JP3635670B2 - Control apparatus and method for spark ignition internal combustion engine - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a spark ignition internal combustion engine, and more particularly to a control device and a control method for a spark ignition internal combustion engine that injects fuel directly into a cylinder.
[0002]
[Prior art]
In order to improve the fuel consumption rate of an internal combustion engine, it is necessary to increase the compression ratio to increase the thermal efficiency and instantly burn a lean air-fuel mixture having a low fuel concentration. Further, in order to generate the maximum output with the determined cylinder volume, it is necessary to make maximum use of the air flowing into the cylinder and burn more fuel efficiently. The former is a diesel engine, and the latter is a gasoline engine combustion method. The present invention relates to a gasoline engine which is a spark ignition internal combustion engine.
[0003]
FIG. 2 shows the combustion state of the engine. FIG. 2A shows the case of a gasoline engine. A uniform air-fuel mixture is formed in the cylinder and ignited by the spark plug 14, and the flame is transmitted around (premixed combustion). When the air-fuel ratio increases, the flame propagation slows down and combustion tends to become unstable. Therefore, the intake air amount is throttled by the throttle valve to prevent the air-fuel ratio from increasing when the torque is small. On the other hand, even if the air-fuel ratio is small, the entire cylinder has a uniform air-fuel ratio. FIG. 2B shows the case of a diesel engine. Hot compressed air is produced in the cylinder, and fuel is injected into the cylinder by a fuel injection valve 13. As the fuel flies through the high-temperature air, each fuel droplet evaporates and burns in a part of the cylinder (stratified combustion). For this reason, since it burns from around the fuel droplets, it can be burned even if the amount of fuel is small (even if the air-fuel ratio is large). However, if the amount of fuel is large (the air-fuel ratio is small), the air around the droplets is consumed by combustion, so air shortage and soot are likely to occur, and the utilization rate of air at high output becomes a problem. .
[0004]
FIG. 3 shows the relationship between the air-fuel ratio of the engine and the torque generated by the engine. The characteristic of the gasoline engine shown by the solid line in FIG. 3 depends on exhaust measures, but most of the torque (operating range) is operated at an air-fuel ratio (A / F) of 14.7 (theoretical air-fuel ratio). That is, when controlling the torque, the fuel amount is controlled in accordance with the air amount, and the air-fuel ratio is kept constant. If more torque is required, the torque is increased by reducing the air-fuel ratio. Under normal operating conditions, the minimum air-fuel ratio is A / F13. On the other hand, in the case of a diesel engine indicated by a broken line, when the amount of fuel is small (torque is small), the air-fuel ratio is large, and the air-fuel ratio decreases as the torque increases. When the air-fuel ratio becomes small and approaches A / F 14.7, as shown in FIG. 2B, air shortage is likely to occur due to stratified combustion, and soot is generated. For this reason, the torque of a gasoline engine is larger.
[0005]
FIG. 4 shows the relationship between the fuel amount and the air amount. In the case of a solid line gasoline engine, both the fuel and air increase, and the increase in air is reduced in that the air-fuel ratio in FIG. The amount of air is determined by the reciprocating motion of the cylinder. For this reason, the gasoline engine changes the amount of mass air entering the cylinder by increasing or decreasing the intake pipe pressure with a throttle valve. For this reason, at a partial load where the throttle valve opening is small (intake pipe pressure is small), a pumping loss (throttle loss) occurs, and fuel consumption decreases. On the other hand, in a diesel engine, the amount of air is almost constant (no throttle loss), and only the fuel increases. For this reason, the fuel efficiency of partial load increases.
[0006]
[Problems to be solved by the invention]
As described above, since the diesel engine is stratified combustion, the fuel efficiency of the partial load is increased, but the maximum output is small. In contrast, a gasoline engine has a large maximum output due to premixed combustion, but at a partial load, fuel consumption is reduced due to pump loss.
[0007]
An object of the present invention is to provide an apparatus and a method that can eliminate pump loss by stratified combustion at a partial load, improve fuel efficiency, and increase output by premixed combustion at the maximum output.
