace time is set to a large value, and as the remaining fuel amount decreases, the grace time becomes a small value. When the remaining fuel amount is near zero, the operation can be maintained. Set to the minimum limit. By using such a relationship between the remaining amount of fuel and the delay time, it is possible to set the idle elapsed time associated with the remaining amount of fuel.

However, if there is a request having a higher priority than the prevention of fuel consumption due to the engine stop, the engine stop may not be performed. For example, there is a case where the heating or cooling effect by stopping the engine cannot be obtained depending on the outside air temperature, which affects the physical condition of the driver.

FIG. 14 shows the fuel cut delay time obtained from the remaining fuel amount and the outside air temperature. When the outside air temperature is lower than a predetermined value, the fuel cut delay time is set regardless of the remaining fuel amount. To a value that does not affect the driving performance of
As the outside air temperature increases, the fuel cut allowance time is shortened as the remaining fuel amount decreases.

When the outside air temperature rises further, the fuel cut allowance time is extended regardless of the remaining fuel amount. Thus, more comfortable driving can be maintained by considering the outside air temperature in addition to the remaining fuel amount. FIGS. 15 and 16 show a sixth embodiment of the engine control device 17.

The fuel consumption reducing means of the engine control device 17 of the sixth embodiment stops the fuel supply in each cylinder 1a from the acceleration performance of the vehicle. Unlike the case where the fuel supply is stopped based on the parameters directly detected from the driving state, the driving mode of the vehicle is considered.

That is, when the engine is operated under acceleration requiring high output, the consumption of fuel is large. Therefore, when the amount of remaining fuel is small, fuel consumption is avoided at the expense of the acceleration performance of the vehicle. FIG. 15 is a flowchart showing the operation of the fuel consumption reduction means. Steps 231 and 235 are the fuel cut calculations in the fourth embodiment when the N range is continued.

Step 232 calculates the acceleration state of the vehicle subject to the fuel supply restriction, and is the same as step 224 of the fourth embodiment. Step 233 is
The number of cylinders for fuel cut of the multi-cylinder engine is calculated in accordance with the acceleration state of the vehicle to avoid fuel consumption for the cylinders for which fuel cut is performed. Therefore, by performing the fuel cut of the predetermined cylinder, the engine output decreases, and the acceleration of the vehicle decreases. Then, a new number of fuel cut cylinders is calculated from the reduced acceleration, and a desired acceleration can be obtained based on the remaining amount of fuel by repeating this calculation. This calculation method will be described later. In step 234, a fuel cut target cylinder suitable for engine operation is selected and fuel cut is performed according to the determined number of fuel cut cylinders.

FIG. 16 shows a specific example of the method of calculating the number of fuel cut cylinders in step 233. Block 261 determines the basic value of the number of fuel cut cylinders from the vehicle speed and the vehicle acceleration. The numbers in the circles in the figure represent the basic value of the number of fuel cut cylinders. That is, in a region where the vehicle speed is high and the acceleration is high, a large engine output is required. Therefore, the fuel cut is set by increasing the number of cylinders.

The block 262 calculates a coefficient for calculating the number of fuel cut cylinders according to the remaining amount of fuel. When the coefficient is large, the number of fuel cut cylinders increases, and when the coefficient is small, the number of fuel cut cylinders decreases. When the coefficient is 0,
The fuel cut is not performed.

That is, when the remaining fuel amount is large, the coefficient is set to a large value, and as the remaining fuel amount decreases, the coefficient becomes a small value. When the remaining fuel amount is near 0, the operation can be maintained. Set to the minimum limit. Then, the number of fuel cut cylinders is calculated from the product of the coefficient and the basic value of the number of fuel cut cylinders.

By calculating the number of fuel cut cylinders as described above, it is possible to cut the fuel under as wide an operating condition as possible, even if the remaining fuel amount becomes small. 17 to 21 show a seventh embodiment of the engine control device 17. FIG. 17 shows the relationship between the accelerator opening and the throttle opening, FIG. 18 shows the relationship between the throttle opening and the engine output, and FIG. 19 shows the relationship between the throttle opening and the intake air amount per intake. FIG. 20 shows the relationship between the remaining amount of fuel in the remaining fuel amount detecting means and the throttle opening limit value serving as a criterion for determining the amount of intake air in each cylinder 1a, and FIG. A method of limiting the acceleration of the vehicle due to the fuel supply amount by operating the opening degree is shown.

