CN102817761A

CN102817761A - Method for restraining engine knock

Info

Publication number: CN102817761A
Application number: CN2011101570808A
Authority: CN
Inventors: 邵永松
Original assignee: ZHENJIANG RUNXIN TECHNOLOGY INFORMATION Co Ltd
Current assignee: ZHENJIANG RUNXIN TECHNOLOGY INFORMATION Co Ltd
Priority date: 2011-06-10
Filing date: 2011-06-10
Publication date: 2012-12-12

Abstract

The invention discloses a method for restraining an engine knock. The method includes that before the engine ignition, a weighting calculation is performed by utilizing parameters in a combustion process, an overlarge knock is predicted, firing time is controlled, when cycles which exceed a critical value are lower than 20% of a total cycle, the possibility of occurrence of the overlarge knock is low, so that a cylinder with the low possibility can be determined to be safe, when cycles excessively exceed the critical value, the possibility of the overlarge knock of the cylinder is high, and the ignition is required to be controlled. The method has the advantages that by means of the data analysis in the combustion process, the occurrence of the overlarge knock can be absolutely predicted, by means of the control of the ignition angle of advance, the damage to the engine is reduced, simultaneously the knock sensor can be replaced, and the cost of the whole vehicle is saved.

Description

A kind of method that suppresses engine knock

Technical field

The present invention relates to a kind of method that suppresses engine knock.

Background technique

The working principle of petrol engine is to suck combination gas, and---effect of these four strokes of compression---work by combustion---exhaust realizes the running that motor goes round and begins again.After motor sucks fuel-steam and AIR MIXTURES, at the compression stroke ignition location of no show design also, because other factors outside controlling cause fuel gas mixture ignition voluntarily.The enormous impact power that produced of burning and piston motion in the opposite direction causes engine vibration, and this phenomenon is called pinking.

Pinking is very harmful phenomenon for motor, and main harm is: engine power decline, oil consumption increase, noise strengthen, deterioration of emission.Can cause in the time of the most serious that engine knock, engine misses and engine mechanical parts destroy.The reason that causes sudden and violent shake mainly contains: firing angle too shifts to an earlier date, the excessive carbon distribution of engine chamber, engine temperature is too high, air fuel ratio is incorrect, octane number of fuel oil is low excessively, the fuel oil turbidity test are not enough.The method that wherein suppresses engine knock the most immediately and effectively is exactly the after-ignition advance angle.

In order to suppress engine knock, for the control of ignition advance angle, method commonly used is to install detonation sensor additional at present.When detecting engine knock, then with ignition advance angle delay not can pinking igniting opportunity, when treating not pinking of motor, ignition advance angle is replied slowly again.But install detonation sensor additional, will inevitably increase the cost of car load.

Summary of the invention

Goal of the invention: the objective of the invention is to deficiency, provide a kind of and need not install detonation sensor additional, but suppress the method for engine knock through the data computing in the engine combustion process to above-mentioned technology.

Technological scheme: the method for inhibition engine knock of the present invention does; Before engine ignition; Utilize the parameter in the combustion process to carry out weighted calculation; Predict excessive pinking and control ignition time: when the periodicity that surpasses critical value be lower than total cycle 20% the time, the possibility that excessive pinking takes place is very little, can judge that such cylinder is safe; And surpassing a lot of cylinder of periodicity of critical value, the possibility that excessive pinking takes place is big, need control igniting.

These parameters comprise: 1, the previous cycle on to middle pressure climbing (dP/d θ) tdc that puts in preceding 20 ° of intervals; 2, maximum pressure Pmax; 3, go up to point pressure Ptdc; 4, mean effective pressure Pmi; 5, the pressure P eo of exhaust valve opening; 6, exhaust process middle pressure Pexhmean; 7, go up pressure difference Δ Ptdc to the some front and back; 8, the breathing process middle pressure Psucmean in same cycle; Pressure P ic when 9, Aspirating valves cuts out; 10, the average differential pressure Pexh-Psuc of exhaust process and breathing process; 11, thermal expansion indices P sucmean/Pmax; 12, the constant of fixing.

The present invention compared with prior art, its beneficial effect is: the inventive method can predict the generation of excessive pinking fully through the data in the analytic combustion process; Through the control ignition advance angle; Minimizing also can substitute detonation sensor simultaneously to the harm of motor, practices thrift the cost of car load.

Description of drawings

Fig. 1 is in ignition advance angle+6 °, the relation of (dP/d θ) tdc and Δ Pmax (pinking).