[0008]
[Means for Solving the Problems]
  The above-described problems include a fuel injection unit that injects fuel into a combustion chamber of an internal combustion engine, an ignition unit that ignites an air-fuel mixture in the combustion chamber, and the combustion chamber.ofIntake air volumeFor controllingA control device for controlling an internal combustion engine having valve means including a throttle valve and an intake valve,
  When the target air-fuel ratio obtained from the target torque is equal to or greater than a predetermined value, the valve opening of the throttle valve is fully opened.The air / fuel ratio becomes the target air / fuel ratio.When the amount of fuel by the fuel injection means is controlled and the air-fuel ratio is smaller than the predetermined value,The air / fuel ratio becomes the target air / fuel ratio.The valve opening of the throttle valve or the lift amount of the cam lift of the intake valveAnd the fuel amount is controlled, and in a section between the first predetermined value and the second predetermined value that is smaller than the first predetermined value, the fuel is skipped in the section. Control the amount of intake air while keeping the amount constantThis is achieved by a control device for an internal combustion engine characterized by the following.
  Further, the above-described problems are a fuel injection means for injecting fuel into a combustion chamber of an internal combustion engine, an ignition means for igniting an air-fuel mixture in the combustion chamber, a throttle valve for controlling intake air into the combustion chamber, and A control device for controlling an internal combustion engine having valve means including an intake valve,
  When the target air-fuel ratio obtained from the target torque is greater than or equal to a predetermined value, the amount of fuel by the fuel injection means is controlled so that the valve opening of the throttle valve is fully opened and the air-fuel ratio becomes the target air-fuel ratio At the same time, when the control device detects a combustion fluctuation, the valve opening of the throttle valve or the lift amount of the cam lift of the intake valve is controlled so as to reduce the amount of intake air into the combustion chamber, and the air-fuel ratio is When the air pressure is smaller than the predetermined value, either the valve opening of the throttle valve or the lift amount of the cam lift of the intake valve and the fuel amount are controlled so that the air fuel ratio becomes the target air fuel ratio. This is also achieved by an engine control device.
  In addition, the above-described problems include a fuel injection unit that injects fuel into a combustion chamber of an internal combustion engine, an ignition unit that ignites an air-fuel mixture in the combustion chamber, and the combustion chamber.ofIntake air volumeFor controllingA control method for controlling an internal combustion engine having valve means including a throttle valve and an intake valve,
  The target air-fuel ratio calculated from the target torque isFirstWhen the value is equal to or greater than the predetermined value, the throttle valve is opened fully.The air / fuel ratio becomes the target air / fuel ratio.Controlling the amount of fuel by the fuel injection means, the air-fuel ratio is theFirstWhen smaller than the predetermined value,The air / fuel ratio becomes the target air / fuel ratio.The valve opening of the throttle valve or the lift amount of the cam lift of the intake valveAnd the fuel amount so as to skip the interval in the interval between the first predetermined value and the second predetermined value smaller than the first predetermined value. Control the intake air volume while keeping the air flow constantThis is achieved by an internal combustion engine control method characterized by the following.
  Further, the above-described problems are a fuel injection means for injecting fuel into a combustion chamber of an internal combustion engine, an ignition means for igniting an air-fuel mixture in the combustion chamber, a throttle valve for controlling intake air into the combustion chamber, and A control method for controlling an internal combustion engine having valve means including an intake valve,
  When the target air-fuel ratio obtained from the target torque is greater than or equal to a predetermined value, the amount of fuel by the fuel injection means is controlled so that the air-fuel ratio becomes the target air-fuel ratio by fully opening the valve opening of the throttle valve. When the control device detects a combustion fluctuation, the valve opening of the throttle valve or the lift amount of the cam lift of the intake valve is controlled so as to reduce the amount of intake air into the combustion chamber, and the air-fuel ratio is An internal combustion engine characterized by controlling either the valve opening of the throttle valve or the lift amount of the cam lift of the intake valve and the fuel amount so that the air-fuel ratio becomes the target air-fuel ratio when smaller than a predetermined value This control method can also be achieved.
