JP2508762B2 - Output control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to an output control device for an internal combustion engine that generates power using a plurality of types of fuel such as gasoline and methanol.

(Prior Art) Generally, the engine of a practically used automobile is divided into a gasoline engine and a diesel engine.
Recently, with the desire to develop energy-saving and low-pollution engines, engines using methanol or the like other than gasoline and light oil as fuel have been considered. This methanol engine
Although there is no structural change to the gasoline engine, the air-fuel ratio, fuel injection timing, ignition timing, etc. need to be changed significantly, and high-precision system control is required.

On the other hand, there are various types of engine control currently in use, which are electronically controlled, and optimal control can be performed under all possible conditions. Therefore, the methanol engine can be controlled by applying this electronic control system.

Therefore, by utilizing the above electronic control system, it is expected that an engine that can use both fuels of gasoline and methanol will be put into practical use in the future. In this case, the control target values such as the air-fuel ratio and the ignition timing may be changed by the control device between when gasoline is used and when methanol is used.

(Problems to be Solved by the Invention) However, when gasoline and methanol are switched as described above, or fuels mixed with each other and having different mixing ratios are switched, and combustion is performed in an internal combustion engine, it is Since there is a difference in the output of the internal combustion engine when using methanol, there is the problem of poor drivability during fuel switching.

In other words, when 100% gasoline fuel and 100% methanol fuel are used, for example, the shaft output at the same throttle opening and the same engine speed is about 10% higher for methanol than gasoline, In particular, if the supplied fuel switches from gasoline to methanol during acceleration, the driver suddenly feels that acceleration has become stronger, and conversely, when switching from methanol to gasoline, the driver suddenly feels that acceleration has weakened. It will be.

Therefore, when switching the fuel, for example, when switching from gasoline to methanol, it is conceivable to set the ignition timing, the compression ratio and the like to values not suitable for methanol to suppress a sudden increase in output and prevent deterioration of drivability. But,
If the engine control such as the ignition timing control or the compression ratio control becomes more complicated, not only the cost will increase but also the reliability will decrease.

The present invention has been made in view of the above problems,
An object of the present invention is to provide an output control device for an internal combustion engine, which can prevent deterioration of drivability at the time of switching fuel without increasing cost and decreasing reliability.

[Configuration of Invention] (Means and Actions for Solving Problems) That is, an output control device for an internal combustion engine according to the present invention is
An alternator driven by the rotational power of the output shaft of the internal combustion engine to perform a power generation operation, and a fuel sensor provided in the fuel supply path to the combustion chamber of the internal combustion engine to detect the composition of the supplied fuel,
The alternator load control means for varying the electric load of the alternator according to the composition detection result of the supplied fuel by the fuel sensor is provided, and the power load applied to the engine output shaft is changed.

(Embodiment) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows its configuration. In FIG. 1, 11 is an engine body, 12 is a fuel injection device provided on the intake side of the combustion chamber of the engine body 11, and 13 is an exhaust pipe provided on the exhaust side. , 14a to 14d are spark plugs provided for each cylinder, 15 is an ignition device thereof, the fuel injection device 12 has an injection timing control signal, and the ignition device 15 has an ignition timing control signal. It is given from the control unit 16 which operates based on the sensor signal.

That is, the vaporized fuel sent from the fuel tank 17 to each cylinder combustion chamber in the engine body 11 via the fuel injection device 12 is
It is ignited, exploded, and burned by the ignition operation of the spark plugs 14a to 14d, and becomes exhaust gas, which is discharged to the outside from the exhaust pipe 13.

Here, a fuel sensor 18 is provided in the fuel supply path between the fuel injection device 12 and the fuel tank 17. The fuel sensor 18 detects the composition of the fuel supplied to the engine side (for example, gasoline, methanol, or a mixture ratio thereof), and the fuel composition detection signal from the fuel sensor 18 is supplied to the control unit 16. It

On the other hand, the rotational power of the crank pulley 21 attached to the crank shaft 19 of the engine body 11 together with the cooling fan 20 is transmitted through the belt 22 to the fan pulley 23a of the alternator 23.
Is transmitted to The alternator 23 is driven by the rotational power of the engine body crankshaft 19 to generate electric power, and the alternator 23 is provided with a regulator 24 to stabilize the fluctuating generated voltage. Then, the battery 25 is connected to the alternator 23 and the generated voltage is charged.

The field coil voltage of the alternator 23 can be changed by a control signal from the control unit 16, and the field coil voltage variable control signal of the alternator 23 is output based on the composition data of the supplied fuel detected by the fuel sensor 18. To be done. Here, for example, if the field coil voltage of the alternator 23 is reduced, the electrical load is reduced, so that the mutual interference with the stator coil is weakened, and the load applied to the crankshaft 19 of the engine body 11 is reduced.

FIG. 2 shows an example of the circuit of the alternator 23, where L _F is a field coil, L _S is a stator coil, and P _W Tr is a power transistor of the regulator 24.
When the key switch KS is closed, the charge lamp CL and resistance R ₆
→ Field coil L _F → The initial excitation current flows through the regulator 24, and at the same time the lamp CL lights up. When the engine body 11 starts and the alternator 23 generates power, the voltage at the terminal L rises and the voltage across the lamp CL becomes equal,
CL goes out. At the same time, the field current is supplied by the triode diode D _T.

That is, in the output control device for an internal combustion engine having the above-described configuration, the fuel tank 17 is, for example, 100% gasoline fuel (G10
0) and 100% methanol fuel (M100) are stored in a state of being separated into upper and lower two layers (top: gasoline, bottom: methanol) due to the difference in specific gravities.

