CN108350813A - The stage, starting for combustion engine control method is generated including warm-up phase and torque - Google Patents

Abstract

A kind of control method of starting for combustion engine（10）, including at least one cylinder, burn cycle sensor and counter comprising：Increase step by means of the fuel pressure of the first combustion mode（105）, temperature ascending step（110）, by means of the second combustion mode and it include at least one burn cycle, burn cycle detecting step（115）, detect successful burn cycle by means of burn cycle sensor and recorded by counter, repeat step（110）With（115）Until being equal to predetermined value, and the torque generation step by means of third combustion mode by the burn cycle number of counter records（120）.

Description

For the start-up of a combustion engine, including a warm-up phase and a torque-generating phase Control Method

technical field

The invention is directed to a control method for starting a combustion engine. The invention is applicable to gasoline, ethanol engine or gasoline and ethanol mixture engine.

For direct injection engines, the invention is particularly advantageously applicable in the combustion mode during the engine start-up phase.

Background technique

In order to start an engine including injection, it is known from the prior art to use a specific combustion mode for starting. This specific combustion mode governs a set of parameters that differ from the engine's operating parameters during normal operation.

It is known from the prior art to initiate a switchover from a combustion mode specific for start-up to a combustion mode dedicated to normal engine operation when an engine speed threshold is reached or when a predetermined time interval has elapsed since the engine started running.

A disadvantage of this system is the need to calibrate the management of the switching from a combustion mode specific for start-up to a combustion mode dedicated to normal operation of the vehicle, based on what is considered the worst-case scenario for the system.

In practice, the combustion mode dedicated to the start-up of the vehicle does not vary from vehicle to vehicle and does not allow to compensate for variability between vehicles, for example due to system ageing, production dispersion or even the characteristics of the fuel used.

As a result, vehicle-to-vehicle variability can lead to prolonged engine cranking times, or even failed cranking.

None of the current systems allow to satisfy all the required demands simultaneously, ie to ensure a start in exactly the required and reliable time regardless of the variability due to the vehicle and the fuel used.

Contents of the invention

The present invention aims to overcome all or some of these disadvantages.

To this end, according to a first aspect, the invention is directed to a control method for the start-up of a combustion engine comprising at least one cylinder, a combustion cycle sensor and a counter, the control method comprising:

• by means of the fuel pressure increase step of the first combustion mode,

• a temperature raising step by means of a second combustion mode and which comprises at least one combustion cycle,

• a combustion cycle detection step, which detects a successful combustion cycle by means of a combustion cycle sensor and registers it by means of a counter,

repeating the temperature raising step and the combustion cycle detection step until the number of combustion cycles recorded by said counter is equal to a predetermined value, and

• Torque generation step by means of the third combustion mode.

By means of these arrangements, the starting sequence of the engine including injection is divided into successive phases comprising at least three combustion modes. In each combustion mode, engine parameters such as ignition, throttle position, number of fuel injections, and fuel injection frequency are controlled. A combustion cycle sensor allows detection of a successful combustion cycle.

Each successful combustion cycle is recorded by a counter. When the number of successful combustion cycles recorded by the counter is greater than a predetermined value, switching from a second combustion mode configured to promote an increase in temperature in the engine to a third combustion mode is performed, and a third combustion mode The mode is configured to facilitate engine torque production.

These settings allow the engine to maintain the second combustion mode for the appropriate amount of time required on each system. Thus, the method object of the present invention allows starting the combustion engine without taking too long and reducing the risk of starting failures.

In other words, the method targeted by the present invention brings robustness against starting, especially for critical starting, for example at low temperatures. The method object of the present invention is particularly suitable for the starting of ethanol engines at low temperatures and the starting of engines supplied with gasoline or mixed fuels at very low temperatures.

The method object of the present invention differs from the prior art in particular in that it allows switching from the first combustion mode to the second combustion mode to be initiated without generating torque and thus speed, based on the number of combustion cycles performed.

In some embodiments, the subject method of the present invention, after the torque generating step, includes:

• The step of decelerating and running the engine normally by means of the fourth combustion mode.

In some embodiments, the first combustion mode does not include gasoline injection.

In some embodiments, the step of increasing the fuel pressure by means of the first combustion mode further includes reducing the pressure in the manifold by means of closing the throttle valve.

By means of these arrangements, the fuel pressure can be increased during the pressure increasing step. Furthermore, the characteristics of the first combustion mode allow reducing the volume of air contained in the cylinder. Reducing the mass of air contained in the cylinder by means of the first combustion mode allows evaporation of a sufficient amount of fuel to initiate cranking.

