JP2000204990A - Gasoline self-igniting internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly perform the switching to spark ignition while suppressing the occurrence of knocking by providing an injection device having a variable valve gear mechanism and capable of injecting water at high load in a self- igniting operation area. SOLUTION: In a four-cycle spark ignition gasoline engine, a fuel injection valve 2 and a water injection valve 1 downstream thereof are mounted on an intake port 5. Fuel and water are supplied from a fuel tank 11 and a water tank 12 to the respective injection valves 1, 2 by exclusive pumps 17, 22, respectively. The injection quantity and injection timing of each injection valve 1, 2 are controlled by an engine control module 13. The quantity and execution or not of water injection are controlled according to operating condition (steady time and transitional time), whereby a homogeneous premix compression ignition and combustion with high efficiency and low NOx discharge can be realized in a wide load range of the engine. The switching with spark ignition can be smoothly performed while suppressing the occurrence of knocking.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gasoline internal combustion engine having self-ignition combustion.

[0002]

2. Description of the Related Art FIGS. 11 and 12 show a conventional example of water injection into a cylinder for the purpose of suppressing knocking of an internal combustion engine, improving output, and the like.
-135515). In the example of FIG. 11, in the gas fuel engine, water is injected into the sub-combustion chamber during the compression stroke, high-pressure ignition gas fuel is injected near the top dead center, and the ignition is performed by the electric heating ignition auxiliary means. Water injection prevents early ignition and knocking, increases output, and reduces NOx in exhaust gas. In the example of FIG. 12, by injecting water into the cylinder at the end of the exhaust stroke and lowering the exhaust gas temperature, the suction-filling efficiency in the next stroke, the suction stroke, can be improved, and the output increases.

[0003]

The compression ignition phenomenon of gasoline premixed gas has a large effect on air-fuel efficiency, knocking occurs on the rich side, and misfire occurs on the lean side.
Inevitably, the operability limits the air-fuel consumption range, that is, the operable load range is limited.

In view of this, it is conceivable to use water injection as a means for suppressing knocking particularly on the rich side of the air-fuel efficiency and expanding the operating range toward the high load side.

However, the conventional water injection mechanism has insufficient control such as injection regardless of the operation range. Therefore, if the conventional water injection mechanism is applied to an engine system having self-ignition combustion, the following problems occur. (1) In the low-load region of the self-ignition operation region, in particular, when water is injected, the self-ignition phenomenon is unlikely to occur, so that the engine operating conditions are disabled and the operable load range is further limited. (2) Since it is difficult to achieve self-ignition combustion over the entire range of engine operating conditions, the engine system is a combination system with spark ignition. Considering this, water injection is a combined system with spark ignition. Considering this, water injection becomes unnecessary during spark ignition operation, especially at low load, and fuel consumption is deteriorated due to water pump drive loss and the like.

SUMMARY OF THE INVENTION The present invention has been made in view of such a problem. When water injection is applied to an engine system having self-ignition combustion, the engine is controlled by controlling the amount, presence or absence of water injection according to operating conditions. It is an object of the present invention to realize homogeneous premixed compression ignition combustion with high efficiency and low Nox emission over a wider load range, and to smoothly switch to spark ignition while suppressing the occurrence of knocking.

[0007]

According to the first aspect of the present invention, there is provided a spark ignition four-cycle internal combustion engine which obtains an output by converting a reciprocating motion of a piston into a rotational motion of a crankshaft.
It has a variable valve mechanism that can make at least the valve opening / closing timing variable, makes the effective compression ratio variable by making the intake valve closing timing variable, and increases the compression ratio according to the engine operating conditions. An injection device capable of switching to homogeneous charge homogeneous charge compression ignition and injecting water under a high load in the self-ignition operation region is provided.

[0008] In the invention according to claim 2, an injection device capable of injecting water at the time of switching from self-ignition combustion to spark ignition combustion or at the time of switching from spark ignition combustion to self-ignition combustion is provided. .

According to the third aspect of the present invention, in the switching from the self-ignition combustion to the spark ignition combustion, when the throttle opening speed is abruptly accelerated, the set water at the same rotation speed and the same load condition in the steady operation is set. It was decided to inject more water than the injection amount.

