effect of valve diameter
What will happen if both the inlet & exhaust valve diameter is decreased maintaining the same initial ratio? What parameters of engine will change?
Member • Jan 3, 2012
Member • Jan 3, 2012
petrol engineCE DesignerDiesel or petrol engine?
Member • Jan 3, 2012
Member • Jan 3, 2012
So, it probably means that whatever engines are manufactured their valve dia is already upto that 'certain limit' of getting maximum engine performance.S.mukherjeeDecreasing valve dia upto a certain limit will increase engine performance of petrol engine . This is so because as valve dia dec. , the pressure of charge at inlet manifold will decrease due to increase in flow velocity. This will result in decrease in temperature of charge, reducing chances of preignition and knocking. So you can easily increase the compression ratio resulting in more power output in same fuel consumption... Thus bsfc increases. The efficiency also increases as a result .
Decreasing the dia too much will result in problems bcoz the charge temp will dec. too much making it difficult for fuel to reach its self ignition temperature.
Member • Jan 3, 2012
Member • Jan 3, 2012
I seriously doubt that. Its because with decreasing valve dia the flow velocity will increase, provided the inlet passage dia remains constant. So amount of fuel shall remain the same.CE DesignerLess fuel = Less compression = less power
Member • Jan 3, 2012
Member • Jan 8, 2012
If there is to be a change in the valve dia then the passage dia should be changed accordingly in order that the valve has a leak proof seat on it.mechkyI seriously doubt that. Its because with decreasing valve dia the flow velocity will increase, provided the inlet passage dia remains constant. So amount of fuel shall remain the same.
Member • Jan 8, 2012