JPS61234269A - Ignition timing control device - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a fluctuation in torque and of shock, by providing a change width regulating means which regulates the change width of an ignition time to a value within a given change width when a map, reading an ignition timing, is changed occasioned by a change in a car speed. CONSTITUTION:A map (d) of plural ignition timing is allotted at each given car speed region by the number of revolutions of an engine and a load, serving as parameter. An ignition timing selecting means (e) reads an optimum ignition timing from the map (d) according to the number of an engine and a load. A change width regulating means (f) is provided for regulating the change width of an ignition timing to a value within a given change width when a map, from which an ignition timing is read, is changed occasioned by a change is a car speed. This enables prevention of the occurrence of a fluctuation in torque and shock, and permits improvement of operating performance.

Description

[Detailed description of the invention] (Technical field) The present invention relates to an ignition timing control device for an engine.

(Prior Art) Generally, the ignition timing is given using engine speed and load as parameters, but the optimum ignition timing also changes depending on the vehicle speed.

For example, in low-speed ranges such as when driving in urban areas, ignition timing that emphasizes exhaust performance rather than combustion efficiency is considered optimal, and even if the engine speed is the same load, in high-speed ranges when driving in suburban areas, etc. Ignition timing that emphasizes fuel efficiency is considered optimal.

Therefore, conventionally, for example, in electronically controlled fuel injection engines, vehicle speed is divided into low speed range and high speed range, and the engine rotation speed and fuel injection pulse width (corresponding to engine load) are set as parameters for each vehicle speed range. It adopted an ignition timing control device that set a map of the ignition timing advance value ([Automotive Engineering Complete Book 4 Gasoline Engine] supervised by Tsutomu Gomi, Sankaido Publishing, [New Edition Automotive Engineering Handbook Volume 4 Engine]).
Edited and published by Society of Automotive Engineers of Japan, reference).

In this conventional ignition timing control device, first, a map corresponding to the vehicle speed is selected, and then an advance angle value is read from the map using the engine speed and fuel injection pulse width as parameters. An ignition signal is output to the distributor at the ignition timing corresponding to the advance value.

Therefore, it is possible to set the ignition timing in accordance with the vehicle speed, which is appropriate for the operating state of the engine, and it is possible to improve exhaust performance and reduce fuel consumption.

(Problem to be Solved by the Invention) However, in such a conventional ignition timing control device, the ignition timing advance value read at a certain point has no relation to the previously read advance value. Since the ignition timing is read out and the ignition timing is set, the vehicle speed changes during the unit ignition interval (the interval between one ignition timing and the next ignition timing).
When the ignition timing map to be read changes, even if the range of change in engine speed and load is small, the newly read and set ignition timing may differ significantly from the previous ignition timing. As a result, the output torque of the engine changes significantly, giving a shock to the vehicle and potentially worsening drivability.

(Purpose of the Invention) Therefore, the present invention prevents torque fluctuations and prevents shock by regulating the range of change in ignition timing within a predetermined range of change in the unit ignition interval when the vehicle speed changes and the map changes. The purpose is to prevent this from occurring and improve driving performance.

(Structure of the Invention) The ignition timing control device according to the present invention, as shown in the basic conceptual diagram in FIG. , a vehicle speed detection means C that detects the vehicle speed of the vehicle, a plurality of ignition timing maps d assigned with engine speed and load as parameters for each predetermined vehicle speed range, and a plurality of 77 blocks based on the vehicle speed. ignition timing selection means e which selects a map corresponding to the vehicle speed from among the maps and reads out the optimum ignition timing from the map based on the engine speed and load; The apparatus is provided with a change range regulating means f for regulating the range of change in ignition timing within a predetermined range of change when the map to be read changes, thereby preventing torque fluctuations and the occurrence of shocks.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIGS. 2 to 4 are diagrams showing one embodiment of the present invention.

