JPS59572A - Knocking controller - Google Patents

Abstract

PURPOSE:To prevent the occurence of an excessive delay angle when a knocking sensor is abnormal, by making the timing for ignition at the maximum of the delay angle value obtained during the knocking feedback operation when the knocking sensor is abnormal. CONSTITUTION:Abnormality of an output of the knocking sensor, for example, breakage of a signal line of the knocking sensor or outward leaking of the output of the knocking sensor, is detected by a step 42. When the knocking sensor is abnormal, theta'kij is read out in a step 409 from a delay angle memory map, and the thetakij is made to be an ignition time delay angle in a step 411. This thetakij is the maximum delay angle when the knocking sensor is normal and the knocking feedback of the time for ignition is performed. It is obtained in steps 407 and 408. Thus, the excessive delay angle can be prevented from occurring when the knocking sensor is abnormal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a knock control device that controls the ignition advance angle to alleviate the occurrence of engine knocking, and more particularly to a fail control device when a knock sensor fails.

Conventionally, when a knock sensor failure is detected, the engine is retarded by a predetermined set value regardless of the presence or absence of a knock signal to prevent damage to the engine due to over-advanced operation (Japanese Patent Laid-Open No. 54-155522 (No. Publication) There was something.

However, MBT operation is possible with engines such as motorcycles in which the degree of soot buildup in the combustion chamber of the engine changes over time, but knocking becomes more severe as the engine ages. If such an engine is retarded by a certain set value in the event of a failure (knock sensor failure), a new engine has the disadvantage that the output torque loss will be large. Furthermore, depending on the setting of the set value that takes into account the variations in each engine and the way in which the degree of safety is expected, it is inevitable that the loss in output torque will be large.

The present invention has been made in view of the above problems, and as a retardation method in the event of a failure, a retardation amount memory map is provided to store the maximum value of the retardation amount obtained during knock feedback operation. The object of the present invention is to provide a knocking control device which sets a retard angle using the value of a retard amount storage map in the event of a failure. For example, in a new engine, the engine is not retarded unnecessarily or at all in the event of a failure, so maximum output can be obtained; in an older engine, the engine is retarded by the necessary amount to alleviate knock in the event of a failure, so the engine will not be destroyed by overadvancing. This effect can be obtained.

An embodiment of a control device according to the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram showing the overall configuration of the ignition advance control device, FIG. 2 is a flowchart showing the arithmetic processing of the knock control portion by the microcomputer in FIG. 1, and FIG. 3 is a retard amount storage map.

1 is a well-known engine rotation angle sensor that sends an engine rotation speed signal to an engine control circuit (hereinafter abbreviated as EltOU) 100.
Output to. 2 is a known pressure sensor that detects the engine load based on the pressure in the intake pipe; 3 is a temperature sensor that detects the temperature of the engine block; and 4 is a known knock sensor. Reference numeral 101 is an advance angle map that determines the basic ignition advance angle based on the engine speed, load condition, and the like. 102 is an advance angle correction map for correcting the ignition advance angle depending on the engine temperature state. Reference numeral 41 denotes a knock detection unit that detects the presence or absence of a knock from the output signal of the knock sensor 4 (Japanese Patent Application Laid-Open No. 1985-1999).
(disclosed in Japanese Patent No. 155322), which emits an output signal when a knock is detected. 42 is knock sensor 4
Fail detection circuit (
(disclosed in Japanese Unexamined Patent Publication No. 155322/1983), when an abnormality of the knock sensor is detected, the output signal f(KN)
emits. Reference numeral 43 denotes an alarm device that lights up an alarm lamp based on the output signal of the fail detection circuit 42.

Reference numeral 103 is a knock advance angle calculation circuit which performs the calculations shown in steps 400 to 406 of the flowchart in FIG. When the knock sensor output is normal, the knock detection section 4
1 knock detection signal F (KN) △θ7 For example, 1°C
Retard every A (steps 401, 402, 403),
When there is no knock signal F (KN) for a certain period of time, for example, 1 second (step 402), the ds is advanced every 1°C, for example (
Step 404), correction θ of the ignition advance angle according to the knock occurrence situation, =I△θ0−ΣΔθS (however, if θ≧0, θ,
When is positive, it indicates that the angle is retarded, and when it is negative, it is indicated that the angle is advanced (step 406). 104 is a maximum retard amount determination memory circuit, which has a retard amount storage map (see Fig. 6) and stores a map value θ' of 1 based on the operating conditions at that time.
．． and the current retard amount θ, are compared (step 407),
It has a function of rewriting the value θν□3 of the retard amount storage map θ′ to the θ adjustment value when θwork>θ′Kij (step 408). However, if θ is ≦02□1, θ' and the map are not rewritten. 105 is a knock advance angle priority selection circuit. If the output of the knock sensor is normal in steps 409 and 410 and 411, the retard amount is controlled by θ by the output of the knock advance calculation unit 103 (step 406). In this case, the map value θ' of the retardation amount memory map θ'□ is 0. FIG. 6 shows a retard amount storage map having the function of determining the retard amount θKN (step 409) and the retard amount θKN (step 411). The engine determines the operating conditions of the engine based on the output values of the engine rotation angle sensor 1 and the pressure sensor 2, and determines the maximum retardation based on a map using each engine rotation speed N and pressure B as parameters. Amount θk
I remember ml. The reading and updating of the stored values shown in steps 409 and 408 in FIG. 2 are carried out using map values θ' and □ corresponding to the output values of N□ and Bl, respectively. This is done every time, and the memory is retained even when the engine is stopped.

