CN2099203U

CN2099203U - Microcomputerized testing apparatus for automobile engine

Info

Publication number: CN2099203U
Application number: CN 90215162
Authority: CN
Inventors: 宋培森; 黄晓虹
Original assignee: Chongqing Shapingba District Traffic Bureau; CHONGQING NORMAL COLLEGE
Current assignee: Chongqing Shapingba District Traffic Bureau; CHONGQING NORMAL COLLEGE
Priority date: 1990-12-03
Filing date: 1990-12-03
Publication date: 1992-03-18

Abstract

The utility model relates to a device, which is especially for detecting the performance of an automobile engine. The utility model is composed of a sensing device for collecting signals, a signal collecting circuit, a microcomputer processing system, a power supply, etc. The utility model can carry out multi-parameter detection to gasoline engine and electrical failures under the condition that an automobile is not disjointed, and a result is displayed digitally. The utility model has the advantages of small volume, light weight, low cost and simple operation, and because the battery of the detected automobile is directly adopted as a power supply, the utility model is conveniently used in field, night and occasions which are far from alternating current power supplies.

Description

Microcomputerized testing apparatus for automobile engine

The utility model relates to a kind of motor car engine micro computer detection device, it is that remanufactured-vehicle business uses, be applicable to four, six, eight cylinders, 12 overhead accumulator igniting types, minus earth, the operating mode major failure of four-stroke motor car engine is carried out the device of comprehensive detection.

At present, the motor car engine detection device that general utility functions are single, mostly with " the platinum signal " of the automotive ignition system that extracts as testing signal, the device that has is except extracting " platinum signal ", also on the bent axle of automobile, extract a tach signal with light fax sensing mode, thereby function increases to some extent, but owing to require on bent axle, to install photoelectric sensor, make on the one hand complexity is installed, and the position that the sequential of tach signal and platinum signal is installed with photoelectric sensor is different a randomness, so it can not detect on the motor car engine and cooperates all relevant parameters with sequential; On the other hand, because apparatus function is single, exist certain narrow limitation in use.The comprehensive detection device of motor car engine is to produce for the detection of satisfying all properties of motor car engine, this class device has Japan cover " the ETS-101 automobile intelligence reason engine ANALYZER " of flourish Co., Ltd. and " the QFC-3 type automotive engine test instrument " of Jinan wireless six factories production etc., they are except extracting " platinum signal ", " cylinder signal " and " high-voltage signal " have also been gathered, the extraction point of signal and the wave mode of each signal are seen Fig. 1, Fig. 2, A among the figure, B, C is respectively " a platinum signal ", " high-voltage signal " reaches the extraction point of " a cylinder fire signal " and their waveform." ETS-101 " adopts the extracting mode of electromagnetic induction to signal, be about to an annular ferrite coiled coil, make the sensor of band clamp port, during use sensor is clipped in respectively on the isolation layer of 3 of ignition wire A, B, C, the induction electromotive force that produces on the coil is exactly the signal that will extract, its sensor is very convenient in use, but its structure and manufacture very complicated." what the QFC-3 instrument adopted is that electric resistance partial pressure is directly gathered fire signal, the bad back of high voltage ignition line insulating layer glass must be contained in sensor on the lead in use, thereby trouble.In addition, " QFC-3 instrument " is from pointer header, nixie tube shows and three aspects of igniting oscillograph obtain data, variation details by igniting oscillograph observation waveform, technical quality to the user is had relatively high expectations, and the switch that is provided with on the instrument, knob, and more than totally two ten of button, thereby the more complicated that operates; The operation of " ETS-101 " is then difficult more to be grasped.These two kinds of devices are all used AC-powered, are restricted when practical application, and in addition, it is big that they exist volume, and expensive deficiency is unfavorable for applying.

The purpose of this utility model is to overcome the deficiency that prior art exists, guaranteeing that measuring ability reduces cost in complete significantly and provide a kind of, also simplify the operation to greatest extent, adaptability is strong, is convenient to the micro computer detection device that can measure motor car engine in the situation that automobile does not disintegrate of popularization and application.