The PP, QQ, RR, SS shown in FIG.
Are the throttle opening determined from the accelerator opening. Here, the remaining fuel amounts are determined in ascending order.
The SS line is a line when the remaining fuel amount is sufficient, and in this case, the restriction of the fuel cut does not work. Therefore, there is no inflection point for the accelerator opening. When the remaining amount of fuel is low, the high opening operation of the throttle indicated by the line RR is prohibited. That is, at the high throttle opening, fuel cut is performed even at the same engine speed as the low throttle opening. When the remaining fuel amount is further reduced, Q
The characteristic shifts to the characteristic shown by the line Q, and the fuel cut is performed at a lower engine speed than the line RR over the entire opening. This is the same for the PP line. As a result, it is possible to prohibit driving with a high engine output and to avoid a driving state in which fuel consumption is large.

FIG. 18 shows the relationship between the throttle opening and the engine output. In the region where the engine speed is low, the maximum output at that speed can be obtained even with a small throttle opening, but in the region where the engine speed is high,
A large throttle opening is required to obtain the maximum output at that rotational speed. This means that the engine output is represented by the product of the engine speed and the engine output torque. The engine output torque is substantially proportional to the intake air amount per intake, the throttle opening and the intake air amount per intake. Are in a relationship as shown in FIG. Since the opening area of the throttle valve 4 and the intake air amount are both normalized by the engine speed, the parameters shown in FIG. 19 are used to accurately correlate the engine output with the throttle opening. Achieved by:

Therefore, the fuel consumption reducing means of the engine control device 17 of the seventh embodiment is different from the one in which the supply of fuel in each cylinder 1a is stopped and restricted as it is from the operation state of various sensors. Output a signal from the engine control device 17 to adjust the opening degree,
FIG. 2 restricts the amount of intake air in each cylinder 1a.
At 0, the throttle opening limit value is compared with the actual throttle opening, and when the actual throttle opening is large, fuel cut is performed.

That is, when the remaining fuel amount is large, the throttle opening limit value is set to a large value. As the remaining fuel amount decreases, the throttle opening limit value becomes smaller, and the remaining fuel amount becomes zero. In the vicinity, it is set to the minimum value at which operation can be maintained. By using such a relationship between the remaining fuel amount and the throttle opening limit value, even if the remaining fuel amount becomes small, it is possible to perform the fuel cut under as wide an operating condition as possible.

FIG. 21 shows an example in which the method of limiting the acceleration of the vehicle by the fuel supply amount shown in FIG. 16 is performed by operating the throttle opening. Block 253 corresponds to block 261 in FIG. 16, and obtains the maximum filling efficiency basic value from the speed and acceleration of the vehicle. Here, the charging efficiency refers to a ratio of an actual intake air amount to a maximum intake air amount of one intake air.

Block 254 corresponds to block 26 in FIG.
This corresponds to 2, and a smaller coefficient is given as in the case of FIG. 16 as the remaining fuel amount decreases, thereby obtaining the maximum filling rate according to the remaining fuel amount and the vehicle acceleration. Block 2
Reference numeral 51 determines the original value of the opening area targeted by the throttle valve 4 with respect to the accelerator opening. This is a relationship between the accelerator opening determined by the mechanical characteristics of the throttle valve 4 and the throttle opening area, and realizes FIG. By dividing the result by the engine speed, FIG.
The parameter on the horizontal axis is obtained.

A block 252 shown in FIG. 20 is used to determine a filling rate according to the accelerator opening from the above parameters. Block 255 compares the fill rate with the maximum fill rate and limits the fill rate with the maximum fill rate. In addition,
In the following processing, a target throttle opening can be obtained by performing reverse processing in the order of block 252 and block 251, and the throttle valve 4 is driven by the engine control device 17. As a result, the throttle valve 4 is driven so as to limit it within the maximum filling rate,
It is possible to prevent operation failure due to running out of fuel, and to secure a driving function.

