Neutral safety switch

A neutral safety switch (NSS) is described for use with a remote engine starting system. The NSS may be attached to each of an emergency brake on, door open, engine running and motion sensor. By sensing the state of the sensor inputs, the NSS determines that the emergency brake has been set, that the vehicle transmission is in neutral and that the driver and passengers have left the vehicle, and if these conditions are not met, disables the remote starting system. The NSS may be used with automatic or manual transmission vehicles.

DETAILED DESCRIPTION A neutral safety switch (NSS) is described which may be beneficially used on either manual or automatic transmission motor vehicles for use with a remote starter system. The NSS senses that the emergency brake has been set, that the driver has opened and closed the door to the vehicle (and presumably left the vehicle) and that the engine was running at the time of exit (indicating that the remote starter system was in a “stop and go” mode whereby the vehicle engine may be left running with the key removed from the ignition) and then turn off the engine, and await remote starting. If the door is subsequently opened (indicating that the driver has returned to the vehicle), the NSS enters a safety mode, disabling the remote starter system. If the emergency brake should be released for any reason, the NSS also enters into the safety mode. Optionally, the NSS may be used with a motion sensor mounted to sense motion within the interior (passenger) portion of the motor vehicle, and if motion is sensed, enter the safety mode. The NSS may optionally be used with a motion sensor, which, if it senses motion (for example, if a passenger is in the vehicle) causes the NSS to enter the safety mode. FIG. 1 shows a block diagram 10 of an NSS 12 in a remote vehicle engine starting system. The NSS may be fitted with one or more sensor inputs. In the embodiment described below, The NSS has three sensor inputs: a door-open sensor 12 , an engine-on sensor 14 , and an emergency brake set sensor 18 . The NSS may also have a motion sensor 20 input. The NSS 12 is connected to a door-open sensor 14 which may be implemented in any convenient way, such as a conventional electrical switch mounted on the door of a vehicle such that when the door is opened, causes the switch to change from on to off or vice versa. Other types of sensors may be used to the same effect, such as, for example, magnetic reed switches mounted on the vehicle so as to respond to a magnet attached to the door. Alternatively, a motion sensor may be utilized which is mounted so as to detect motion in the interior (passenger) portion of the motor vehicle. The NSS is connected to an engine-on sensor 16 . In one embodiment, the engine-on sensor provides pulses from a tachometer to the NSS which indicate that the engine is running. In another embodiment, the engine-on sensor provides pulses from a fuel injector which indicates that fuel is flowing to the engine, and hence the engine is on. In one embodiment, the NSS will sense that three pulses have been received within one second as an indication that the engine is running. Other types of sensors and methods of interpretation may be used beneficially to the same effect, such as, for example, a sensor responsive to a magnet mounted on a flywheel such that an electrical pulse is generated on each turn of the flywheel. The NSS is connected to an emergency brake sensor, which indicates if the emergency brake has been set. Such a sensor may be an electrical switch mounted in a manner so as to change from off to on (or on to off) based upon the location of the emergency brake lever. Other forms and types of sensors may be beneficially utilized. Optionally, the NSS may also be connected to a motion sensor 20 , mounted so as to detect motion in the interior of the motor vehicle. FIG. 2 shows a flow chart of one embodiment of an NSS logic flow 30 . Beginning at the start 32 , the NSS enters a safety mode 34 wherein the remote starter is disabled. Unless various conditions (described below) are met, the NSS always returns to the safety mode 34 . The NSS senses whether the emergency brake has been set 36 . If not, NSS stays in safety mode 34 . If the brake has been set, the NSS senses if the engine is running 38 , indicating that the transmission is in neutral. If the engine is not running, the remote starter has not been set into stop and go mode, and the NSS returns to safety mode 34 . If the engine is running, the NSS then disables 40 the ignition controller, and checks to see that the engine has stopped 42 . If the engine does not stop within a set time, the NSS returns to safety mode 34 . In one embodiment, the ignition controller is wired so as to be in parallel with the ignition key switch. Thus, if the key is in the ignition, disabling the ignition controller will not turn off the engine. Thus, if the key remains in the ignition, the NSS will stay in safety mode. If the engine has stopped, the door open sensor is sensed. The NSS waits for a set period of time (five minutes in one embodiment) to see if the door has opened and closed (indicating that the driver has left the vehicle). If the door is not opened and closed within the set period, the NSS returns to the safety mode 34 . If the foregoing conditions have been met, the NSS enables the remote starting system. The NSS continues to monitor the door open sensor input 48 and the brake released sensor input 50 . If either the door is opened or the emergency brake released, the NSS enters safety mode 34 , disabling the remote starter. If provided with a motion sensor, NSS will also enter safety mode if motion is detected 52 in the interior of the motor vehicle. Accordingly, if the driver has not, in fact, exited the vehicle, or if a passenger remains in the vehicle, the remote starter is disabled. The NSS′ remote starter controller output may be wired in series with the remote starter system power feed to the motor vehicle's starter motor, so as to effectively enable and disable the remote starter system from providing power to the starter motor. Other configurations accomplishing the same result may be utilized, such as, for example, controlling an enable input provided on a remote starter system. The invention can be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. Apparatus of the invention can be implemented in a computer program product tangibly embodied in a machine-readable storage device for execution by a programmable processor; and method steps of the invention can be performed by a programmable processor executing a program of instructions to perform functions of the invention by operating on input data and generating output. The invention can be implemented advantageously in one or more computer programs that are executable on a programmable system including at least one programmable processor coupled to receive data and instructions from, and to transmit data and instructions to, a data storage system, at least one input device, and at least one output device. Suitable processors include, by way of example, both general and special purpose microprocessors. Generally, a processor will receive instructions and data from a read-only memory and/or a random access memory. Storage devices suitable for tangibly embodying computer program instructions and data include all forms of non-volatile memory, including by way of example semiconductor memory devices, such as EPROM and flash memory devices. Any of the foregoing can be supplemented by, or incorporated in, ASICs (application-specific integrated circuits). Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the following claims. For example, the steps of the invention can be performed in a different order and still achieve desirable results.