Apparatus for control of operational characteristics of supercharger in internal combustion engine

An apparatus is provided for controlling the operational characteristics of a supercharger in an internal combustion engine with the supercharger, including a compressor. The apparatus comprises a pressure sensor positioned in an intake passage downstream of the compressor for detecting the pressure of the compressor at a revolution sensor operatively coupled to the engine for detecting the revolution speed of the engine. An arithmetic means has its inputs coupled to the pressure sensor and revolution sensor and arithmetically operates on the output signals of the pressure sensor and revolution sensor in accordance with predetermined control characteristics for providing an output signal in accordance therewith. A control means is coupled to the output of the arithmetic means for controlling the pressure of the compressor in accordance with the output signal of the arithmetic means, and changing means are provided for manually changing the predetermined control characteristics of the arithmetic means.

BACKGROUND OF THE INVENTION 
This invention relates to a control apparatus for the operational 
characteristics of a supercharger in an internal combustion engine, that 
is, for controlling the supercharging characteristics of the engine, 
chiefly used for a vehicle such as a motorcycle or the like. 
In general, it is desirable to be able to control the operational 
characteristics of a supercharger. That is, the supercharging 
characteristics should be freely, manually changeable. Accordingly, the 
output characteristics of the engine can be changed freely in accordance 
with a user's or driver's desire. For instance, it is desirable to be able 
to select at will the operation of a motorcycle as either a sports or 
racing type or as a family or cruising type. 
SUMMARY OF THE INVENTION 
It is the primary object of the present invention to provide an apparatus 
for controlling the operational characteristics of a supercharger. 
It is another object of the present invention to provide an apparatus for 
controlling the operational characteristics of a supercharger wherein the 
apparatus includes means for changing the operational characteristics. 
It is a further object of the present invention to provide a means for 
manually changing the operational characteristics of the supercharger. 
The present invention is directed to an apparatus for controlling the 
operational characteristics of a supercharger in an internal combustion 
engine with the supercharger, including a compressor. The apparatus 
comprises a pressure sensor positioned in an intake passage downstream of 
the compressor for detecting the pressure of the compressor and a 
revolution sensor operatively coupled to the engine for detecting the 
revolution speed of the engine. An arithmetic means has its inputs coupled 
to the pressure sensor and revolution sensor, and arithmetically operates 
on the output signals of the pressure sensor and revolution sensor in 
accordance with predetermined control characteristics for providing an 
output signal in accordance therewith. A control means is coupled to the 
output of the arithmetic means for controlling the pressure of the 
compressor in accordance with the output signal of the arithmetic means, 
and changing means are provided for manually changing the predetermined 
control characteristics of the arithmetic means.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
Referring to the drawings, an internal combustion engine 1 for a motorcycle 
or the like is provided with a supercharger 6 comprising an exhaust 
turbine 3 provided in an exhaust passage 2 of the engine 1, and a 
compressor 5 provided in an intake passage 4 of the engine 1. The 
compressor 5 is driven by the turbine 3. 
A pressure sensor 7 is provided on the downstream side of the compressor 5 
for detecting the pressure of the compressor 5. A revolution sensor 8 is 
provided adjacent the crankshaft 1a of the engine 1 for detecting the 
speed of revolution of the engine 1. An arithmetic means 9 is provided for 
carrying out an arithmetic operation on output signals of the two sensors 
7, 8 in accordance with predetermined control characteristics of a control 
means. A control means 10 controls the pressure of the compressor 5 in 
accordance with the output obtained from the arithmetic means 9. 
The arithmetic means 9 comprises a comparator 9C, and is arranged so that 
the output signal of the pressure sensor 7 is applied to an input terminal 
9a of the comparator 9C via a buffer circuit 11, a low-pass filter 12 and 
an A-D converter 13. The output signal of the revolution sensor 8 is 
applied to another input terminal 9b of the comparator 9C, via an 
arithmetic circuit 14, address decoder 15, an address line 16, and a 
memory 17. The elements including arithmetic circuit 14 (or arithmetic 
circuit means), address decoder 15 (or address decoder means), A/D 
converter 13, memory 17, and comparator 9c can be collectively referred to 
by the term processing means. 