[0010]
【Example】
FIG. 1 shows the configuration of a control system according to the first embodiment of the present invention. Fuel is sent from the fuel tank 1 to the fuel pump 2 and pressurized. The pressurized fuel is detected by the pressure sensor 3 and a pressure signal is sent to the control circuit 5. The control circuit 5 compares with a predetermined target, and if it is equal to or greater than the set value, opens the spill valve 4 of the fuel pump 2 and controls the fuel pressure to the target pressure. The pressurized fuel is sent to the fuel injection valve 13. A signal (torque signal) intended by the driver is sent from the accelerator pedal 19 to the control circuit 5. In response to this, the control circuit 5 calculates the injection amount per time in consideration of the signal of the engine speed sensor 10 and sends it to the injection valve drive unit 20 of the fuel injection valve 13. As a result, the fuel injection valve 13 is opened and fuel is injected into the combustion chamber 7. The fuel injection timing and the injection amount (injection time) at this time are selected as optimum values by the control circuit 5. The fuel injected into the combustion chamber 7 is sent a signal from the control circuit 5 to the ignition circuit 22 at an optimal ignition timing, and a high voltage is generated in the ignition circuit 22, which is sent to the spark plug 14, and spark ignition causes Ignited. The pressure in the combustion chamber 7 increases, acts on the piston 9, imparts rotational force to the crankshaft 16, and drives the tires 18 a and 18 b from the transmission 15 via the differential gear 17 to travel. The generated torque of the engine 6 is detected by the pressure sensor 8 by detecting the combustion pressure in the combustion chamber 7 and sent to the control circuit 5 to be compared with the signal of the accelerator pedal 19 that is intended by the driver. This comparison result is reflected in the fuel injection of the next cylinder. The air amount of the engine 6 is measured by an air amount detector, and the flow rate is controlled by a throttle valve. The air is controlled by a swirl control valve 28 disposed in the intake pipe 27 so that appropriate turbulence can be generated in the cylinder. The valve lift control device 11 controls the valve lift of the intake valve 12. The combustion gas is exhausted from the exhaust valve 21.
[0011]
A first embodiment of the present invention will be described with reference to a longitudinal sectional view of the combustion chamber in FIG. A fuel injection valve 13 and a spark plug 14 are installed in the auxiliary combustion chamber 23 formed in the engine head 25. The positional relationship between the fuel injection valve 13 and the ignition plug 14 at this time is preferably such that the ignition plug 14 is installed on the downstream side of the spray of the fuel injection valve 13. This is because the flame kernel formed by the spark plug 14 is easily dispersed in the cavity 24 installed in the combustion chamber 7 and the piston 9 by spraying. However, if the spark plug 14 is too close to the spray, the spark plug 14 may get wet with the spray and cause ignition failure, so the positional relationship is important. Moreover, the ejection speed of the flame kernel can be adjusted by narrowing the outlet portion 26 of the auxiliary combustion chamber 23. Even in this case, if the pressure is excessively reduced, pressure loss is caused and the thermal efficiency is lowered.
[0012]
FIG. 6 shows the relationship between the air-fuel ratio A / F and the exhaust gas (HC, NOx). When the fuel injection timing is 90 ° crank angle, the peak value of NOx is close to A / F16. Such a change in the NOx emission amount tends to be observed in the case of a uniform air-fuel mixture. This is because the spray sprayed is dispersed throughout the cylinder due to the movement of the piston and the flow of air in the cylinder due to the intake air until the injection timing is 90 ° and the middle of the intake stroke. As the injection timing increases, the generated air-fuel ratio of the NOx peak value increases. At the same time, the generation of NOx becomes gentle. In addition, the amount of HC emission also changes. Comparing the injection timing 90 ° and the injection timing 180 °, the HC near A / F 15 is 3800 ppmC at the injection timing 90 ° and 6500 ppmC at the injection timing 180 °. The reason why the HC is different at the same air-fuel ratio is that the air-fuel ratio at which the combustion is performed is different. That is, the air-fuel ratio of the place where the combustion is actually performed is smaller at the injection timing of 180 °. For this reason, when the air-fuel ratio becomes large, combustion failure (misfire) occurs at a small air-fuel ratio when the injection timing is 90 °. The reason why the air-fuel ratio for stable combustion (HC does not increase) increases when the injection timing is increased as described above is that the ignition timing becomes closer to the ignition timing when the injection timing increases, and the fuel becomes difficult to disperse and becomes a stratified mixture. It is. By selecting the injection timing in this way, a uniform mixture and a stratified mixture can be freely formed. Therefore, when the engine torque is small, the injection timing is increased to approach the ignition timing. As the torque increases, the injection timing is reduced to approach a uniform mixture.
