RU2676749C2 - Method for controlling internal combustion engine during its operation - Google Patents

Abstract

FIELD: engines and pumps.SUBSTANCE: invention relates to the engine building. This technical result is achieved by adjusting the flow of air into the inlet channel of the combustion chamber by the throttle valve associated with the driver's pedal. In the method, the pulse-width modulator of the electronic engine control unit delivers a pulse of fuel to the nozzle at the moments of the operating positions of the engine shaft. Further, the pulse duration is proportional to the absolute static air pressure in the intake channel. And the acceleration mode signal is received via the frictional bond of the sensor – the limit switch with throttle movement, and the idle signal is received via the bond of the position sensor – the final switch of the throttle position. Moreover, the proportional factors are switched using sensor signals and corrected to the optimum in engine operating conditions.EFFECT: technical result consists in saving fuel and choosing the driving mode at the required engine power.1 cl

Description

The invention relates to engine building and can be used in the field of regulating an automobile internal combustion engine equipped with an Electronic Control Unit, which, according to the signals of the engine operating parameters sensors and the position of the throttle valve of the air intake channel into the combustion chamber controlled by the driver’s pedal, generates synchronous with the shaft operating position engine impulse of variable duration to the fuel injection valve in the combustion zone. The start-up and idle, acceleration and uniform operation of the internal combustion engine are determined by the ECU, which controls the air / fuel ratio in the combustible mixture and the quantity of the mixture in various engine operating modes, supporting typical parameters of the environmental cleanliness of gas emissions, economy and power of the internal combustion engine depending on operating conditions . Actual tasks and operating conditions may differ from typical ones. The presence of the “economical - sporty” engine operating mode switch for some models does not provide precise engine tuning in a wide range of loads. This leads to irrational use of engine power and increased fuel consumption.

The well-known "Method of regulating the power of an internal combustion engine with external mixture formation and a device for its implementation" according to copyright certificate SU 1677359, IPC F02D 41/02, 35/00, 28/00. The method includes measuring in a digital code the frequency of rotation of the engine shaft, the vacuum in the intake manifold, calculating the effective moment on the engine shaft, comparing it with a given moment from an external driver and adjusting the angle of the throttle position using a controlled drive. In this case, the correction is carried out according to the control tabular data of the speed characteristics recorded in the device memory and related to this type of engine. However, a method using this table is not effective when changing the conditions of external mixture formation and the influence of uncontrolled factors (engine wear, fuel quality and composition, air composition, etc.). Consideration of a greater number of influencing factors on the operation of the engine is possible by equipping it with various parameter sensors associated with an ECU based on a microcomputer that controls electromagnetic or piezoelectric regulating actuators. An exemplary set of sensors and actuating control devices for an internal combustion engine is given in another well-known description of the invention to the patent “Fuel injection device and method of controlling it” RU 2434158 C2, IPC F02D 41/40, patent holder “Toyota Jidosia Kabushiki repent”. The device contains sensors for the accelerator, the opening angle of the throttle, the speed and position of the crankshaft of the engine, the pressure and air flow rate in the inlet channel, the temperature of the engine and exhaust gas, the composition of the exhaust gas, etc., as well as the fuel injection solenoid valves, the electric actuator for controlling the opening angle inlet throttle etc. The disadvantages of this method of engine control include the complexity of the hardware and software for highlighting the parameters of the transient acceleration mode, the need for duplication of the sensors and equipment responsible for the safety of movement for the reliability of their work, the complexity of the ECU tuning by specialists. Despite the investigation of a set of typical speed characteristics on internal combustion engines at ICEs and under operating conditions in various operating modes and on writing standard control data to the permanent memory of the ECU microcomputer of a specific commercially available internal combustion engine, there are drawbacks in regulating the engine, which has certain deviations from the standard. Research results may constitute a trade secret of the manufacturer. Operational adjustment in the field of a specific ICE according to operating conditions, wear and repair, fuel quality is not provided. A lot of sensors, actuators, complexity and "opacity" of the software and hardware of the engine management system algorithms - all this reduces the reliability and maintainability of ICE in the field. Repair of the engine management system recommended by microcomputer diagnostics of a car in specialized service stations, which are not enough in sparsely populated areas, does not seem real. In the event of malfunctioning sensors and equipment malfunctions, the microcomputer control system switches to emergency operation, which does not guarantee fuel economy, sufficient ICE power, and environmental cleanliness of gas emissions during operation. There is a tendency to complicate measurement methods and devices for obtaining pressure data in the inlet window of the working cavity in order to increase the accuracy of air charge measurements taking into account the dynamics of filling and calculation accuracy for controlling the operation of the engine in transient acceleration mode (Description of the invention “Data acquisition method (options) and a data acquisition system pressure data in the inlet window of the cylinder ”to patent RU 2584747, IPC F02D 9/02, F02D 41/18, F02D 41/22. However, improving the accuracy of measuring only the air charge in the cylinder is not enough. accurately measured dose of fuel from the nozzle and create a stoichiometric air / fuel ratio.

