Akroyd Stuart or Diesel?

Browse pages
Current page

1

Current page

2

Current page

3

Current page

4

Current page

5

Current page

6

Current page

7

Current page

8

Current page

9

Current page

10

Current page

11

Current page

12

Current page

13

Current page

14

Current page

15

Current page

16

Current page

17

Current page

18

Current page

19

Current page

20

Current page

21

Current page

22

Current page

23

Current page

24

Current page

25

Current page

26

Current page

27

Current page

28

Current page

29

Current page

30

Current page

31

Current page

32

Current page

33

Current page

34

Current page

35

Current page

36

Current page

37

Current page

38

Current page

39

Current page

40

Current page

41

Current page

42

Current page

43

Current page

44

Current page

45

Current page

46

Current page

47

Current page

48

Current page

49

Current page

50

Current page

51

Current page

52

Current page

53

Current page

54

Current page

55

Current page

56

Current page

57

Current page

58

Current page

59

Current page

60

Current page

61

Current page

62

Current page

63

Current page

64

Current page

65

Current page

66

Current page

67

Current page

68

Current page

69

Current page

70

Current page

71

Current page

72

Current page

73

Current page

74

Current page

75

Current page

76

Current page

77

Current page

78

Current page

79

Current page

80

Current page

81

Current page

82

Current page

83

Current page

84

Current page

85

Current page

86

Current page

87

Current page

88

Current page

89

Current page

90

Current page

91

Current page

92

Current page

93

Current page

94

Current page

95

Current page

96

Current page

97

Current page

98

Current page

99

Current page

100

Current page

101

Current page

102

Current page

103

Current page

104

Current page

105

Current page

106

Current page

107

Current page

108

Current page

109

Current page

110

Current page

111

Current page

112

Current page

113

Current page

114

Current page

115

Current page

116

Current page

117

Current page

118

Current page

119

Current page

120

Current page

121

Current page

122

Current page

123

Current page

124

Current page

125

Current page

126

Current page

127

Current page

128

Current page

129

Current page

130

Current page

131

Current page

132

Current page

133

Current page

134

Current page

135

Current page

136

Current page

137

Current page

138

Current page

139

Current page

140

Current page

141

Current page

142

Current page

143

Current page

144

Current page

145

Current page

146

Current page

147

Current page

148

Current page

149

Current page

150

Current page

151

Current page

152

Current page

153

Current page

154

Current page

155

Current page

156

Current page

157

Current page

158

Current page

159

Current page

160

Current page

161

Current page

162

Current page

163

Current page

164

Current page

165

Current page

166

Current page

167

Current page

168

Current page

169

Current page

170

Current page

171

Current page

172

Sir,

With regard to John Stickland’s letter expressing interest in the engines of Pool, Diesel and Akroyd (note correct spelling) Stuart. Over the last 60 years internal-combustion engine specialists have devoted a great deal of time to who was first with the compression ignition engine, Diesel or Akroyd Stuart. However what should be realised is that these two innovators were in no way in direct competition as their products differed considerably.

Herbert Akroyd Stuart was born’ in 1864 in Halifax and raised in Bletchley, Bucks. His father ran the Bletchley Iron & Tin Plate Works. So after working as a junior assistant in the Mech. Eng. Dept. of the City of Guilds of London Technical College, Finsbury, Herbert joined his father at the Iron Works. He devoted his time to developing a paraffin vaporising engine and took out his first patent in 1886, followed by a more relevant patent in 1890. So it is beyond dispute that he had a satisfactory “oil engine” before Diesel. Basically what Akroyd Stuart had invented was “automatic-ignition”, because prior to 1890, oil engines required a blow lamp to be permanently in contact with the vaporiser while in motion. Akroyd Stuart arranged the vaporiser and engine cycle in such a manner that the lamp could be removed as soon as the engine was started, the combustion chamber then maintained a high enough temperature by heat retained from previous explosions assisted by the heat of compression of air. When the “air only” was compressed into the already hot vaporiser, the ignition was controlled by timing the injection of the oil spray near the end of the compression stroke which obviated somewhat but not completely the pre-ignition troubles which worried oil engine manufacturers at that time. The compression pressure used in his early engines was only in the region of 40/50 lb. sq. in. In later years this type of engine operation became known as “hot-bulb” or “surface-ignition” and more unfortunately the term “semi-diesel” was used. All these terms especially the latter, robbed the inventor of the right amount of credit due to him.

Rudolph Diesel aimed at developing an engine with the highest possible efficiency and several years of theory had taught him that in order to do this, he would have to compress the air to the highest degree possible. He was well aware that fuel injected into highly compressed “red hot” air would burn without any ignition devices at all, or need any form of pre-heating to obtain the first explosions. In one of his first engine tests, a compression temperature off 500°C was seen when using a compression of  425 lb./sq. in. In 1893 the first trials of Diesel’s engine began. Surely here is the true term “compression ignition” engine. As so often happens with great innovators, prophets and the like, neither men ended their days reaping the fruits of the part they had played in the evolution of the successful oil engine. Akroyd Stuart, MIMechE, after selling his patents to Richard Hornsby & Co., constantly had to defend his invention against the  name of semi -diesel when he claimed it should have been “Akroyd-cycle”. He emigrated to Australia in 1899 and died there in 1927. It seems a pity that his great engineering achievements seem to have been forgotten with the passing of time disappeared. However it appears that Pool was rated as one of the better than average innovators, in fact it is said that more than one competitor visited Chipstable in the hope of seeing something useful! It is however · very doubtful if he had any association with Akroyd Stuart as the latter’s ideas for automatic ignition came about because of an accident which took place in the Bletchley workshop.

DAVID W. EDGINGTON

Related articles

Related products