[0013]
FIG. 7 shows a second embodiment in a longitudinal sectional view of the combustion chamber. In this embodiment, the fuel injection valve 13 protrudes into the combustion chamber 7 and the injection port is perforated so that the fuel is widely dispersed in the cylinder. In such a case, when fuel is injected near the bottom dead center where the piston is lowered, the fuel directly hits the cylinder wall surface, and a wall surface flow is created. In such a state, good combustion cannot be expected. Therefore, in the case of such an injection valve with a wide spray, the cavity 24 is near the top dead center, and it is necessary to blow at a timing at which fuel can be blown into the cavity 24. As an example, fuel injection can be performed in a plurality of times as shown in FIG. Pre-injection is performed at a crank angle near 0 degrees to create a uniform mixture. A homogeneous mixture formed by pre-injection is rapidly burned by making a fire type by post-injection that is injected near the ignition timing. Since the injection amount can be adjusted by either post-injection or pre-injection, injection can be performed in an optimum state. In this way, when dividing into two times before and after, it is effective even with the injection valve having a small injection angle shown in FIG.
[0014]
FIG. 9 shows a flowchart for calculating the fuel injection time in the case of pre-injection and post-injection. In step 101, the accelerator opening α and the engine speed Ne are read. If the air amount is measured at this time, the air amount Qa may be added. In step 102, the fuel amount Qf is calculated. In step 103, Qf> Qf1 is determined. In the case of NO, the process proceeds to step 109, and the injection time Tp2 is calculated by adding the invalid injection amount Qx. In step 110, Tp2 is injected at the time of post-injection. If step 103 is Yes, the process proceeds to step 104, where Qf2 is calculated by subtracting the minimum injection amount Qf0. In step 105, the injection time Tp1 is calculated by adding the invalid injection amount Qx to Qf2. Tp1 is injected at the timing of the previous injection. In step 107, Qp is added to Qf0 to calculate Tp2, and Tp2 is injected at the time of post injection. Thus, it is necessary to add the invalid injection amount Qx for each of the front and rear injections.
[0015]
FIG. 10 shows a fuel pressure control device. Fuel from the fuel tank 1 is sent from the fuel pump 2. The fuel pump 2 is driven by a motor 30 and sends pressurized fuel to the high-pressure pipe 34. The high-pressure pipe 34 is provided with injection valves 13a to 13d, an accumulator 33, a fuel pressure sensor 3, and a relief valve 32. In the relief valve 33, gas is sealed as a damper, and when the fuel pressure increases, the fuel flows into the accumulator. When the pressure drops, the fuel is sent out to the high pressure pipe 34. The relief valve 32 prevents the pressure from rising by causing the fuel to flow away when the fuel becomes too high. The fuel pressure sensor 3 sends a signal proportional to the pressure to the control circuit 5, sends it to the electromagnetic spill device 4 of the fuel pump 2, controls the discharge amount of the fuel pump 2, and controls the fuel pressure. Further, a signal is sent to the controller 31 of the motor 30 to control the number of revolutions of the fuel pump 30 to control the fuel pressure. In this embodiment, both the electromagnetic spill device 4 and the controller 31 are installed, but the fuel pressure can be controlled by either one. However, when the fuel pump 2 is driven by the engine, the motor 30 is not provided, so that only the electromagnetic spill device 4 is provided.