The known method used when duplicating control in the invention according to the patent "Engine Management System" RU 2267021 C1, IPC F02D 11/02, having a standard and emergency diesel control system. The standard control system contains sensors, a control microcomputer, an electromagnetic drive for positioning the fuel rail. When the standard control system fails, the emergency system is turned on. The emergency control system contains a spring-loaded membrane pneumatic actuator for the position of the fuel rail. The pneumatic actuator is connected by a pipeline to the vacuum cavity behind the air damper, which is installed at the inlet to the turbocompressor. The air damper is connected through the emergency mode enable mechanism to the control pedal. In the invention, a method is used that includes the selection of the vacuum behind the air damper and transmission through the pipeline to a spring-loaded diaphragm pneumatic actuator, which, by moving the fuel control rail, maintains engine speed according to the given position of the air damper from the control pedal. The disadvantage of this emergency control system is the use as a control parameter of the vacuum behind the air damper installed at the inlet to the turbocharger. The specified vacuum does not correspond to the actual filling of the engine working cylinder with air. There is also no operational correction of the air / fuel ratio for various engine operating modes.

The environmental cleanliness of the exhaust gases, the efficiency and increased power of the internal combustion engine depend on the amount of fuel-air mixture in the engine at the intake phase and the air / fuel ratio in the working volume of the combustion chamber. The amount of fuel in the pulse dose of the internal combustion engine is set by the position of the diesel fuel supply rail or by the activation time of the fuel supply actuator (electromagnetic or piezoelectric valve of the fuel injector) and the absolute pressure difference at the inlet and outlet of the nozzle. The dose of fuel is supplied synchronously with the working position of the engine shaft. The fuel pressure at the nozzle inlet is usually kept constant by a pressure regulator.

The closest analogue of this invention is the "Method of controlling an internal combustion engine depending on operating conditions" according to patent application RU 2013122001 A. The method dispenses fuel with an electromagnetic nozzle in proportion to the absolute static air pressure in the cylinder inlet and synchronously with the operating positions of the engine crankshaft. At the same time, the proportionality coefficient is adjusted depending on the operating conditions at the request of the driver in choosing the “economical or sporting” nature of movement.

When communicating with the inlet channel of the combustion chamber of the engine, the working air mass is determined by the absolute static air pressure in the inlet channel, which occurs after throttling the air flow by the damper. The mass of air entering the combustion chamber during the inlet phase is determined from the equation of state of an ideal gas.

PV = RTM / k, where

P - absolute static pressure in the inlet;

V is the working volume of the combustion chamber;

T is the absolute temperature of the air;

R is the gas constant;

M is the mass of air in the working volume of the combustion chamber;

k is the apparent molecular weight of air.

Obviously, the mass M of air in the working volume of the combustion chamber is

and is proportional to the absolute static pressure P in the inlet channel. Therefore, by opening and closing the throttle, we adjust the absolute pressure and air mass in the working volume of the combustion chamber in the inlet channel. The dosed mass of fuel, for example, with a nozzle in the working volume V of the combustion chamber can be determined from the expression

, где

where

m is the mass of the dose of fuel;

q is the density of liquid fuel;

s is the working section of the fuel nozzle outlet;

u is the fuel speed at the outlet of the nozzle;

t is the fuel dosing time.

The fuel speed is determined from the condition that the velocity head of the fuel is equal to the differential pressure difference of the fuel at the inlet and outlet of the nozzle according to the expression

, где

where

z is the pressure drop across the nozzle (the difference between the absolute inlet fuel pressure at the nozzle and the absolute pressure in the fuel injection area);

u is the fuel speed at the outlet of the nozzle.

Therefore, the fuel speed from equation (3) is equal to

The mass of the dose of fuel is determined by substituting equation (4) in expression (2)

From equation (5) it is seen that the mass of the dose of fuel is proportional to the time of dosing of fuel.

The ratio of the mass M of air to the mass m of fuel is expressed by equation (6)

From the expressions (6) it can be seen that if the mass of the fuel dose m or the dosing time t are proportional to the absolute static air pressure P in the inlet channel, then the air / fuel ratio (6) is constant up to variations of the influencing values in the coefficients

The actual air / fuel ratio (6) depends on the totality of the structural, physical, and chemical quantities affecting the coefficient (7). These are air and engine temperatures, fuel quality and dispersion, air composition and consumption, engine wear, inlet duct leakage, deposits on nozzle nozzles, etc. However, the method does not specify the signs and actions for determining the engine acceleration mode during operation, which is the purpose of the proposed invention.