In some embodiments, the parameters manipulated in the second combustion mode are spark, throttle position, number of fuel injections, and fuel injection frequency.

Due to these arrangements, the second combustion mode allows increasing the temperature in at least one cylinder.

In some embodiments, the parameters manipulated in the third combustion mode are spark, throttle position, number of fuel injections, and fuel injection frequency.

A third combustion mode that promotes torque production is known in the prior art, ie it includes in particular the opening of the throttle valve, the increase of the injected fuel mass and the advance of the spark allowing to obtain the optimum torque.

Due to these settings, the third combustion mode allows engine torque to be produced.

In some embodiments, the combustion cycle sensor is a tooth signal sensor.

Thanks to these settings, the angular position of the crankshaft is determined. The sensor measures a signal indicative of the angular position of the crankshaft. The predetermined value of the angular position of the crankshaft corresponds to a top dead center position. The cylinder pressure sensor allows to determine when the cylinder is at top dead center and thus allows to detect the combustion cycle of the cylinder.

Advantageously, the tooth signal sensor allows an inexpensive implementation of the method according to the invention. In fact, the tooth signal sensor is installed in series on most of the models in the cycle.

In some embodiments, the combustion cycle sensor is a knock sensor.

Thanks to these settings, the sensor measures the vibrations emitted by the cylinder. The vibrations emitted by the cylinder are data representative of the position of the piston which allow to determine when the cylinder is at top dead center and thus detect the combustion cycle of the cylinder.

In some embodiments, the combustion cycle sensor is a cylinder pressure sensor.

Thanks to these arrangements, during the combustion cycle, the pressure in at least one cylinder is measured. The measured pressure is data indicative of cylinder position and it allows determining when the combustion cycle is operating correctly. A cylinder pressure sensor allows determining when a cylinder is at top dead center and thus detecting the cylinder's combustion cycle.

Advantageously, the cylinder pressure sensor allows accurate and real-time measurement of pressure, thereby allowing precise determination of the occurrence of a combustion cycle and quantification of the energy produced by that combustion.

According to a second aspect, the object of the present invention is a device implementing the method of control for the start-up of a combustion engine comprising at least one cylinder, a combustion cycle sensor and a counter, implementing the method object of the invention.

Since the purpose, advantages and specific features of the device are similar to those of the target method of the present invention, they will not be repeated here.

Description of drawings

Further advantages, objects and specific features of the present invention will emerge from the following non-limiting description of at least one specific embodiment of the device, method and system object of the present invention, with reference to the accompanying drawings, in which:

- Figure 1 shows an embodiment of the method object of the invention in the form of a flowchart,

- Figure 2 shows an embodiment of the method object of the present invention in the form of a graph of the rotational speed of the engine as a function of time,

- Figure 3 shows in graph form the temperature inside the cylinder as a function of the angular position of the crankshaft at an absolute pressure of 1 bar,

- Figure 4 shows in graph form the temperature inside the cylinder as a function of the angular position of the crankshaft at an absolute pressure of 0.3 bar, and

- Figure 5 schematically shows a specific embodiment of a device for carrying out the method object of the invention in a cross-sectional view.

Detailed ways

The present description describes in a non-limitative manner that each feature of one embodiment can be combined in an advantageous manner with any other feature of any other embodiment.

For now, note that the drawings are not drawn to scale.

In FIG. 1 can be seen a control method 10 for the start of a combustion engine, comprising at least one cylinder, a combustion cycle sensor and a counter, comprising:

• By means of a fuel pressure increase step 105 for the first combustion mode,

• temperature raising step 110 by means of a second combustion mode and comprising at least one combustion cycle,

• Combustion cycle detection step 115, detecting a successful combustion cycle by a combustion cycle sensor and recording by a counter,

Repeat steps 110 and 115 until the number of combustion cycles recorded by the counter is equal to a predetermined value, and

• Torque generation step 120 by means of the third combustion mode.

In other words, the method that is the object of the invention breaks down the starting of the engine including injection into different phases. These stages are each realized by means of a specific combustion mode.

Combustion mode refers to all controlled features during the engine operating phase. Controlled characteristics include ignition, throttle position, number of fuel injections, location of injections in the combustion cycle, amount of each injection, and pressure of injected fuel.

During a pressure increase step 105, the fuel pressure is increased by means of the first combustion mode.

In some embodiments, the step 105 of increasing the fuel pressure by means of the first combustion mode also includes reducing the pressure in the manifold by means of the closing of the throttle valve.

