JPH051392B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an automobile engine ignition control device,
In particular, the present invention relates to an automobile engine ignition control device suitable for performing optimal ignition timing control by detecting engine knocking and correcting ignition timing.

[Background of the invention]

Control that detects engine knocking and corrects ignition timing (hereinafter referred to as knocking control) is
This is an effective means to improve engine output, and its control methods include two methods: uniformly correcting the ignition timing of all cylinders when knocking is detected, and one method that corrects the ignition timing of all cylinders uniformly when knocking is detected. A method of correcting the ignition timing independently of each cylinder (hereinafter referred to as a cylinder-specific knock control method) is known (see Japanese Patent Application Laid-Open No. 1997-1997). In particular, the latter control method is effective as a method for performing more optimal knock control depending on differences in knock detection sensitivity and ease of knocking between cylinders. However, with this method, the ignition timing is corrected independently for each cylinder, so if there is a significant difference in knocking detection sensitivity between cylinders due to engine variations or knocking sensor variations, the ignition timing for each cylinder may be adjusted. has become very different,
This may lead to instability of engine rotational torque.

[Purpose of the invention]

An object of the present invention is to provide an automobile engine ignition control device that can perform ignition timing control in a cylinder-by-cylinder knock control system so that the difference between cylinders in ignition timing does not exceed a certain value and stable torque is obtained. It is about providing.

[Summary of the invention]

In order to achieve such an object, the automobile engine ignition control device according to the present invention stores an ignition timing correction amount due to notching for each cylinder, and compares the maximum value and minimum value among them. death,
If the difference exceeds a predetermined value, set the new correction amount by adding a certain value to the minimum correction amount, so that the ignition timing difference between cylinders always maintains the predetermined value. It is designed to control the noise so that it does not become louder.

[Embodiments of the invention]

The basic system configuration in this example is the first
It is as shown in the figure. The main input signals are a rotation angle signal (POS) obtained from a rotation angle sensor 1 that detects the crankshaft rotation angle, and a reference position sensor 2 that detects a specific rotation angle position of the crankshaft.
Reference position signal (REF) obtained from , first cylinder identification signal (PHASE) from sensor 3 for identifying the first cylinder, intake pipe pressure signal (P) from sensor 4, cooling water temperature signal from sensor 5 (TW), intake temperature signal (Ta) from sensor 6, battery voltage signal (V _B ) from sensor 7, knock signal (KNOCK) from sensor 8, etc., and the output signals are integrated into the ignition coil 10. This is an ignition control signal (IGN) that controls the base of the power transistor 11 that is regulated. By controlling the High time of this IGN signal, the primary energization time of the ignition coil can be controlled, and by controlling the switching timing of the IGN signal from High to Low, the ignition timing can be controlled. The control device 9 is controlled by a microprocessor, and the ignition timing is determined based on the engine speed and intake pipe pressure (16×
16) Determine the basic ignition timing by interpolating the ignition map of the points, add correction values based on cooling water temperature and intake air temperature to this value, and add the correction value due to knocking when knocking is detected. The final ignition timing is then determined. That is, the ignition timing θ can be expressed as follows.

θ=θ(N,P)+θ(TW)+θ(Ta)+θ
(KNOCK) Here, θ is the final ignition timing, θ (TW) is the correction value based on the water temperature, θ (Ta) is the correction value based on the intake air temperature, and θ (KNOCK) is the correction value based on the knock signal. Note that the engine rotation speed N can be obtained by counting POS signals (for example, signals every 1°) at a constant time.

Here, θ (N, P) θ (TW), θ (Ta)
is a common value for all cylinders.

