Vehicle with an Internal Combustion Engine

Field of the Invention

The present invention relates to a "Vehicle with an Internal combustion Engine" and more particularly to a spark ignition internal combustion engine, preferably a two wheeler or a three wheeler, with a single control unit for ignition control, instrument cluster control and indicator control with multiplex transmission.

Brief description of the prior art

Vehicles with Spark Ignition Internal Combustion Engines commonly have an electronic control unit for controlling the ignition timing, a second controller for instrument cluster control and the electrical load sharing between the flywheel magneto and battery is generally not controlled. Another timer circuit generally controls indicators.

The US Patent 2002007976A1 discloses a control device for a saddle type vehicle wherein a single electronic control unit performs the meter display control and ignition control. But this unit does not perform load sharing and indicator control. Also the ignition circuit is located outside the control unit.

Multiplex transmission is already known from JP 61066436 (Signal processor for a motorcycle) wherein a front side control section receives an output from left/right handle switches of the motorcycle and a rear side control section receives an output of a detection means to form information suitable for control and multiplex.

A single electronic control unit for a vehicle with internal combustion engine performing the ignition control, instrument cluster control, electrical load sharing control and indicator control with multiplex transmission control is not known in the prior art. If a single control unit can perform these functions, significant cost reduction, part count reduction and size reduction are possible.

Hence, the principal object of this invention is to provide a control unit for a vehicle with spark ignition internal combustion engine performing ignition control, instrument cluster control, electrical load sharing control and indicator control.

Another object of this invention is to provide a multiplex transmission to reduce the cost of wiring harness.

It is a further object of this invention to provide a wiring harness to enable the control unit to perform the above said functions.

Brief description of the invention

A control unit comprising a signal conditioning circuit, micro controller, ignition driver circuit, LCD driver circuit and power electronic circuit is placed beneath the instrument cluster at the front end of the vehicle. The above said control unit also provides signal to ignition coil located near the engine, to the instrument cluster and control power supply to the various electrical loads. The above said control unit also provide signal to a decoder at the rear end of the vehicle for controlling the electrical loads at the rear end of the vehicle.

Brief description of the drawings

Figure 1 illustrates the block diagram of the electronic control unit along with other elements in the vehicle system

Detailed description

A two-wheeler or a three-wheeler has an instrument cluster at the front end of the vehicle. The instrument cluster has an LCD device for displaying vehicle parameters like vehicle speed, fuel level, battery voltage level, lamp status and turn signal indicator status.

A fuel sender unit located inside the fuel tank generates a signal indicative of the fuel level in the tank. An engine speed sensor located outside a flywheel magneto generates a signal indicative of the engine speed.

There is an ignition coil assembly located close to the internal combustion engine and mounted on the vehicle chassis. The ignition coil assembly consists of a primary coil and a secondary coil magnetically coupled for generating high voltage required for producing spark inside the combustion chamber of the engine. The ignition coil secondary is connected to a spark plug by means of a high-tension cord. The spark plug is mounted on the cylinder of the engine.

A master controller is located at the front end of the vehicle inside a control unit beneath the instrument cluster. The control unit also has a signal conditioning circuit for providing input signals to the master controller. The control unit also has an LCD driver electrically connected with the LCD device. Based on the signal provided by the master controller, the LCD driver enables the LCD device to display the vehicle parameters.

A wiring harness connects various electrical loads like lamps, horn and indicators at the front of the vehicle to the control unit. The wiring harness also carries signals from the master controller to a decoder located at the rear end of the vehicle.

A battery is mounted in the chassis of the vehicle for providing DC power supply for the electrical loads. The battery has electrical connections with the control unit through the wiring harness.

Switches at the front end of the vehicle for control of the lamps, horn, and other electrical loads are connected to the control unit through the wiring harness. The fuel sender unit is also connected to the control unit by means of the wiring harness.

A wheel speed sensor is located in the wheel assembly that generates a signal indicative of the vehicle speed. The wheel speed sensor output is also connected to the control unit through the wiring harness.

A throttle position sensor is located on the chassis that generates a signal indicative of the throttle position that is controlled by the user to accelerate and decelerate the vehicle. The throttle position sensor output is also connected to the control unit by means of the wiring harness.

A battery voltage sensor is mounted on the chassis and connected to the battery terminals to sense the battery voltage continuously. The output of the battery voltage sensor is also connected to the control unit through the wiring harness.

There is a decoder at the rear end of the vehicle for controlling turn signal indicators and lamps at the rear end of the vehicle based on the signals from the master controller. The decoder at the rear end is also mounted on the chassis at the rear end of the vehicle and has electrical connections with the turn signal lamps and rear warning lamps located at the rear end of the vehicle. The rear end decoder receives signals from the master controller located at the front end of the vehicle by means of a wiring harness. The user controls these turn signal lamps and warning lamps by means of the switches provided at the front end of the vehicle. The master controller, based on the input from the switches, provides suitable signals to the decoder at the rear end of the vehicle and thereby controls the electrical loads at the rear end of the vehicle. Thus the number of wires from the switches at the front end of the vehicle to the electrical loads at the rear end of the vehicle is reduced. The power supply for the decoder is obtained from the vehicle battery.