Closing of the throttle valve allows blocking of the air inlet and thus reducing the amount of air in the cylinder.

In some embodiments, the pressure is increased to about eighty bars.

In some preferred embodiments, the first combustion mode does not include gasoline injection.

During step 105 , the amount of air absorbed into the cylinder is reduced, this arrangement allowing to promote evaporation of the sprayed gasoline during step 110 of temperature increase.

During a temperature raising step 110, the temperature in at least one cylinder is raised by means of the second combustion mode.

In some preferred embodiments, the parameters manipulated in this second combustion mode are ignition, throttle position, number of fuel injections and fuel injection frequency.

The second combustion mode is configured to produce an increase in temperature without producing engine torque.

During step 115, a combustion cycle sensor detects a successful combustion cycle. Each successful combustion cycle is counted by a counter. The temperature raising step 110 and the detecting and recording successful combustion cycles step 115 are repeated as many times as necessary such that the counter reaches a predetermined number of successful combustion cycles.

In some embodiments, the combustion cycle sensor is a tooth signal sensor.

A tooth signal sensor measures a signal indicative of the angular position of the crankshaft. The predetermined value of the angular position of the crankshaft corresponds to a top dead center position.

In some embodiments, the combustion cycle sensor is a knock (cliquetis) sensor. In some embodiments, the knock sensor is a piezoelectric sensor and the signal measured is data representative of the position of the piston, which allows determining when the cylinder is at top dead center and thus detecting the combustion cycle of the cylinder.

In some preferred embodiments, the combustion cycle sensor is a cylinder pressure sensor. A cylinder pressure sensor measures pressure in at least one cylinder during a combustion cycle. The measured pressure is data indicative of cylinder position. A cylinder pressure sensor allows determining when a cylinder is at top dead center and thus detecting the cylinder's combustion cycle.

In some embodiments, the pressure values measured by the cylinder pressure sensors are compared to a reference curve. Since the pressure values in the cylinders are known for cycles with fuel combustion and also for cycles without combustion, comparing these reference values with the values measured by the cylinder pressure sensor allows to determine when the fuel is burning The cylinder cycle has already been achieved in the case.

In some embodiments, the temperature is measured by means of a temperature sensor. In some embodiments, switching from step 110 to step 115 is performed when the temperature measured in the cylinder is greater than or equal to a predetermined value.

In some embodiments, the transition from step 115 to step 120 is performed when the temperature is greater than or equal to a predetermined threshold and the number of successful combustion cycles recorded by the counter is greater than or equal to a predetermined value.

In some embodiments, the temperature is measured in the cylinder. Preferably, the sensors provided in the method of the invention are sensors capable of measuring the temperature and pressure in the cylinder.

In other embodiments, at least one temperature sensor is located on the cylinder wall. In other embodiments, the temperature sensor is located at the exhaust.

During a torque generating step 120 , engine torque is generated by means of a third combustion mode. The third combustion mode is configured to generate engine torque and increase engine revolutions per minute.

In some embodiments, the controlled characteristics include ignition, throttle position, number of fuel injections, location of injections in the combustion cycle, amount of each injection, and pressure of injected fuel.

In some embodiments, the method 10 after the torque generating step 120 includes:

• A step 125 of decelerating and running the engine normally by means of the fourth combustion mode.

Step 125 corresponds to leaving the engine start phase to run the engine under normal operating conditions.

A curve can be observed in FIG. 2 , which represents in the form of a graph a specific example of the course of the control method for starting a combustion engine that achieves the object of the invention. This graph shows engine speed (expressed in revolutions per minute) over time (expressed in time units). In some preferred embodiments, during steps 105 and 110, respectively increasing pressure and increasing temperature, the speed of the engine is substantially stable.

In some embodiments, during torque generating step 120, the speed of the engine is increased until a predetermined speed value is reached. When the speed of the engine is greater than or equal to the predetermined speed, a transition from the torque generating step 120 to the step 125 of decelerating the engine and running it normally is performed.

In other embodiments, a switch from torque generating step 120 to engine deceleration and normal operation step 125 is performed when the absolute value of the rotational speed is exceeded.

The variation of the temperature in the cylinder with the angular position of the crankshaft in the form of a graph is observed in FIGS. 3 and 4 in the method object of the invention.

3 and 4 show temperature (expressed in Kelvin and plotted on ordinate 160 ) as a function of angular position of the crankshaft (plotted on abscissa 165 ).

