JPS603451A - Fuel injector of electronic control engine - Google Patents

Abstract

PURPOSE:To improve starting performance by providing a fuel injection valve which injects fuel into an intake passage and fuel increasing and reducing means which increases and reduces the quantity of fuel to be injected during a cranking period. CONSTITUTION:A standard fuel injection quantity calculating means 90 calculates a standard quantity Tp of fuel to be injected on the bases of flow rate Q of intake air and engine rpm. N. A fuel increasing means 92 calculates a coefficient St of for-start fuel increase which is the function of the temperature of engine cooling water. A fuel reducing means 94 detects a specified lapse A from a point at which a clock 96 generates an output, and calculates a reduction coefficient K in the cranking period following the specified lapse A. The fuel injection quantity calculating means 98 computes the quantity Tau of fuel to be injected from the expression of Tau=TpXStXK and controls the opened period of a fuel injection valve 41. An ignition plug may be thereby prevented from smoking, hence improving starting performance.

Description

[Detailed description of the invention]

The present invention relates to a fuel injection device 11 for an electronically controlled engine that improves fuel injection during the cranking period. In a conventional fuel injection device for an electronically controlled engine that injects fuel from the fuel injection valve to the intake passage, The amount of fuel injection i1 from the fuel VA injector was increased, and the final fuel injection amount due to increase 841 was almost constant throughout the cranking period.Therefore, the cranking period was long. The amount of combustion in the combustion chamber exceeds the appropriate value, increasing the noise and causing smoldering of the spark plug and fuel fogging, resulting in poor starting performance. An object of the present invention is to provide a fuel injection device for an electronically controlled engine that can properly control the amount of fuel and achieve good startability (i.e., 7υ'). The injection device includes a fuel injection valve that injects fuel into the intake passage, a fuel injection valve that injects fuel into the intake passage, an increasing means that increases the amount of fuel 'B injection from the fuel 2A injection valve in cranking 1) Jri!jJ, and a fuel injection valve that injects fuel into the intake passage. A means is provided to gradually reduce the amount of fuel injected from the injection side valve over time during the subsequent cranking period. Fuel injection from the fuel amount u/I valve by the amount increasing means: 1