According to the present invention, when switching from self-ignition combustion to spark ignition combustion, during a rapid acceleration operation in which the throttle opening speed is abrupt, a water supply delay time after water injection is performed and water is supplied into the cylinder. After that, spark ignition is started.

[0011] In the invention according to claim 5, in the switching from the self-ignition combustion to the spark ignition combustion, the water injection period is set to be at least longer than a required time in a compression ratio switching cycle.

In the sixth aspect of the invention, both the fuel injection and the water injection are stopped when the throttle is fully closed and the fuel is cut during deceleration.

According to the present invention, when switching from spark ignition combustion to self-ignition combustion, when the throttle closing speed is abruptly decelerated, the setting is performed under the same rotation speed and the same load condition in the steady operation. It was decided to inject more water than the amount of water injection.

In the invention described in claim 8, in switching from spark ignition combustion to self-ignition combustion, the water injection period is set to at least a required time in a compression ratio switching cycle.

In the ninth aspect of the present invention, in the switching from the spark ignition combustion to the self-ignition combustion, the ignition is terminated after the self-ignition combustion occurs.

According to a tenth aspect of the present invention, there is provided a spark ignition four-cycle internal combustion engine which obtains an output by converting a reciprocating motion of a piston into a rotational motion of a crankshaft, and having a variable valve mechanism capable of at least changing a valve opening / closing timing. By changing the intake valve closing timing to make the effective compression ratio variable and increasing the compression ratio in accordance with the engine operating conditions, switching from spark ignition to self-ignition combustion, that is, homogeneous charge homogeneous charge gas compression ignition is performed, and the self-ignition is performed. Equipped with an injection device that can inject water at a high load in the operating region, a knock sensor is installed on the engine body such as an engine cylinder block, and when the knock sensor output at the time of knocking becomes greater than a predetermined value, water injection is started, The water injection charge is controlled according to the knock sensor output value, and water injection is performed when the knock sensor output value falls below an allowable value. It was decided to Ryosuru.

In the eleventh aspect, a temperature sensor and a humidity sensor are set in the intake system, and the target humidity is set according to the intake air temperature during engine operation.
The water injection charge was controlled.

[0018]

According to the first aspect of the present invention, water injection is performed during a preset self-ignition high-load operation to improve knock resistance and increase the amount of supplied fuel. As a result, the operating range to a high load range is expanded, and low emission and low fuel consumption are achieved in a wider operating range.

According to the second aspect of the present invention, when switching from self-ignition combustion to spark ignition combustion (high compression ratio →
Water injection is performed in the "high compression ratio + spark ignition" region caused by the response delay in switching the compression ratio when switching from spark ignition combustion to self-ignition combustion (low compression ratio → high compression ratio). Avoid knocking. Thereby,
The switching of combustion becomes smooth, and a combination of self-ignition combustion and spark ignition combustion becomes possible.

According to the third aspect of the present invention, in the "high compression ratio + spark ignition" region which is present at the time of switching from self-ignition combustion to spark ignition combustion at the time of rapid acceleration, the same rotational speed and the same during steady operation. Injection of a larger amount of water than the set water injection amount under the load condition avoids occurrence of knocking due to delay in supply of the water injection amount. Thereby, even at the time of sudden acceleration, combustion switches smoothly.

According to the fourth aspect of the present invention, at the time of a sudden switch from self-ignition combustion to spark ignition combustion, ignition is started after water supply is completely performed, and "high compression ratio +
Even with "spark ignition", knocking is avoided. This ensures that smooth combustion is switched even during rapid acceleration.

According to the fifth aspect of the present invention, the water injection period in the “high compression ratio + spark ignition” region caused by the response delay of the compression ratio switching when switching from self-ignition combustion to spark ignition combustion is reduced. The period is equal to or longer than the ratio switching cycle, and after the compression ratio is reliably switched to the low compression ratio, the water injection is stopped to surely avoid knocking. Thereby, smooth combustion switching is reliably performed.

In the sixth aspect of the present invention, both the fuel injection and the water injection are stopped when the throttle is fully closed and the fuel is cut during deceleration. As a result, unnecessary cooling of the cylinder is stopped beforehand, so that low emission and low fuel consumption can be achieved.