The memory 17 is set as to have predetermined control characteristics 
stored therein. That is, a characteristic curve a.sub.1 of a relationship 
between revolution speeds and pressures has been previously stored 
therein. Thus, the actual pressure detected at the pressure sensor 7 and 
the set pressure stored in the memory 17 are compared to one another in 
the comparator 9C, so that a corresponding outcome signal may be obtained 
on the output side of the comparator 9C. The control means 10 is operated 
in accordance with the output signal of the foregoing comparison and 
serves to vary the actual pressure so it is equal to the set pressure. The 
control means 10 comprises a waste gate valve 10a interposed in a bypass 
3a of the turbine 3 and a frequency or control valve 10b for controlling 
the positive pressure in the intake passage that acts on the valve 10a. 
The output signal of the comparator 9C is applied to an operating solenoid 
for the valve 10b through a controller 18 and a power amplifier 19, such 
that the pressure of the compressor 5 may be controlled in a predetermined 
manner through the waste gate valve 10a. 
Though, as mentioned above, the arithmetic means 9 carries out the 
arithmetic operation in accordance with the predetermined control 
characteristics, it is so arranged, according to this invention, that the 
control characteristics can be manually changed for any desired use. 
Namely, in the illustrated example, in FIG. 1, the memory 17 can be 
replaced by another memory 17a at will as an occasion demands. The other 
memory 17a has another characteristic curve a.sub.2 previously stored 
therein. 
The memory 17 and the other memory 17a can be carried, for example, in 
plug-in type modules which simply connect into a socket on the apparatus. 
Thus, when a different operational characteristic for the supercharger is 
desired, memory 17 can be unplugged and removed, and memory 17a can be 
plugged in or vice versa. 
In the illustrated embodiment in FIG. 1, the memory 17 has additionally a 
characteristic curve b.sub.1 of the relationship between revolution speeds 
and ignition angles previously stored therein, and this characteristic 
curve b.sub.1 can be replaced with another characteristic curve b.sub.2 
additionally provided in the other memory 17a. 
The operation of this invention apparatus will be explained as follows: 
When the memory 17, for instance, is in use as illustrated, the 
relationship between the pressure of the compressor 5 and the revolution 
speed of the engine 1 become equal to those shown by the curve a.sub.1. In 
other words, the supercharging characteristics of the supercharger 6 
becomes equal to that shown by the curve a.sub.1. Accordingly, if the 
revolution speed is increased, the pressure of the compressor 5 is greatly 
increased to offer a large supercharging effect. If the memory 17 is then 
replaced manually by the other memory 17a, the operation characteristics 
becomes equal to that shown by the curve a.sub.2. Accordingly, in this 
case, even if the revolution speed is increased, the pressure of the 
compressor 5 is not so greatly increased, and thus the increase in the 
supercharging effect becomes small. 
In FIG. 1, an ignition timing control means 20, a boost pressure 
compensating circuit 21, a back pressure compensating circuit 22, a boost 
pressure sensor 23, and a back pressure sensor 24 can be provided in the 
engine. 
As another changing means for exchanging between the memory 17 and the 
memory 17a, a data selector 25 may be utilized as shown in FIG. 2. In this 
embodiment, the memory 17 and the memory 17a can be selectively operated 
by the data selector 25. 
Thus, according to this invention, by changing the memory to that of 
different control characteristics at will, the operational characteristics 
of the supercharger are changed. This is advantageous in that a single 
engine can be operated at any one of several desired output 
characteristics. 
The present invention may be embodied in other specific forms without 
departing from the spirit or essential characteristics thereof. The 
presently disclosed embodiments are, therefore, to be considered in all 
respects as illustrative and not restrictive, the scope of the invention 
being indicated by the appended claims, rather than the foregoing 
description, and all changes which come within the meaning and range of 
equivalency of the claims are, therefore, to be embraced therein.