JPS5855329B2 - gasoline engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a supercharged or non-supercharged gasoline engine using a positive displacement supercharger or a complex supercharger.

It is well known that the Lysholm compressor or complex supercharger, which has traditionally been used as a positive displacement supercharger, is capable of supercharging at a high pressure ratio over the entire engine speed range. It is being

However, at such a high pressure ratio, the compression temperature is high, and even if it is cooled by a charge air cooler, the temperature of the compression path of the engine is high, so that knocking is inevitable in a gasoline engine.

Therefore, reducing the compression ratio to suppress knocking will result in an increase in fuel consumption due to a decrease in thermal efficiency, and reducing the boost pressure will not result in a large increase in output, making supercharging useless. It becomes meaning.

Due to the above-mentioned drawbacks, the actual situation is that the development of supercharged gasoline engines using positive displacement superchargers or complex superchargers has been hindered.

Therefore, the present invention eliminates the above-mentioned drawbacks, increases thermal efficiency, prevents knocking under high charge air pressure by applying charge air cooling and Miller cycle, and achieves high expansion due to low compression ratio and low compression temperature. The purpose is to ensure high thermal efficiency below the ratio.

The □large cycle refers to a phenomenon in which the intake air temperature in the cylinder is lowered by advancing the intake valve closing timing from bottom dead center.

The present invention is characterized in that a control valve is disposed in the middle of the supply to each cylinder of the engine, and this adjustment means for adjusting the opening/closing timing of the control valve sends a knocking signal from a knock sensor. It is in.

Embodiments of the present invention will be described based on the drawings.

First, an example of a supercharged gasoline engine using a positive displacement supercharger will be explained. As shown in FIG. 1, a positive displacement supercharger 1 is provided with a drive shaft (crankshaft) 2, A pulley 3 is attached to the shaft, and this pulley has an endless V
The belt 4 is wound around, and the V-belt is wound around a pulley 7 which is fixed to the crankshaft 6 of the engine 5.

The pulleys 3 and 7 have a continuously variable transmission mechanism (not shown) using a V-belt 4, and when the output is low, the supercharger is driven by the crankshaft at a low rotation ratio, and as the required output increases, the rotation ratio increases. The supercharger is equipped with a mechanism to increase the amount of air fed into the engine.

In addition, the air or mixture sucked through the intake port 8 is adiabatically compressed by the positive displacement supercharger 1, and its temperature and density increase.
After passing through the intake pipe 9, the supply air is cooled to near atmospheric temperature 1 by the supply air cooler 10, and then from the intake manifold 11 to each intake branch pipe 1.
2 and is supplied to each cylinder of the engine 5.

Engine exhaust gas is discharged through the exhaust pipe 13.

By the way, since a control valve such as a rotary pulp 14 is disposed in the middle of supplying air or air-fuel mixture to each cylinder of the engine 5 from the intake branch pipe 12, details of this configuration and means for adjusting the opening/closing timing of this pulp will be explained below. , will be explained with reference to FIGS. 2 to 4.

As shown in FIG. 2, a piston 16 is disposed within the cylinder 15 so as to be able to reciprocate, the upper end of a piston rod 17 is swingably connected to this piston, and the lower end of the piston rod 17 is connected to the crankshaft 6. There is.

A cylinder head 18 is mounted on the cylinder 15, which is of course provided with a spark ignition device (not shown), and has an intake port 19 and an exhaust port 20 formed therein. intake valve 21 and exhaust valve 2, respectively.
2 are arranged.

The engine 5 is located inside the intake branch pipe 12 connected to the intake port 19.
A rotary pulp 14 is provided as a control valve that is driven from the crankshaft of the engine via a gear transmission mechanism.

Therefore, the drive mechanism of the rotary pulp 14 will be explained based on FIG. 3.

The rotary pulp 14 is fixed to the drive shaft 23 by a pin 24.

