US3888215A

US3888215A - Fuel-air mixture control

Info

Publication number: US3888215A
Application number: US379611A
Authority: US
Inventors: Paul E Maier
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-07-16
Filing date: 1973-07-16
Publication date: 1975-06-10
Anticipated expiration: 1992-06-10

Abstract

An improved fuel-air mixture control for connection between the control unit and a temperature sensor of a fuel injection system of a vehicle. The fuel-air mixture control is located adjacent the area occupied by the vehicle operator and has a selector switch which selectively disconnects the temperature sensor from the control unit and connects the control unit to a variable resistor.

Description

United States Patent Maier June 10, 1975 FUEL-AIR MIXTURE CONTROL Primary Examiner-Charles J. Myhre Assistant Examiner-Ronald B. Cox [76] lnvsmor' gl g' 22 253? Runnels Fort Attorney, Agent or Firm-Richards. Harris &

Medlock [22] Filed: July 16, I973 [21] Appl. No.: 379,611 [57] ABSTRACT An improved fuel-air mixture control for connection 5 CL. 123/32 123/193 123/193 3 between the control unit and a temperature sensor of 51 Int. Cl. F02h 3/00 a fuel injection System of a vehicle The fuel-air [58] Field of Search 123/32 EA We comm is located adjacent ma Occupied by the vehicle operator and has a selector switch which [56] References c selectively disconnects the temperature sensor from UNITED STATES PATENTS the control unit and connects the control unit to a variable resistor.

3,05l,l52 8/1962 Paule ct al l23/32 EA 1 Claim, 2 Drawing Figures PATENTEDJUH 10 m5 CONTROL UNIT FIG. 7

l ?6 5a 44 37 68 72 bill 58 6 W 704 qso] *1 /L Ji J 59 CONTROL UNIT FIG. 2

FUEL-AIR MIXTURE CONTROL BACKGROUND OF THE INVENTION The present invention relates generally to improvements in fuel injection systems. In another aspect, this invention relates to a new and improved fuel-air mixture control for a fuel injection system which can control the fuel used by the engine to improve efficiency and performance.

DESCRIPTION OF THE PRIOR ART Internal combustion engines with fuel injection systems have been used on vehicles for a number of years. One such system in present use was designed by Robert Bosch for use on the Volkswagen automobile.

The Bosch electronic injection system is of the type which uses a low-pressure. intermittently operating time injection system with fuel injected by electromagnctically actuated injectors. The injectors are of a constant lift type, and since the fuel is injected under constant pressure, the injected quantity is a function of time only.

The required amount of fuel injected is determined according to parameters of the engine such as speed, load (manifold pressure) and temperature. Transducers are provided on the engine which measure these parameters. These transducers are connected to an electronic control unit which contains electronic circuitry which controls the quantity of fuel injected in response to the output of these trnasducers. Thus, the basic fuel quantity requirement is determined by a combination of the factors of engine speed, engine load and temper ature.

For example, when an engine is started cold, extra fuel is required and this information is supplied by a temperature transducer mounted in the head of the engine. As the temperature of the engine increases, the amount of fuel necessary for operation of the engine is decreased.

One problem which has been present in the operation of these fuel injection systems is the provision ofa convenient means by which the amount of fuel injected on each cycle can be conveniently adjusted by the vehicle operator during periods of prolonged operation at constant speeds and torques. An example is highway driving when the engine is operated at a high speed and a low torque. During the highway driving, it is sometimes desirable to adjust the fuel-air mixture to maximize power or fuel use efficiency of the engine. In addition, in some instances, a failure or misadjustment of the various components of the system make it desirable to manually control the fuel-air mixture of the engine.

Therefore, according to the present invention, an improved fucl-air mixture control is provided in the vehicle adjacent to the operator which includes a switching means for interrupting the connection between the temperature transducer of the engine and its respective control unit and substituting a variable resistance means which can be adjusted by the operator of the vehicle during use of the vehicle.

OBJECTS OF THE INVENTION An object of the present invention is the provision of an improved fuelair mixture control system for a fuel injection system.

Another object of the present invention is the provision of an improved fuel-air mixture control which allows manual adjustment of the fuel mixture of the fuel injection system during operation of the vehicle.

A further object of the present invention is the provision of an improved fuel-air mixture control which is simple and inexpensive to manufacture, install and operate.

Other objects and many of the attendant advantages of this invention will be readily appreciated by those of ordinary skill in the art as the same becomes better understood by reference to the following Detailed Description when considered in connection with the accompanying Drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I illustrates a schematic diagram of a conventional fuel injection system of a vehicle; and

FIG. 2 is a schematic diagram ofa portion of the fuel injection system illustrated in FIG. 1 with the improved fuel-air mixture control of the present invention installed.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the Drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is illustrated in FIG. I a schematic diagram of the low-pressure Bosch fuel injection system which is used on various Volkswagen and Porsche automobiles. An example is found on the Porsche 9144 which is powered by the Volkswagen 4]] engine and the August I967 through I973 Vollc swagens with type three engines.

This fuel injection system 10 comprises a fuel tank I2 with a fuel supply line 14, a fuel filter l6 and a fuel pump 18 connected thereto. Pump 18 supplies pressurized fuel through a fuel line 20 to a fuel manifold system 22. This system 22 is in turn connected by means of fuel line 24 to a pressure regulator valve 26 which maintains manifold 22 at a constant pressure. When the pressure in the manifold 22 exceeds the desired minimum (approximately two atmospheres) fuel is returned to tank I2 from the manifold 22 through valve 26 and return line 28.

Fuel manifold 22 has a plurality of fuel ports 30 which correspond in number to the number of cylinders in the particular engine. In the present case, four ports 30 are provided with each port connected by means of a conduit to a separate fuel injector 32. In FIG. I only one fuel injector 32 is illustrated, but it is to be understood, of course, that the other cylinders each have an identical fuel supply configuration.