First, the configuration will be explained. In FIG. 2, 1 is a multi-cylinder engine, and intake air is supplied to each cylinder of the engine 1 through an intake pipe 2. A fuel injection valve 3 that injects fuel to each cylinder is attached to the intake pipe 2, and the amount of intake air supplied to the engine 1 is controlled by a throttle valve 4 provided at a gathering part of the intake pipe 2. . The throttle valve 4 is interlocked with the accelerator pedal of the vehicle, and the fully closed state of the throttle valve 4 is detected by a throttle sensor 5. Intake air flow! (Intake amount) Qa is air flow meter 6
The temperature of the cooling water is detected by the water temperature sensor 7. Further, the engine rotation speed N is detected by a crank angle sensor 8 (rotation speed sensor), and the crank angle sensor 8 includes a signal disk plate 8a attached to the engine crankshaft and provided with a protrusion on the outer periphery, and a signal disk plate 8a. Magnetic deck 8 that detects the protrusions of
b. The engine 6 and crank angle sensor 8 constitute load detection means for detecting the load on the engine. A transmission 9 is connected to the engine 1, and the rotational speed of an output shaft 10 of the transmission 9 is detected by a vehicle speed sensor (vehicle speed detection means) 11 and output as a voltage signal proportional to the vehicle speed Vs.

Further, an ignition plug 12 is attached to the engine 1, and the ignition plug 12 discharges between its electrodes to ignite the air-fuel mixture.

Signals from the throttle sensor 5, air flow meter 6, water temperature sensor 7, crank angle sensor 8, and vehicle speed sensor 11 are input to a control unit 13, which controls the CPU 14, ROM 15,
, RAM 16 and I10 boat 17. The CPU 14 takes in necessary external data from the I10 port 17 according to the program written in the ROM 15, and also sends and receives data to and from the RAM 16, processing the data to the I1.
Output to 0 port 17. The ROM 15 stores a program for controlling the CPU 14, and the RAM 16 is composed of, for example, a non-volatile memory, and stores data used for calculating ignition timing and combustion injection amount in the form of a map, etc. is maintained even after the engine is stopped. Signals from the throttle sensor 5, air flow meter 6, water temperature sensor 7, crank angle sensor 8, and vehicle speed sensor 11 as well as signals from various sensors (not shown) are input to the I10 port 17, and analog input signals are converted to digital signals. is converted to Further, an injection signal Si is output from the I10 port 17 to the fuel injection valve 3, and an ignition signal Ti is output to the spark plug 12. The control unit 13 has an ignition timing map and functions as an ignition timing selection means and a variation range regulating means.

Next, the effect will be explained.

Within the control unit 13, the fuel injection amount is calculated and an injection signal Si is output to the fuel injection valve 3, and the ignition timing is calculated based on this fuel injection amount (a parameter representing the magnitude of the load) and the vehicle speed Vs. and outputs the ignition signal Ti to the spark plug 12.

This ignition timing control will be explained based on the flowchart shown in FIG. In addition, P and ~PIS in FIG. 3 indicate each step of the flow.

In step P, the engine speed N, intake air amount Qa, and vehicle speed Vs are read, and in step P2, the basic injection amount 'rp
is calculated using the following formula.

However, K: is a coefficient determined by the characteristics of the fuel injection valve 3 and the value of the target air-fuel ratio.

This basic injection amount Tp corresponds to the load of the engine 1, and although it is not shown in this flow, various corrections are made to this basic injection amount Tp based on water temperature etc. to calculate the final fuel injection amount. The injection signal St is output to the fuel injection valve 3 at a predetermined injection timing.

In step P3, the vehicle speed Vs is compared with a preset reference vehicle speed Vo, and if the vehicle speed Vs is faster than the reference vehicle speed Vo (Vs≧Vo), in step P4, the engine speed is set as a high-speed ignition advance value in advance. The ignition advance value ADn is looked up from the map A stored using the number N and the basic injection amount Tp as parameters, and the process proceeds to step PB.

In step P, when the vehicle speed Vs is slower than the reference vehicle speed ■0 (Vs<Vo), in step P, the engine rotation speed N and the basic injection amount T are set as the ignition advance value for low speed in advance.
The ignition advance value ADn is looked up from map B stored with p as a parameter, and the process proceeds to step P6.

Steps P to P function as an ignition timing selection means, and select the optimal ignition timing according to the vehicle speed even under the same load.