FIG. 22 shows an eighth embodiment of the engine control device 17, and is an operation flowchart of the fuel remaining amount detection means and the warning display means. The engine control device 17 allows the driver to recognize that the fuel consumption reducing means is in an operating state when the remaining fuel amount is low, by the fuel remaining amount detecting means and the warning display means. It is. This is because, when the fuel cut of the embodiment is performed, the driver cannot erroneously recognize that the engine is defective because the intended engine output cannot be obtained. Therefore, the warning lamp is turned on when the fuel consumption reducing means is in the operating state.

In step 241, it is determined whether or not the remaining fuel amount is a predetermined value required to turn on the warning light. The predetermined value is equal to or larger than the remaining fuel amount at which the fuel cut can occur. If the remaining fuel amount is large, step 244
Then, the process goes to step 242 to turn off the warning light. If the remaining fuel amount is low, the process proceeds to step 242, and the blinking cycle of the warning light is obtained from the remaining fuel amount. The blinking cycle causes the driver to feel that the severity is low when the blinking interval of the warning light is slow, and that the severity is high when the blinking sense is fast.
Step 243 is equivalent to step 244 or step 242
Operate each warning light from the result of. As a result, the driver can be warned in advance of a fuel cut when the remaining fuel amount is low, and can avoid a feeling of strangeness of the driver.

Although some embodiments of the control device of the present invention have been described in detail, the present invention is not limited to the above-described embodiments, but departs from the spirit of the invention described in the appended claims. Various changes can be made in the design without departing from the scope of the invention. That is, the above embodiments can be combined, or each element of the above embodiments can be combined. For example, the fuel cut can be realized by comparing the target value of the engine speed limit with the actual engine speed, and appropriately restricting the charging efficiency, the target throttle opening, or a parameter therebetween.

Further, each of the above embodiments is an engine using a liquid as fuel such as gasoline, but may be an engine using a gas such as compressed natural gas or liquefied propane gas as fuel. Rather, gaseous fuel is effective because the energy density per unit volume is lower than that of liquid, so that the operable range tends to be short. In this case, the remaining fuel amount detecting means is a means corresponding to the gaseous fuel.

[0072]

As can be understood from the above description, the engine control device according to the present invention can prevent operation failure due to running out of fuel, and can ensure normal engine operation functions as much as possible.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an engine including an engine control device according to an embodiment.

FIG. 2 is a diagram showing a distribution of a fuel efficiency ratio between an engine speed and an output torque.

FIG. 3 is a diagram showing a relationship between a fuel remaining amount and a fuel cut rotation speed in the first embodiment of the engine control device of FIG. 1;

FIG. 4 is a timing chart showing the operation state of FIG.

FIG. 5 is a diagram showing a second embodiment of the engine control device of FIG. 1;

FIG. 6 is a diagram showing a third embodiment of the engine control device of FIG. 1;

FIG. 7 is a flowchart showing the operation of the fuel consumption reduction means of FIG. 6;

FIG. 8 is a view showing an example of a correction value calculation of the fuel cut rotation speed in FIG. 6;

FIG. 9 is a diagram showing an example of a calculation of a correction value of the fuel cut rotation speed in FIG. 6;

FIG. 10 is a diagram showing a fourth embodiment of the engine control device of FIG. 1;

FIG. 11 is a timing chart showing an operation state of a fifth embodiment of the engine control device of FIG. 1;

FIG. 12 is a flowchart showing the operation of the fuel consumption reduction means of FIG. 11;

FIG. 13 is a diagram showing an example of a comparison value calculation with a timer elapsed time in FIG. 12;

FIG. 14 is a diagram illustrating an example of a comparison value calculation with a timer elapsed time in FIG. 12;

FIG. 15 is a diagram showing a sixth embodiment of the engine control device of FIG. 1;

FIG. 16 is a flowchart showing the operation of the fuel consumption reduction means of the fifth embodiment of the engine control device of FIG. 1;

FIG. 17 is a diagram showing a relationship between an accelerator opening and a throttle opening in a seventh embodiment of the engine control device of FIG. 1;

FIG. 18 is a diagram showing the relationship between the throttle opening and the engine output in FIG. 17;

FIG. 19 is a diagram showing the relationship between the throttle opening and the amount of intake air per intake air in FIG. 17;

FIG. 20 is a diagram showing the relationship between the remaining fuel amount and the throttle opening limit value serving as a criterion for limiting the intake air amount in each cylinder 1a in the remaining fuel detecting means in FIG. 17;