The amount of fuel in the combustion chamber quickly increases to an appropriate value by increasing the amount of , an increase in the amount of fuel+B in the combustion chamber is prevented. As a result, over-rich air-fuel mixture in the combustion chamber and fuel fogging of the spark plug due to surplus fuel are prevented. This generates a steady ignition spark and maintains good starting performance even if the cranking period becomes long. Note that reducing the fuel injection amount after a predetermined period of time has elapsed saves fuel. It is preferable that the predetermined time period that determines the start time of reduction of the fuel injection amount and the reduction rate of the fuel injection amount are set so that the air-fuel ratio of the combustion chamber is maintained at a value that most easily causes startup for a while in the vicinity of this predetermined time period. The present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of an electronic control device to which the present invention is applied. The air sucked from the air cleaner 1 is transferred to an air flow meter 2, a throttle valve 3, a surge tank 4, and an intake boat 5.
, and is sent to the combustion chamber 8 of the engine body 7 through an intake path 'F69 including the intake valve 6. The throttle valve 3 is linked to an accelerator pedal 10 in the driver's compartment. The combustion chamber 8 is defined by a cylinder head 11, a cylinder block 12, and a piston 13, and the air-fuel mixture in the combustion chamber 8 is combusted by the ignition of the spark plug 14, and then the IJ1 air valve 15.1;
, till-air branch pipe 17, and exhaust pipe 18 to the atmosphere. The bypass passage 21 connects the current of the throttle valve 3 and the surge tank 4, and the ISC valve (idle rotation speed control valve) 22 controls the flow cross-sectional area of the bypass passage 21 to control the engine rotation speed during idling. Constant sweetness 1.
hold The intake air temperature sensor 28 is provided in the air flow meter 2 to detect the intake air temperature, and the
detects the opening degree of the throttle valve 3. The water temperature sensor 30 is located in the cylinder block】2 gy 4CJ and the cooling water temperature is
That is, the engine temperature is detected, the oxygen sensor 3 is installed in the collecting part of the bleed air branch pipe 17 and detects the oxygen expansion pressure in the collecting part, and the crank angle sensor 32 is installed in the collecting part of the bleed air branch pipe 17.
The shaft 3 of the power distributor 33 is coupled to the crankshaft (not shown) of the
The crank angle of the crankshaft is detected from the rotation of 4, and a pulse is generated every time the crank angle changes by 30 degrees, and the starter switch 35 generates an on signal during the starter's operating period and an off signal during the non-operating period. These sensors 2, 28, 29, 30, 3L32, 35
The output of is sent to the electronic control unit 40. Fuel injection valve 41
are provided near each intake boat 5 in correspondence with each cylinder, and inject fuel toward the intake boat 5. The electronic control unit 40 calculates the fuel injection amount from the input signals of each sensor, and sends an electric pulse with a pulse width corresponding to the divided fuel injection amount to the fuel injection valve 41. The electronic control device 40 also
controls the isc valve 22 and the ignition device 46. The secondary current of the ignition device 46 is delivered to the ignition plaque 14 via the power distributor 33. FIG. 2 is a block diagram of the inside of the electronic control device. C.P.
U56. ROM 57. RAM 58. Backup RAM 59. A multiplexer-equipped A/D (analog/digital converter) 60 and 10 (input/output interface) 61 are connected to each other via a bus 62 . The backup 17ΔM50 is connected to an auxiliary power source, and even when the ignition switch is turned off and the engine is stopped, a predetermined power can be supplied and the memory can be maintained. Air flow meter 2, intake temperature sensor 28
, and the analog signal from the water temperature sensor 30 is 8/I)
Sent to 60. The outputs of the throttle position sensor 29, oxygen sensor 31, crank angle sensor 32, and starter switch 35 are sent to the ISC valve 22,
Fuel, injection side valve 41. And ignition equipment! and j4Ci is l10
An input signal is sent from [6]. FIG. 3 is a flowchart of the fuel and injection amount separate calculation routine during the cranking period = 1-. This routine is executed once per revolution of the crankshaft at a predetermined crank angle. Starter switch 35 determines whether it is in the cranking period or not.
1] 1), and the fuel injection b"kTau during the cranking period is calculated by the basic fuel injection amount Tp x starting increase coefficient St.
× reduction coefficient 1 (is).The starting increase coefficient 5t is almost constant over the entire range of the cranking period, whereas the reduction coefficient 1 (is held at 1 until a predetermined time A has elapsed,
After the predetermined time A has elapsed, the fuel injection amount T'au decreases by a predetermined amount ΔK (however, Δ1 (positive value)) each time the crankshaft moves once.
decreases gradually over time. To describe each step, step 66 is the starter switch 3.
5 determines whether it is on or off, and if it is on, step 68
If it is off, the routine ends. Step 6
In step 8, it is determined whether the deep rotational speed N is 400 rpm or less or if it is a cup, and if the determination is positive, proceed to step 70-\, and if not, the routine is terminated. N>40 Orpm does not realize that the start has been successful, and detects the end of the cranking period from turning off the starter switch 35 at step 68.
can be omitted. In step 70, it is determined whether a predetermined time A (A is approximately 10 to 20 seconds, for example) has elapsed since the starter switch 35 was turned on, and if the determination is positive, step 7
If not, the process proceeds to step 72. In step 72, I is substituted into the reduction coefficient 1. In step 771, 1
(Substitute -Δ1( to 1(. ΔI( is, for example, sail 001
It is. In step 7, the intake air flow rate Q and idle rotational speed N are acquired. In step 78, the basic fuel injection amount Tp is calculated based on Q/N. In step 80, the starting increase coefficient 51 is calculated as a function of the interrow cooling water temperature. In step 82, 'rp Substitute the fuel injection amount Tau.In step 84, 'rau
Substitute K for Tau. FIG. 4 shows temporal changes in the fuel injection amount Tau and the amount of fuel in the combustion chamber 8 during the cranking period when starting is not successful. In the conventional device, the fuel injection amount Tau is maintained almost constant over the entire range of the cranking period, so the amount of fuel 'B in the combustion chamber 8 only increases over time, and finally reaches 7 This causes combustion, fogging, and smoldering of the spark plug 14, which deteriorates the starting performance. On the other hand, in misfire 18), after the predetermined time A has passed, the fuel injection mT old 1 decreases over time, and as a result, the amount of fuel in the combustion chamber remains constant or decreases, and the spark plug 14 is prevented from smoldering, and good starting performance can be maintained. Note that the predetermined time A and the reduction amount Δ are determined so that, around the predetermined time A, the air-fuel ratio in the combustion chamber 8 is maintained for a while at a value at which starting is most likely to occur. FIG. 5 is a functional block diagram of the present invention. The basic fuel injection amount calculating means 90 calculates the basic fuel injection amount 1'p based on the intake air flow rate Q/engine rotational speed N, and the increasing LTk means 92 calculates the starting amount increase coefficient which is a function of the engine cooling water temperature. St is calculated, and the reducing means 94 detects the elapse of a predetermined time A from the output of the clock 96 (83). During the cranking period after the elapse of the predetermined time A, the reduction means 94 calculates a predetermined value of 5"i-:IIΔ1( The reduction coefficient 1 (t
Count l. The fuel B injection fA calculation means 98 calculates Tau=T.
The fuel injection amount T au is calculated from p X St X K and the opening period of the fuel injection valve 41 is created in relation to 'I'au.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an electronic control device to which the present invention is applied, FIG. 2 is a block diagram of the electronic control device of FIG. 1. FIG. 4 is a diagram showing the temporal evolution of fuel injection amount, etc. during the cranking period when starting is not successful, and FIG. 5 is a functional block diagram of the present invention. 9... Intake passage, 35... Starter switch, 41
...Fuel injection valve, 92...Increasing IIL means, 94...
・Reduction means. Patent applicant: Toyota Motor Corporation 4＼ Representative patent attorney: Osamu Naka 1, -

Claims (1)

[Claims] A fuel injection valve that injects fuel into the intake passage, an increase hand that increases the amount of fuel B injected from the fuel injection valve during the cranking period, and a fuel injection valve that injects fuel into the intake passage during the cranking period after a predetermined time has elapsed from the cranking start time. 1. A fuel injection device for an electronically controlled engine, comprising a reducing means for gradually reducing the amount of fuel injected from an n-side valve over time.