[0016]
FIG. 11 shows an EGR control system diagram. Air enters the engine 6 through the air flow meter 35, the throttle valve 37, and the intake pipe 27, becomes exhaust, and is discharged to the exhaust pipe 41. The exhaust pipe 41 has a catalyst 39. Here, when EGR is required, a signal is sent from the control device 5 to the EGR valve 38 to open the EGR valve. Further, a signal is sent to the throttle valve actuator 36, the throttle valve 37 is closed, and the pressure in the intake pipe 27 is made lower than the atmospheric pressure. Then, the exhaust gas flows from the exhaust pipe 41 to the intake pipe 27 via the EGR valve 38 in proportion to the intake pipe pressure. Since the flow rate of the exhaust at this time is proportional to the intake pipe pressure, this intake pipe pressure is detected by the intake pipe pressure sensor 40, sent to the control circuit 5, and the throttle valve actuator 36 adjusts the opening of the throttle valve 37. To do. If the opening degree of the throttle valve 37 is controlled, the pressure of the intake pipe 27 can be controlled, and the EGR amount can be accurately controlled by feedback control.
[0017]
FIG. 12 shows a third embodiment of the present invention. The air is adjusted by the throttle valve 213 and is sucked into the engine via the intake pipe 214. The lift of the intake valve 208 can be changed by switching cams 203 having different shapes. The cam is switched by switching the rocker arm 210 with the hydraulic control valve 202. The hydraulic control valve 202 is performed by an electromagnetic solenoid, for example. The opening of the throttle valve is controlled by the motor 212. A sensor 220 for detecting the in-cylinder pressure is attached to the engine. An injection valve 204 that directly injects fuel into the cylinder is attached. A sensor 205 for detecting the air-fuel ratio of the exhaust is attached to the exhaust pipe. A catalyst is attached to the exhaust pipe. A catalyst that can remove NOx even under excessive oxygen conditions is desirable. Further, under the theoretical air-fuel ratio condition, a function is required for the three-way catalyst that can simultaneously remove HC, CO, and NOx. Further, a part of the exhaust is controlled by valves 215 and 218 that control the exhaust pipe flow rate. This lowers the combustion temperature and reduces NOx. These control valves are controlled by the control device 201. In order to reduce fuel consumption, it is desirable to reduce the pumping loss by bringing the pressure in the intake pipe close to atmospheric pressure. Therefore, the throttle valve 212 is fully opened as much as possible. However, when exhaust gas recirculation is performed from the pipe 216, the throttle valve is closed because the pressure in the intake pipe needs to be smaller than the pressure in the exhaust pipe.
[0018]
FIG. 13 shows the operation of the third embodiment of the present invention. The lift of the intake valve cam is changed as shown in FIG. 13 according to the operating conditions. When a large amount of air is required, the intake valve lift is set to A. When the amount of air is small, the lift of the intake valve is changed to lift B and lift C. By changing the lift, the overlap with the exhaust valve is also changed. During high output operation, the overlap period of the exhaust valve and intake valve is increased. In this way, the amount of air can be changed by the lift of the intake valve.
[0019]
FIG. 14 shows an example of the configuration of the rocker arms 221, 223, 224 and cams 225, 226, 227. Driven by the rocker arm 223 and the cam 225, the intake valve is reciprocated. The rocker arm 226 and the cam 224 are not fixed and are in a free state. When switching cams, rocker arm 224 and cam
226 is driven to reciprocate the intake valve. The rocker arm 223 and the cam 225 are not fixed and are in a free state. In this way, the cam can be switched. In this example, the lift of the cam is changed. However, the timing of opening and closing the valve may be controlled simultaneously by changing the shape of the cam.
[0020]
FIG. 15 shows a map of cam selection with respect to the accelerator opening and the engine speed. In this example, cam switching was selected in three stages. When the engine speed is low and the accelerator opening is small, the cam A having a small lift is selected. As the engine speed and accelerator opening increase, the cam is switched to a larger lift.
[0021]
FIG. 16 shows a map of cam selection with respect to engine torque and engine speed. In this example, cam switching was selected in three stages. The engine torque is a target torque determined in advance with respect to the accelerator opening. When the engine speed is low and the engine is small, the cam A having a small lift is selected. As the engine speed and engine torque increase, the cam is switched to a cam with a higher lift.