The fuel used in the process shown in Figures 3 and 4 is pure ethanol, also known as E100. Curve A of the fuel evaporation temperature can be observed in FIGS. 3 and 4 .

It is also possible to observe two curves B and C corresponding to the temperature in the cylinder when the combustion cycle is in two different configurations. Curve B corresponds to the temperature of the air contained in the cylinder in the presence of fuel vaporization, and curve C corresponds to the temperature of the air contained in the cylinder in the absence of fuel vaporization.

The cylinder temperature shown by curves B and C should be greater than the fuel evaporation temperature for allowing fuel to evaporate. The angular range favorable to fuel injection is defined as the section of curve B in which the vaporization temperature of fuel is smaller than the cylinder temperature.

The combustion cycle shown in Figure 3 is at a pressure of 0.3 bar absolute.

The combustion cycle shown in Figure 4 is at 1 bar absolute and includes the throttle valve in a closed position, which favors the pressure increase.

It is observed that the conditions set forth in FIG. 4 with the throttle valve in the closed position allow the emergence of an angular range favorable to fuel injection, wherein this range is bounded at angles of -39° and 22° by two vertical dashed lines 180 and 185 respectively.

Thus, the arrangement achieved by the method of the invention shown in FIG. 5 results in a greater angular range favorable to fuel injection.

In FIG. 5 a device 20 for a control method 10 for starting a combustion engine comprising at least one cylinder 205 , a combustion cycle sensor 210 and a counter 215 for implementing the method object of the invention can be seen.

Device 20 also includes injector 260 , air inlet 265 and exhaust outlet 270 .

In some preferred embodiments, counter 215 is integrated into processor 225 .

In some embodiments, device 20 includes at least one of the following sensors: tooth signal sensor 230 , knock sensor 235 , cylinder pressure sensor 240 , and temperature sensor 250 .

In some embodiments, processor 225 collects and processes data measured by at least one sensor. Processing of data may include the implementation of one or more mathematical calculations or algorithms.

In other words, the processor 225 may be referred to as an engine control unit.

In some embodiments, processor 225 compares the data measured by the sensors to predetermined values stored in memory 220 .

In some embodiments, processor 225 determines the secondary value based on the primary value measured by the sensor. In some embodiments, the position of the piston 255 within the cylinder 205 is determined by the processor based on at least one data measured by at least one sensor.

In some embodiments, at least one data recorded by at least one of the sensors 210 , 230 , 235 , 240 , 250 is recorded in memory 220 .

Claims (10)

1. a kind of control method of starting for combustion engine（10）, including at least one cylinder, burn cycle sensor And counter, which is characterized in that the method includes：

Increase step by means of the fuel pressure of the first combustion mode（105）,

Temperature ascending step（110）, by means of the second combustion mode and it include at least one burn cycle,

Burn cycle detecting step（115）, detect successful burn cycle by means of burn cycle sensor and pass through counting Device is recorded,

Repeated temperature ascending step（110）With burn cycle detecting step（115）, followed until by the burning of the counter records Ring number is equal to predetermined value, and

Step is generated by means of the torque of third combustion mode（120）.

2. according to the method for claim 1（10）, step is generated in the torque（120）Include later：

By means of the 4th combustion mode engine retard and normal operation the step of（125）.

3. method according to any one of claim 1 to 2（10）, wherein first combustion mode does not include gasoline Injection.

4. according to the method in any one of claims 1 to 3（10）, wherein by means of the institute of first combustion mode It states fuel pressure and increases step（105）Further include reducing the pressure in manifold by means of the closing of throttle valve.

5. method according to claim 1 to 4（10）, wherein it is controlled in second combustion mode Feature includes eject position in igniting, throttle position, number of fuel injections, burn cycle, the amount sprayed every time and spray Penetrate the pressure of fuel.

6. the method according to any one of claims 1 to 5（10）, the controlled feature packet in the third combustion mode Include the eject position in igniting, throttle position, number of fuel injections, burn cycle, the amount sprayed every time and injection fuel Pressure.

7. method according to any one of claim 1 to 6（10）, wherein the burn cycle sensor is tooth signal Sensor.

8. method according to any one of claim 1 to 6（10）, wherein the burn cycle sensor is that pinking passes Sensor.

9. method according to any one of claim 1 to 6（10）, wherein the burn cycle sensor is cylinder pressure Force snesor.

10. a kind of controlling party for implementing the starting according to any one of claim 1 to 9 for combustion engine Method（10）Device（20）, which is characterized in that described device（20）Including at least one cylinder（205）, burn cycle sensor （210）And counter（215）.