According to the seventh aspect of the present invention, in the "high compression ratio + spark ignition" region, which is present at the time of rapid switching from spark ignition combustion to self-ignition combustion during rapid deceleration, the same rotation during steady operation is performed. Injection of a larger amount of water than the set water injection amount under the same number of load conditions prevents the occurrence of knocking due to a delay in supply of the water injection amount. Thereby, even at the time of sudden deceleration, combustion switches smoothly.

According to the present invention, the water injection period in the “high compression ratio + spark ignition” region caused by the delay in response to the compression ratio switching at the time of switching from spark ignition combustion to self-ignition combustion is defined as The cycle is longer than the in-house non-switching cycle, the compression ratio is switched to the high compression ratio without fail, the water injection is stopped after the self-ignition operation is reliably performed, and the knocking is reliably avoided. As a result, smooth combustion switching can be reliably performed.

According to the ninth aspect of the present invention, at the time of switching from spark ignition combustion to self-ignition combustion, the compression ratio is reliably switched to a high compression ratio, and ignition is stopped after the self-ignition operation is reliably performed. To ensure stable operation of the engine. As a result, smooth combustion switching can be reliably performed.

According to the tenth aspect of the present invention, a knock sensor is provided on an engine cylinder block or the like.
When knocking occurs, water injection is started when the knock sensor output exceeds a predetermined value, and the water injection amount is controlled according to the knock sensor output value, and when the knock sensor output value falls below the allowable value. The water injection is terminated, and the water injection is controlled so as to always suppress knocking. Thereby, control according to the knock sensor output becomes possible, and knocking is always accurately suppressed.

According to the eleventh aspect of the present invention, a temperature sensor and a humidity sensor are provided in the intake system so that knocking does not easily occur at a predetermined optimum humidity corresponding to the intake air temperature during engine operation. Then, the water injection amount is controlled. Thereby, knocking is always suppressed.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of the first embodiment of the present invention. First, in a four-cycle spark ignition gasoline engine, a fuel injection valve 2 and a water injection valve 1 downstream thereof are attached to an intake port 5, and a fuel tank 11 and a water tank Fuel and water are supplied from 12 by the respective dedicated pumps 7 and 22.
The injection quantity and the injection timing of each of the injection valves 1 and 2 are controlled by an engine control module (ECM) 13. A humidity sensor 8 and an intake temperature sensor 24 are set in the intake port 5, and a knock sensor 9 is set in the cylinder block, and the output is input to the ECM 13. The engine is provided with a variable valve mechanism (not shown) that can change at least the intake valve closing timing, so that the effective compression ratio can be varied.

(Operation) Next, the operation will be described. In the present engine system, the combustion mode is changed in an operation region as shown in FIG. 2, for example. That is, the auto-ignition operation region is set up to the middle rotation / medium load region, the intake valve closing timing is brought close to the intake bottom dead center position, the effective compression ratio is set to a high state (for example, 18), and other high compression ratios are set. The rotation / high load region is a spark ignition operation region, the intake valve closing timing is close to the compression top dead center position, and the effective compression ratio is set to a low state (for example, 12). The closing timing of the intake valve for switching the compression ratio is performed by a variable valve mechanism (not shown), and is controlled using a relationship between an operation region and a compression ratio that are mapped in advance. Here, an outline of the region in which the water injection is performed is roughly on the high load side of the self-ignition region (for example, 0.5MP
a) and the transition region where auto ignition combustion and spark ignition combustion are switched.

Next, a detailed control flow of water injection will be described. FIG. 3 shows a basic control flow of the engine system. First, under the condition that the engine is operating, the throttle opening speed (differential (dθ /
The acceleration state, the deceleration state, and the steady state are determined based on the sign of dt). In the case of the acceleration state, it is determined whether the acceleration is the rapid acceleration or the slow acceleration based on the magnitude relationship of the current throttle opening speed with respect to V1 (the throttle opening lower limit value at the time of the rapid acceleration) set in advance. Similarly, in the case of a deceleration state, it is determined whether the current throttle closing speed is a sudden deceleration or a slow deceleration based on a magnitude relationship of a current throttle closing speed with respect to a preset V2 (a lower limit value of the throttle closing speed at the time of rapid deceleration).