Each injector 32 comprises a valve which is electrically controlled through a line 33 from control unit 35 as will be hereinafter described in more detail, to inject a quantity of fuel into the intake port 34 behind the intake valve 36. An example of this control unit is commercially available on the I970 Volkswagen type III and has part number 3 II 906 OZID.

The fuel injected into port 34 is mixed with a quantity of air flowing through the intake air distributor line 38. A pressure transducer is electrically connected to control unit 35 through conductor 42 to measure the parameter of engine load. Through this connection, control unit 35 can monitor the pressure in line 38.

In addition, a variable resistance temperature sensor 44 is provided attached to the head 37 of the vehicle engine. This temperature transducer or sensor 44 is of the resistance type and varies in resistance in response to the temperature of the head. Sensor 44 is connected by means of a conductor 46 to control unit 35 so that control unit 35 can monitor the temperature of head 37. This sensor is commercially available from the Volkswagen Company as part number 31 l 906 l6lC.

The distributor 48 of the engine is also connected by means of conductor 50 to control unit 35 so that the control unit can monitor the speed of the engine.

In operation, as the temperature of the head 37 varies, transducer 44 varies in resistance. Appropriate circuitry is provided in the control unit so that the change in resistance will be sensed and injector 32 will be caused to inject more fuel into intake port 34. Likewise, as the engine becomes hotter, control unit 35 will cause injector 32 to inject less fuel into the intake port on each cycle. In addition, the pressure of the inlet air and the speed of rotation as monitored will effect the amount of fuel injected during each cycle.

Turning now to FIG. 2, the improved fuel air-mixture control of the present invention is illustrated. In this figure, temperature transducer 44 is illustrated grounded at its case with its conductor 46 disconnected from conductor 46 and control unit 35 and attached to conductor 52. This conductor 52 is connected to the mixture control circuit 54 of the present invention. This circuit 54 is positioned in the automobile adjacent to the operator so that the circuit can be adjusted during operation of the vehicle. The conductor 52 is connected to one contact 56 of a single pole triple throw switch 58. The switch has a control arm 59 which operates a switch arm or wiper 60 which is connected to control unit 35 by means of the conductor 46. Thus by moving wiper 60 so that it makes contact with contact 56, the temperature transducer 44 can be connected to control unit 35 in the conventional manner.

A second contact 64 is provided on the switch 58 and is connected to a k ohms variable resistor 66. The contact 64 is connected to the wiper 68 of resistor 66 while one end of the resistor 66 is grounded at 70. A control arm 71 is provided for adjusting the resistor 66. By operating the switch 58 to connect the wiper 60 to contact 64, control unit 35 can be connected to resistor 66. The resistor 66 can then be manually adjusted by arm 71 to vary the fuel-air mixture as desired during operation of the engine.

A third contact 72 is provided on the switch 58 and this contact is left blank. By moving the switch 58 to a position such that wiper 60 is connected to contact 72,

control unit 35 is disconnected from either the resistor 66 or the temperature transducer 44, and in this position, the engine will not start.

During normal operation of the engine, the switch 58 is left in position wherein the wiper is connected to contact 56 and control unit 35 is connected to the temperature sensor 44. During long highway trips, and the like where it is desired to economize on fuel or increase power, the switch 58 can be moved until wiper 60 is connected to contact 64 with resistor 66 connected to control unit 35. The control arm 71 of the potentiometer 66 can then be adjusted to achieve the maximum power by holding the accelerator in a given position. In this manner, the fuel economy can be improved by leaning out the engine.

It is to be understood, of course, that the foregoing relates to only the preferred embodiment of the present invention and numerous alterations may be utilized to practice the present invention without departing from the spirit and scope as defined in the appended claims.

I claim:

1. In combination with a fuel injection system for a vehicle engine of the type wherein a temperature responsive variable resistance transducer is placed in contact with the engine, the transducer varies in resistance and is connected to a fuel control means to vary the amount of fuel injected into the engine in response to the temperature of the engine, the improvement which comprises:

a. a variable resistor means adjustable within the operating range of said transducer;

b. triple throw switch means which when engaged can selectively:

I. connect said variable resistor means to said control means whereby the operator of the vehicle may manipulate the variable resistor means to control the amount of fuel injected into the engine,

2. connect said transducer to said control means,

and

3. disconnect said control means and said variable resistor means from said transducer whereby starting of the engine is prevented; and

c. said variable resistor means and said switch means are positioned on said vehicle so that the operator thereof can manipulate said variable resistor means and said switch means while operating said vehicle.

Claims

1. In combination with a fuel injection system for a vehicle engine of the type wherein a temperature responsive variable resistance transducer is placed in contact with the engine, the transducer varies in resistance and is connected to a fuel control means to vary the amount of fuel injected into the engine in response to the temperature of the engine, the improvement which comprises: a. a variable resistor means adjustable within the operating range of said transducer; b. triple throw switch means which when engaged can selectively: 1. connect said variable resistor means to said control means whereby the operator of the vehicle may manipulate the variable resistor means to control the amount of fuel injected into the engine, 2. connect said transducer to said control means, and 3. disconnect said control means and said variable resistor means from said transducer whereby starting of the engine is prevented; and c. said variable resistor means and said switch means are positioned on said vehicle so that the operator thereof can maniPulate said variable resistor means and said switch means while operating said vehicle.

2. connect said transducer to said control means, and

3. disconnect said control means and said variable resistor means from said transducer whereby starting of the engine is prevented; and c. said variable resistor means and said switch means are positioned on said vehicle so that the operator thereof can maniPulate said variable resistor means and said switch means while operating said vehicle.