JPS5841231A - Method of electronic controlling for fuel injection - Google Patents

Abstract

PURPOSE:To control fuel injection appropriately without imapiring the engine performance, by controlling the fuel increasing and decreasing ratio according to the width of a datum fuel injection pulse by use of a means which controls the injection quantity of fuel through metering of air-flow rate, and making the air-fuel ratio lean in a low-load range to meet with the level of the load. CONSTITUTION:When an engine is started with a key switch 15 and a starter switch 14 turned ON, calculation of a mainr outine is started and the temperature of cooling water is read from an analogue input port 204. The quantity of correction for fuel is calculated from the result of the above calculation and the result is stored in a RAM206. Then, a CPU200 proceeds to performing an interruption processing routine by a signal from an interruption control section 202, and a datum injection quantity of fuel Tp determined by engine speed N, air-flow rate Q and a constant F is calaculated deriving the engine speed N from an engine speed counter 201 and the flow rate Q of intake air from the input port 204. The load is detected from the value Tp and the mode of operation is selected. On the basis of this selection, each quantity of correction is read out from a ROM207 through judgement of increase, feedback or decrease of fuel. Then, the air-fuel ratio is determined from the quantity of correction obtained by the main routine.

Description

[Detailed description of the invention] Zero firing @Hiro electronically controlled fuel injection method mKIl 0-O
The method is used, for example, in a mass flow type electronically controlled fuel injection system. In the conventional configuration, Tl = 1 + T, (
K is determined as a constant and T is determined as an ineffective injection time), and is established so that the air-fuel ratio is constant. In a system using a taS sensor and a three-way catalyst, the O1 concentration in the exhaust gas is detected based on the air-fuel ratio set at the above injection/medium pulse, and the stoichiometric air-fuel ratio (λ :1) Closed loop control is performed. Recently, the requirements for twin engines include, of course, the purification of exhaust gas,
Demand for improved fuel consumption efficiency is also increasing. It is a well-known fact that when considering improvement in fuel consumption efficiency from the perspective of the quality of the air-fuel mixture supplied to the engine, the air-fuel ratio (~↑) makes a fairly large contribution. It is generally believed that the higher the air-fuel ratio (leaner) at 1 m, the higher the fuel consumption efficiency, but in reality, unless special modifications are made to the engine body, misfires occur at around ↑ = 19 to 20. Therefore, the air-fuel ratio that can be used practically is 18 to 19.

However, when the air-fuel ratio of the air-fuel mixture supplied to the engine is made leaner, the torque decreases significantly, and in the fully open (wo'r) state, the torque decreases significantly compared to the output air-fuel ratio (12-13). #) In terms of vehicle drivability, the trench becomes unfavorable. Strictly speaking, current systems do not perform control according to engine load (manifold pressure), and if such control is attempted, a new load detection device such as an intake pressure sensor is required. However, simply controlling the air-fuel ratio to lean or rich will reduce the amount of Co, HC.

Currently, the above-mentioned closed-loop control is performed in all engine load ranges to avoid deterioration of exhaust gases such as Now. In other words, it is impossible to control the air-fuel ratio to -, -, or -1 with a three-way catalyst system.

The above fuel control method has the following drawbacks. Typically%
HCI Co # The higher the load on the engine, the higher the amount of harmful exhaust gases such as NOx is emitted, and a large amount is emitted during high-speed driving and acceleration. However, under low-speed, light-load driving conditions, the original rate of harmful gas generation is small, and even if the air-fuel ratio is not controlled to the stoichiometric air-fuel ratio in such a region, the amount of harmful gas generated is small. Although it is possible to operate at a lean air-fuel ratio, it is set to the stoichiometric air-fuel ratio, which is a disadvantageous use from the standpoint of fuel consumption efficiency.

In view of the above-mentioned problems in the prior art, the main purpose of the present invention is to calculate the basic calculation nodal width ν of a maskro one-way electronic fuel injection system, where Q is the amount of intake air and N is the engine speed, Based on the concept of increasing or decreasing the final fuel injection amount in response to the TPO size as a hirameter that is approximately proportional to There is a particular thing.