θ(KNOCK) is determined as follows.
When knocking occurs in the engine, approximately 0.5 msec to 3 msec after ignition occurs.
A peculiar engine vibration occurs for a period of about 1 msec to 1 msec. This engine vibration is converted into an electrical signal by a knock sensor 8 using a piezoelectric element, etc., and is input to the control device. A knock signal detection circuit section 13 in the control device processes this signal and outputs a pulse train of a number corresponding to the knocking intensity. This pulse train signal will be referred to as a knock pulse. This knock pulse is input to the control logic section 14 as an interrupt signal. The control logic section 14 is composed of a microprocessor and an I/O control section. The interrupt processing routine activated by a knock pulse counts the number of knock pulses. Further, a REF signal set to, for example, 60° BTDC is also input as an interrupt signal to the control logic section. The interrupt processing routine activated by the REF signal compares the counted number of knock pulses with a predetermined value (for example, 6), and if the number is greater than that, it is assumed that knocking has occurred, and If it is small, it is assumed that nokking has not occurred. The cylinder in which knocking has occurred is identified, and a value θ _K to be corrected by one knock is added to a register (specific address in the memory) that holds the knock correction value corresponding to that cylinder. The cylinder can be identified by setting the time when the first cylinder identification signal is input as the first cylinder, and sequentially updating the cylinder number each time the REF signal is input. The REF signal is set to be generated at a specific position (for example, 60 degrees BTDC) in one-to-one correspondence with each cylinder. In this way, the knock correction amount is set independently for each cylinder. Here, from the knock correction amount θ ₁ (KNOCK) of the first cylinder, for example, 4
In the case of a cylinder engine, the knock correction amount for the 4th cylinder is θ ₄
(KNOCK), the maximum value θ _Knax and the minimum value θ _Knio
and calculate the difference Δθ _K = θ _Knax −θ _Knio ,
When this value is larger than a predetermined value Δθ _KO , the new correction amount is determined by adding (Δθ _K −Δθ _KO ) to the cylinder with the minimum correction amount. That is, if θ _Knio = θ _i (correction amount for cylinder i) θ _Knax = θ _j (correction amount for cylinder j), Δθ _K = θ _Knax −θ _Knio = θ _j −θ _i Δθ _K −Δθ _KO = ( θ _j −θ _i )−Δθ _KO Now, the sum of (Δθ _KO −Δθ _K ) to θ _i is θ _i ′
Then, θ _i ′=θ _i + (Δθ _K −Δθ _KO ) Therefore, θ _j −θ _i ′=θ _j −θ _i −(Δθ _K −Δθ _KO ) = θ _j −θ _i −(θ _j −θ _i )+Δθ _KO =Δθ _KO That is, the difference in knock correction amount between cylinders can always be kept below Δθ _KO .

The final ignition timing is determined by adding the knock correction amount thus obtained together with separately calculated θ(N,P), θ(TW), and θ(Ta).

Since θ(N,P), θ(TW), and θ(Ta) are common to all cylinders, the difference in final ignition timing among the cylinders can also be suppressed to less than Δθ _KO . In this way, the difference in ignition timing between cylinders can be suppressed to a certain value or less in the cylinder-by-cylinder knock control, so that there is no fluctuation in torque and stable engine rotation can be obtained.

Furthermore, in an embodiment in which a plurality of knock sensors are used to detect knocking in separate cylinders, it is possible that one sensor malfunctions or deteriorates for some reason and the knocking detection ability is significantly reduced. Even in such a case, a certain degree of knock correction is performed in response to knocking in other normal cylinders, so there is also a fail-safe effect to prevent engine damage.

〔Effect of the invention〕

As is clear from the above description, according to the automobile engine ignition control device according to the present invention, it is possible to prevent the difference in ignition timing between cylinders from exceeding a certain value, so that stable torque can be obtained. become.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of an automobile engine ignition control device according to the present invention, and FIG. 2 is an explanatory diagram showing the operating principle of the automobile engine ignition control device according to the present invention. 1... Rotation angle sensor, 8... Knock sensor, 9...
Control device, 10...Ignition coil, 11...
Power transistor, 13... knock signal detection circuit section, 14... control logic section.

Claims (1)

[Claims] 1. In an automobile engine ignition control device that has means for detecting engine knocking and has a function of correcting ignition timing accordingly when knocking occurrence is detected, the cylinder in which knocking has occurred is identified and each cylinder is independently controlled. 1. An automobile engine ignition control device characterized in that, when correcting the ignition timing by adjusting the ignition timing, the difference between the cylinders in the ignition timing correction amount does not exceed a predetermined value.