JPH025744A - Device for distinguishing using fuel of engine - Google Patents

Abstract

PURPOSE:To distinguish the type of a using fuel by detecting the width of variation of engine speed at the time of idling. CONSTITUTION:At the time of the idling operation of an engine 1, a controller 9 calculates an actual width of variation based on an engine speed signal which is fed back from a distributor 18. The actual width of variation is collated with the map of a reference width of variation to judge whether the fuel in present use is high-octane gasoline or regular gasoline. Thereby, when, e.g., high-octane gasoline is in use, an ignition signal and a fuel injection quantity are regulated to be proper values set in a high-octane gasoline map to control ignition timing and air-fuel ratio. Thus, since the types of using fuel can be distinguished in an ordinary using zone of idling operation, etc. in which no knocking occurs, even when the fuel fed to the engine 1 is changed, the control of ignition timing and air-fuel ratio can be favorably carried out at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a device for determining the type of fuel used in a motor vehicle engine, particularly a gasoline engine.

(Prior art) As fuels used in gasoline engines for automobiles, the market has grown in the coexistence of regular gasoline, which is used for gasoline engines, and so-called high-octane gasoline, which has a higher octane number and is mainly used in high-output engines. Currently, it is supplied to

On the other hand, with the remarkable development of electronics in recent years, this type of gasoline engine for automobiles tends to be subject to severe control based on preset control parameters in order to improve exhaust performance and fuel efficiency. In this case, the combustion characteristics differ depending on the fuel used, so the manufacturer has a so-called regular specification engine with a compression ratio determined for regular gasoline, and a so-called high-octane specification engine with a higher compression ratio. In addition to setting appropriate control parameters for each engine, fuel is also specified for each engine.

However, despite the fact that the fuel to be used is specified for each engine, in reality, due to user requests or mistakes, for example, high-octane gasoline is refueled in a regular specification engine, fuel other than the specified fuel is used. There is a concern that it may be supplied to the engine and cause engine trouble.

To deal with this, there are attempts to control engines with a single specification with different characteristics depending on the fuel used. As an example of such control, for example, Japanese Patent Application Laid-Open No. 58-570
According to Publication No. 72, the appropriate ignition timing corresponding to the octane number of the fuel is set and stored in advance, and the engine is equipped with a knock sensor that detects knocking due to detonation, etc., and the engine is used based on the determination result of the signal from this knock sensor. A configuration is disclosed in which the fuel is determined and the ignition timing set for the fuel used is selected.

(Problem to be Solved by the Invention) However, with the method of determining the fuel used by the engine using a knock sensor as described in the above publication, the type of fuel can only be determined within a limited range of engine operating conditions. The disadvantage is that it cannot be done. In other words, in this type of gasoline engine, knocking occurs only in very limited cases, such as when the engine is operated at low rotational speeds and high loads. Therefore, since the phenomenon of knocking is almost never observed under normal usage conditions such as idling and light load conditions, it is not only impossible to determine the type of fuel in such areas, but also knocking. In the worst case scenario, the engine is operated for an extended period of time with control parameters set for a different fuel than the one currently being used, which could have an undesirable effect on exhaust performance and fuel efficiency. It is conceivable that it may cause

By the way, when this type of engine is operated with regular gasoline and when it is operated with high-octane gasoline, the atomization property of high-octane gasoline is worse than that of regular gasoline. As shown in (B), the test results showed that there was a difference in the rotational fluctuation range during idling. In other words, when an engine with the same specifications is run at idle under the same conditions with only the fuel changed, in the case of regular gasoline, the result will be as shown in Figure (A).
As seen in Figure (B), the actual fluctuation width ΔN with respect to the target engine speed No falls within the range of the arbitrarily set standard fluctuation width ΔNo, whereas in the case of high-octane gasoline, as seen in Figure (B) In addition, the actual fluctuation range, 4jN, may exceed the reference fluctuation range ANO.

Therefore, the present invention focuses on the fluctuations in the engine speed during idling that occur when the fuel used is changed, and has developed a method for determining the type of fuel used in normal use, such as idling operation that does not cause knocking. An object of the present invention is to provide a device for determining the fuel used in an engine.

(Means for Solving the Problems) That is, as shown in FIG. 1, the engine fuel determination device according to the present invention allows the control means A to control the engine B with different characteristics depending on the fuel used. In this configuration, there is provided a rotational variation range detection means C for detecting the variation range of the rotational speed of the engine B during idling, and a use for determining the type of fuel used based on the variation range detected by the detection means C. Equipped with fuel discrimination means.

(Function) According to the above configuration, the type of fuel used can be reliably determined by the fuel used discrimination means based on the difference in the fluctuation width of the engine speed during idling detected by the rotation fluctuation range detection means C. It turns out. Then, the control means A that receives this determination result controls the engine B with characteristics according to the fuel used, so that, for example, the fuel supplied to the engine B is changed when performing ignition timing control, air-fuel ratio control, etc. will always be performed well.

(Example) Examples of the present invention will be described below.

As shown in FIG. 2, the engine 1 includes a cylinder head 2.
An intake passage 5 that communicates with the combustion chamber 4 via the intake valve 3 of the cylinder head 2 and an exhaust passage 7 that communicates with the combustion chamber 3 via the exhaust valve 6 of the cylinder head 2 are provided. One intake passage 5
A throttle valve 8 is disposed at the throttle valve 8, and an injector 10 controlled by a controller 9 is disposed at a position downstream of the throttle valve 8 and close to the combustion chamber 4. Note that a throttle opening sensor 11 is attached to the above-mentioned throttle valve 8.
The opening of the throttle valve 8 detected by the throttle opening sensor 11 is sent to the controller 9 as an electric signal.
It is designed to be input to .

