puzzle pieceHeaded back full force down the road of GMC Trucks in Thunder Bay and the variable valve timing they have under the hood, we step back to 1960 in order to examine the origin of such an awesome feature.  “In the 1960s, automakers began developing variable valve timing systems that allowed intake and exhaust valves to open earlier or later in the 4-stroke cycle.”  So, we know that the concept is not a new one.  The purpose at the time was to improve volumetric efficiency, decrease NOx emissions, and decrease pumping losses. To this day, we have two main types of variable valve timing. They are known as cam phasing and cam changing.  Let’s look at them individually so that we can better understand the Thunder Bay GMC Trucks in Canada that have such innovative technology under the hood, shall we?

When looking at cam changing style VVT, we see that the ECU selects a different cam profile based on engine load and speed.  When we examine the other, cam phasing, we see that an actuator rotates the camshaft, changing the phase angle. There are dozens of ways to go about varying valve timing, lift, and duration, this all seems to vary based on the specific vehicle we are discussing.

Another important aspect of variable valve timing under the hood of a new GMC truck in Thunder Bay, according to your GMC Truck service in Ontario, is the subject of sensors.  “VVT systems use all sorts of sensors, but the most important are the camshaft and crankshaft position sensors (which are often hall effect sensors). The ECU uses these sensors to monitor the relationship between the piston’s location and the valves’ positions. The crankshaft is connected to the rod and piston, and the camshaft’s lobes trigger valve lift events.”  It is through this that the ECU is able to learn just how fast the engine is rotating.