In the case of rapid acceleration, a subroutine 1 shown in FIG.
Is controlled by The fuel injection pulse width Tp is widened by ΔT with respect to the steady-state injection pulse width Tpl at the throttle opening θ in consideration of fuel supply delay and the like to increase the fuel supply amount. Next, if the throttle opening θ switches between self-ignition and ignition combustion in accordance with the engine speed at that time, if the throttle opening θ1 is larger or smaller than the throttle opening θ1, that is, if it is larger, there is a possibility of switching from self-ignition to ignition combustion. Yes, if it is smaller, it is determined that self-ignition is maintained without switching. If the mode is not switched to the ignition combustion, it is determined whether or not to perform water injection according to a water injection map mapped in advance. At this time, the pulse width of the water injection valve is increased by ΔTw with respect to the steady state (Tpw) in consideration of the water supply delay. When θ ≧ θ1, the combustion state before acceleration is determined based on the value of the compression ratio (intake valve closing timing = determined from the set state of the valve timing of the variable valve mechanism). That is, in the case of the low compression ratio state, rapid acceleration occurs in the ignition combustion state. At that time, the presence or absence of water injection is determined based on the water injection map. In the case of a high compression ratio, it is determined that the mode has switched from self-ignition to spark ignition, water injection is immediately started (there is an increase), and switching from high to low compression ratio is performed by a variable valve mechanism. Next, after a preset water supply response delay (N1 cycle) when the water injection amount is increased, ignition is started. At this time, since the water is surely supplied into the cylinder, the compression ratio switching delays the response, and even if ignition is performed in the high compression ratio state, knocking is avoided. Exceeds the number of compression ratio switching cycles N2,
When the low compression ratio state is definitely reached, the necessity of water injection is determined from the water injection map. When performing water injection, the injection amount is Tpl in a steady state.

In the case of gentle acceleration, subroutine 2 shown in FIG.
Is controlled by The difference from the rapid acceleration of FIG. 4 is that the fuel injection pulse width Tp is the steady-state injection pulse width Tp.
l. The transient increase (ΔTw) of the water injection amount is not added. When switching to ignition combustion, ignition is started without considering the delay in water supply (water injection frequency N1 in FIG. 4). It is.

In the case of sudden deceleration, subroutine 3 shown in FIG.
Is controlled by When the throttle opening is 0, that is, when the throttle is fully closed (engine brake), the fuel injection and the water injection are cut to improve the fuel efficiency, and the self-ignition combustion mode (ignition O
FF, high compression ratio state). When the throttle is not fully closed, the fuel injection pulse width Tp is set to the steady-state injection pulse width Tpl, and then the throttle opening θ is switched from ignition combustion to self-ignition in accordance with the engine speed at that point in time. If the degree θ3 is larger or smaller, that is, smaller, the ignition combustion may be switched to the self-ignition combustion, and if larger, the ignition combustion is maintained without switching. If the mode is not switched to the self-ignition combustion, it is determined whether or not to perform water injection only according to a water injection map mapped in advance. At that time, the pulse width of the water injection valve is different from that in the steady state (Tpw).
In consideration of the delay in water supply, the amount is increased by ΔTw. θ ≦
In the case of θ3, the determination of the combustion state before deceleration is made based on the value of the compression ratio (intake valve closing timing = determined from the set state of the valve timing of the variable valve mechanism). That is, in the case of the high compression ratio state, rapid deceleration occurs in the self-ignition state. At that time, the presence or absence of water injection is determined based on the water injection map. In the case of a low compression ratio, it is determined that the mode has switched from spark ignition to self-ignition, water injection is immediately started (there is an increase), and switching from low to high compression ratio is performed by a variable valve mechanism. Next, the self-ignition occurs when the compression ratio switching cycle number N2 is exceeded and the high compression ratio state is ensured.
Turn off the ignition. At this time, although there are operating conditions of high compression ratio and ignition combustion, knocking is suppressed by water injection. After the ignition is turned off, the necessity of water injection is determined from the water injection map by water injection. When performing water injection,
The injection amount is assumed to be Tpwl in a steady state.