Further, a catalytic exhaust purifier 12 is disposed in the other exhaust passage 7, and an 02 sensor 13 for detecting the oxygen concentration contained in the exhaust gas is installed upstream of the exhaust purifier 12. An electrical signal indicating the residual oxygen concentration detected by the 02 sensor 13 is also input to the controller 9. Note that the cooling water jacket 14 provided in the engine 1 is provided with a water temperature sensor 15 for detecting the cooling water temperature, and the cooling water temperature detected by the water temperature sensor 15 is input to the controller 9 as an electrical signal. be done.

An igniter 16 is connected to the controller 9, and an ignition signal outputted from the igniter 16 is directed to a spark plug 17 installed so as to pass through the cylinder 2 and into the combustion chamber 3. Utah 1
8. As is well known, the engine speed is picked up from the distributor 18, and this engine speed is fed back to the controller 9 as an electrical signal.

In the controller 9, parameters for controlling the ignition timing and air-fuel ratio, which are set in advance to be suitable when regular gasoline or high-octane gasoline is used, are stored in the form of a map.

In addition, the controller 9 is set to a value that is larger than the maximum rotational fluctuation width at idle when regular gasoline is used, and smaller than the maximum rotational fluctuation width that can occur when high-octane gasoline is used. The reference fluctuation width ΔN0 is similarly mapped and stored.

That is, the controller 9 is connected to the distributor 1
By calculating the actual fluctuation range ΔN based on the rotation speed signal fed back from 8 and comparing this actual fluctuation range, 6N, with the map of the reference fluctuation range aNO,
Determines whether the fuel currently being used is high-octane gasoline or regular gasoline. For example, when high-octane gasoline is used, the controller 9 comprehensively determines the state of the engine 1 based on the engine speed, etc.
The ignition timing is controlled by adjusting the ignition signal output to the igniter 16 to the appropriate value set in the map for high-octane gasoline.
Based on the residual oxygen concentration detected by the sensor 13,
The air-fuel ratio is controlled by adjusting the amount of fuel injected from the injector 10 to an appropriate value similarly set in the map for high-octane gasoline.

Next, the control operation of the controller 9 will be explained according to the flowchart of FIG.

That is, when the program starts, the controller 9 first detects the throttle opening sensor 11 in step S+.
The throttle opening sensor 11 determines whether the engine 1 is in an idling state by inspecting the signal from the throttle opening sensor 11.
Wait for the idle signal to be output from. When the controller 9 confirms the idle operation of the engine 1 based on the signal from the throttle opening sensor 11, it executes step S2, and calculates the rotational fluctuation range of the engine 1 based on the rotational speed signal fed back from the distributor 18. At the same time, in step S3, the cooling water temperature of the cooling water jacket 14 output from the water temperature sensor 15 is input.

Next, the controller 9 uses the stored reference fluctuation range AN.
After comparing o with the actual fluctuation range ΔN calculated in step S2, it is determined whether the actual fluctuation range ΔN is larger than the reference fluctuation range ΔNo (steps S4 and S5). In addition, when the water temperature of the cooling water jacket 14 increases during the idling period, the fluctuation range of the engine speed during idling tends to increase. The reference fluctuation range ΔNo is corrected in advance based on the cooling water temperature input in .

Then, in step S, the controller 9 sets the actual variation range ΔN to the reference variation range ΔN. If it is determined that it is larger than , select a pre-memorized map for high-octane gasoline,
Based on this high-octane gasoline map, step S6
In addition to executing predetermined ignition timing control in step s
A predetermined air-fuel ratio control is executed in the second step.

On the other hand, the controller 9 controls the actual fluctuation range Δ in step s5.
If it is determined that N is smaller than the reference fluctuation range ΔNO, a map for regular gasoline is selected, and predetermined ignition timing control and air-fuel ratio control are respectively executed based on this map for regular gasoline (step S,
,S,).

In this way, the engine speed during idling is within the reference variation range AN preset in the controller 9. When the engine speed fluctuates more than ΔN, it is determined that high-octane gasoline is being used, and when the engine speed fluctuates within a range that does not exceed the standard fluctuation range ΔN, it is determined that regular gasoline is being used. The range in which the fuel used can be determined is greatly expanded, and the engine 1 can be controlled with characteristics according to the fuel used even in idle or low load conditions.

(Effects of the Invention) As described above, according to the present invention, the type of fuel being used can be reliably determined by the fuel determining means based on the difference in the fluctuation range of the engine speed during idling detected by the revolution fluctuation range detecting means. This has the effect of being done. Then, the control means that receives this discrimination result will control the engine with characteristics according to the fuel used, so that, for example, ignition timing control and air-fuel ratio control will always be effective even if the fuel supplied to the engine changes. It has the advantage of being carried out.

[Brief explanation of the drawing]

Fig. 1 is a functional block diagram of the present invention, Figs. 2 and 3 show embodiments of the present invention, Fig. 2 is an engine control system diagram, and Fig. 3 shows processing operations executed by the controller. It is a flowchart figure shown. Figures 4(A) and 4(B) are for explaining the basic principle of the present invention, and Figure 4(A) is a characteristic diagram showing the change in engine speed over time when regular gasoline is used as fuel. , the same figure (
B) is a characteristic diagram showing the change in engine speed over time when high-octane gasoline is used. DESCRIPTION OF SYMBOLS 1... Engine, 9... Rotation fluctuation range detection means, fuel used discrimination means (controller).

Claims (1)

[Claims] (1) A device for determining the fuel used in an engine, which performs predetermined control with different characteristics depending on the fuel used, comprising a rotation fluctuation range detection means for detecting the fluctuation range of the rotation speed when the engine is idling; 1. A fuel usage determination device for an engine, comprising fuel usage determination means for determining the type of fuel used based on the fluctuation range detected by the detection means.