The utility model is made up of collecting part, main frame and the power supply three parts of signal, the signal of being gathered is " platinum signal ", " high-voltage signal ", " a cylinder fire signal " and voltage signal, wherein shield type capacitance-voltage-distributing type fire signal sensor LB, LC have been adopted in the collection of " high-voltage signal " and " a cylinder fire signal ", this sensor is one to have the clip of a pair of circular arc clevis mouth, it is by shielding casing (8), a pair of induction electrode (9), dividing potential drop capacitor C ", high frequency transmission line (7) forms; Induction electrode is separately fixed in the screening can, and the both sides of folder mouth constitute two circular arc clamp faces, the dividing potential drop capacitor C " a termination screening can, the other end is connected two induction electrodes serial connection back with high frequency transmission line; Employing metal holder KA, KD to " platinum signal " and voltage signal.

The circuit part of main frame is by the signal acquisition circuit part, function coding circuit (15) and form with basic microcomputer system and A/D converter that the read-only memory of 8031 computer processors and 8K * 8 constitutes; " the cylinder fire signal " that sensor LC takes imported a cylinder signal Acquisition Circuit (10), meets 8031 middle fracture INT through shaping circuit (12) ₀" the platinum signal " that platinum signal emitter KA gathers divides two-way, one tunnel input platinum signal acquisition circuit (11), meet 8031 interruption inlet INT1 through shaping circuit (12), 8031 P10 mouth with select the cylinder cutoff, survey and meet platinum signal emitter KA after element circuitry (14) connects, the cylinder cutoff is selected in control, the high-voltage signal that sensor LB gathers is accepted and believed the A/D converter that circuit (13) is sent into microcomputer system through high-voltage signal, and the voltage signal that sensor KD gathers is directly by A/D converter input microcomputer system; Function coding circuit (15) is by being arranged on the menu cutter multithrow switch K8 on the host machine casing panel and forming as two 8 three state buffer IC81, IC82 being connected with microcomputer system in the dial-up dish K82 that selects cylinder and the machine.

Power supply unit adopts the storage battery (1) of tested automobile.

The utility model has following accompanying drawing:

Accompanying drawing 1 is the basic block diagram of automotive ignition system;

Accompanying drawing 2 is the wave mode of each signal extraction point;

Accompanying drawing 3 is the " structural representation of shielding capacitance-voltage-distributing type fire signal sensing LB, LC;

Accompanying drawing 4 is the schematic block circuit diagram of host machine part;

Accompanying drawing 5 is the conspectus of microprocessor system;

Accompanying drawing 6 is the schematic representation of a cylinder signal Acquisition Circuit (10) and platinum signal acquisition circuit (11);

The schematic representation of accompanying drawing 7 high-voltage signal Acquisition Circuit (13);

Accompanying drawing 8 is the schematic representation of function coding power supply (15);

Accompanying drawing 9 is for selecting the schematic representation of cylinder cutoff, survey element circuitry (14);

Accompanying drawing 10 is the power supply input circuit schematic representation.

Above-mentioned accompanying drawing has provided a most preferred embodiment of the present utility model, below in conjunction with accompanying drawing present embodiment is described in detail:

As shown in Figure 1: the ignition system among the figure is by storage battery (1), spark coil elementary (2), and distributor cam (3), platinum touches (4), distributor (5), each cylinder spark plug compositions such as (6).The rotating band moving cam (3) of motor car engine rotates, make platinum touch (4) opening and closing constantly, form the self induction electromotive force of 100～300V at the A point in open moment, and form high pressure at the B point of the inferior line of spark coil, simultaneously B point high pressure passes to certain point among C～H through split fire head (5), and the spark plug that punctures this cylinder then makes the oil gas mixed combustion of this cylinder, the work done of promotion piston, certain of C～H a bit from the refire time of lighting a fire for the first time, can make four stroke engine change two commentaries on classics.