106 is an ignition advance angle calculation section. The signals of the basic ignition advance angle (θB) of the advance angle map 101, the advance angle correction value (θ, ) according to the advance angle correction map 102, and the knock advance angle correction value (θKN) of the knock advance angle priority selection section 105 are It has a function of outputting the ignition advance angle (01g) based on the calculation result of 0□8=03+01+θKN. 5 is the igniter,
The discharge timing of the ignition device 6 is determined based on the output value of the ignition advance angle calculation section, and an activation signal for the ignition device 6 is issued.

The operation of the apparatus of the present invention will be explained below. During normal light load operation without knocking, or in a new engine with no knocking, set 1 ignition advance i Do not perform knock retardation θ = 0 advance angle mass 10
1 and advance angle correction map 102, and the ignition device 6 is operated.

Also, if no abnormality is found in the output of knock sensor 4,
The fail detection circuit 42 does not output an output signal, but based on the knock occurrence signal, a knock advance angle correction value (θ
KN) is determined, and the advance angle correction is performed in the same manner as in the prior art depending on whether or not knocking occurs and the circumstances of its occurrence.

Also, when this knock advance angle correction is performed.

The knock retardation amount θ at each time and the retardation amount memory map value θaccording to the operating state at that time (however, θ'Kij is stored in advance at an address corresponding to the engine speed and intake pipe pressure at each time). θ, and θ'K
ij), and the retardation amount memory map is always updated so that the retardation amount is maximized considering the driving condition.

In addition, if an abnormality is found in the knock sensor output due to a break in the signal line of the knock sensor or external leakage of the knock sensor output, the fail detection circuit 42 issues an output signal, and the knock advance angle correction value θKN is set as described above. The retardation amount storage map value θ' is determined, and the alarm device 43 is activated to warn the driver.

In this way, even when the knock sensor is abnormal, the knock advance angle correction value θK
N can be determined. Therefore, in an engine state where knock does not occur, the engine output will not be too high or too low due to an excessive knock advance correction value, and the problem of excessive knock noise due to an insufficient knock advance angle correction value will be eliminated. .

Furthermore, an appropriate amount of retardation at the time of failure can be obtained in accordance with the difference in the state of knock occurrence due to aging of the engine or variations in engine manufacture.

Also, the retardation amount memory pine! Since θ is determined using the engine load and rotation speed as parameters, it is possible to determine the amount of retardation when the knock sensor is abnormal depending on the difference in the knock occurrence situation due to the difference in engine operating conditions. At the same time, this advantage can also be achieved.

In the above-mentioned embodiment, the initial setting (at the time of shipment) of the map value θ' and i for each operating condition in the retardation amount memory map θ is set in advance to a degree that does not reach 4 degrees that would damage the engine. The value may be set depending on the operating conditions. Also, depending on the capacity of the microcomputer in the microcomputer control system, for example, when the capacity is insufficient, it is possible to calculate the maximum retardation amount across the engine conditions all at once, abolishing the map and replacing it with a single value. . In addition, in this embodiment, the retardation amount at the time of failure is the maximum value θ′ during normal operation.
, □4, but the retardation amount l9 including the safety factor (K)
Fa□, - can be set to xθ'. The value of K is set to 1<K<10 for engines that are easily destroyed, such as air-cooled motorcycles, and for four-wheeled vehicles where the risk of damage due to engine overadvance is small. It is also possible to set 0<K<1 to compensate for the lack of output or to emphasize the safety of the engine. Furthermore, as shown in FIG. 4, a weighting section (step 413) may be provided to set the amount of retardation at the time of failure in accordance with the characteristics of the engine.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the device of the present invention, FIG. 2 is a flowchart showing the calculation process of the device in FIG. 1, and FIG. 6 is a flowchart showing the calculation process of the device in FIG. It is a partial flowchart which shows a process. 4................................................... Knock sensor 41... Knock detection circuit section 42.
...Fail detection circuit section 103...
... Knock advance angle calculation circuit section 104 ... Retard amount storage circuit section agent Asamura Kogai 4 people Fig. 2 Fig. 3 Fig. 4

Claims (1)

[Scope of Claims] (1) A knock sensor that detects the occurrence of knock from the engine, a fail detection circuit that detects an abnormality regarding the detection output of the knock sensor, and the occurrence of knock due to the detection signal of the knock sensor. a knock detection circuit section that discriminates and detects the presence or absence of 3 degrees, a knock advance calculation circuit section that corrects the ignition advance angle based on the determined output value of the knock detection circuit section, and a retard amount of the calculation circuit section. and a retardation amount storage circuit section that selects and updates the memory of the maximum value (Q'k) of the retardation amount according to the output value (Qk), and the fail detection circuit section detects an abnormality of the knock sensor. A knocking control device characterized in that an ignition retard amount is corrected by a maximum value (θ'k) stored in the retard amount storage circuit section. (2. In the control device according to claim 1,
The retard amount storage circuit section is configured to store the knock sensor's 0<K<1.
1. A knocking control device comprising a circuit for weighting a constant value of 0). (3) In the control device according to claim 1 or 2, the stored value in the retard amount storage circuit section is composed of a two-dimensional map with engine load and engine rotation speed as variables. A knocking control device characterized by: