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System for displaying water temperature for an engine and a retarder in the same display

IP.com Disclosure Number: IPCOM000009987D
Publication Date: 2002-Oct-04
Document File: 3 page(s) / 60K

Publishing Venue

The IP.com Prior Art Database

Abstract

The invention relates to a system, computer program and a method. The method comprises the following steps: receiving continuously a first temperature value from a first temperature sensor for sensing the water temperature in a cooling system for the engine; receiving continuously a second temperature value from a second temperature sensor for sensing the water temperature in the cooling system immediatly after a retarder; determining whether a condition is satisfied, said condition being that the braking power of the retarder is above a predetermined braking power (in e.g. kW) for more than a predetermined time at the same time as the engine output is below a predetermined engine output ( in e.g. kW); and displaying in the display means either the temperature sensed by the second temperature sensor if the condition is satisfied or the temperature sensed by the first temperature sensor if the condition is not satisfied.

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System for displaying water temperature for an engine and a retarder in the same display

Technical Field of the Invention

The present invention relates to a system in a vehicle for displaying a water temperature of either an engine or an auxiliary brake unit of the vehicle. The water temperatures of the engine and the auxiliary brake unit are displayed in the same display means.

Background of the invention

It is very common in vehicles, such as trucks, busses and cars, to display the water temperature of the cooling water for cooling an engine of a vehicle. The water temperature is sensed by a temperature sensor, which transmit a signal to an ECU (Electronic Control Unit). The water temperature is then displayed on an analogue or digital display means.

Some vehicles, e.g. busses and trucks for heavy goods, may comprise an auxiliary brake system comprising an exhaust brake and an hydraulic brake in addition to the wheel brakes. The auxiliary brake system increased braking force and less wear on the wheel brakes. The hydraulic brake is sometimes called the retarder, which hereinafter will be used instead of the term hydraulic brake. The retarder is most efficient when the velocity of the vehicle is high. A control system increases the hydraulic oil in the retarder when the velocity decreases and the braking performance of the retarder may therefore typically be maintained down to 20 km/h.

When the retarder applies its braking force on the vehicle, the oil is heated and must be cooled. A separate cooling system for the retarder is possible, but the ordinary cooling system for the engine is typically utilized. The control system decreases the braking effect of the retarder when the water temperature of the cooling system after the retarder is above a certain predetermined water temperature. When the water temperature has decreased to a normal level, the retarder may be used again with full effect. The water temperature is typically measured immediately after the water has passed the retarder.

The brake action performed by a brake system with an auxiliary brake system as described above, is for instance dependent on the operation from a driver. A coolant pump of the engine is for instance most effective at high engine speeds and the driver shall therefore keep the engine speed high in order to utilise a maximum braking effect, which is directly proportional to the engine speed, from the auxiliary brake.

Summary of the invention

It is an object of the invention to make it easier for a driver to control the brake action of a retarder and therefore enable a more efficient brake action.

The present invention relates to a display system for displaying the water t...