Fig. 2 is waveform and the sequential of 3 of A, B, C, by measuring the cycle of C point pulse, can calculate the rotating speed of motor; From receiving the pulse of C point, when certain predetermined value is arrived in the A point pulse that adds up, force A point short circuit a period of time by main frame, can cause certain cylinder cutoff like this, measure again the C point pulse interval simultaneously, can calculate the speed drop of motor, thus the horsepower balance of each cylinder of measured engine; Equally,, can calculate the igniting electromotive force of each cylinder, ignition voltage, short-circuit voltage (being rotor clearance voltage) in conjunction with the B point; When motor quickens, in certain scope, measure initial velocity and end speed, and write down 2 time, can calculate mean acceleration; The rotary inertia of binding engine self can be measured power indirectly; Can draw with the closing time of platinum and the ratio of opening the time and to weigh the poor of contact breaker gap whether correct quantity factor " angle of attachment ", the maximum value of in the one-period of C point pulse, measuring A point each cycle of pulse and minimum value, can check cam whether to have and wear and tear to reach and whether become flexible; After the platinum closure, survey the voltage drop that A is ordered, can check the quality of platinum.This shows, the utility model by gathering 3 of A, B, C signal and to their processing, can finish comprehensive detection to motor car engine.In addition, by checking the voltage of automobile storage battery, storage battery exports that voltage drops to minimum under the situation of big electric current in the time of can measuring engine start, with this whether estimate after the quality of storage battery and the engine rotation whether adjust to storage battery charging and regulator proper etc.

As shown in Figure 3, the shell (8) of shield type capacitance-voltage-distributing type fire signal sensor LB, LC is made by the metal of energy magnetic conduction, reaches the purpose of double electromagnetic shielding with this.Influence electricity level (9) adopts sealing compound to be bonded in the shielding case, during use this sensor clip is held on the external insulation glue-line of the high voltage wire that B point or C order, at this moment, lead and induction electrode (9) in the high voltage wire glue-line are split into an equivalent capacitance C ', "; the igniting high pressure is through C ', C " forms dividing potential drop owing to be provided with the dividing potential drop capacitor C in the sensor, the signal V that takes out from high voltage wire external insulation glue-line with induction electrode (9) ₀Send into main frame by high frequency transmission line, V ₀Be directly proportional with ignition voltage Vi actual on the high voltage wire.

V ₀＝ (C′)/(C′＋C″) Vi （3.1）

As seen, choose C " capability value, just can obtain distortionless transducing signal.

Accompanying drawing 4 is circuit block diagrams of main frame, four road signals that sensor LB, LC, KA, KD gather are sent into electronic circuit thereafter respectively, wherein a cylinder signal Acquisition Circuit (10) is gathered the signal of a cylinder signal sensor LC, platinum signal acquisition circuit (11) is gathered the signal of platinum sensor KA, and this two paths of signals is sent in the microcomputer system two middle fracture INT of 8031 respectively after shaping circuit (12) shaping ₀, INT1; High-voltage signal Acquisition Circuit (13) is gathered the signal of high pressure sensor under 8031 control, and sends into microcomputer system by A/D converter; Voltage signal sensor KD sends into microcomputer system with voltage signal by A/D converter; Under the control of P10 8031,, survey element circuitry (14), by platinum sensing KA output cutoff signal through selecting the cylinder cutoff; The effect of function coding circuit (15) is so that " interactive mode is notified microcomputer system, realizes conversion function with the manually-operable on the instrument panel.