[0022]
FIG. 17 shows a method of controlling the intake air amount when switching the air-fuel ratio A / F. If a throttle valve is fully opened or a cam with a large lift is selected, the amount of fuel increases and the shaft torque increases as the air-fuel ratio decreases. When the air-fuel ratio is around 16, the amount of NOx emission tends to increase, so the air-fuel ratio is skipped from 18 to 15. At this time, if the air-fuel ratio is switched to 15 while leaving the air amount as it is, the amount of fuel increases, the shaft torque increases like C, and a sense of incongruity is felt. Therefore, when switching the air-fuel ratio, the amount of air is reduced to prevent an increase in the amount of fuel, the shaft torque is changed from A to B, and the shock is reduced. The air volume is adjusted by switching the throttle valve or cam. When the throttle valve is used, the pressure in the intake pipe is reduced, and the pumping loss is increased. Further, even if the shaft torque becomes small, for example, even if the air-fuel ratio is set to 70 or more, even if the target shaft torque is not reached, the air amount is adjusted with a cam or a throttle valve.
[0023]
FIG. 18 shows the relationship between the fuel amount and the shaft torque. Since the shaft torque can be increased by increasing the amount of fuel, the shaft torque can be controlled by the amount of fuel.
[0024]
FIG. 19 shows a fourth embodiment of the present invention. The fuel injection amount Qf is obtained by an engine state detection unit 301 that detects the engine state such as the accelerator opening degree α and the engine speed N, and then a fuel injection amount calculation unit 302 that calculates the fuel injection amount Qf. Based on the charging efficiency map 303, the air amount of the engine is calculated at 304, the air amount of each cam is obtained, and the air-fuel ratio is calculated. In step 305, it is determined whether the air-fuel ratio is in the combustible range. In step 306, the cam is selected, and in step 307, the throttle valve opening is determined. If the amount of air is too large, the air-fuel mixture becomes lean, so switch to a cam with less lift. In-cylinder injection directly controls the air-fuel mixture in the cylinder, so that the limit of the lean air-fuel mixture can be made larger than that of a conventional intake port injection system, so the range of shaft torque that can be controlled by the fuel amount is wide. Therefore, the shaft torque can be controlled by the fuel amount without finely controlling the air amount as in the prior art.
[0025]
FIG. 20 shows a fifth embodiment of the present invention. The accelerator opening is detected at 311 and the target torque is determined at 312. The fuel amount is determined by the fuel amount calculation means 313 from the target torque. If the air-fuel ratio is determined in advance with respect to the shaft torque, the air amount Qa can be obtained. When the air-fuel ratio is determined at 316 and the air-fuel ratio is 18 or more,
In 318, the throttle valve is fully opened, the torque detecting means 319 detects the engine torque, and the fuel injection amount is controlled so as to reach the target torque. On the other hand, when the air-fuel ratio is 18 or less, the air amount is controlled so as to reach the target air-fuel ratio at 321. The amount of air is determined by, for example, throttle valve opening or cam lift. Here, the air amount may be detected by the air amount sensor 322, and the air amount may be controlled so as to become the target air amount.
[0026]
FIG. 21 shows a map of the target air-fuel ratio. As the shaft torque increases, the air-fuel ratio decreases, but at point B, the air-fuel ratio is switched to point C so that air-fuel ratio 16 is skipped. When the torque is further increased, the air-fuel ratio is decreased so as to be directed to point D. If the air-fuel ratio is further reduced, the air-fuel mixture becomes too rich. Therefore, it is desirable to perform air-fuel ratio control by detecting the air amount in this region.
[0027]
FIG. 22 shows the relationship between the throttle valve opening θth and the engine speed N and the intake air amount Qa. When the air amount is controlled by the throttle valve, the throttle valve opening is obtained from the map for the intake air amount. When more precise control is performed, the amount of air is detected and feedback is applied.
[0028]
23 and 24 show a sixth embodiment of the present invention. If the air-fuel ratio is 18 or more, the air-fuel mixture may be too lean and the operability and exhaust purification may be reduced, so the throttle valve opening or cam lift is set to detect combustion fluctuations and reduce the amount of air. To do.
