System and method for selectively limiting engine output
AssigneeDetroit Diesel Corporation
InventorsS. Miller Weisman, II, Dennis M. LeTang
Life of this patent
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Abstract
A system and method for controlling an engine to limit engine output include determining engine speed, determining vehicle speed, determining a ratio based on the engine speed and the vehicle speed, comparing the ratio to a threshold, and controlling the engine to limit engine output based on the comparison. The ratio used for comparison may be selected from a plurality of ratios based on a current gear ratio which may be an actual or virtual (computed) gear ratio. The threshold may represent a low gear torque limit threshold in one embodiment. A vehicle speed sensor fault may also be considered to determine whether to limit the engine output. In one embodiment, engine output is limited by limiting engine torque.
Claims29
A system for controlling an internal combustion engine to selectively limit engine torque, the system comprising:
- means for determining a gear ratio;
- means for comparing the determined gear ratio to a threshold value corresponding to a predetermined actual gear ratio and limiting engine torque when the determined gear ratio exceeds the threshold value.
A computer readable storage medium having stored data representing instructions executable by a microprocessor to control a diesel engine to selectively limit engine output, the storage medium comprising data representing:
- instructions for calculating a gear ratio;
- instructions for comparing the calculated gear ratio to a threshold value representing a predetermined actual gear ratio;
- instructions for controlling the diesel engine to limit engine output when the calculated gear ratio exceeds the threshold.
A system for controlling an engine to limit engine output under certain conditions, the system comprising:
- an engine speed sensor for providing an engine speed signal indicative of engine rotational speed;
- a vehicle speed sensor for providing a vehicle speed signal indicative of vehicle speed;
- a controller in communication with the engine speed sensor and the vehicle speed sensor, the controller including a microprocessor in communication with a memory having instructions executable by the microprocessor for determining engine speed based on the engine speed signal, instructions for determining vehicle speed based on the vehicle speed signal, instructions for determining a ratio based on the engine speed and the vehicle speed, instructions for comparing the ratio to a threshold value, and instructions for controlling the engine to limit engine output based on the comparison.
A method for controlling a diesel engine having an engine speed sensor for providing a signal indicative of engine rotational speed, the engine mounted in a vehicle having a vehicle speed sensor for providing a signal indicative of vehicle speed, the method comprising:
- processing the signal indicative of engine rotational speed to determine an engine speed;
- processing the signal indicative of vehicle speed to detect a vehicle speed sensor fault;
- and
- reducing available engine torque when the vehicle speed sensor fault is detected.
A method for controlling an engine, the method comprising:
- determining a vehicle speed;
- determining an engine speed;
- computing a gear ratio based at least in part on the determined engine speed and vehicle speed;
- comparing the gear ratio to a threshold value;
- and
- limiting engine output when the gear ratio differs from the threshold value by a predetermined amount.
A method for controlling an engine, the method comprising:
- determining engine speed;
- determining vehicle speed;
- determining a ratio based on the engine speed and the vehicle speed;
- comparing the ratio to a threshold value;
- and
- controlling the engine to limit engine output based on the step of comparing.
Dependencies are inferred from the claim text.