As shown in Figure 5: the microcomputer processing fundamental system is made of IC51～IC55.IC51 is 8031 single-chip microcomputers, IC52 is the low eight bit address latch of 74L5373, IC53 is that model is the read-only memory of 2764 8K * 8, and IC54 is that model is 8 road successive approximation type a/d converters of ADC0809, and IC55 is that model is the sift register of 74LS221.P14～P17 of IC51 is the scanning mouth of the dynamic demonstration of four nixie tubes, and RXD, the TXD of IC51 export font with serial mode, and sift register IC55 is latched in QA～QH with font, finishes Presentation Function under the control of program; IC51 controls IC34 and exports control signal by P10 to function coding circuit (15) by the line selection mode with RD, WR and P20～P22, exports control signal by P11 to high-voltage signal Acquisition Circuit (13).

As shown in Figure 6: a cylinder signal Acquisition Circuit (10) is by resistance R 601～R607, capacitor C 61, C62, triode BG61, comparator IC61 forms, R601 is connected between a cylinder signal input end (6-1) and the BG61 ground level, R602 is connected between 8V power supply and the BG61 base stage, they are that starting point current potential with signal moves to 8V, when a cylinder signal arrives, (6-1) current potential of end descends, what extract in the base stage of BG61 is the partial pressure value of signal, by emitter output, improves the load capacity of pipe with this; R603 is connected between 8V power supply and the emitter-base bandgap grading, R604 is connected between emitter-base bandgap grading and the ground, they have set up an emitter current potential, also set up simultaneously the starting point current potential of negative input end for IC61, R605 and R606 are serially connected between 8V power supply and the ground, for IC61 provides a comparative voltage, what C61, R607, C62 formed is mode filter, it has also reduced the requirement to comparator IC61 Frequency Response except playing anti-interference effect, make it to adopt prevailing operational amplifier just; Low level of IC61 output is exported a high level when a cylinder signal arrives at ordinary times, through model is to hold the middle fracture INT0 that transports to IC51 by (6-3) after the monostable circuit IC63 shaping of 74LS221.

Platinum signal acquisition circuit (11) is by resistance R 608-R612, triode BG62, diode D61, capacitor C 63, comparator IC2 forms, the platinum signal is by the input of (6-2) end, through R608, send into the base stage of BG12 after the R609 dividing potential drop, the collector electrode of BG62 connects the 8V power supply, emitter-base bandgap grading is connected in series the back meets IC62 by the D61 positive pole positive input terminal with the D61 negative pole, R610, C63 is connected on the positive input terminal of IC62 respectively, R610, C63 is connected on respectively between IC62 positive input terminal and the ground, R611 and R612 are serially connected between 8V power supply and the ground, for IC62 provides a comparative voltage, BG62, D61, C63, the effect of R610 is the suitable broadening of platinum signal with input, to reduce IC62 comparator performance demands.The signal of IC62 output is imported the middle fracture INT1 of IC31 by (6-4) end after the IC63 shaping.

High-voltage signal Acquisition Circuit (13) is as shown in Figure 7: because each cylinder igniting high pressure output is the high-voltage pulse more negative than power cathode, detect the igniting high pressure, must solve problem and the anti-interference problem that single supply is handled negative peak; At first the signal that high pressure sensor LB is sent here moves to 6V with this signal along forward after doubly decaying by 2:1000, and the signal of 6V is remained on the minimum value Vmm that microcomputer can extract by circuit, thereby the actual calculated value that selects cylinder high pressure V is:

V＝k（6－Vmm）（7.1）

K is a scaling factor in the formula.