Sleeves 25 and 26 are fixed to the drive shaft 23 and are arranged to sandwich the rotary pulp 14, and ball bearings 27 and 2B are arranged between the sleeves and the wall of the intake pipe 12. , 29, the drive shaft 23 is rotatably supported.

This drive shaft 23 is attached to a frame 30 with a ball bearing 31.
32 and is connected via an adjustment piece 35 of an opening/closing timing adjustment means to a rotating shaft 34 driven by a gear 33 which is rotatably supported by a crankshaft and a gear mechanism.

As shown in FIG.
The engine is driven at a rotational speed of one-half of six revolutions of the crankshaft.

- 10,000, the intake stroke period of the engine 5 is about 1800 degrees in terms of crankshaft rotation angle, so the rotary pulp 14, like the intake valve 21, is about 180 degrees in terms of crankshaft rotation angle.
It has an opening period of .

Next, regarding the structure of the opening/closing timing adjustment means of the rotary valve 14, as shown in FIGS. It is formed with twists in opposite directions.

Protrusions 35a and 35b formed on the inner periphery of the adjustment piece 35 are engaged with the helical spline, respectively, and by moving the adjustment piece 35 to the left in FIG. It is angularly displaced in a predetermined direction, and by moving to the right, it is angularly displaced in the opposite direction.

In this way, by moving the adjustment piece 35 in the axial direction, the rotation timing of the drive shaft is changed, and the opening/closing timing of the rotary valve 14 is adjusted.

The adjustment piece 35 is driven to move in the axial direction by swinging an adjustment lever 36 whose one end is fitted into an annular locking groove 35c formed on the outer periphery of the adjustment piece.

As shown in the first diagram, a crank gear 37 is attached to the end of the drive shaft 6 of the broken engine 5, and a timing gear 38 is attached to the end of the drive shaft 6 of the broken engine 5.
At the same time, it meshes with the gear 33.

Next, engine output adjustment and knocking suppression using the adjustment lever 36 are performed by the following configuration.

In FIG. 1, the adjustment lever 36 is rotatably attached to the tip of a rod 44 via a pin 45.

If you want to adjust the output of the engine 5, for example to increase the output, use an output regulator or, in the case of a car, press the accelerator pedal, etc. to attach the pin 4 to the lower end of the lever 36.
The structure is such that the rod 4T, which is rotatably connected via the rod 6, is moved to the left.

When the lower end of the adjustment lever 36 moves to the left, this lever rotates clockwise about the pin 45, and the adjustment piece 35 having the locking groove 35c engaged with the upper end of the lever
moves to the right.

The cutoff of the rotary valves 14 is delayed to increase the output of the engine 5.

Conversely, when the lower end of the bar 36 is moved to the right by adjusting it in the opposite direction, the output is reduced.

Also, a knock sensor 39 is attached to the outer wall of the engine 5, which emits a signal in response to engine vibration caused by knocking.
; 42, the occurrence of knocking is transmitted, and this servo motor receives electrical energy from a power source 43 via wiring.

Therefore, when the servo motor 40 receives a knocking signal from the knock sensor 39, the rod 44 extends to the left.

At this time, the adjustment lever 36 rotates counterclockwise around the pin 46 at the lower end, so that the adjustment piece 35 at the upper end of the lever
is moved to the left, causing the cut-off of the rotary valve 14 to be brought forward.

Next, the operation of the present invention will be explained.

During idle operation or extremely low output operation, positive displacement turbocharger 1
The rotation ratio is low, and the boost pressure is almost atmospheric pressure.

According to the present invention, the intake air or air-fuel mixture amount of the engine is not adjusted by controlling the engine, but by advancing the cut-off of the rotary valve.

FIG. 5 shows the P-■ line of a normal four-stroke gasoline engine, and is used for reference to show that the output is adjusted by adjusting the intake air.

As a result, the pressure during the intake stroke is lower than atmospheric pressure, so the area valve shown by hatching performs negative work, which is one of the causes of increased fuel consumption during low load in gasoline engines. It has become.