Fig. 2 is in ignition advance angle+6 °, the relation of Pmax and Δ Pmax (pinking).

Fig. 3 is another cylinder in ignition advance angle+6 °, the relation of (dP/d θ) tdc and Δ Pmax (pinking).

Fig. 4 is another cylinder in ignition advance angle+6 °, the relation of Pmax and Δ Pmax (pinking).

Fig. 5～8th, under the identical operating conditions, situation during difference cylinder ignition advance angle+4 °.

Fig. 9～10 are the excessive pinking amplitude of each cycle portions and the dependency relation of exhaust process middle pressure.

Figure 11,12 expressions be advance angle+4 ° the time with the difference of the situation of+6 ° of advance angles.

Embodiment

Be elaborated in the face of technological scheme of the present invention down, but protection scope of the present invention is not limited to said embodiment.

Embodiment:

A kind of method that suppresses engine knock before engine ignition, utilizes the parameter in the combustion process to carry out weighted calculation, predicts excessive pinking and control ignition time.Said parameter comprise the previous cycle on to put middle pressure climbing in preceding 20 ° of intervals, maximum pressure, go up pressure, exhaust process middle pressure, go up to the point pressure difference to point pressure, mean effective pressure, exhaust valve opening, the breathing process middle pressure in same cycle, average differential pressure, the fixing constant of thermal expansion exponential sum of pressure, exhaust process and breathing process when Aspirating valves cuts out.

Fig. 1,2 have represented in ignition advance angle+6 ° the relation of (dP/d θ) tdc and Pmax and Δ Pmax (pinking).Can very clearly see, in Fig. 1,, and among Fig. 2, when Pmax surpasses 105bar, the above strong pinking of peak swing 30bar take place as (dP/d θ) when tdc has surpassed 2.3bar/ °.And under the same case, excessive pinking does not take place in other cylinder.Like Fig. 3, shown in 4, so can find out from Fig. 1-4.When the periodicity that surpasses critical value be lower than total cycle 20% the time, the possibility that excessive pinking takes place is very little, can judge that such cylinder is safe.And surpassing a lot of cylinder of periodicity of critical value, the possibility that excessive pinking takes place is big, need control igniting.

Fig. 5-the 8th, under the identical operating conditions, situation during ignition advance angle+4 °.Visible by figure, to compare during with+6 °, critical value diminishes a little, but same situation when also appearing with+6 °.

Fig. 9, the excessive pinking amplitude of 10 each cycle portions and the dependency relation of exhaust process middle pressure.Excessive pinking wherein appears among Fig. 9.And do not have among Figure 10.Can see that from Fig. 9 exhaust process pressure also becomes greatly when maximum pinking occurring, and is a negative and very big value.This is because the thermal distortion that higher numerical value of the pressure meter that causes of excessive heat load and negative pressure cause, and this phenomenon is inevitable physical phenomenon.Such situation occurs with the grievous injury motor, should avoid as far as possible.

Figure 11,12 expressions be advance angle+4 ° the time with the difference of the situation of+6 ° of advance angles, even No. 3 maximum cylinders of pinking do not have middle pressure to become the result of negative pressure in exhaust process, running state is also normal.

So utilize doping that the exhaust process middle pressure can be correct whether to have big pinking to take place.

As stated, although represented and explained the present invention that with reference to specific preferred embodiment it shall not be construed as the restriction to the present invention self.Under the spirit and scope of the present invention prerequisite that does not break away from the accompanying claims definition, can make various variations in form with on the details to it.

Claims

1. method that suppresses engine knock; It is characterized in that: before engine ignition; Utilize the parameter in the combustion process to carry out weighted calculation; Predict excessive pinking and control ignition time: when the periodicity that surpasses critical value be lower than total cycle 20% the time, the possibility that excessive pinking takes place is very little, can judge that such cylinder is safe; And surpassing a lot of cylinder of periodicity of critical value, the possibility that excessive pinking takes place is big, need control igniting.

2. the method for inhibition engine knock according to claim 1 is characterized in that: said parameter comprise the previous cycle on to put middle pressure climbing in preceding 20 ° of intervals, maximum pressure, go up pressure, exhaust process middle pressure, go up to the point pressure difference to point pressure, mean effective pressure, exhaust valve opening, the breathing process middle pressure in same cycle, average differential pressure, the fixing constant of thermal expansion exponential sum of pressure, exhaust process and breathing process when Aspirating valves cuts out.