High-voltage signal assembly circuit (13) is by resistance R 701～R710, operational amplifier IC71～IC73, capacitor C 71, triode BG71, BG72 form, R707 and R708 provide a comparison signal to IC72, the control signal of the P10 pin of IC51 enters the positive input terminal of IC72 by (7-2) end, the output terminal of IC72 is connected on the base stage of GB72 by R706, the collector electrode of BG72 connects the 8V power supply by R705 respectively, connect the base stage of BG71 by R704, the emitter grounding of BG72, the emitter-base bandgap grading of BG71 connects the 8V power supply, and the collector electrode of BG71 connects the positive input terminal of IC73 by R703; The positive pole of D71 connects the output terminal of IC71, and negative pole 7a connects the IC73 positive input terminal and connects the 8V power supply by C71.High-voltage signal is by the input of (7-1) end, after R701, R702 decay, move to 6V, " emitter follower " that constitute through transport and placing device IC71 enters the negative peak holding circuit that is made of D71, C71, because when working as the high-voltage signal arrival of being surveyed, it is " low level " that microcomputer is held program control with (7-2), thereby BG71 is ended, the current potential that 7a is ordered reduces with input end and keeps, the emitter follower that constitutes by transport and placing device IC73 then, after R709, R710 dividing potential drop, send into A/D converter IC54 by (7-3) end, and by the microcomputer collecting treatment.When the igniting high pressure not to or be not in the time of will testing the signal of cylinder, it is high level that microcomputer is held program control by the P10 pin of IC51 with (7-2), thereby make the BG61 conducting, the current potential that 7a is ordered can not be held and rise to 6.6v, the also inoperative A/D converter of while microcomputer, so both realize the negative peak detection, bled off non-test cylinder igniting peak value residual on C61 by BG61 again.

As shown in Figure 8, function coding circuit (15) is eight three state buffer IC81 of 74LS244 by two models, IC82, the hilted broadsword 8 throw switch K81 and the model that are located on the machine shell panel are binary system dial-up dish K82, and 4 bit digital K switch, 83 compositions, K81 selects as the function of device, this switch is accessed a sky to be thrown and can form nine kinds of 8 codings, K82 is used to select cylinder number, K83 is as the fine setting of k value in (7.1) formula, throw the input end that meets IC81 respectively for 8 of K81, K82, K83 also constitutes one group of 8 coding, connect the input end of IC82, IC81, the output terminal of IC82 is connected with the D0-D07 of IC52～IC54 end, (8-1), (8-2) end is respectively IC81, the gating end of IC82, IC81,16 input ends of IC82 all pass through resistance eutral grounding, make it to present low level, work as K81, K82, when K83 pushes required two positions, to make IC81, the IC82 corresponding input end is received high level, this has just formed two groups of 8 codings, P20 as IC51, the P21 pin is by (8-2), (8-3) gating IC81, behind the IC82, make corresponding processing intelligently by regularly inquiring about identification in the microcomputer system.

As shown in Figure 9: select the cylinder cutoff, survey element circuitry (14) mainly by 555 time base circuit IC94, operational amplifier IC92～IC93, triode BG91, BG92, diode D91～D93, capacitor C 91, C92, resistance R 901～R912 forms; K switch 81 in function coding circuit (15) pushes the position of surveying element, when promptly being communicated with (9-4) end, (9-3) end is high level, D92 ends, 5V voltage just is added to by R901 simultaneously, R902, IC94, C94, on the time base circuit that C92 forms, at this moment an oscillator signal footpath of the 3 pin output R903 by IC94 sends into comparator IC92, after anti-phase, send into emitter follower IC92 through D91, behind R911, drive high-power switch tube BG92 by BG91 again, make it repeatedly saturated with end, platinum opens and closed operating mode when being 1700 rev/mins with the rotating speed of this simulated automotive motor, at this moment, if the negative collector electrode that meets BG92 with the fire coil arc, promptly (9-1) holds, the positive pole of positive termination power, then on spark coil secondary, produce the igniting high pressure, thereby the quality of check point fire coil and spark plug separately, R913 be connected on after D93 connects between (9-1) end and the ground, platinum sealing voltage signal is taken out by (9-2) end of drawing between R913 and D93, be sent to the input end IN4 of the A/D converter IC54 of microcomputer system, when K81 pushes other function, IC94 does not work, and the cutoff system only is subjected to (9-1) end to come from the control of the P11 pin of IC51, if need certain cylinder cutoff when detecting, low level of P11 pin output, make IC93 output high level, make the BG92 conducting at last, when the platinum contact disconnects, owing to the afterflow effect of BG92, make the secondary high pressure that do not produce of spark coil.

