search.noResults

search.searching

dataCollection.invalidEmail
note.createNoteMessage

search.noResults

search.searching

orderForm.title

orderForm.productCode
orderForm.description
orderForm.quantity
orderForm.itemPrice
orderForm.price
orderForm.totalPrice
orderForm.deliveryDetails.billingAddress
orderForm.deliveryDetails.deliveryAddress
orderForm.noItems
TORQUE SENSING


Sensors measure the rub for smooth running


Torque sensor is helping to reduce engine emissions and improve economy of automotive lubrication system.


T


orque sensors are being used as part of a project to develop an intelligent lubrication system for automotive power trains to reduce engine emissions and improve economy.


With engine efficiency under the spotlight like


never before, automotive companies are exploring all avenues for improving performance. And because engines have a rotating power output, torque is one of the key measurements.


STANDARD LUBRICATION Current engine lubrication systems have very little in the way of intelligence. They have a simple mechanical pump which has been sized to ensure an adequate supply of oil in the worst operating condition, which is typically a hot engine at idle. The pump is thus hugely oversized for most of the rest of the speed range and, as a consequence, nearly 60% of its output is dumped straight back into the sump via the relief valve. It will also deliver the same amount of oil to every part of the engine regardless of what that system might actually need. The pump is also insensitive to engine load and thus the bearings will receive the same oil supply at a given speed regardless of the load. This is a very inefficient system. In addition the pump forces nearly a ton of oil per hour through the filter, and when the oil is cold this takes a huge amount of energy.


PUTTING INTELLIGENCE INTO LUBRICATION Recently, one UK automotive company approached Powertrain Technologies to design an intelligent lubrication system and to analyse its effects on engine friction and parasitic losses. In response, the company built a highly specialised


test rig for the project and since accuracy in measuring small changes in drive torque reliably and repeatably was a critical requirement, a key part of the rig was a TorqSense transducer from Sensor Technology. The engine being tested was a current production diesel and the test bed was configured for motored friction tests with a 6,000rpm 32kW electric motor driving the engine.


20 /// DAQ, Sensors & Instrumentation Vol 2 No. 2


❱ ❱ Torque analysis is helping to identify lubrication strategies for different parts of the engine under different conditions


According to Andrew Barnes of Powertrain, the company completely re-designed the engine lubrication system and installed a bank of five computer controlled oil pumps.


“Each is capable of supplying individual parts of the engine with oil under conditions unique to that part of the engine and sensitive to the engine operating conditions,” he says. An example is supplying the head with oil at pressures different to the block in addition to supplying the bearings with more oil when the engine is under high load. The idea is to completely profile the performance of the engine under various lubrication conditions and to derive optimum configurations of the intelligent systems for best performance. “Intelligent lubrication has the potential to improve


performance no end, although quantifying the best configuration is painstaking work,” he continues.


TORQUE SENSING The torque sensor forms a critical part of the project since the object of the exercise is to measure the effect on friction of a range of different oil supply strategies and oil types. Thus the changes in friction are represented by a change in the motored drive torque of the engine. TorqSense supplied non-contact wireless devices for the project, removing the need to wire slip rings for each new measurement. The device measures radio frequency (RF) waves generated by two Surface Acoustic Wave (SAW) devices fixed onto a rotating shaft and converts them to a torque measurement using two tiny SAWs made of ceramic piezoelectric material with frequency resonating combs laid down on their surface. Powertrain’s research has now progressed to the


next stage in which the test rig is forsaken and the engine installed in a car to quantify the effect on fuel economy. n


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32