The P-■ line of the present invention is shown in FIG. 6, and even at extremely low loads, intake is performed at atmospheric pressure, and after the necessary air-fuel mixture is taken in, the port-tally valve 14 is closed, and the internal cylinder volume is At the same time, the volume between the intake valve 21 and the rotary valve 14 expands adiabatically, and the intake stroke ends by following the line 1--2.

In the compression stroke, after the intake valve closes, only the internal cylinder volume is adiabatically compressed following the path ■-■.

Therefore, as shown in the slope part and as seen in comparison with Fig. 5, only an extremely small area becomes a negative amount of work.
The rate of decrease in cycle efficiency is small.

The P-■ line at medium load is as shown in FIG.

At this time, in a normal engine, as in the case of extremely low output in Fig. 5, the amount of negative work due to intake ripples is reduced compared to when the output is extremely low, so the amount of negative work due to intake ripples is reduced, but still exists. , which causes an increase in fuel consumption.

In the present invention, the supercharger is still designed to rotate at a low rotation ratio, and the supercharging pressure is almost the same as atmospheric pressure.

In Fig. 7, the intake starts from ■1 as in the case of extremely low output.
The rotary valve 14 is closed and cut off as shown in steps 1 and 2.

From ■, the intake air expands adiabatically, the pressure and temperature decrease, and the intake ends at ■.

Of course, the cut-off of the rotary valve is delayed compared to the time of product output, and the air-fuel mixture is sufficiently sucked into the cylinder 15.

The line a-■-■ is the compression stroke, and adiabatic compression starts from ■, which is below atmospheric pressure, the pressure and humidity rise, and when it reaches ■, the temperature becomes atmospheric pressure and temperature again, and the compression stroke continues. ■
Press the button to end the compression process.

In a normal engine, compression starts at a dog air mixture level of 1, and the compression ratio is such that the compression temperature does not cause knocking (usually 8).
Therefore, the actual compression ratio of the present invention is the line ■−■
It is.

If the cutoff is advanced, the compression ratio will naturally decrease and the compression temperature will also decrease.

If the compression ratio of the line ■-■ becomes, for example, 8.5 and knocking occurs, the knock sensor 39 shown in FIG. Extend it to the left.

Therefore, the adjustment piece 35 also moves to the left, the cutoff of the rotary valve 14 becomes earlier, and the compression ratio decreases, for example, 8.
Therefore, knocking can be controlled.

This means that regardless of supercharging or non-supercharging, by applying the knock sensor 39, it is possible to operate a gasoline engine at the optimum compression ratio under a constant expansion ratio, making it possible to achieve high output and low fuel consumption. There is.

Subsequently, the expansion stroke is performed following the line ■-■-■-■.

The P-■ line at full load of a normal gasoline engine follows the line ■-■-■-■-■ and produces the output of the valve with an area surrounded by this line.

According to the present invention, for example, if the compression ratio is set to 8 and the expansion ratio is set to 10, the expansion stroke increases by the line -■-.
The output increases by an amount equal to the area surrounded by the line ■-■-■-■ subtracted from the area surrounded by the line ■-■-■, and naturally the thermal efficiency also improves.

Next, under full load, the positive displacement supercharger 1 uses a continuously variable transmission mechanism to move the pulleys 7 and 3 from the crankshaft 6 at a high gear ratio.
and generates a boost pressure with a high pressure ratio (for example, 3).

In other words, Boo'J3 and 7 have a built-in continuously variable transmission mechanism that changes the rotation ratio according to the required output, and are configured to increase the rotation ratio of the positive displacement supercharger 1 to the crankshaft 2 as the required output increases. be.

When the output is low, the boost pressure is low, the power consumed by the supercharger is small, and the fuel consumption rate does not increase during partial loads.

When a high pressure ratio supercharging pressure is generated, with normal supercharging methods, knocking occurs due to high compression start humidity, or the compression ratio is reduced to suppress knocking, which is not practical due to a decrease in thermal efficiency. It cannot be used as a gasoline engine.