In the case of slow deceleration, subroutine 4 shown in FIG.
Is controlled by The difference from the rapid deceleration in FIG. 6 is that the transient increase (ΔTw) of the water injection amount is not added. It is.

In the steady state, a subroutine 5 shown in FIG.
Is controlled by In this case, the injection amount and the presence or absence of the injection are controlled by a water injection map mapped in advance. Further, in addition to the control described above, the following two controls may be always performed. The first is control by knock sensor 9 shown in FIG. Water injection is controlled by the ECU 13 using the permissible knock level grasped in advance and the knock sensor output Vn at that time so that the knock sensor output ≦ Vn. The water injection amount is also changed by the knock sensor output. The second is the control by the humidity sensor 8 and the intake air temperature sensor 24 shown in FIG. The water injection is set to EC so that the optimal humidity for self-ignition combustion (optimal humidity with respect to the intake air temperature during operation) that is grasped in advance is obtained.
By controlling with U13, stable self-ignition combustion can be obtained.

[0037]

As described above, according to the present invention, in the internal combustion engine system combining the two of the self-ignition combustion and the spark ignition combustion, the water injection is adapted and the operating conditions (steady state and transient state) ), The homogeneous premixed compression ignition combustion with high efficiency and low NOx emissions is realized over a wider load range of the engine, and the occurrence of knocking is suppressed. However, switching to spark ignition can be performed smoothly.
According to the first aspect of the present invention, the operating range to a high load range is expanded, and low emission and low fuel consumption are achieved in a wider operating range. According to the second aspect of the present invention, the switching of the combustion becomes smooth, and the combination of the self-ignition combustion and the spark ignition combustion becomes possible. According to the third aspect of the present invention, the combustion is switched smoothly even during rapid acceleration. According to the invention described in claim 4, even during sudden acceleration,
Smooth combustion switching is ensured. According to the fifth aspect of the present invention, the smooth combustion switching is reliably performed. According to the sixth aspect of the present invention, it is possible to reduce the emission and the fuel consumption by stopping the cooling of the cylinder more than necessary. According to the seventh aspect of the present invention, combustion is switched smoothly even at the time of sudden deceleration. According to the eighth aspect of the invention, smooth combustion switching can be reliably performed. According to the ninth aspect of the present invention, smooth combustion switching can be reliably performed. According to the invention described in claim 10, control according to the knock sensor output becomes possible, and knocking is always accurately suppressed. According to the eleventh aspect, knocking is always suppressed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration in an embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between an operation region and a combustion mode.

FIG. 3 is a view showing a water injection control flow of the internal combustion engine shown in FIG. 2;

FIG. 4 is a flowchart showing details of subroutine 1 in FIG. 3 (control flow at the time of sudden acceleration).

FIG. 5 is a flowchart showing details of subroutine 2 in FIG. 3 (control flow at the time of gentle acceleration).

6 is a flowchart showing details of subroutine 3 in FIG. 3 (control flow at the time of sudden deceleration).

7 is a flowchart showing details of subroutine 4 in FIG. 3 (control flow at the time of slow deceleration).

FIG. 8 is a flowchart showing details of subroutine 5 in FIG. 3 (control flow in a steady state);

FIG. 9 is a control flow chart by a knock sensor.

FIG. 10 is a control flowchart by an intake air temperature and humidity sensor.

FIG. 11 is a diagram showing Conventional Example 1.