As shown in figure 10, power supply is by the storage battery (1) of tested automobile, two models are respectively 7805,7808 compositions such as three terminal regulator T1B, T2B, and after power switch K closed, voltage divided two-way to provide 8V or 5V voltage through two three terminal regulators and for other circuit.

Compare with prior art, the utility model has the following advantages:

1, test item is many, can detect automobile engine and electric system fault in the situation that automobile does not disintegrate, and can test separately spark plug and ignition coil again, namely has the element of survey function.

2, have higher high interference ability and certainty of measurement.

3, by the storage battery power supply of tested measuring car, applicability is wide, can be used for driving under field, night and the various mal-condition repairing personnel's quick diagnosis fault.

4, volume is little--80 * 80 * 20mm ³, in light weight--about 3.5kg, the power consumptive province--about 8 watts.

5, simple in structure, the price performance height.

6, operation is very simple, is easy to general personnel and grasps use.

Claims

1, a kind of motor car engine micro computer detection device, collecting part, main frame and power supply three parts by signal are formed, wherein the collecting part of signal comprises sensor LD and the LC that gathers a high-voltage signal and a cylinder fire signal, gathers sensor KA, the KD of platinum signal and voltage signal; Main frame is by operated key on casing, the casing and switch, and the electronic circuit in the casing constitutes, and it is characterized in that:

1) sensor LB, LC one have the clip of a pair of circular arc clevis mouth, it is by shielding casing (8), a pair of induction electrode (9), dividing potential drop capacitor C "; high frequency transmission line (7) is formed, and induction electrode is separately fixed in the screening can, and on the both sides that press from both sides mouth; " on the termination shielding case, the other end is connected two induction electrodes serial connection back with high frequency transmission line, and KA, KD are metal clip to constitute two circular arc clamp faces; the dividing potential drop capacitor C;

2) circuit part of main frame is by signal acquisition circuit (10,11,13,14), function coding circuit (15) and with 8031 chips of MCS-51 series, the read-only memory of 8K * 8, the basic microprocessing systems that A/D converter constitutes is formed, the signal that sensor LC takes is imported a cylinder signal Acquisition Circuit (10), meets 8031 middle fracture TNTO through shaping circuit (12); The signal input platinum signal acquisition circuit (11) that sensor KA gathers connects 8031 through shaping circuit (12) and interrupts inlet TNT1,8031 P10 pin with select the cylinder cutoff, survey and meet sensor KA after element circuitry (14) connects; The signal that sensor L8 gathers is sent into the A/D converter of microcomputer system through high-voltage signal Acquisition Circuit (13), and imports microcomputer system, and the signal that sensor KD gathers directly is input into microcomputer system by A/D converter; The circuit of function coding (15) is by being arranged on the menu cutter 8 throw switch K81 on the host machine casing panel and forming as two eight three state buffer IC81, IC82 being connected with microcomputer system in the dial-up dish K82 that selects cylinder and the machine.

2, motor car engine micro computer detection device according to claim 1, it is characterized in that a cylinder signal circuit (10) is by resistance R 601-R607, capacitor C 61, C62, triode BG61, comparator IC61 forms, R601 is connected between signal input part (6-1) and the BG61 base stage, R602 is connected between 8V power supply and the BG61 base stage, R603 is connected between power supply BG61 and the emitter-base bandgap grading, R604 is connected between emitter-base bandgap grading and the ground, R605 and R606 are serially connected between 8V power supply and the ground, for IC61 provides a comparative voltage, C61 is connected back ground connection with the end of BG61 and R607, the other end of R607 and the negative input end that meets IC61 after C62 is connected, the other end of C62 is connected on the 8V power supply, and signal is sent to the IC63 shaping after by IC61 output.