Another purpose of the present invention is to use a three-way catalyst and 03 sensor as an exhaust gas countermeasure, and to reduce CO, IC, and NOx.
By performing conventional feedback control in the high load range where O emissions are high, and by controlling the light load range where exhaust gas is relatively low in a lean manner according to the load as described above, emissions and carbon dioxide purification and fuel consumption efficiency are achieved. The aim is to improve the

In this case, as one form of the invention, an electronically controlled fuel injection device that measures the amount of air and adjusts the amount of fuel injection is used, and the amount of fuel increases or decreases according to the size of the basic fuel injection/9 pulse width (TP). An electronically controlled fuel injection control method for adjusting a quantity ratio is provided.

In addition, in this case, as another form of the invention, an electronically controlled fuel injection device that measures the amount of air and adjusts the amount of fuel injection is used, and according to the size of the basic fuel injection nozzle width (T, ), The fuel increase/decrease ratio is adjusted, and in a region where the basic fuel injection pulse width corresponding to a predetermined engine load is equal to or greater than a predetermined value, the predetermined engine is controlled to perform closed roots control using an ol senna and a three-way catalyst. An electronically controlled fuel injection control method is provided in which the air-fuel ratio is set to one level in accordance with the value of the basic fuel injection/flush width in a region where the load is lighter.

An apparatus to which an electronically controlled fuel injection control method as an embodiment of the present invention is applied is shown in FIG.

The engine (1) is a 4N spark ignition engine installed in a car, and the combustion air is supplied through an air cleaner (2λ intake pipe (3
), inhale via throttle pulse f(4). In addition, the fuel control method 2o is based on the electromagnetic fuel injection valve (ISl).
) to (56) are opened and supplied to each cylinder. Exhaust gas after combustion is passed through exhaust manifold P (6)% exhaust pipe (7)
etc., and is released into the atmosphere. The intake pipe (3) is equipped with a tensile meter type intake air amount sensor (8) that detects the amount of intake air taken into the engine (1) and outputs an analog voltage corresponding to the amount of intake air. At the entrance of the senna,
A thermistor-type intake temperature sensor is installed that detects the temperature of intake air and whose resistance value changes depending on the intake air temperature. ti, engine (1) K is equipped with a ti star type water temperature sensor (10) that detects the coolant temperature and changes the resistance value according to the coolant temperature, and the rotation speed sensor (11) is installed in the engine (1). 1) Outputs a frequency (DI4 pulse signal) according to the rotational speed of the crankshaft. As this rotational speed sensor, for example,
The ignition coil of the ignition device may be used, and the ignition/9 pulse signal from the primary terminal of the coil may be used as the rotational speed signal. In addition, the exhaust system is equipped with a known oxygen concentration sensor (12) that outputs an output according to the concentration of CO2 and HC when the exhaust gas is at the stoichiometric air-fuel ratio.

A three-way catalyst device (13) is provided that simultaneously purifies the three components of NOx at a high purification rate. The control circuit (20) is a circuit that calculates the fuel injection amount based on the detection signals of each sensor (8) to (12), and is a circuit that calculates the fuel injection amount based on the detection signal of each sensor (8) to (12).
), the air-fuel ratio is adjusted by controlling the valve opening time.

The multi-purpose control circuit 20 in FIG. 2 will be explained.

200 is a micro derosé that calculates the fuel injection amount.