The signal conditioning circuit inside the control unit converts the input signals provided by the fuel sender unit, engine speed sensor, switches, vehicle speed sensor and throttle position sensor into voltage levels suitable for the master controller to process. The master controller processes the signals and provides output signal to the LCD driver for enabling the LCD device to display the vehicle parameters.

The flywheel magneto coupled to the crankshaft of the engine generates alternating voltage for supplying to the AC loads and for charging the battery.

The control unit has power electronic devices in the power electronic circuit for rectifying and regulating the alternating voltage generated by the magneto. The magneto is connected to the control unit through the wiring harness. Since the lamps, indicators, horn and other electrical loads located at the front end of the vehicle are connected to the control unit through the switches and since the electrical loads in the rear end of the vehicle are connected to the rear end decoder which in turn receives signals from the master controller, all the electrical loads can be controlled by the master controller.

The power electronic devices in the control unit convert the alternating voltage generated by the magneto into direct current for charging the battery and provide regulated alternating current for supplying to the AC loads. The master controller can decide based on engine operating conditions, battery voltage level and user inputs regarding the electrical load sharing between the battery and the magneto. The electrical loads at the front end of the vehicle like headlamp, turn signal lamp and horn can either be provided with AC or DC supply by controlling the power electronic devices.

The electrical loads at the rear end of the vehicle are supplied with direct current from the battery.

The control unit also has an ignition driving circuit that is in turn connected to the ignition coil assembly through the wiring harness. The ignition driver circuit provides supply for the ignition coil primary based on the signal provided by the master controller. The master controller processes the engine speed signal received from the engine speed sensor and throttle position signal received from the throttle position sensor. The master controller then provides signal to the ignition driver circuit to charge the primary coil and then interrupt the current in the coil for high voltage generation in the secondary of the ignition coil. Due to the high voltage generated in the secondary coil, a spark is produced across the spark plug by dielectric break down phenomenon.

The control unit also has electronic switches in the power electronic circuit that are controlled by the master controller to provide supply to the indicators at the front end of the vehicle periodically and to provide signal to the rear end periodically for blinking of the indicators at both the front and rear ends when turn signal lamp switch is turned ON by the user.

At low engine speeds, during idling conditions, the master controller enables the power electronic devices to connect the DC supply from the battery to the electrical loads as per the user requirement. For example, whenever the user turns ON the head lamp at low engine speeds, the master controller senses the speed through the engine speed sensor signal and controls the power electronic devices like MOSFETs and IGBTs to connect the DC supply from battery to the head lamp. At high engine speeds, the power electronic devices are controlled to connect the regulated AC output from the magneto to the headlamp when the headlamp switch is ON.

The master controller also identifies low battery voltage condition through the battery voltage sensor and controls the power electronic devices to connect the electrical loads only to the magneto. Until the battery is charged to a voltage greater than a pre determined low level, the master controller maintains this condition. The electrical loads are thus shared between the magneto and the battery to maintain good performance of the electrical loads (luminosity for head lamp) and the battery is not continuously drained.

In addition to the LCD device, there are LEDs and bulbs in the instrument cluster that are also in connection with the control unit.

The master controller works on a priority basis. Ignition control is given the highest priority. Instrument Cluster control is given the next priority and electrical load sharing is next followed by the indicator control.

The DC electrical loads like LCD device, DC relay and starter motor are always provided DC supply from the battery.

We claim:

1. A control unit for a vehicle with an internal combustion engine, which comprises:
a master controller;
a signal conditioning unit;
a ignition driver circuit;
a power electronic circuit;
a LCD driver circuit;
said master controller, signal conditioning unit, power electronic circuit,
ignition and LCD driver circuit having parameters selected such that master
controller takes input signals from signal conditioning unit, and gives output
controlling signals to ignition driver circuit, LCD driver circuit, power electronic
circuit and signal conditioning unit.

2. The control unit for a vehicle with an internal combustion engine as claimed in claim 1, whereby the said signal conditioning circuit converts the input signals from fuel sender unit, an engine speed sensor, control switches, vehicle speed sensors, and a throttle position sensor into voltage levels suitable for the master controller to process.

3. The control unit for a vehicle with an internal combustion engine as claimed in claim 1, whereby the said power electronic circuit has rectifying and regulating means for AC voltage generated by a magneto which in turn supplies to various AC loads as directed by the input signal from master controller.

4. The control unit for a vehicle with an internal combustion engine as claimed in claim 1, whereby the said ignition driver circuit is connected to an ignition coil means and supplies for the ignition coil primary based on the input signal received from the said master controller.

5. A control unit for a vehicle with an internal combustion engine, which comprises a master controller along with a power electronic circuit, whereby when head lamp of the vehicle is in ON condition, the said master controller senses the speed through an engine speed sensor and controls the power rectifying and regulating means to connect the DC supply from power storage means to the said head lamp of the said vehicle.

6. A control unit for a vehicle with an internal combustion engine as claimed in claim 5, whereby at high engine speeds the said master controller controls the regulating and rectifying means to connect the regulated AC output from magneto to said head lamp when the head lamp is in ON condition.