First, when methanol is sucked from the fuel tank 17 and sent into each cylinder combustion chamber in the engine body 11 via the fuel injection device 12, spark plugs 14a to 14d for each cylinder are preset in the control unit 16, respectively. The ignition is driven in synchronization with the ignition timing for methanol fuel. Then, the methanol fuel sent into the combustion chamber is ignited, exploded, and burned, and rotational power is generated on the crankshaft 19.

Here, as shown in FIG. 3, the methanol (M10
The state of the engine output when the methanol fuel is consumed and the fuel is switched to the gasoline fuel (G100) at a certain time A during the acceleration running by burning 0) will be described below.

When the methanol in the fuel tank 17 is exhausted and gasoline is sucked instead, the changeover from methanol to gasoline is detected by the fuel sensor 18 and the control unit 16 is notified. Then, the control unit 16 calculates the time Tl at which the injected fuel switches from methanol to gasoline based on the predetermined distance l from the fuel sensor 18 to the fuel injection device 12, and corresponds to this switching time Tl. The alternator
23 field coil voltage is controlled to fall. By doing this, at the time A when the combustion fuel is switched from methanol to gasoline, that is, when the engine output decreases by about 10%, the load of the alternator 23 on the crankshaft 19 of the engine body 11 becomes light, and as shown by the solid arrow a. Moreover, the substantial reduction in output is suppressed to a small amount. After that, the control unit 16 gradually recovers the field coil voltage of the alternator 23 to a specified level. Although this eventually reduces the engine output due to the use of gasoline fuel G100,
The shock due to the output difference will be greatly alleviated.

On the other hand, contrary to the above case, the state of the engine output when the fuel supplied to the engine combustion chamber is switched to methanol (M100) at a certain time point A during acceleration running by burning gasoline (G100) It will be described below.

When methanol is sucked out of the fuel tank 17 instead of gasoline, the switching from gasoline to methanol is detected by the fuel sensor 18 and the control unit 16 is notified.
Then, the control unit 16 calculates the time Tl at which the injected fuel switches from gasoline to methanol based on the predetermined distance l from the fuel sensor 18 to the fuel injection device 12, and this switching time Tl is counted. Until then, the field coil voltage of the alternator 23 is gradually lowered.
In this way, the load of the alternator 23 on the crankshaft 19 of the engine body 11 becomes gradually lighter at the point A when the combustion fuel is switched from gasoline to methanol, that is, before the engine output sharply increases by about 10%, and the broken line Arrow b
As indicated by, the engine output gradually increases in advance. Then, the control unit 16 controls the combustion fuel switching time Tl.
Is counted, the field coil voltage of the alternator 23 is immediately restored to the specified level. At this time, since the load of the alternator 23 on the crankshaft 19 becomes large again, the engine output is increased in advance corresponding to the time Tl. It will be canceled and the shock due to the output difference will be greatly alleviated.

Therefore, according to the output control device of the internal combustion engine having the above configuration, when the fuels having different combustion outputs are switched,
Since the steep output difference can be moderated, it is possible to prevent the drivability from deteriorating at the time of switching the supply fuel of an automobile powered by the dual fuel internal combustion engine.

In the above embodiment, the load of the alternator 23 itself is reduced by reducing the field coil voltage of the alternator 23, but in order to reduce the alternator load, for example, the regulator voltage by the regulator 24 is reduced. You may comprise.

Further, in the above embodiment, the engine output state at the time of fuel switching during acceleration traveling has been described, but during constant speed traveling, deceleration traveling, and any other traveling state,
The same effect as above can be obtained.

Further, although the fuels used in the above-mentioned examples were 100% gasoline fuel and 100% methanol fuel, the stepwise output difference when using two fuels having different mixing ratios, respectively, is the same as above. Can be relaxed. In this case, the fuel sensor 18 may detect gasoline rich and methanol rich to perform the output control.

[Effects of the Invention] As described above, according to the present invention, an alternator that is driven by the rotational power of the output shaft of an internal combustion engine to generate electric power, and a composition of the supplied fuel that is provided in a fuel supply path to the combustion chamber of the internal combustion engine are detected. And a alternator load control means for varying the electric load of the alternator according to the composition detection result of the supplied fuel by the fuel sensor.
Since it is configured to change the power load on the engine output shaft, it is possible to prevent deterioration of drivability at the time of fuel switching without performing complicated engine control and increasing cost and lowering reliability. An engine output control device can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing an output control device for an internal combustion engine according to an embodiment of the present invention, FIG. 2 is a circuit diagram showing an example of the alternator in FIG. 1, and FIG. 3 is an output control device for the internal combustion engine. FIG. 6 is a diagram showing an output control operation according to FIG. 11 ... Engine body, 12 ... Fuel injection device, 14a-14d ...
… Spark plug, 16 …… control unit, 17 …… fuel tank, 18…
… Fuel sensor, 19 …… Crankshaft, 21 …… Crank pulley, 22 …… Belt, 23 …… Alternator, 23a …… Fan pulley, 24 …… Regulator, 25 …… Battery.

Claims (1)

(57) [Claims] 1. An output control device for an internal combustion engine, which uses a plurality of types of fuel to generate power, and an alternator driven by rotational power of the output shaft of the internal combustion engine to generate electric power, and a fuel for a combustion chamber of the internal combustion engine. A fuel sensor provided in the supply path for detecting the composition of the supplied fuel, and an alternator load control means for varying the electric load of the alternator according to the result of detection of the composition of the supplied fuel by the fuel sensor. Output control device for internal combustion engine.