(CPU). Reference numeral 201 denotes a rotation number counter, which reads the signal from the rotation speed (number) sensor 11 and the engine rotation speed.

t+, the rotation number counter 201 sends an interrupt command signal to the interrupt control section 202 in synchronization with the engine rotation. When the interrupt control unit 202 receives this signal, it outputs an interrupt signal to the CPU 200 via the common path 212. The digital input date 203 transmits to the CPU 200 a digital signal such as a starter signal from the starter switch 14 that turns on and off the operation of a starter (not shown). The analog input port 204 consists of an analog multiplexer and an A-D converter, converts each signal from the intake air amount sensor 8 and the cooling water temperature sensor 9 from A to D, and sequentially sends the signals to the CPU.
The output information of each of these units 201, 202, 203, and 204 having the function of being read into the CPtJ 200 is transmitted to the CPtJ 200 through the common bus 212. 2
05 is a power supply circuit, which is connected to a battery 16 through a key switch 15.

206 is a random access memory (RAM) that can be read and written. 207 is! Read-only memory (ROM) that stores programs and various constants, etc.
It is. 208 is a fuel injection time control counter including a register, which is composed of a down counter, and converts a digital signal representing the opening time of the electromagnetic fuel injection valves 51 to 56 calculated by the CPU 200, that is, the fuel injection amount, to the actual electromagnetic fuel. Nof of the pulse time width that gives the opening time of the injection valves 51 to 56
Convert to a pulse signal. 209 is an electromagnetic fuel injection valve 51~
56. 210 measures the elapsed time with a timer and transmits it to CPtT2O0.

The rotational speed counter 201 measures the carrot rotational speed once per engine rotation (based on the output of the rotational speed sensor 10), and supplies an interrupt command signal to the interrupt control section 202 at the end of the measurement. The interrupt control unit 202 generates an interrupt signal in response to the signal, and causes the CPU 200 to execute an interrupt processing routine for calculating the fuel injection amount.

FIG. 3 (- indicates a schematic flowchart of the CPU 200. Based on this flowchart, the CPU 200
The functions of the system will be explained as well as the operation of the entire configuration.

When the key switch 15 and starter switch 14 are turned on and the engine 1 is started, the calculation process of the main routine is started at step 80, and step 81
Initialization processing is executed in step S2, and nine digital values are read in accordance with the cooling water temperature from the analog input (-) 204 in step S2. In step S3, the fuel correction lid is calculated based on the result, and the result is stored in the RAM 206.

When Stella f83 ends, the process returns to step S2.

Normally, the CPU 200 repeatedly executes the main routine processing from 82 to S3 in FIG. 3(a) according to the control program. When an interrupt signal is input from the interrupt control unit 202, the CPU 200 immediately interrupts the main routine even if it is in progress, and executes the interrupt processing in step 840 shown in FIG. 3(b). Move on to the routine. The step fS41 takes in a signal representing the engine speed N from the rotation speed counter 201, and then the step f8
At step 42, a signal representing the intake air amount Q is input from the analog input port 204. At step 843, the basic bottle fuel injection amount (basic injection time) determined from the engine rotation speed N1 intake air amount and constant y is input. Calculate the width TP). The calculation formula is 'f p w iP X-.

Next, in step 844, the basic injection amount T is determined to be increased, returned, or decreased depending on K, and each correction amount is read out from the ROM 207 in step 845. After that, the fuel determined in the main routine is Set the correction amount for injection to R
A final correction calculation is made to determine the air/fuel ratio by reading from the AM 206, and the process then returns to the main routine via step 846.

Next, load control of the air-fuel ratio in the present invention will be explained. t
First, a method for detecting engine load will be explained.

Figure 4 shows the so-called L-J@ fuel injection control system.
This figure shows what happens to the fuel injection time when trying to obtain the same air-fuel ratio characteristics at each engine load when a tronla type engine is used. In general, the volumetric efficiency changes depending on the engine speed, so it is not linear, but the injection time is almost proportional to the load. In other words, the value ψ can be thought of as a nodal meter that represents the engine load.

The basic injection amount TPo that the engine can handle in all operating ranges is large.
There are limits to sharpness. Since Tν at full throttle is not a constant value (depending on the rotation), we will exclude it and consider it as a representative of the region considered to be high load (intake pipe negative pressure -50 to -150 mHg). T,
is TpH, and the representative T in the range where the throttle is considered to be fully closed (the same (approximately -500wHH to -600■Hg)
, is TPo.