3, motor car engine micro computer detection device according to claim 1, it is characterized in that platinum signal acquisition circuit (11) is by resistance R 608-R612, triode BG62, diode D61, capacitor C 63, comparator IC62 forms, signal is by the input of (6-2) end, through R608, send into the base stage of BG62 after 609 dividing potential drops, the collector electrode of BG62 connects the 8V power supply, emitter-base bandgap grading is connected in series the back meets IC62 by the D61 positive pole positive input terminal with the D61 negative pole, R610, C63 is connected on respectively between IC62 positive input terminal and the ground, R611 and R612 are serially connected between 8V power supply and the ground, and for IC62 provides a comparative voltage, signal is transported to the IC63 shaping by IC62.

4, motor car engine micro computer detection device according to claim 1, it is characterized in that high-voltage signal Acquisition Circuit (13) is by resistance R 701～R710, operational amplifier IC71-IC73, capacitor C 71, triode BG71, BG72 forms, R707 and R708 are connected between 8V power supply and the ground and provide a comparative voltage for IC72, the input end of IC72 (7-2) connects the P10 pin of IC51, the output terminal of IC72 is connected on the base stage of BG72 by R706, the collector electrode of BG72 connects the 8V power supply by R705, connects the base stage of BG71, BG72 emitter grounding by R704, the emitter-base bandgap grading of BG71 connects the 8V power supply, and its collector electrode connects the positive input terminal of IC73 by R703; The positive pole of D71 connects the output terminal of IC71, negative pole connects the IC73 positive input terminal and connects the 8V power supply by C71, signal is by the input of (7-1) end, decay after the emitter follower that IC71 constitutes through R701, R702, the emitter follower input that is made of IC73 is sent into IC54 by (7-3) end after R709, R710 dividing potential drop at last.

5, motor car engine micro computer detection device according to claim 1, it is characterized in that function coding circuit (15) is eight three state buffer IC81 of 74LS244 by two models, IC82, being located at hilted broadsword 8 throw switch K81 on the machine shell panel and model and being 8421 dial-up dish K82 and 4 bit digital K switch 83 forms, throw the input end that meets IC81 respectively for 8 of K81, K82, K83 connects the input end of IC82, IC81, the output terminal of IC82 is connected with the D0-D07 of IC52-IC54 end, (8-1), (8-2) end is respectively IC81, the gating end of IC82, they respectively with the P20 of IC51, the P21 pin connects, IC81,16 input ends of IC82 all make it to be low level by resistance eutral grounding, and the switch terminal of K81-K87 is connected on the 5V power supply.

6, motor car engine micro computer detection device according to claim 1, it is characterized in that selecting the cylinder cutoff, survey element circuitry (14) mainly by time base circuit IC94, operational amplifier IC92-IC93, triode BG91, BG92, diode D91-D93 capacitor C 91, C92, resistance R 901-R912 forms, (9-3) the P10 pin of termination IC51, and connect the negative input end of IC93 by R907, R908, R909 is connected between 8V power supply and the ground, for IC93 provides comparative voltage, IC93 output termination D92 anode, (9-4) connection function coding circuit (15), R904, R906 is connected between (9-4) end and the ground, for IC92 provides dividing potential drop, R901, R902, IC94, C91, C92 forms time base circuit, the oscillator signal of the 3 pin output of IC94 enters the negative input end of IC92 through R903, R95 is connected between 8V power supply and the IC92 negative input end, the output termination D91 anode of IC92, D91, D92, negative terminal meets follower IC91, and connect the BG91 base stage through R911, and the collector electrode of BG91 is connected on the 8V power supply, and emitter-base bandgap grading connects the base stage of BG92 by R912, the BG92 emitter grounding, collector electrode is by the P11 pin of (8-1) termination IC51, and R913 and D93 are connected between (9-1) end and the ground, the input end IN4 of (9-2) the termination IC54 that draws between R913 and the D93.

7, motor car engine micro computer detection device according to claim 1 is characterized in that the storage battery (1) that its power supply that adopts is institute's survey automobile.