In step P6, if the current map is different from the map when the flow was executed last time, in step P7 the previous final advance angle value ADV n-+ is read from the memory, and in step P
s, the current lead angle value ADn and the previous final lead angle value AD
Difference ΔAD from V n-+ (ΔAD=AD n −A
D V n-+ ) is calculated. At step P8, the difference Δ
AD is compared with a predetermined set value Ao. When ΔAD>Ao, step P determines whether the difference ΔAD is positive or not (whether the lead angle is on the leading side or the lagging side), and when the difference ΔAD is positive, it is determined that it is on the leading side and the step pH is set. The final advance value A
DVn is the value obtained by adding the preset maximum advance angle width M to the previous final advance angle value A DV n-.
= ADV n-1+M) is adopted. This maximum advance angle width M has been determined in advance through experiments as an ignition advance width at which no torque difference is felt even if the ignition angle changes at a unit ignition interval. In step P7, the flag D is set to 1, and in step PI3, the current final advance angle value ADVn is stored in the memory. Then, in step P, the final advance value ADVn
The ignition signal Ti is sent from the I10 boat 17 to the spark plug 12.
Output to.

In step PKl, when the difference ΔAD is negative, it is determined that the injection amount is on the delayed side, and in step Pls, the final injection amount ADVn
The value obtained by subtracting the maximum advance width M from the previous final advance value ADVn-1 (ADVn=ADVnJ-M) is adopted as the value, and the process proceeds to step P12.

That is, steps P6 to P6 function as a change width regulating means, and when the vehicle speed changes and the map changes, the ignition advance value ADn read from the map will be the previous final ignition advance value A. When the ignition timing changes from D V n-1 by more than the set value Ao, the ignition timing change width in the unit ignition interval is limited to the maximum advance width M that does not make a torque step difference. Therefore, for example, as shown in Fig. 4, if the map changes due to a change in vehicle speed and the read-out advance value is b, and the previous final advance value was a, if the ignition timing is changed as it is, then , the torque changes from Ta to Tb and a torque step difference (ΔT=Tb-Ta) is felt. However, in this embodiment, the maximum change width of the ignition timing is restricted to the maximum advance width M, and a, a + M, a +
Since it changes as 2M, ---, b, you won't feel any torque difference. As a result, the occurrence of shock can be prevented and driving performance can be improved.

Furthermore, if the map is unchanged from the previous execution in step P6, the flag D is set to 1 in step P+6.
If the flag D is 1, it is determined that the range of change in the ignition timing was regulated at the time of the previous execution, and the process proceeds to step P7.
to prevent large changes in ignition timing.

When the flag D is 0 in step P1&, the map does not change and the range of change in ignition timing is not regulated at the time of the previous execution, so it is determined that the range of change in ignition timing is not large, and step P1. Then, the ignition advance value ADn looked up in step P4 or step Ps is adopted as the final ignition advance value ADVn, the flag D is set to O in step PIQ, and the process proceeds to step PI3.

Further, if the difference ΔAD is smaller than the set value Ao in step P, it is determined that even if the map changes, the range of change in ignition timing is not large enough to make a torque difference feel, and the process proceeds to step Pl'l.

In the above embodiment, the load is detected as the fuel injection amount, but it goes without saying that the present invention is not limited to this.

(Effects) According to the present invention, when the map changes due to a change in vehicle speed, the range of change in ignition timing in a unit ignition interval is regulated within a predetermined range of change, thereby preventing torque fluctuations and the occurrence of shock. It is possible to improve driving performance.

[Brief explanation of the drawing]

FIG. 1 is a basic conceptual diagram of the present invention. Figures 2 to 4 are diagrams showing one embodiment of the present invention, with Figure 2 being an overall configuration diagram thereof, Figure 3 being a flowchart showing its ignition timing control, and Figure 4 being its ignition timing and torque. FIG. 1---Engine, 8--Crank angle sensor (rotation speed detection means), 1
1.----1 vehicle speed sensor (vehicle speed detection means), 13.-
-----Control unit (ignition timing selection means, variation range regulation means).

Claims (1)

[Claims] a) rotation speed detection means for detecting the rotation speed of the engine; b) load detection means for detecting the load on the engine; c) vehicle speed detection means for detecting the vehicle speed; and d) a predetermined speed detection means for detecting the vehicle speed. e) select a map corresponding to the vehicle speed from among the multiple maps based on the vehicle speed; ignition timing selection means for reading out the optimum ignition timing from the map based on the rotational speed and load; f) when the map for reading out the ignition timing changes due to a change in vehicle speed at a unit ignition interval;
An ignition timing control device comprising: a variation range regulating means for regulating a variation range of ignition timing within a predetermined variation range.