JPH0237154A - Start controller for engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an engine starting control device that is improved to improve engine starting performance.

(Prior Art) In an engine control device, for example, a fuel injection type engine control device, the operating position of a cylinder is detected as a reference, and based on this detection result, the timing and timing of fuel injection to each cylinder are determined. Types that determine ignition timing are known. For example, such a control device is disclosed in Japanese Patent Laid-Open No. 57-59032.

In this type of device, in order to detect the reference operating position of the cylinder, a slit or the like is formed in a portion corresponding to the reference operating position, and this slit is inserted into the cylinder using an electromagnetic or optical sensor. It is designed to be detected every cycle.

The detection signal obtained by such a mechanism consists of a pulse train corresponding to the detection of the slit.・Here, the detection signal generally contains noise, and in order to avoid erroneous slit detection due to noise added to the detection signal, the detection signal is compared with a certain threshold, and the level above this value is This pulse is considered to be the fin slit detection pulse.

(Problems to be Solved by the Invention) However, the pulse level of such a detection signal tends to be lower than that during normal driving when the engine starting resistance is large when the engine is started. In this case, the pulse cannot be read until the signal level becomes high, and therefore the ignition timing and fuel injection timing cannot be calculated based on this. As a result, a problem arises in that the transition from the starting state to the normal driving state is slightly delayed.

The purpose of the present invention has been made in view of this point,
An object of the present invention is to realize an engine starting control device that can quickly read a pulse indicating the operating position of a reference cylinder, thereby improving engine starting performance.

(Means for Solving the Problems) In order to solve the above problems, in the engine starting control device of the present invention, at the time of starting, noise is removed from the signal pulse indicating the operating position of the reference cylinder. The set threshold level is set to a lower value than in normal driving conditions, so that the signal pulse can be read early after the engine is started.

How low the above threshold level should be set should be set individually for each engine. Further, since the noise level is high immediately after starting, it is preferable to lower the threshold level after a certain period of time has passed from immediately after starting.

(Effects of the Invention) As described above, in the engine starting control device of the present invention, the threshold value for removing noise from the signal pulse representing the operating position of the reference cylinder is normally set for a predetermined period after the engine starts. It is set lower than when driving. Therefore, even if the level of the signal pulse obtained at the time of starting is low, this pulse can be read, and based on this, the ignition timing, fuel injection timing, etc. can be calculated, and combustion can be started at an early stage. Therefore, the startability of the engine can be improved.

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

FIG. 1 is a schematic block diagram showing an engine starting control device according to an embodiment of the present invention.
In Figure 0, 1 is a control unit composed of a microcomputer, and various information indicating the operating status of the engine is input to this unit. The inputs for the control of the present invention include a cylinder discrimination signal G indicating the reference position of the reference cylinder and a reference pulse generated as the crankshaft rotates. This is signal R.

The cylinder discrimination signal G is input to the unit 1 via the comparator 2. On the other hand, the ignition mechanism 3 and fuel injection mechanism 4 of each cylinder are connected to the output side of the control unit.

The comparator 2 compares the level of the cylinder discrimination signal G with a reference threshold value Lo, and supplies only signals having a level equal to or higher than this value to the control unit 1. Furthermore, the signals G are not compared until a certain period t' 1 has elapsed after the start of the engine, and during the period from then until the elapse of period t2, the signals G are not compared under the control of the control unit 1. In addition, the level of the signal G is determined using a lower threshold value L1 instead of the above-mentioned threshold value LoO. In the control unit 1, the ignition timing is calculated based on the signal obtained from the comparator 2 and the reference signal R, and a drive pulse signal IGT corresponding to the calculated timing is supplied to the ignition mechanism 3.

Furthermore, a drive pulse signal Tnj corresponding to the similarly calculated fuel injection timing is outputted to the fuel injection mechanism 4 as well.

FIG. 2 is a timing chart showing an example of a control operation performed by the above-mentioned startup control device. In the figure, at time T1, the ignition switch is turned on to start the engine. During a period t1 from after this to time T2, the cylinder discrimination signal G is not read (masking period). Next, during a period t2 from time T2 to time T3, L1 is adopted as the threshold value of the comparator 2, and a signal G having a level equal to or higher than this value L1 is input to the control unit 1. That is, a pulse Gl of a level equal to or higher than the normal threshold value LO, which is smaller than the normal threshold value LO, is input to the control unit. The control unit l calculates the ignition timing and the fuel injection timing based on the input pulse Gl, and the drive pulse signals IGT and Inj corresponding to the calculated timing are supplied to the ignition mechanism 3 and the fuel injection mechanism 4, respectively. Ru. That is, drive pulses IGTI-3 and Injl are supplied.

Next, after time T3, the threshold level of comparator 2 is returned to Lo, and pulses G2.3.
4-. are sequentially supplied to the control unit. As described above, the control unit returns to these pulses, calculates the ignition timing, and the fuel injection timing, and calculates the drive pulses IGT4.5.6-... and Inj corresponding to these timings.
Output 2.3.4 respectively.

In this manner, the control device of this example can read the cylinder discrimination signal G immediately after starting the engine. Therefore, fuel injection and ignition are performed in response to this, and the engine speed increases.

On the other hand, according to conventional control, the pulse G1 of the low-level cylinder discrimination signal is not read, and the pulse G2 that occurs thereafter is read for the first time.

Therefore, the first ignition timing is the timing represented by the pulse IGT4, which is delayed compared to the control of this example. As a result, the rise of Ne at engine speed is
As shown by the broken line in the figure, it is clear that the startability is poorer than the control of this example.

As described above, according to the control device of this example, reading of the cylinder discrimination signal can be started at an early stage after starting, and therefore the ignition timing or fuel injection timing can be calculated based on this. Therefore, engine startability is improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic block diagram of a control device according to an embodiment of the present invention, and FIG. 2 is a timing chart for explaining the operation of the device shown in FIG. Explanation of symbols 1--Start control device 2--Comparator 3--Ignition mechanism 4--Fuel injection mechanism

Claims (1)

[Claims] a detection means for detecting a specific operating position in a reference cylinder of the engine in the form of a pulse signal; a comparison means for detecting that the signal level of the detected pulse signal has exceeded a preset threshold; calculation means for calculating the ignition timing and fuel injection timing based on the pulse generation timing of the pulse signal after the level reaches the threshold value, and the comparison means for calculating the ignition timing and fuel injection timing based on the pulse generation timing of the pulse signal; An engine starting control device comprising: changing means for changing the threshold value to a lower value.