FIG. 12 is a diagram showing a second conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water injection valve 2 Fuel injection valve 3 Water pipe 4 Fuel pipe 5 Intake port 6 Exhaust port 7 Spark plug 8 Humidity sensor 9 Knock sensor 10 Piston 11 Fuel tank 12 Water tank 13 ECM 14 Fuel return pipe 15 Fuel pressure regulator 16 Fuel Filter 17 Fuel pump 18 Electric motor for driving fuel pump 19 Water return pipe 20 Pressure regulator for water 21 Water filter 22 Water pump 23 Electric motor for driving water pump 24 Intake air temperature sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F02M 25/022 F02M 25/02 R (72) Inventor Akihiro Iiyama 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor In-house F term (reference) 3G023 AA02 AA05 AA06 AB06 AC02 AG00 3G084 AA00 BA11 BA23 CA04 CA06 DA01 DA02 DA10 DA38 FA02 FA10 FA14 FA25 3G092 AA01 AA02 AA05 AA11 AB17 BB01 BB10 DA01 DA08 DD03 EA01 FA17 FA14 FA16 FA14 GA13 GA14 HA00Z HA04Z HA07Z HC05Z

Claims (11)

[Claims] 1. A spark-ignition four-cycle internal combustion engine that obtains an output by converting a reciprocating motion of a piston into a rotary motion of a crankshaft, has a variable valve mechanism that can change at least a valve opening / closing timing, and varies a closing timing of an intake valve. By making the effective compression ratio variable by increasing the compression ratio according to the engine operating conditions,
A gasoline self-ignition internal combustion engine, comprising: an injection device that performs switching from spark ignition to self-ignition combustion, that is, homogeneous charge homogeneous charge compression ignition, and injects water at a high load in the self-ignition operation region. 2. The gasoline according to claim 1, further comprising an injection device capable of injecting water at the time of switching from self-ignition combustion to spark ignition combustion or at the time of switching from spark ignition combustion to self-ignition combustion. Self-igniting internal combustion engine. 3. When switching from self-ignition combustion to spark ignition combustion, during rapid acceleration operation in which the throttle opening speed is sharp, more water is injected than the set water injection amount under the same rotation speed and the same load condition in steady operation. 2. The method according to claim 1, wherein
Or a gasoline self-ignition internal combustion engine according to claim 2. 4. In the switching from self-ignition combustion to spark ignition combustion, during rapid acceleration operation in which the throttle opening speed is sharp, after water injection is performed and after a water supply delay time in the cylinder elapses, spark ignition is performed. 4. The gasoline self-ignition internal combustion engine according to claim 1, wherein the internal combustion engine is started. 5. The water injection period at the time of switching from self-ignition combustion to spark ignition combustion is set to be at least longer than a required time during a cycle of switching the compression ratio. Gasoline self-ignition internal combustion engine. 6. The gasoline self-ignition internal combustion engine according to claim 1, wherein both the fuel injection and the water injection are stopped when the throttle is fully closed and the fuel is cut during deceleration. 7. In switching from spark ignition combustion to self-ignition combustion, during rapid rapid deceleration operation with a rapid throttle closing speed, more water injection than the set water injection amount under the same rotation speed and the same load condition in steady operation. The gasoline self-ignition internal combustion engine according to any one of claims 1 to 6, wherein: 8. The method according to claim 1, wherein in switching from the spark ignition combustion to the self-ignition combustion, the water injection period is set to be at least longer than a required time in a cycle of switching the compression ratio. Gasoline self-ignition internal combustion engine. 9. The gasoline self-ignition internal combustion engine according to claim 1, wherein in switching from spark ignition combustion to self-ignition combustion, ignition is terminated after self-ignition combustion has occurred. 10. A spark ignition four-cycle internal combustion engine that converts piston reciprocating motion into crankshaft rotational motion and obtains an output, has a variable valve mechanism that can change at least the valve opening / closing timing, and makes the intake valve closing timing variable. By changing the effective compression ratio to increase the compression ratio in accordance with the engine operating conditions, switching from spark ignition to self-ignition combustion, that is, homogeneous charge homogeneous charge compression ignition, water is discharged at a high load in the self-ignition operation region. Equipped with an injection device capable of injecting, installing a knock sensor on the engine body such as an engine cylinder block, etc., starts water injection when the knock sensor output at the time of knocking becomes a predetermined value or more, according to the knock sensor output value Gasoline characterized by controlling the water injection charge and terminating the water injection when the knock sensor output value falls below an allowable value. Self-igniting internal combustion engine. 11. A temperature sensor and a humidity sensor are set in an intake system, and a water injection charge is controlled so that a target humidity is obtained according to an intake air temperature during engine operation. A gasoline self-ignition internal combustion engine according to claim 1.