JPS6223545A - Electronic fuel injection control device - Google Patents

Abstract

PURPOSE:To avoid unstable action of an engine due to a vapor-lock, by providing an injection quantity increase correcting means which increases only in a fixed proportion for a predetermined period a fuel injection quantity calculated by an injection quantity calculating means. CONSTITUTION:An injection quantity calculating means calculates a fuel injec tion quantity T to an engine in accordance with a n engine speed and an intake air quantity. A hot start detecting means detects the engine to be started in a hot condition. An injection quantity increase correcting means, when a hot start of the engine is detected, increases the fuel injection quantity T, calculated by the injection quantity calculating means, by a fixed proportion DELTAT for a predetermined period after stopping operation of a starter motor. In this way, a control device enables the engine to avoid its unstable action due to a vapor- lock.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electronic fuel injection control device, and particularly to one capable of controlling injection so as to ensure operational stability of an engine during hot restart.

(Conventional ball technique) In general, electronic fuel injection control devices calculate the fuel injection amount using the engine speed and intake air amount as basic parameters, and immediately after the engine is started by the scooter motor, this calculation The amount increase correction is performed to quickly shift the engine to a warm-up state. Furthermore, after the engine shifts to the idling state, there is also an engine that similarly performs an increase correction at a constant rate in order to ensure stability in the idling state (Japanese Utility Model Publication No. 57-26035). reference). Therefore, according to such a control device, a large amount of fuel is controlled to increase for warm-up immediately after starting when the engine water temperature is low, but in a state where the water temperature is high such as during a hot restart, the fuel amount is increased after starting. The injection amount is hardly increased, and the amount is increased at a certain rate only after the engine is in an idling state.

(Problems to be Solved by the Invention) However, when the engine room is overheated, such as during a hot restart, the fuel system is overheated and vapor lock is likely to occur. When vapor lock occurs, there is a shortage of injected fuel, resulting in a high air-fuel ratio, resulting in a reduction in engine output and, in some cases, an inability to rotate. The risk of such vapor lock occurring is increasing due to the increased output of engines and the use of alcohol fuels with low vaporization points. Therefore, even during a hot restart when the engine water temperature is high, in order to avoid engine instability caused by insufficient fuel supply due to vapor lock,
It is extremely effective to perform fuel increase control from the time the engine starts until the idling fuel increase control. The present invention
This was done in view of this point.

(Means for Solving the Problems) Therefore, in the present invention, after the engine is started by the scooter motor, when the engine is in a hot state, the fuel injection amount is increased for a predetermined period.

That is, as shown in FIG. 1, the device of the present invention includes an injection amount calculation means for calculating fuel injection ff1T to the engine according to operating conditions using the engine rotation speed and intake air amount as basic parameters, and a hot start detection means for detecting that the engine has started in a hot state; and a hot start detection means for detecting a start in a hot state; The present invention is characterized by comprising an injection amount increase correction means for increasing the injection amount by a proportion ΔT.

The detection by the hot start detection means is, for example, an intake air temperature (T
A) and the cooling water temperature (W).

In addition, in the case of an engine equipped with a means for performing an increase correction during idling, the increase correction by the above-mentioned injection amount increase correction means may be performed at least during a period from when the starter motor stops to when the engine shifts to idling.

(Example) The present invention will be described in detail below with reference to the drawings.

FIGS. 2 and 3 are an overall configuration diagram showing an embodiment of the present invention and a flowchart showing its operation. Second
In the figure, 1 is the engine, 3 is the combustion chamber of the engine 1,
5 is an intake passage that supplies intake air into the combustion chamber 3. The upstream side of this intake passage 5 ([ljl) communicates with the atmosphere via an air cleaner 7, and a throttle valve 9 is disposed in the middle of the passage. The injection port of the fuel injection valve 13 faces the vicinity of the downstream side of this communicating intake passage.The injection valve 13 is supplied with fuel from a fuel tank (both not shown) by a fuel pump, and therefore, By controlling the opening time of the injection valve 13, a predetermined amount of fuel is injected into the intake passage 5, and a mixture having a predetermined air-fuel ratio is supplied to the combustion chamber 3.

On the other hand, 15 is an exhaust passage, which communicates with the combustion chamber 3 via an exhaust port 17, and the downstream side of the passage communicates with the atmosphere via a catalyst concha 19. Reference numeral 21 denotes a control unit consisting of a microcomputer, etc.; engine rotation IN is input to this unit, throttle opening θ is input from the throttle valve 9, intake air ffi is input from the air flow meter 25 (J1 intake temperature sensor 2
Signals indicating the intake air temperature TΔ from 7, the cooling water temperature W, etc. from the water temperature sensor 29 are manually input, and furthermore, a scooter signal 23S indicating the operating state of the starter motor 31 is input manually. This control unit 21 calculates the fuel injection amount as the valve opening time T based on the above-mentioned human power, and drives and controls the injection valve 13 based on this. Further, after the engine is started by the start, the amount of injected fuel is corrected to increase as shown in FIG.

