It is known that the optimal power characteristics of the engine of the vehicle with traditional contact ignition system can be achieved (if other being equal) only in case of correctly selected time closed, and means, and an open state of contact breaker ignition system. It it is important because the time of the closed state and actually determines the number the energy provided by the ignition coil in each cycle of sparking, and the time open - burning time of the fuel mixture. When the electronic ignition module incorrectly set time conditions may lead to failures and run the ignition system.
Unfortunately, the majority of motorists underestimates the above-mentioned factor. Usually the gap between the breaker contacts (namely the size of the gap depends time contacts closed state) set "by eye", not using any devices. It is clear that this approach can lead to loss of power and loss of efficiency of the engine. About solutions to this important problem the magazine reported more than once. The author offers another solution.
About the time of the closed state of the contacts (KYC) breaker is usually judged on the corner, which at this time rotates the shaft breaker-way valve of the engine. The angle of rotation is conveniently determined using the average voltage Ucp, measured, for example, the breaker contacts [1]. This voltage is linearly decreases with increase in angle so the scale reading of the voltmeter should be in the opposite direction, in accordance with the formula (in the fair the case for four-cylinder engine):
αзск(deg.)=90(East Ucp)/East (1).
A simplified circuit diagram of measurement (she used in industrial shape) shown in the figure.
Described in [1] method of measurement of the angle KYC does not require prior calibration device when servicing of any vehicles, but has a significant drawback - the need to "reverse" the scale of the device and its pre-digitization. In fact, the instrument measures the angle of an open condition of the contacts.
You can measure the angle of KYC and conventional DC voltmeter as described in [2]. In this case, the average voltage measured at low voltages conclusions ignition coil. The process is performed in two steps - first by working the engine measure the voltage Uб.with the onboard network, and then on the findings of the coil ignition measure average voltage Ucp. Then the angle KYC (in degrees) for four-cylinder engine will be equal to: αзск=90Uср/Uб.with (2). The scale of this appliance direct, and measures the angle he KYC.
The advantages of this method are obvious, but it is associated with the necessity of computing, in most cases, of course, is inconvenient. Without the calculations in this if not do because the vehicle voltage even on the same car may change for many reasons, different the car it is always variously. This means that continuous grading scale αзск cannot be fundamentally.
However, there is a way to directly measure the angle normal KYC widely common DC voltmeter (avometra) performing the function integrator.
Let us return to the formula (2) and rewrite it in a slightly different form:
αзск=PR/n6.with (3),
where n6.with the number of divisions of the scale of the voltmeter, which deviated arrow when measuring U6.with a RPS is the same WHEN measured on the same scale). Take n6.with a constant value. In this case αзск=K. RPS (4) where K=90/n6.C=const.
Thus, we obtain the linear equation with constant coefficient, showing how many degrees of angle KYC account for one division of the scale. It is easy to see that if K=1, i.e. Pb.with taken equal to 90 scale divisions, RPS will directly reflect the angle of the legislative Assembly in degrees:
αэск=1ncp(5).
In practice it is usually not necessary to measure the angle of KYC in the range from zero to maximum deflection. It is enough to highlight the scale of the plot acceptable (recommended) values of the angle, and this phase may be calculated and charted in advance,provided that the number of SDS.since then constant for all measurements. The absolute value of Pb.with may be taken by any, but to reduce measurement error should be selected at the end of the scale and preferably such that It was an integer. Very udobno why the scale voltmeter with 90 or 100 divisions, allowing the direct reading of the angle KYC in accordance with (5) though (4) shows that the possible variety varianty of the scale.
As a device for measuring fit any ready voltmeter DC current or avometr, having among other subbands 0...1 or 0...10 V. Connect the device to the conducting circuit through the serial variable resistor (rheostat); it is integrated in a housing of the voltmeter, moving the handle to one side walls, or made as a separate pristavki.
The resistance of the variable resistor (in kiloomah) can be approximately calculated by the formula:
R=1,5 - 103(U6 C-Unp)/In.Oh,
where Unp - limit scale voltmeter,; I n.on - current full deflection arrows, mA.
The process of measuring the angle KYC is not fundamentally different from those described in [2], but contains one new operation. When measuring voltage CHD incremental variable resistor set the voltmeter to a pre-selected value of the PBS (and do this at each measurement angle KYC), and then measure the actual the angle of the direct readout of its value on the scale.
In the most General case, the scale of the instrument when you select graduate or mark to the extent necessary by the formula (4). To increase objectivity setup measurement PBS and withdrawal indications ncp should be conducted on a sustainable low engine speed.
Measurement error angle KYC depends mainly on the accuracy class used a pointer device and is normally in the range 3...5% (specified in [2] the accuracy of 0.3% is incorrect). This is enough, because technical conditions allow quite a significant variation in the angle (Zhiguli engine, for example, 52...58 deg.). To set the same angle with KYC an error of less than 2...3 degrees, almost impossible because of the backlash of the mechanism of the motor.
Those who have already repeated the device described in [2], advise again to enter subrange 0...1 V and embed a variable resistor that allows the installation of PBS near the end or at the end of the scale. At independent fabrication voltmeter you can use a microammeter with a current full deflection from 50 to 500 μa and the resistance of from 200 to 2000 Ohms. When awkward on the scale graduations I recommend to allocate it only sector required (valid) values of the angle KYC and extreme areas to designate as "More" or "Less". The boundaries of sector determined by the formula (4), and PBS chosen at the end of the scale. In the simplest case the calculated values of the angle just write on the front panel.
For the voltmeter is enough two ranges: 0...1 or 0...15 V (or 0...20 V), and the first of them is possible to withdraw only to measure the angle KYC.
The described device provides the installation angle KYC breaker battery system ignition with the required accuracy, tested by the author in practice. If the car is equipped with electronic ignition unit, it is possible to set the angle we have to return to the battery system.
Literature
Author: G. Karasev, St. Petersburg