Tamper proof method and apparatus for adjusting a control parameter of a controlled apparatus

• US 5,016,180 A
• Filed: 08/04/1989
• Issued: 05/14/1991
• Est. Priority Date: 10/01/1986
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Fujisawa, Masaaki
• Primary Examiner(s): Lall, Parshotam S.
• Assistant Examiner(s): Mattson, Brian M.
• Application Number:
  US07/391,704
• Time in Patent Office: 648 Days
• Field of Search: 364/424.01, 364/431.03, 364/431.04, 364/431.05, 364/431.07, 123/339, 123/416, 123/417
• US Class Current: 701/102
• CPC Class Codes: F02D 41/2435 characterised by the writing medium, e.g. bar code

Abstract

A method and apparatus for controlling a control parameter of a controlled device, such as the idle speed of an internal combustion engine, permits the setting of the control parameter in a tamper-proof manner. A control unit receives an adjustment value in the form of a compensation signal from an adjusting device, such as a potentiometer, during an adjustment mode and calculates a control value to control the parameter of the controlled device. When adjustment of the control parameter is complete, a normal mode is entered in which the calculated control value is stored in a non-volatile memory for use in controlling the controlled device, and the control unit ignores further signals received from the adjusting device.

Claims

1. An adjustment device for controlling an operation parameter of an apparatus, comprising:

manually settable compensation amount determining means for producing a compensation amount signal representing an amount of compensation of a control value used in controlling said operation parameter;

mode decision means for selectively producing a mode signal indicating an adjustment mode or a normal mode; and

control means connected to said manually settable compensation amount determining means and said mode decision means for producing a control output signal for controlling said operation parameter based on a control value corrected by a compensation value, including memory means for storing a compensation value, and processing means for;

(a) storing in said memory means a compensation value based on said compensation amount signal and producing said control output signal based on said compensation value when said mode signal indicates an adjustment mode, and

(b) producing said control output signal based on a compensation value previously stored in said memory means and without regard to said compensation amount signal when said mode signal indicates a normal mode.

2. The adjustment device according to claim 1, wherein said manually settable compensation amount determining means comprises a potentiometer.

3. The adjustment device according to claim 1, wherein said mode decision means comprises a manually operable switch connected to a signal source.

4. An adjustment device for controlling an operation parameter of an apparatus, comprising:

manually settable compensation amount determining means for producing a compensation amount signal representing an amount of compensation of a control value used in controlling said operation parameter;

mode decision means for selectively producing a mode signal indicating an adjustment mode or a normal mode; and

control means connected to said manually settable compensation amount determining means and said mode decision means for producing a control output signal for controlling said operation parameter based on a control value corrected by a compensation value, including memory means for storing a compensation value, and processing means for;

(a) storing in said memory means a compensation value based on said compensation amount signal and producing said control output signal based on said compensation value when said mode signal indicates an adjustment mode, and

(b) producing said control output signal based on a compensation value previously stored in said memory means and without regard to said compensation amount signal when said mode signal indicates a normal mode;

wherein said memory means includes a first memory and a second memory, and further including memory command means for generating a command signal to indicate to said processing means that a predetermined condition of said apparatus has been reached, said processing means being responsive to said mode signal indicating said adjustment mode for storing said compensation value based on said compensation amount signal in said first memory and for shifting said compensation value from said first memory to said second memory upon receipt of said command signal, and said processing means being responsive to said mode signal indicating said normal mode for producing said control output signal based on a compensation value stored in said second memory.

5. An adjustment apparatus for an engine control system, comprising:

first memory means for storing a control program and fixed control values;

second memory means, of a type in which data can be rewritten and stored in a non-volatile manner, for storing compensation values;

third memory means for temporarily storing compensation values;

control means connected to said first, second and third memory means for generating a control output signal to perform a predetermined engine control processing according to (i) the control program and a fixed control value stored in said first memory means and (ii) a compensation value stored in said second memory means, including;

(a) mode decision means for producing a mode signal indicating an adjustment mode for correcting a compensation value;

(b) compensation amount determining means for producing a compensation amount signal representing an amount of compensation for a control value;

(c) memory command means for generating a command signal to indicate that a predetermined engine condition is reached; and

(d) processing means connected to said mode decision means and said compensation amount determining means for storing in aid third memory means a compensation value based on a a compensation amount signal received from said compensation amount determining means when said mode signal indicating an adjustment mode is received from said mode decision means and for transferring a compensation value from said third memory means to said second memory means when said command signal is received from said memory command means while said mode signal indicates an adjustment mode.

6. The adjustment apparatus according to claim 5, wherein said compensation amount determining means comprises a manually adjustable potentiometer.

7. The adjustment apparatus according to claim 5, wherein said mode decision means comprises a manually operable switch connected to a signal source.

8. The adjustment apparatus according to claim 5, wherein said memory command means comprises a manually operable switch connected to a signal source.

9. A method of controlling adjustment of an operation parameter of an apparatus, comprising the steps of:

(a) continuously producing a compensation amount signal representing an amount of compensation of a control value used in controlling said operation parameter by means of a manually adjustable device;

(b) calculating a compensation value from said compensation amount signal during an adjustment mode period of time;

(c) storing said compensation value in a memory device; and

(d) during a normal mode of operation following said adjustment mode period of time, generating a control signal for controlling said operation parameter based on a compensation value stored in said memory device and without regard to said compensation amount signal.

10. A tamper-proof adjustment device for controlling an operation parameter of an apparatus, comprising:

a detachable control amount determining unit including manually settable means for producing a control amount signal representing an amount of a control value used in controlling said operation parameter; and

control means selectively connectable to said control amount determining unit for producing a control output signal for controlling said operation parameter based on a stored control value, including means for determining a control value from a control amount signal received when said control amount determining unit is attached to said control means, means for storing the control value determined by said determining means and means for producing said control output signal based on the control value stored in said storing means when said control amount determining unit is detached from said control means.

11. A tamper-proof adjustment apparatus for an engine control system for controlling an operation parameter thereof, comprising:

a manually settable and detachable compensation amount determining unit including means for producing a compensation amount signal representing an amount of compensation of a control value used in controlling said operation parameter; and

control means connectable to said manually settable and detachable compensation amount determining unit for producing a control output signal for controlling said operation parameter based on a control value corrected by a compensation value, including memory means, of a type in which data can be re-written and stored in a non-volatile manner, for storing a compensation value determined from a compensation amount signal received from said manually settable and detachable compensation amount determining unit and processing means for;

(a) storing in said memory means a compensation value based on said compensation amount signal and controlling said control means to produce said control output signal based on said compensation value when said manually settable and detachable compensation amount determining unit is attached to said control means; and

(b) producing said control output signal based on a compensation value previously stored in said memory means when said manually settable and detachable compensation amount determining unit is detached from said control means.