T de 0 to TP! , is divided into n equal parts, and each TP value is plotted as 79 lameter in Figure 4. Also, TPα is T,
, (TPα<'r,n), and it is appropriate to take a value corresponding to a load of approximately -400 to -2001g. The increase/decrease ratio is set according to the TPo value at (step 545).Furthermore, at medium load, factory feedback control is performed.

The above can be summarized as shown in the table below.

〔table〕

T, 愼 Load classification Operation mode Tt0≦Tp<
Tea 4! Load lean control T? α≦Tt<T
yB Medium load λ=1. Feedback control TFnriTP
HIGH LOAD OUTPUT AIR FUEL RATIO CONTROL The aforementioned 70-charts are shown in FIGS. 3 and 5. That is, step fs44 determines the load based on the magnitude of IfiTp and selects an operation mode, and step 7'845 calculates the increase value, decrease value, or feedback control value for each mode, and calculates the correction amount. After going through Se and Toshi, he returned after going through Ste and De 846. This control is determined for each injection cycle. Examples of air-fuel ratio settings determined in this way are shown in FIGS. 6 and 7. Figure 6 schematically shows the setting increase/decrease, T? .

≦TP＜↑? In α, the lean control amount is determined to achieve the optimal air-fuel ratio according to each size, and TFα≦TP≦
In the region of TP1m, since feedback control of λ=1 is performed, no increase or decrease is set. Also, %TP≧T,! At a high load of 1, the increase ikgjL is determined so as to reach the output air-fuel ratio (in this case, the basic air-fuel ratio is based on λ=1.00). The tR7 diagram shows O when set as shown in Figure 6.
This shows what the intake pipe pressure and air-fuel ratio become when the engine speed is: In addition to the above-mentioned embodiments, the present invention can also be considered as a straight-O variant. For example, in the above-mentioned embodiment, the control is open-loop control, and when consideration is given to compatibility with nine, two, and three systems, the following system may also be considered. This is a known system that performs open-loop control of the air-fuel ratio using a three-way catalyst %Ol sensor. It is possible to improve fuel consumption efficiency without significantly deteriorating the emitter capacity. In this case, feedback control is performed in the high-load area where a large amount of energy is excreted. Delicious.

According to the present invention, it is possible to perform appropriate fuel injection control without impairing the drivability of the vehicle, and at the same time, it is possible to obtain the advantages of preventing deterioration of emission snow and improving fuel consumption efficiency.

[BRIEF DESCRIPTION OF THE DRAWINGS] Figure IIII is an overall configuration diagram of a device to which an electronically controlled fuel injection control method as an embodiment of the present invention is applied; FIG. 2 is a block diagram of a control circuit in the device shown in FIG. 1; 1143
The figure shows a schematic 70-chart of the execution contents of the microgrosse and suction in the circuit shown in Figure 2. Figure 4 shows that the basic fuel injection amount is a function of the load. ``Buried by Kazuyuki Nishidate, Ben Misaki! Mourning i4+1% Engine rotation speed (x10'rpm) Figure 5

Claims (1)

[Claims] L An electronically controlled fuel injection device that measures the amount of air and adjusts the amount of fuel injection is used, and the basic fuel injection pulse width (Ty) is 0.
An electronically controlled fuel injection control method that adjusts the fuel zero increase/decrease ratio according to the size. $L1fiUsing an electronically controlled fuel injection device that measures the air flow and adjusts the fuel injection amount, the fuel increase/decrease ratio is adjusted according to the basic fuel injection pulse width (decimal), and the fuel injection amount is adjusted to a specified level. In order to correspond to the 0-engine y load, closed-loop control is performed using an Ol senna and a three-way catalyst in the region i where the basic fuel injection pulse width is equal to or greater than a predetermined value. Basic fuel injection pulse width O11mK
An electronically controlled fuel injection control method that sets an air-fuel ratio -yK accordingly.