[0029]
FIG. 25 shows a seventh embodiment of the present invention. An electrode 234 is embedded in a cylinder gasket 231 of the engine, and a high voltage is applied from the electrode 232. The gasket has a hole 233 for screwing.
[0030]
FIG. 26 is a longitudinal sectional view of FIG. A high voltage is applied between the electrodes 238 and 239 from the ignition coil, causing a spark discharge. As a result, the air-fuel mixture is ignited from the cylinder wall surface and from multiple points, so that the combustion speed increases. Moreover, since combustion is performed from near the wall surface, so-called quench regions near the wall surface are reduced, unburned hydrocarbons are reduced, and knocking is less likely to occur. Insulating layers on the top and bottom of the gasket
235 and 237 are provided. In the case where the electrode 239 is grounded, the insulating layer 237 may not be provided.
[0031]
【The invention's effect】
According to the present invention, the combustion time is shortened, knocking can be prevented, the compression ratio of the engine is increased, the thermal efficiency is increased, and the fuel consumption is increased. The generation of unburned hydrocarbons can be prevented by stratified intake. In-cylinder direct fuel injection increases fuel responsiveness and improves drivability.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing a configuration of a control system according to a first embodiment of the present invention.
FIG. 2 is a conceptual diagram showing a combustion state in a combustion chamber of an engine.
FIG. 3 is a correlation diagram between an air-fuel ratio and generated torque.
FIG. 4 is a correlation diagram between a fuel amount and an air amount.
FIG. 5 is a longitudinal sectional view of a combustion chamber.
FIG. 6 is a correlation diagram of air-fuel ratio A / F and HC and NOx in exhaust gas.
7 is a longitudinal sectional view of a combustion chamber similar to FIG. 5, showing a second embodiment of the present invention.
FIG. 8 is a chart showing fuel injection timing.
FIG. 9 is a flowchart of calculation of fuel injection time.
FIG. 10 is a block diagram of a fuel pressure control device.
FIG. 11 is a conceptual diagram showing an EGR control system.
FIG. 12 is a conceptual diagram showing the configuration of the control system according to the third embodiment of the present invention.
FIG. 13 is a time chart showing the operation of the intake valve.
FIG. 14 is a perspective view showing a configuration of a rocker arm.
FIG. 15 is a map of engine speed, accelerator opening, and cam selection.
FIG. 16 is a map diagram of selection of engine speed, engine torque, and cam.
FIG. 17 is a correlation diagram of air-fuel ratio A / F and shaft torque.
FIG. 18 is a correlation diagram between fuel amount and shaft torque.
FIG. 19 is a block diagram of the present control system showing a fourth embodiment of the present invention.
FIG. 20 is a block diagram of the present control system, showing a fifth embodiment of the present invention.
FIG. 21 is a map of target air-fuel ratio with respect to engine torque.
FIG. 22 is a correlation diagram of the throttle valve opening degree with respect to the engine speed and the intake air amount.
FIG. 23 is a block diagram of the present control system, showing a sixth embodiment of the present invention.
FIG. 24 is a block diagram of the present control system, similar to FIG.
FIG. 25 is a top view showing a configuration of an engine cylinder gasket according to a seventh embodiment of the present invention.
26 is a longitudinal sectional view of FIG. 25. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Fuel tank, 2 ... Fuel pump, 3 ... Fuel pressure sensor, 4 ... Electromagnetic spill device, 5 ... Control circuit, 6 ... Engine, 7 ... Combustion chamber, 8 ... Combustion pressure sensor, 9 ... Piston, 12 ... Intake valve , 13 ... fuel injection valve, 14 ... spark plug, 19 ... accelerator pedal, 21 ... exhaust valve, 24 ... cavity, 28 ... swirl control valve.