FIG. 21 is a diagram showing a method of restricting the acceleration of the vehicle by the fuel supply amount by operating the throttle opening in FIG. 17;

FIG. 22 is an operation flowchart of a fuel remaining amount detection unit and a warning display unit in an eighth embodiment of the engine control device of FIG. 1;

[Explanation of symbols]

 Reference Signs List 1 engine 1a cylinder 2 electromagnetic intake valve 3 electromagnetic exhaust valve 4 throttle valve 5 air cleaner 6 intake port 7 air flow meter 8 collector 9 cylinder 10 intake pipe 11 fuel tank 12 fuel pump 13 injector 14 fuel pressure regulator 15 ignition coil 16 ignition plug 17 Engine control device 18 Crank angle sensor 19 Crankshaft 20 Exhaust pipe 21 Catalyst 22 A / F sensor 23 Fuel remaining amount sensor

 ────────────────────────────────────────────────── ─── Continued on front page (72) Inventor Masahiro Sato 2477 Takaba, Hitachinaka-shi, Ibaraki F-term in Hitachi Car Engineering Co., Ltd. (Reference) 3G084 AA00 AA03 BA05 BA13 BA33 CA00 CA03 CA04 DA00 DA28 EA11 EC03 FA00 FA02 FA05 FA06 FA32 FA33 3G301 HA01 HA06 HA22 JB00 JB10 KA00 KA07 KA08 KA09 LA03 LB01 MA01 MA11 MA24 NA08 NB02 NB11 ND01 NE14 NE17 NE23 PA01Z PA10Z PA14Z PB00Z PD02A PD02Z PE01Z PE03Z PE06Z PF01Z PF02Z PF01Z PF02Z

Claims (11)

[Claims] 1. An operating state detecting means for detecting an operating state of an engine, a fuel remaining amount detecting means for detecting a remaining amount of fuel in a fuel tank, and the operating state detecting means and the fuel remaining amount detecting means. An engine control device comprising: a fuel consumption reducing unit that reduces the fuel consumption of the engine based on the output signal of the engine, wherein the fuel consumption reducing unit includes: An engine control device for reducing fuel consumption of the engine by restricting fuel supply to each cylinder of the engine. 2. An operating state detecting means for detecting an operating state of an engine, a remaining fuel amount detecting means for detecting a remaining amount of fuel in a fuel tank, the operating state detecting means and the remaining fuel amount detecting means. An engine control device comprising: a fuel consumption reducing unit that reduces the fuel consumption of the engine based on the output signal of the engine, wherein the fuel consumption reducing unit includes: An engine control device, wherein the amount of fuel consumed by the engine is reduced by limiting the amount of intake air of the engine. 3. The fuel consumption reducing means operates when an engine speed is equal to or higher than a predetermined value, and the predetermined value is calculated from a remaining amount of fuel in the fuel tank. Item 3. The engine control device according to item 1 or 2. 4. The engine control device according to claim 3, wherein the predetermined value is calculated from a remaining amount of fuel in the fuel tank and an output torque of an engine. 5. The fuel consumption reducing means is activated when the engine has been idle for a predetermined time, and the predetermined time is calculated from a remaining amount of fuel in the fuel tank. The engine control device according to claim 1. 6. The engine control device according to claim 5, wherein the predetermined time is calculated from a remaining amount of fuel in the fuel tank and an outside air temperature. 7. The fuel consumption reducing device according to claim 1, wherein the fuel consumption reducing device operates when the power transmission device of the vehicle does not connect the engine to the driving wheels. Engine control device. 8. The fuel consumption reducing means is activated when an acceleration state of the vehicle is equal to or higher than a predetermined value, and the predetermined value is calculated from a remaining amount of fuel in the fuel tank. The engine control device according to any one of claims 1 to 7. 9. The engine control device according to claim 8, wherein the predetermined value is calculated from a remaining amount of fuel in the fuel tank, an acceleration state of the vehicle, and a speed of the vehicle. . 10. The engine control device includes warning display means for issuing a warning to a driver when the remaining amount of fuel in the fuel tank is low, based on an output signal from the fuel remaining amount detecting means. 2. The method according to claim 1, wherein
The engine control device according to any one of claims 9 to 9. 11. The fuel for the engine is a liquid fuel or a gaseous fuel.
The engine control device according to claim 1.