Automatic engine stop-restart system

• US 4,494,497 A
• Filed: 06/14/1982
• Issued: 01/22/1985
• Est. Priority Date: 07/20/1981
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kogyo Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kogyo Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Akatsuka, Takao, Kawamura, Takahide, Uchida, Shigekatsu
• Primary Examiner(s): Dolinar, Andrew M.
• Application Number:
  US06/387,819
• Time in Patent Office: 953 Days
• Field of Search: 123/179 B, 123/179 BG, 123/179 A, 123/198 DB, 123/198 DC, 180/54 R, 307/10 R, 290/37 A
• US Class Current: 123/179.4
• CPC Class Codes: F02D 17/04 rendering engines inoperative or idling, e.g. caused by abnormal conditions dependent on lubricating conditions F01M1/22; dependent on cooling F01P5/14
• CPC Class Codes: F02D 2400/08 Redundant elements, e.g. two sensors for measuring the same parameter
• CPC Class Codes: F02N 11/0818 Conditions for starting or stopping the engine or for deactivating the idle-start-stop mode
• CPC Class Codes: F02N 11/105 when the engine is already running F02N11/0848 takes precedence
• CPC Class Codes: F02N 2200/022 Engine speed
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

In automatically stopping or restarting an engine on a basis of detecting an operational state of each component of a vehicle with the engine mounted thereon, judgement as to whether first condition of setting the function of allowing the engine to automatically stop and restart, second condition of automatically stopping the engine after the function is set and third condition of automatically restarting the engine after the function is set are fulfilled or not, respectively, is made by "and" of a plurality of signals including at least two or more signals out of a signal indicating an engine rotational speed, a signal indicating the generating condition of an alternator and a third signal indicating readiness or unreadiness for starting of the vehicle.

Claims

1. A system for automatically stopping and restarting a motor vehicle engine having an alternator that is coupled to said engine in response to predetermined conditions comprising:

stopping means coupled to said engine for stopping said engine;

starting means coupled to said engine for restarting said engine;

engine rotational speed sensor means coupled to said engine for detecting an engine'"'"'s rotational speed to generate a speed signal corresponding to said engine'"'"'s rotational speed;

alternator output level sensor means coupled to said alternator for detecting an output level of said alternator to generate an alternator signal corresponding to said output level;

a first judging means coupled to said engine'"'"'s rotational speed sensor means for judging as to whether said speed signal indicates said engine'"'"'s rotational speed exceeding a predetermined level to produce a first signal indicative of said engine being rotating;

a second judging means coupled to said alternator output level sensor means for judging as to whether said alternator signal indicates the output level exceeding a predetermined level to produce a second signal indicative of said alternator being generating;

switching means manually operated for producing a third signal while said switching means is turning on;

a third judging means coupled to said first and second judging means and said switching means for producing an enable signal when at least said first, second and third signals are received by said third judging means;

a fourth judging means coupled to said third judging means and various sensors detecting engine operational conditions for judging as to whether a first condition for automatic engine stop is fulfilled to produce a first activating signal when fulfilled, said first condition including at least a presence of said enable signal, and said stopping means being energized by said first activating signal; and

a fifth judging means coupled to said third judging means and said various sensors for judging as to whether a second condition for automatic engine restart is fulfilled to produce a second activating signal when fulfilled, said second condition including the presence of said enable signal, and said starting means being energized by said second activating signal.

2. A system according to claim 1, wherein said stopping means comprises a relay connected to an ignition circuit and a solenoid valve for cutting off fuel to a fuel injection valve, and wherein said starting means comprises a starter relay and a starter connected thereto.

3. A system according to claim 1, wherein said engine rotational speed sensor means receives a pulse signal outputted from an ignition circuit to process the received pulse signal in such a manner so as to produce said speed signal.

4. A system according to claim 1, wherein said system further comprises:

a door switch means for detecting a closed state of a driver'"'"'s seat door to produce a door signal when the driver'"'"'s seat door is closed, and said third judging means is further connected to said door switch to produce the enable signal when said first, second and third signals and said door signal are receive by said third judging means.