Claims (8)

Fuel injection means for injecting fuel into a combustion chamber of an internal combustion engine, ignition means for igniting an air-fuel mixture in the combustion chamber, and valve means including a throttle valve and an intake valve for controlling the amount of intake air into the combustion chamber A control device for controlling an internal combustion engine having
When the target air-fuel ratio obtained from the target torque is equal to or greater than a first predetermined value, the fuel amount by the fuel injection means is set so that the valve opening of the throttle valve is fully opened and the air-fuel ratio becomes the target air-fuel ratio. When the air-fuel ratio is smaller than the first predetermined value , either the valve opening of the throttle valve or the lift amount of the cam lift of the intake valve so that the air-fuel ratio becomes the target air-fuel ratio , and While controlling the fuel amount, in a section between the first predetermined value and the second predetermined value that is smaller than the first predetermined value, the fuel amount is kept constant so as to skip the section. A control device for an internal combustion engine, which controls the intake air amount . According to claim 1, wherein the first intake air amount control to skip the air-fuel ratio is an interval between the predetermined value and the second predetermined value is performed by controlling the valve opening degree of said valve means control apparatus for an internal combustion engine, characterized in that. Fuel injection means for injecting fuel into a combustion chamber of an internal combustion engine; ignition means for igniting an air-fuel mixture in the combustion chamber; valve means including a throttle valve and an intake valve for controlling intake air into the combustion chamber; A control device for controlling an internal combustion engine having
When the target air-fuel ratio obtained from the torque target is a predetermined value or more, the air-fuel ratio of the valve opening degree of the throttle valve fully opened to control the amount of fuel by said fuel injection means so that the target air-fuel ratio At the same time, when the control device detects a combustion fluctuation, the valve opening of the throttle valve or the lift amount of the cam lift of the intake valve is controlled so as to reduce the amount of intake air into the combustion chamber, and the air- fuel ratio is when the smaller than the predetermined value, internal combustion, characterized in that the air-fuel ratio is controlled either, and the fuel amount of the lift of the cam lift of the valve opening degree or the intake valve of the throttle valve so that the target air-fuel ratio Engine control device.   3. The control apparatus for an internal combustion engine according to claim 1, wherein the first predetermined value is 18 and the second predetermined value is 15. Fuel injection means for injecting fuel into a combustion chamber of an internal combustion engine, ignition means for igniting an air-fuel mixture in the combustion chamber, and valve means including a throttle valve and an intake valve for controlling the amount of intake air into the combustion chamber A control method for controlling an internal combustion engine having
When the target air-fuel ratio obtained from the target torque is equal to or greater than a first predetermined value, the fuel amount by the fuel injection means is set so that the valve opening of the throttle valve is fully opened and the air-fuel ratio becomes the target air-fuel ratio. When the air-fuel ratio is smaller than the first predetermined value , either the valve opening of the throttle valve or the lift amount of the cam lift of the intake valve so that the air-fuel ratio becomes the target air-fuel ratio , and In a section between the first predetermined value and the second predetermined value that is smaller than the first predetermined value by controlling the fuel amount, the fuel amount is kept constant so as to skip the section. A control method for an internal combustion engine, characterized in that an intake air amount is controlled . According to claim 5, wherein the first intake air amount control to skip the air-fuel ratio is an interval between the predetermined value and the second predetermined value is performed by controlling the valve opening degree of said valve means a control method for an internal combustion engine, characterized in that. Fuel injection means for injecting fuel into a combustion chamber of an internal combustion engine; ignition means for igniting an air-fuel mixture in the combustion chamber; valve means including a throttle valve and an intake valve for controlling intake air into the combustion chamber; A control method for controlling an internal combustion engine having
When the target air-fuel ratio obtained from the torque target is a predetermined value or more, the amount of fuel controlled by the fuel injection means so that the air-fuel ratio becomes the target air-fuel ratio of the valve opening as a fully open the throttle valve , when the control device detects the combustion variation, to control the lift of the cam lift of the valve opening degree or the intake valve of the throttle valve so as to reduce the amount of intake air into the combustion chamber, the air-fuel ratio is the An internal combustion engine characterized by controlling either the valve opening of the throttle valve or the lift amount of the cam lift of the intake valve and the fuel amount so that the air-fuel ratio becomes the target air-fuel ratio when smaller than a predetermined value Control method.   7. The method of controlling an internal combustion engine according to claim 5, wherein the first predetermined value is 18 and the second predetermined value is 15.

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