A specific example of the operation of the present invention in this case will be explained with reference to FIG. 1 and FIG. 8. The temperature of the supply air adiabatically compressed by the supercharger 1 rises to about 200'C.

This air supply can be cooled by the cooler 10 to an atmospheric humidity of about 140°C.

Normally, when the atmospheric temperature is 20°C, the temperature of the supply air entering the cylinder 15 of the engine 5 is 60°C.

The intake stroke starts at ■ in FIG. 8, but the rotary valve 14 is cut off at ■, adiabatically expands in the subsequent intake stroke, and the temperature decreases until the intake stroke ends at ■.

The compression stroke begins at (1), and the mixture is adiabatically compressed, and when the pressure before adiabatic expansion is reached at (2), the temperature of the mixture in the cylinder becomes almost equal to the temperature at (2).

The air-fuel mixture at approximately 60°C is further adiabatically compressed, and the compression stroke is completed at step (3).

In this case, the compression ratio of car (2) can be determined as a compression ratio suitable for a normal engine.

Since the temperature at the beginning of compression is approximately 60°C, a compression ratio of 7 is possible for an engine of normal design, and as mentioned above, it has a large expansion ratio, and even a slight decrease in the compression ratio can be achieved. The cutoff of the rotary valve 14 is adjusted by the knock sensor 39 and the servomotor 40 to select the optimum compression ratio for the operating condition of the engine 5, as in the case of medium load. There is.

The positive displacement supercharger 1 is preferably a highly efficient one that performs internal compression, such as a Lysholm type or a vane type.

Next, an embodiment using a complex type supercharger will be described based on FIG. 9.

Except for the use of rotor 1A, the other structure is substantially the same as in Fig. 1, which uses a positive displacement supercharger, so it is indicated by the same reference numerals. ing.

In the case of this complex type, unlike the case of positive displacement type, the supply air pressure can be increased by the pulsating pressure of the exhaust.
It has high efficiency at low speeds and is suitable for superchargers for vehicle engines.

The rotor 1A is driven by the crankshaft 2, but by simply changing the phase of the rotor, there is no power absorption from the crankshaft, and higher thermal efficiency is expected than in a supercharged engine with a displacement supercharger. I can do it.

A supercharged gasoline engine with the above configuration can prevent knocking with a low compression ratio and low compression temperature under high air supply pressure, and can ensure high thermal efficiency under a high expansion ratio, resulting in a low fuel consumption rate. It is also extremely effective in reducing

[Brief explanation of drawings]

Figure 1 is a route map when a positive displacement supercharger is used, Figure 2 is an enlarged sectional view of the engine, Figure 3 is a sectional view along the line ■-■ in Figure 2, and Figure 4 is a diagram of the opening/closing timing adjustment means. An enlarged sectional view, FIG. 5 is a PV diagram of a conventional gasoline engine, FIG. 6 is a P-■ diagram of the present invention at extremely low load, and FIG. 7 is a P at medium load.
- ■ diagram, Figure 8 is the P - ■ diagram at full load, Figure 9
The figure is a route map when a complex type supercharger is used. DESCRIPTION OF SYMBOLS 1... Positive displacement supercharger, 5... Engine, 9... Intake pipe, 10... Charge air cooler, 12... Intake branch pipe, 14... Control valve, 35...・Adjustment piece, 39...Knock sensor 40...Servo motor, 1 person...Rotor of complex type supercharger.

Claims (1)

[Claims] 1. A spark ignition device is provided in a combustion chamber constituted by a piston, cylinder, and cylinder head, and an intake valve and an exhaust valve are provided in this cylinder head, and a control device is provided during the supply of air to the intake valve. A gasoline engine is provided with a valve, the closing timing of the control valve is earlier than the closing timing of the intake valve, and an adjusting means for adjusting the opening/closing timing of the control valve. A gasoline engine characterized in that a knock sensor is provided to send a knocking signal for timing adjustment to the adjustment means. 2. The gasoline engine according to claim 1, wherein the control valve is a rotary valve.