That is, as shown in FIG. 3, steps STI to ST
In step 3, it is determined from the intake air temperature TA and the cooling water temperature W whether or not the engine is in a hot start state.

If it is not a hot start state, the process proceeds from step ST2 or Sr1 following the flow of "NO" to step 5T12, where normal mode control is performed. That is, the fuel injection FW, 7 is calculated using the intake air amount (J and engine speed N as main parameters), and the drive control of the injection valve 13 is performed based on this calculated value. Air temperature TA and cooling water temperature W are each set to a predetermined value TA.
If I, W1 or more, it is determined that a hot start has occurred, and the process proceeds to step ST4. The engine is started by the starter motor 31, and then the starter motor 31 is stopped.
When detected by the starter signal 31S, step ST6
Then, the first and second timers built into the control unit 21 start counting. Here, the first
The count time by the timer is set shorter than the count time of the second timer, and is set to be longer than the time sufficient for the engine to shift to the idle link state after starting. While the first timer is counting, the loop of steps ST7 and Sr1 is repeated,
Hot increase it;lI control is performed. That is, the fuel injection amount T is calculated, and the calculated injection amount T is increased by a certain percentage ΔT, and this corrected injection amount T'
The injection valve 13 is driven and controlled based on (-T+ΔT).

Next, when the first timer finishes counting, the process proceeds from step ST7 to rYEsJ, repeating the loop of progressive ST9 to ST5T11, and while the engine is in an idling state and the second timer is counting, Fuel H' to stabilize idling condition
Performs fuel injection correction (idling weight increase control).

That is, in step 5TII, the fuel injection amount T
After calculating the injection amount T, adjust the injection amount T' to a certain ratio.
Perform an increase correction.

Note that after the second timer finishes counting, or when the engine shifts from an idling state to another state, such as a partial load state such as when driving, step 5TIO,
Alternatively, proceed from Sr1 to step 5T12 and inject 9
Injection control is performed based on T.

FIG. 4 is a curve diagram showing an example of changes in engine speed due to such control. As shown in the figure, after the starter motor stops operating (OFF), the increase correction (T'-T+△T) in step ST8 is performed during period T1, and then until the end of period T2. The interval is the increase correction (T"-T+△T') in step 5TII above.
) is carried out. Here, as mentioned above, the period Tl is
This period is set to be longer than a period sufficient for the engine to shift to idling after the start is turned off, and is set to be, for example, about 3 seconds, although it varies depending on the engine. Similarly, period T2 is set to about 600 seconds, for example. In this example, injection 1 is increased during a period when vapor lock is likely to occur after the scooter is turned off during a hot start. , it is possible to avoid fuel supply shortage due to paper lock,
Therefore, the operational stability of the engine is ensured, and the engine can quickly shift to idling increase correction.

(Effects of the Invention) As explained below, according to the present invention, since the increase in fuel is corrected for a predetermined period after the starter motor stops operating at the time of thermal start, engine operation becomes unstable due to vapor lock. You can avoid becoming

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is an overall configuration diagram showing an embodiment of the present invention, FIG. 3 is a flowchart showing the operation of the device shown in FIG. 2, and FIG. 4 is an engine rotation diagram. It is a curve diagram showing the transition of the number. 21... Control unit, 25...
...Air flow meter, 27...Intake temperature sensor, 29...
Water temperature sensor, 31...Scooter motor.

Claims (1)

[Scope of Claims] 1) An injection amount calculation means that calculates the amount of fuel injected into the engine according to operating conditions using the engine rotation speed and intake air amount as basic parameters, and an injection amount calculation means that calculates the amount of fuel injected into the engine according to operating conditions, and detects that the engine is started in a hot state. a hot start detection means for detecting a hot start; and an injection amount increase correction for increasing the fuel injection amount calculated by the injection amount calculation means by a certain percentage for a predetermined period from the stop of the starter motor when a hot start is detected. An electronic fuel injection control device comprising: means. 2) In the apparatus according to claim 1, the injection amount calculation means is adapted to perform an increase correction on the calculated injection amount when the engine is in an idling state, and the injection amount increase The correction control period by the correction means is
An electronic fuel injection control device characterized in that the period is a period from when the starter motor stops operating until the engine shifts to an idling state.