The goal of the proposed invention "Method of regulating the internal combustion engine during operation" is achieved with an adjustable air supply to the inlet of the combustion chamber by a throttle valve connected by a mechanical drive to the engine control (driver’s pedal), by measuring the absolute static pressure in the inlet of the combustion chamber by a sensor, conversion The pulse-width modulator of the measured pressure in a proportional pulse of fuel metering inlet or combustion chamber and proportional correction in ICE operating modes. In this case, the operation mode of the internal combustion engine ECU when accelerating the movement is determined by the signal of the sensor - the limit switch of the direction of movement of the throttle valve in the opening direction.

To achieve this goal, they use well-known PWM ECU electrical circuits and end switch designs, a detailed description of which is not required in the opinion of the author. The electrical circuit of a specific PWM synchronized from the rotation of the engine shaft at ignition times, and generating pulses to the coil of the electromagnetic nozzle with a duration directly proportional to the voltage supplied to the PWM control input, is presented in the description of the invention to patent RU No. 2107179 “Device for controlling the supply of fuel to the internal engine combustion ”in FIG. 2. In the method proposed by the author, the control voltage is supplied to the PWM from a GAZ 745.3829 type absolute pressure sensor (GAZ 745.3829 (Russia), which is connected with a short vacuum hose to the inlet channel cavity after the throttle valve. The start synchronization of the PWM ECU is taken along the front of the differentiated pulse from the switch of the ignition system, controlled by the signals of the Hall sensor of the working position of the engine shaft. The proportion of the conversion of the control voltage at the input to the PWM ECU to the pulse width at the output for controlling the fuel supply to the inlet channel or combustion chamber depends on the timing trimmer resistor of the integrated PWM ECU, which is used for correction. For the operation of the proposed method, the PWM ECU and the DBP are installed on a Volkswagen Golf 2 car for controlling the internal combustion engine as a single injection. The intake channel of the internal combustion engine has a nozzle for fuel injection, a spring-loaded throttle valve controlled by a cable from the driver’s pedal. For ease of control of the idle position of the throttle and limit switch XX, a flexible shaft for manual drive is installed instead of the electric drive. ICE operation modes are determined by switching the limit switches in the XX position of the throttle and the limit switch of the direction of movement of the throttle in the direction of opening or closing. A micro switch type MP9-P1 (Russia) is used as a limit switch for the direction of movement, which is mounted on the bracket of the mono-injection unit near the throttle valve and is controlled by a slider dressed on a cable from the driver’s pedal. Moreover, the slider is equipped with a spring-loaded friction coupling with a cable. Moving the slider is limited by the working area of the limit switch direction of movement. The contacts of the limit switch XX and the contacts of the limit switch of the direction of movement switch the tuning resistors of the time-varying integrated resistive-capacitive circuit of the PWM ECU in the start mode and XX, accelerated or uniform movement. Trimmer resistors are tuned to the optimal air / fuel ratio (6) when the driver controls the shaft speed using a frequency meter on the driver’s dashboard, the vehicle’s torque, the cost-effectiveness of reducing the trimmer resistance in various modes of engine operation under operating conditions.

The proposed invention "Method for regulating an internal combustion engine during operation" works as follows. During the rotation of the ICE shaft, the Hall working position sensor sends voltage control pulses to the ignition system switch, the amplified pulses from the switch differentiate and the front of the pulse turns on the electronic key of the ECU by the nozzle and simultaneously starts the capacitor charge of the PWM PWM circuit to the control voltage from the DBP. At the end of the charge, the electronic nozzle control key is closed. The time of charging and turning on the nozzle for fuel supply is proportional to the absolute pressure in the inlet channel of the internal combustion engine and also depends on the value of the tuning time-setting resistor in the integrated charge circuit of the capacitor. Under the control of the driver’s pedal, the movement of the cable changes the position of the throttle in the intake channel of the combustion chamber. The limit switches XX and the throttle direction of movement determine the operating mode of the internal combustion engine and turn on their corresponding electrical contacts the corresponding tuning timing resistor of the PWM ECU integrated capacitance circuit, the resistance value of which is adjusted by the driver upon the optimal operation of the internal combustion engine on real fuel, achieving economical fuel consumption by reducing the tuning resistance in acceleration mode in the field.

The advantage of the proposed method includes: the simplicity and reliability of determining the acceleration modes of the internal combustion engine ECU according to the signal of the sensor, the limit switch, frictionally connected with the movement of the throttle valve in the inlet channel of the combustion chamber; the possibility of economical fuel consumption and optimal regulation of the air / fuel ratio to reduce the tuning resistance in all engine operating conditions under operating conditions.

Claims (1)

A method of regulating an internal combustion engine during operation, including an adjustable air supply to the inlet of the combustion chamber by a throttle valve connected to the driver’s pedal, generating, by the electronic control unit signals from the working sensors of the impulse of an impact on the fuel metering actuator, proportional to the absolute air pressure in the inlet channel and synchronously with the working position of the engine shaft, characterized in that they determine the mode of acceleration of the engine according to the sensor signal - con ary switch frictions associated with the throttle movement.